The noble gas xenon provides protection and trophic stimulation to midbrain dopamine neurons.

PubMed

Lavaur, Jérémie; Le Nogue, Déborah; Lemaire, Marc; Pype, Jan; Farjot, Géraldine; Hirsch, Etienne C; Michel, Patrick P

2017-07-01

Despite its low chemical reactivity, the noble gas xenon possesses a remarkable spectrum of biological effects. In particular, xenon is a strong neuroprotectant in preclinical models of hypoxic-ischemic brain injury. In this study, we wished to determine whether xenon retained its neuroprotective potential in experimental settings that model the progressive loss of midbrain dopamine (DA) neurons in Parkinson's disease. Using rat midbrain cultures, we established that xenon was partially protective for DA neurons through either direct or indirect effects on these neurons. So, when DA neurons were exposed to l-trans-pyrrolidine-2,4-dicarboxylic acid so as to increase ambient glutamate levels and generate slow and sustained excitotoxicity, the effect of xenon on DA neurons was direct. The vitamin E analog Trolox also partially rescued DA neurons in this setting and enhanced neuroprotection by xenon. However, in the situation where DA cell death was spontaneous, the protection of DA neurons by xenon appeared indirect as it occurred through the repression of a mechanism mediated by proliferating glial cells, presumably astrocytes and their precursor cells. Xenon also exerted trophic effects for DA neurons in this paradigm. The effects of xenon were mimicked and improved by the N-methyl-d-aspartate glutamate receptor antagonist memantine and xenon itself appeared to work by antagonizing N-methyl-d-aspartate receptors. Note that another noble gas argon could not reproduce xenon effects. Overall, present data indicate that xenon can provide protection and trophic support to DA neurons that are vulnerable in Parkinson's disease. This suggests that xenon might have some therapeutic value for this disorder. © 2017 The Authors. Journal of Neurochemistry published by John Wiley & Sons Ltd on behalf of International Society for Neurochemistry.

Ultraviolet-B radiation enhancement in dielectric barrier discharge based xenon chloride exciplex source by air

NASA Astrophysics Data System (ADS)

Gulati, P.; Prakash, R.; Pal, U. N.; Kumar, M.; Vyas, V.

2014-07-01

A single barrier dielectric barrier discharge tube of quartz with multi-strip Titanium-Gold (Ti-Au) coatings have been developed and utilized for ultraviolet-B (UV-B) radiation production peaking at wavelength 308 nm. The observed radiation at this wavelength has been examined for the mixtures of the Xenon together with chlorine and air admixtures. The gas mixture composition, chlorine gas content, total gas pressure, and air pressure dependency of the UV intensity, has been analyzed. It is found that the larger concentration of Cl2 deteriorates the performance of the developed source and around 2% Cl2 in this source produced optimum results. Furthermore, an addition of air in the xenon and chlorine working gas environment leads to achieve same intensity of UV-B light but at lower working gas pressure where significant amount of gas is air.

Antiapoptotic activity of argon and xenon

PubMed Central

Spaggiari, Sabrina; Kepp, Oliver; Rello-Varona, Santiago; Chaba, Kariman; Adjemian, Sandy; Pype, Jan; Galluzzi, Lorenzo; Lemaire, Marc; Kroemer, Guido

2013-01-01

Although chemically non-reactive, inert noble gases may influence multiple physiological and pathological processes via hitherto uncharacterized physical effects. Here we report a cell-based detection system for assessing the effects of pre-defined gas mixtures on the induction of apoptotic cell death. In this setting, the conventional atmosphere for cell culture was substituted with gas combinations, including the same amount of oxygen (20%) and carbon dioxide (5%) but 75% helium, neon, argon, krypton, or xenon instead of nitrogen. The replacement of nitrogen with noble gases per se had no effects on the viability of cultured human osteosarcoma cells in vitro. Conversely, argon and xenon (but not helium, neon, and krypton) significantly limited cell loss induced by the broad-spectrum tyrosine kinase inhibitor staurosporine, the DNA-damaging agent mitoxantrone and several mitochondrial toxins. Such cytoprotective effects were coupled to the maintenance of mitochondrial integrity, as demonstrated by means of a mitochondrial transmembrane potential-sensitive dye and by assessing the release of cytochrome c into the cytosol. In line with this notion, argon and xenon inhibited the apoptotic activation of caspase-3, as determined by immunofluorescence microscopy coupled to automated image analysis. The antiapoptotic activity of argon and xenon may explain their clinically relevant cytoprotective effects. PMID:23907115

Ultraviolet-B radiation enhancement in dielectric barrier discharge based xenon chloride exciplex source by air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gulati, P., E-mail: pgulati1512@gmail.com; Department of Physics, Banasthali University, P.O. Banasthali Vidyapith, Rajasthan 304022; Prakash, R.

2014-07-07

A single barrier dielectric barrier discharge tube of quartz with multi-strip Titanium-Gold (Ti-Au) coatings have been developed and utilized for ultraviolet-B (UV-B) radiation production peaking at wavelength 308 nm. The observed radiation at this wavelength has been examined for the mixtures of the Xenon together with chlorine and air admixtures. The gas mixture composition, chlorine gas content, total gas pressure, and air pressure dependency of the UV intensity, has been analyzed. It is found that the larger concentration of Cl{sub 2} deteriorates the performance of the developed source and around 2% Cl{sub 2} in this source produced optimum results. Furthermore, anmore » addition of air in the xenon and chlorine working gas environment leads to achieve same intensity of UV-B light but at lower working gas pressure where significant amount of gas is air.« less

Pathway to Cryogen Free Production of Hyperpolarized Krypton-83 and Xenon-129

PubMed Central

Six, Joseph S.; Hughes-Riley, Theodore; Stupic, Karl F.; Pavlovskaya, Galina E.; Meersmann, Thomas

2012-01-01

Hyperpolarized (hp) 129Xe and hp 83Kr for magnetic resonance imaging (MRI) are typically obtained through spin-exchange optical pumping (SEOP) in gas mixtures with dilute concentrations of the respective noble gas. The usage of dilute noble gases mixtures requires cryogenic gas separation after SEOP, a step that makes clinical and preclinical applications of hp 129Xe MRI cumbersome. For hp 83Kr MRI, cryogenic concentration is not practical due to depolarization that is caused by quadrupolar relaxation in the condensed phase. In this work, the concept of stopped flow SEOP with concentrated noble gas mixtures at low pressures was explored using a laser with 23.3 W of output power and 0.25 nm linewidth. For 129Xe SEOP without cryogenic separation, the highest obtained MR signal intensity from the hp xenon-nitrogen gas mixture was equivalent to that arising from 15.5±1.9% spin polarized 129Xe in pure xenon gas. The production rate of the hp gas mixture, measured at 298 K, was 1.8 cm3/min. For hp 83Kr, the equivalent of 4.4±0.5% spin polarization in pure krypton at a production rate of 2 cm3/min was produced. The general dependency of spin polarization upon gas pressure obtained in stopped flow SEOP is reported for various noble gas concentrations. Aspects of SEOP specific to the two noble gas isotopes are discussed and compared with current theoretical opinions. A non-linear pressure broadening of the Rb D1 transition was observed and taken into account for the qualitative description of the SEOP process. PMID:23209620

Oriented xenon hydride molecules in the gas phase

NASA Astrophysics Data System (ADS)

Buck, Udo; Fárník, Michal

The production of the xenon hydride molecules HXeX with X = I and Cl in the gas phase is reviewed. These molecules are generated by the photolysis of the hydrogen halide HI and HCl molecules on the surface of large xenon Xen clusters. Molecular dynamics simulations show that the flexible H atoms react with the heavy XeX moiety and form the desired molecules with nearly no rotational motion. They are observed by photodissociation with subsequent detection of the kinetic energy of the H atom fragment. During the generating process, the cluster starts to evaporate and the hydride molecule is left essentially free. For further discrimination against the H atom fragments from HX, the HXeX molecules are oriented in a combined pulsed laser field and a weak electrostatic field. The three topics which represent the background of our experiments are briefly reviewed: the nature and generation of rare gas hydrides, the alignment and orientation of molecules in electric fields, and the photodissociation of selected molecules in rare gas clusters. The conditions for detecting them in the gas phase are discussed. This is the trade off between the stability, which requires high electron affinity, and the conditions for orientation, which necessitate large polarizability anisotropies and dipole moments. Finally the prospects of detecting other classes of molecules are discussed.

Is xenon eldest?

NASA Technical Reports Server (NTRS)

Zahnle, K.

1994-01-01

It is well known that the solubility of noble gases in magmas decreases with increasing atomic weight. Xenon, the weightiest of the stable noble gases, is the least soluble atmospheric gas in magma. It is not unreasonable to suppose that the noble gases should have degassed from (or equilibrated with) a bubbling mantle in order of increasing solubility, such that xenon was the most rapidly degassed and helium the least. The apparent relative ages of the famous radiogenic noble gas isotopes agrees, at least qualitatively, with this premise. When atmospheric loss processes are assigned their proper place, several long-standing xenonological puzzles become added evidence for xenon's relative antiquity. Xenon being the afore-mentioned sense the oldest atmospheric gas, will have been most greatly subject to escape, be it impact-driven or EUV-driven. Nonradiogenic xenon's pronounced isotopic fractionation has already been attributed to escape; why it should be more fractionated than krypton would be assigned to xenon's greater atmospheric age. The small atmospheric inventory of xenon relative to the other nonradiogenic noblegases, known as the 'missing xenon' problem, could easily be explained by differential escape. The relatively tiny atmospheric inventories of the radiogenic daughter products of 129 Iodine and 244 Plutonium, both much smaller than would be expected from the inferred abundances of the parents in meteorites, offer a third and fourth data to support the hypothesis that Earth has lost most of its xenon.

Emission characteristics of plasma based on xenon-rubidium bromide mixture

NASA Astrophysics Data System (ADS)

Heneral, A. A.; Avtaeva, S. V.

2017-10-01

Luminescence spectra of a longitudinal pulse-periodic discharge in xenon mixture with rubidium bromide vapors (Xe-RbBr) are studied experimentally at low pressures. The conditions leading to the appearance of intense bands of ultraviolet radiation of exciplex XeBr* molecules in the spectral interval between 200 and 400 nm are found. The highest yield of UV radiation of XeBr* molecules is achieved when the temperature of discharge-tube walls is equal to 750°C. A maximum power of UV radiation from the entire plasma volume as high as 4.8 W is obtained.

Method for the simultaneous preparation of Radon-211, Xenon-125, Xenon-123, Astatine-211, Iodine-125 and Iodine-123

DOEpatents

Mirzadeh, Saed; Lambrecht, Richard M.

1987-01-01

A method for simultaneously preparing Radon-211, Astatine-211, Xenon-125, Xenon-123, Iodine-125 and Iodine-123 in a process that includes irradiating a fertile metal material then using a one-step chemical procedure to collect a first mixture of about equal amounts of Radon-211 and Xenon-125, and a separate second mixture of about equal amounts of Iodine-123 and Astatine-211.

The electroluminescence of Xe-Ne gas mixtures: A Monte Carol simulation study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santos, F.P.; Dias, T.H.V.T.; Rachinhas, P.J.B.M.

1998-04-01

The authors have performed a Monte Carlo simulation of the drift of electrons through a mixture of gaseous xenon with the lighter noble gas neon at a total pressure of 1 atm. The electroluminescence characteristics and other transport parameters are investigated as a function of the reduced electric field and composition of the mixture. For Xe-Ne mixtures with 5, 10, 20, 40, 70, 90, and 100% of Xe, they present results for electroluminescence yield and excitation efficiency, average electron energy, electron drift velocity, reduced mobility, reduced diffusion coefficients, and characteristic energies over a range of reduced electric fields which excludemore » electron multiplication. For the 5% Xe mixture, they also assess the influence of electron multiplication on the electroluminescence yield. The present study of Xe-Ne mixtures was motivated by an interest in using them as a filling for gas proportional scintillation counters in low-energy X-ray applications. In this energy range, the X rays will penetrate further into the detector due to the presence of Ne, and this will lead to an improvement in the collection of primary electrons originating near the detector window and may represent an advantage over the use of pure Xe.« less

In Vivo Measurement in Pigs of Wash-In Kinetics of Xenon at its Site of Action.

PubMed

Froeba, Gebhard; Adolph, Oliver

2016-01-01

Xenon (Xe) in many respects is an ideal anaesthetic agent. Its blood/gas partition coefficient is lower than that of any other anaesthetic, enabling rapid induction of and emergence from anaesthesia. While the whole body kinetics during wash-in of inhalational anaesthesia is well known, data describing the pharmacokinetics of xenon in the cerebral compartment at the site of action are still largely missing. In order to illuminate xenon's cerebral pharmacokinetics, we anaesthetised five pigs and measured arterial, mixed- and sagittal sinus-venous blood, as well as end-expiratory gas concentrations of xenon by gas chromatography-mass spectrometry (GCMS) up to 30 minutes after starting the anaesthetic gas mixture. Despite xenon's fast onset of effect the half-time for equilibration between xenon concentration in arterial blood and at the site of action is measured to be 1.49 ± 0.04 minutes versus 3.91 ± 0.1 minutes. Successful loading of xenon in the brain during inhalational anesthesia was accomplished after approximately 15 minutes although the end-expiratory xenon concentration reached a plateau after 7 minutes. Thus cerebral xenon uptake rate is only moderate, xenon fast onset of action being largely due to its extremely fast alveolar uptake. To ensure safety and precise control during anaesthesia we need a profound knowledge about to what extent the measured end-tidal concentrations reflect the drug concentrations in the target tissue. The results of this study expand our knowledge about the temporal characteristics of xenon´s pharmacokinetics at its site of action and provide the basis for appropriate clinical protocols and experimental designs of future studies.

Separation and purification of xenon

DOEpatents

Schlea, deceased, Carl Solomon

1978-03-14

Xenon is separated from a mixture of xenon and krypton by extractive distillation using carbon tetrafluoride as the partitioning agent. Krypton is flushed out of the distillation column with CF.sub.4 in the gaseous overhead stream while purified xenon is recovered from the liquid bottoms. The distillation is conducted at about atmospheric pressure or at subatmospheric pressure.

Gas mixtures for gas-filled radiation detectors

DOEpatents

Christophorou, Loucas G.; McCorkle, Dennis L.; Maxey, David V.; Carter, James G.

1982-01-05

Improved binary and ternary gas mixtures for gas-filled radiation detectors are provided. The components are chosen on the basis of the principle that the first component is one molecular gas or mixture of two molecular gases having a large electron scattering cross section at energies of about 0.5 eV and higher, and the second component is a noble gas having a very small cross section at and below about 1.0 eV, whereby fast electrons in the gaseous mixture are slowed into the energy range of about 0.5 eV where the cross section for the mixture is small and hence the electron mean free path is large. The reduction in both the cross section and the electron energy results in an increase in the drift velocity of the electrons in the gas mixtures over that for the separate components for a range of E/P (pressure-reduced electric field) values. Several gas mixtures are provided that provide faster response in gas-filled detectors for convenient E/P ranges as compared with conventional gas mixtures.

Gas mixtures for gas-filled particle detectors

DOEpatents

Christophorou, Loucas G.; McCorkle, Dennis L.; Maxey, David V.; Carter, James G.

1980-01-01

Improved binary and tertiary gas mixtures for gas-filled particle detectors are provided. The components are chosen on the basis of the principle that the first component is one gas or mixture of two gases having a large electron scattering cross section at energies of about 0.5 eV and higher, and the second component is a gas (Ar) having a very small cross section at and below aout 0.5 eV, whereby fast electrons in the gaseous mixture are slowed into the energy range of about 0.5 eV where the cross section for the mixture is small and hence the electron mean free path is large. The reduction in both the cross section and the electron energy results in an increase in the drift velocity of the electrons in the gas mixtures over that for the separate components for a range of E/P (pressure-reduced electron field) values. Several gas mixtures are provided that provide faster response in gas-filled detectors for convenient E/P ranges as compared with conventional gas mixtures.

Microscopic simulation of xenon-based optical TPCs in the presence of molecular additives

NASA Astrophysics Data System (ADS)

Azevedo, C. D. R.; González-Díaz, D.; Biagi, S. F.; Oliveira, C. A. B.; Henriques, C. A. O.; Escada, J.; Monrabal, F.; Gómez-Cadenas, J. J.; Álvarez, V.; Benlloch-Rodríguez, J. M.; Borges, F. I. G. M.; Botas, A.; Cárcel, S.; Carrión, J. V.; Cebrián, S.; Conde, C. A. N.; Díaz, J.; Diesburg, M.; Esteve, R.; Felkai, R.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Goldschmidt, A.; Gutiérrez, R. M.; Hauptman, J.; Hernandez, A. I.; Morata, J. A. Hernando; Herrero, V.; Jones, B. J. P.; Labarga, L.; Laing, A.; Lebrun, P.; Liubarsky, I.; Lopez-March, N.; Losada, M.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; McDonald, A. D.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Vidal, J. Muñoz; Musti, M.; Nebot-Guinot, M.; Novella, P.; Nygren, D.; Palmeiro, B.; Para, A.; Pérez, J.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Rogers, L.; Santos, F. P.; dos Santos, J. M. F.; Serra, L.; Shuman, D.; Simón, A.; Sofka, C.; Sorel, M.; Stiegler, T.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Webb, R.; White, J. T.; Yahlali, N.

2018-01-01

We introduce a simulation framework for the transport of high and low energy electrons in xenon-based optical time projection chambers (OTPCs). The simulation relies on elementary cross sections (electron-atom and electron-molecule) and incorporates, in order to compute the gas scintillation, the reaction/quenching rates (atom-atom and atom-molecule) of the first 41 excited states of xenon and the relevant associated excimers, together with their radiative cascade. The results compare positively with observations made in pure xenon and its mixtures with CO2 and CF4 in a range of pressures from 0.1 to 10 bar. This work sheds some light on the elementary processes responsible for the primary and secondary xenon-scintillation mechanisms in the presence of additives, that are of interest to the OTPC technology.

Measuring xenon in human plasma and blood by gas chromatography/mass spectrometry.

PubMed

Thevis, Mario; Piper, Thomas; Geyer, Hans; Thomas, Andreas; Schaefer, Maximilian S; Kienbaum, Peter; Schänzer, Wilhelm

2014-07-15

Due to the favorable pharmacokinetic properties and minimal side effects of xenon, its use in modern anesthesia has been well accepted, and recent studies further demonstrated the intra- and postoperative neuro-, cardio-, and reno-protective action of the noble gas. Since the production of the hypoxia-inducible factor 1α (HIF-1α) and its downstream effector erythropoietin as well as noradrenalin reuptake inhibition have been found to play key roles in this context, the question arose as to whether the use of xenon is a matter for doping controls and preventive doping research. The aim of the present study was hence to evaluate whether the (ab)use of xenon can be detected from doping control samples with the instrumentation commonly available in sports drug testing laboratories. Plasma was saturated with xenon according to reported protocols, and the target analyte was measured by means of gas chromatography/time-of-flight and triple quadrupole mass spectrometry with headspace injection. Recording the accurate mass of three major xenon isotopes at m/z 128.9048, 130.9045 and 131.9042 allowed for the unequivocal identification of the analyte and the detection assay was characterized concerning limit of detection (LOD), intraday precision, and specificity as well as analyte recovery under different storage conditions. Xenon was detected in fortified plasma samples with detection limits of approximately 0.5 nmol/mL to 50 nmol/mL, depending on the type of mass spectrometer used. The method characteristics of intraday precision (coefficient of variation <20%) and specificity demonstrated the fitness-for-purpose of the analytical approach to unambiguously detect xenon at non-physiological concentrations in human plasma and blood. Eventually, authentic plasma and blood samples collected pre-, intra-, and post-operative (4, 8, and 24 h) were positively analyzed after storage for up to 30 h, and provided proof-of-concept for the developed assay. If relevant to

Xenon and Other Volatile Anesthetics Change Domain Structure in Model Lipid Raft Membranes

PubMed Central

Weinrich, Michael; Worcester, David L.

2014-01-01

Inhalation anesthetics have been in clinical use for over 160 years, but the molecular mechanisms of action continue to be investigated. Direct interactions with ion channels received much attention after it was found that anesthetics do not change the structure of homogeneous model membranes. However, it was recently found that halothane, a prototypical anesthetic, changes domain structure of a binary lipid membrane. The noble gas xenon is an excellent anesthetic and provides a pivotal test of the generality of this finding, extended to ternary lipid raft mixtures. We report that xenon and conventional anesthetics change the domain equilibrium in two canonical ternary lipid raft mixtures. These findings demonstrate a membrane-mediated mechanism whereby inhalation anesthetics can affect the lipid environment of trans-membrane proteins. PMID:24299622

Improved gas mixtures for gas-filled radiation detectors

DOEpatents

Christophorou, L.G.; McCorkle, D.L.; Maxey, D.V.; Carter, J.G.

1980-03-28

Improved binary and ternary gas mixtures for gas-filled radiation detectors are provided. The components are chosen on the basis of the principle that the first component is one molecular gas or mixture of two molecular gases having a large electron scattering cross section at energies of about 0.5 eV and higher, and the second component is a noble gas having a very small cross section at and below about 1.0 eV, whereby fast electrons in the gaseous mixture are slowed into the energy range of about 0.5 eV where the cross section for the mixture is small and hence the electron mean free path is large. The reduction in both the cross section and the electron energy results in an increase in the drift velocity of the electrons in the gas mixtures over that for the separate components for a range of E/P (pressure-reduced electric field) values. Several gas mixtures are provided that provide faster response in gas-filled detectors for convenient E/P ranges as compared with conventional gas mixtures.

Improved gas mixtures for gas-filled particle detectors

DOEpatents

Christophorou, L.G.; McCorkle, D.L.; Maxey, D.V.; Carter, J.G.

Improved binary and tertiary gas mixture for gas-filled particle detectors are provided. The components are chosen on the basis of the principle that the first component is one gas or mixture of two gases having a large electron scattering cross section at energies of about 0.5 eV and higher, and the second component is a gas (Ar) having a very small cross section at and below about 0.5 eV; whereby fast electrons in the gaseous mixture are slowed into the energy range of about 0.5 eV where the cross section for the mixture is small and hence the electron mean free path is large. The reduction in both the cross section and the electron energy results in an increase in the drift velocity of the electrons in the gas mixtures over that for the separate components for a range of E/P (pressure-reduced electron field) values. Several gas mixtures are provided that provide faster response in gas-filled detectors for convenient E/P ranges as compared with conventional gas mixtures.

Physiological response of rats to delivery of helium and xenon: implications for hyperpolarized noble gas imaging

NASA Technical Reports Server (NTRS)

Ramirez, M. P.; Sigaloff, K. C.; Kubatina, L. V.; Donahue, M. A.; Venkatesh, A. K.; Albert, M. S.; ALbert, M. S. (Principal Investigator)

2000-01-01

The physiological effects of various hyperpolarized helium and xenon MRI-compatible breathing protocols were investigated in 17 Sprague-Dawley rats, by continuous monitoring of blood oxygen saturation, heart rate, EKG, temperature and endotracheal pressure. The protocols included alternating breaths of pure noble gas and oxygen, continuous breaths of pure noble gas, breath-holds of pure noble gas for varying durations, and helium breath-holds preceded by two helium rinses. Alternate-breath protocols up to 128 breaths caused a decrease in oxygen saturation level of less than 5% for either helium or xenon, whereas 16 continuous-breaths caused a 31.5% +/- 2.3% decrease in oxygen saturation for helium and a 30.7% +/- 1. 3% decrease for xenon. Breath-hold protocols up to 25 s did not cause the oxygen saturation to fall below 90% for either of the noble gases. Oxygen saturation values below 90% are considered pathological. At 30 s of breath-hold, the blood oxygen saturation dropped precipitously to 82% +/- 0.6% for helium, and to 76.5% +/- 7. 4% for xenon. Breath-holds longer than 10 s preceded by pre-rinses caused oxygen saturation to drop below 90%. These findings demonstrate the need for standardized noble gas inhalation procedures that have been carefully tested, and for continuous physiological monitoring to ensure the safety of the subject. We find short breath-hold and alternate-breath protocols to be safe procedures for use in hyperpolarized noble gas MRI experiments. Copyright 2000 John Wiley & Sons, Ltd.

Minimum alveolar concentration (MAC) for sevoflurane and xenon at normothermia and hypothermia in newborn pigs.

PubMed

Liu, X; Dingley, J; Elstad, M; Scull-Brown, E; Steen, P A; Thoresen, M

2013-05-01

Neuroprotection from therapeutic hypothermia increases when combined with the anaesthetic gas xenon in animal studies. A clinical feasibility study of the combined treatment has been successfully undertaken in asphyxiated human term newborns. It is unknown whether xenon alone would be sufficient for sedation during hypothermia eliminating or reducing the need for other sedative or analgesic infusions in ventilated sick infants. Minimum alveolar concentration (MAC) of xenon is unknown in any neonatal species. Eight newborn pigs were anaesthetised with sevoflurane alone and then sevoflurane plus xenon at two temperatures. Pigs were randomised to start at either 38.5°C or 33.5°C. MAC for sevoflurane was determined using the claw clamp technique at the preset body temperature. For xenon MAC determination, a background of 0.5 MAC sevoflurane was used, and 60% xenon added to the gas mixture. The relationship between sevoflurane and xenon MAC is assumed to be additive. Xenon concentrations were changed in 5% steps until a positive clamp reaction was noted. Pigs' temperature was changed to the second target, and two MAC determinations for sevoflurane and 0.5 MAC sevoflurane plus xenon were repeated. MAC for sevoflurane was 4.1% [95% confidence interval (CI): 3.65-4.50] at 38.5°C and 3.05% (CI: 2.63-3.48) at 33.5°C, a significant reduction. MAC for xenon was 120% at 38.5°C and 116% at 33.5°C, not different. In newborn swine sevoflurane, MAC was temperature dependent, while xenon MAC was independent of temperature. There was large individual variability in xenon MAC, from 60% to 120%. © 2013 The Acta Anaesthesiologica Scandinavica Foundation.

Magnetic resonance imaging of convection in laser-polarized xenon

NASA Technical Reports Server (NTRS)

Mair, R. W.; Tseng, C. H.; Wong, G. P.; Cory, D. G.; Walsworth, R. L.

2000-01-01

We demonstrate nuclear magnetic resonance (NMR) imaging of the flow and diffusion of laser-polarized xenon (129Xe) gas undergoing convection above evaporating laser-polarized liquid xenon. The large xenon NMR signal provided by the laser-polarization technique allows more rapid imaging than one can achieve with thermally polarized gas-liquid systems, permitting shorter time-scale events such as rapid gas flow and gas-liquid dynamics to be observed. Two-dimensional velocity-encoded imaging shows convective gas flow above the evaporating liquid xenon, and also permits the measurement of enhanced gas diffusion near regions of large velocity variation.

Optical pumping and xenon NMR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raftery, M. Daniel

1991-11-01

Nuclear Magnetic Resonance (NMR) spectroscopy of xenon has become an important tool for investigating a wide variety of materials, especially those with high surface area. The sensitivity of its chemical shift to environment, and its chemical inertness and adsorption properties make xenon a particularly useful NMR probe. This work discusses the application of optical pumping to enhance the sensitivity of xenon NMR experiments, thereby allowing them to be used in the study of systems with lower surface area. A novel method of optically-pumping 129Xe in low magnetic field below an NMR spectrometer and subsequent transfer of the gas to highmore » magnetic field is described. NMR studies of the highly polarized gas adsorbed onto powdered samples with low to moderate surface areas are now possible. For instance, NMR studies of optically-pumped xenon adsorbed onto polyacrylic acid show that xenon has a large interaction with the surface. By modeling the low temperature data in terms of a sticking probability and the gas phase xenon-xenon interaction, the diffusion coefficient for xenon at the surface of the polymer is determined. The sensitivity enhancement afforded by optical pumping also allows the NMR observation of xenon thin films frozen onto the inner surfaces of different sample cells. The geometry of the thin films results in interesting line shapes that are due to the bulk magnetic susceptibility of xenon. Experiments are also described that combine optical pumping with optical detection for high sensitivity in low magnetic field to observe the quadrupoler evolution of 131 Xe spins at the surface of the pumping cells. In cells with macroscopic asymmetry, a residual quadrupolar interaction causes a splitting in the 131Xe NMR frequencies in bare Pyrex glass cells and cells with added hydrogen.« less

Optical pumping and xenon NMR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raftery, M.D.

1991-11-01

Nuclear Magnetic Resonance (NMR) spectroscopy of xenon has become an important tool for investigating a wide variety of materials, especially those with high surface area. The sensitivity of its chemical shift to environment, and its chemical inertness and adsorption properties make xenon a particularly useful NMR probe. This work discusses the application of optical pumping to enhance the sensitivity of xenon NMR experiments, thereby allowing them to be used in the study of systems with lower surface area. A novel method of optically-pumping [sup 129]Xe in low magnetic field below an NMR spectrometer and subsequent transfer of the gas tomore » high magnetic field is described. NMR studies of the highly polarized gas adsorbed onto powdered samples with low to moderate surface areas are now possible. For instance, NMR studies of optically-pumped xenon adsorbed onto polyacrylic acid show that xenon has a large interaction with the surface. By modeling the low temperature data in terms of a sticking probability and the gas phase xenon-xenon interaction, the diffusion coefficient for xenon at the surface of the polymer is determined. The sensitivity enhancement afforded by optical pumping also allows the NMR observation of xenon thin films frozen onto the inner surfaces of different sample cells. The geometry of the thin films results in interesting line shapes that are due to the bulk magnetic susceptibility of xenon. Experiments are also described that combine optical pumping with optical detection for high sensitivity in low magnetic field to observe the quadrupoler evolution of 131 Xe spins at the surface of the pumping cells. In cells with macroscopic asymmetry, a residual quadrupolar interaction causes a splitting in the [sup 131]Xe NMR frequencies in bare Pyrex glass cells and cells with added hydrogen.« less

Development and evaluation of a silver mordenite composite sorbent for the partitioning of xenon from krypton in gas compositions

DOE PAGES

Garn, Troy G.; Greenhalgh, Mitchell; Law, Jack D.

2015-12-22

A new engineered form composite sorbent for the selective separation of xenon from krypton in simulant composition off-gas streams resulting from the reprocessing of used nuclear fuel has been developed and evaluated. A sodium mordenite powder was incorporated into a macroporous polymer binder, formed into spherical beads and successfully converted to a 9 wt.% silver form composite sorbent. The final engineered form sorbent retained the characteristic surface area indicative of sodium mordenite powder. The sorbent was evaluated for xenon adsorption potential with capacities measured as high as 30 millimoles of xenon per kilogram of sorbent achieved at ambient temperature andmore » 460 millimoles of xenon per kilogram sorbent at 220 K. Xenon/krypton selectivity was calculated to be 22.4 with a 1020 µL/L xenon, 150 µL/L krypton in a balance of air feed gas at 220 K. Furthermore, adsorption/desorption thermal cycling effects were evaluated with results indicating sorbent performance was not significantly impacted while undergoing numerous adsorption/desorption thermal cycles.« less

Evaluation of pulmonary function using single-breath-hold dual-energy computed tomography with xenon

PubMed Central

Kyoyama, Hiroyuki; Hirata, Yusuke; Kikuchi, Satoshi; Sakai, Kosuke; Saito, Yuriko; Mikami, Shintaro; Moriyama, Gaku; Yanagita, Hisami; Watanabe, Wataru; Otani, Katharina; Honda, Norinari; Uematsu, Kazutsugu

2017-01-01

Abstract Xenon-enhanced dual-energy computed tomography (xenon-enhanced CT) can provide lung ventilation maps that may be useful for assessing structural and functional abnormalities of the lung. Xenon-enhanced CT has been performed using a multiple-breath-hold technique during xenon washout. We recently developed xenon-enhanced CT using a single-breath-hold technique to assess ventilation. We sought to evaluate whether xenon-enhanced CT using a single-breath-hold technique correlates with pulmonary function testing (PFT) results. Twenty-six patients, including 11 chronic obstructive pulmonary disease (COPD) patients, underwent xenon-enhanced CT and PFT. Three of the COPD patients underwent xenon-enhanced CT before and after bronchodilator treatment. Images from xenon-CT were obtained by dual-source CT during a breath-hold after a single vital-capacity inspiration of a xenon–oxygen gas mixture. Image postprocessing by 3-material decomposition generated conventional CT and xenon-enhanced images. Low-attenuation areas on xenon images matched low-attenuation areas on conventional CT in 21 cases but matched normal-attenuation areas in 5 cases. Volumes of Hounsfield unit (HU) histograms of xenon images correlated moderately and highly with vital capacity (VC) and total lung capacity (TLC), respectively (r = 0.68 and 0.85). Means and modes of histograms weakly correlated with VC (r = 0.39 and 0.38), moderately with forced expiratory volume in 1 second (FEV1) (r = 0.59 and 0.56), weakly with the ratio of FEV1 to FVC (r = 0.46 and 0.42), and moderately with the ratio of FEV1 to its predicted value (r = 0.64 and 0.60). Mode and volume of histograms increased in 2 COPD patients after the improvement of FEV1 with bronchodilators. Inhalation of xenon gas caused no adverse effects. Xenon-enhanced CT using a single-breath-hold technique depicted functional abnormalities not detectable on thin-slice CT. Mode, mean, and volume of HU histograms of xenon images

High-pressure Xenon Gas Electroluminescent TPC Concept for Simultaneous Searches for Neutrino-less Double Beta Decay & WIMP Dark Matter

NASA Astrophysics Data System (ADS)

Nygren, David

2013-04-01

Xenon is an especially attractive candidate for both direct WIMP and 0- decay searches. Although the current trend has exploited the liquid phase, gas phase xenon offers some remarkable performance advantages for energy resolution, topology visualization, and discrimination between electron and nuclear recoils. The NEXT-100 experiment, now beginning construction in the Canfranc Underground Laboratory, Spain, will operate at 12 bars with 100 kg of ^136Xe for the 0- decay search. I will describe recent results with small prototypes, indicating that NEXT-100 can provide about 0.5% FWHM energy resolution at the decay 2457.83 keV Q-value, as well as rejection of -rays by topology. However, sensitivity goals for WIMP dark matter and 0- decay searches indicate the need for ton-scale active masses; NEXT-100 provides the springboard to reach this scale with xenon gas. I describe a scenario for performing both searches in a single high-pressure ton-scale xenon gas detector, without significant compromise to either. In addition, -- even in a single, ton-scale, high-pressure xenon gas TPC, an intrinsic sensitivity to the nuclear recoil direction may exist -- plausibly offering an advance of more than two orders of magnitude relative to current low-pressure TPC concepts. I argue that, in an era of deepening fiscal austerity, such a dual-purpose detector may be possible, at acceptable cost, within the time frame of interest, and deserves our collective attention.

International comparison CCQM-K113—noble gas mixture

NASA Astrophysics Data System (ADS)

Lim, Jeong Sik; Lee, Jinbok; Moon, Dongmin; Tshilongo, James; Qiao, Han; Shuguo, Hu; Tiqiang, Zhang; Kelley, Michael E.; Rhoderick, George C.; Konopelko, L. A.; Kolobova, A. V.; Vasserman, I. I.; Zavyalov, S. V.; Gromova, E. V.; Efremova, O. V.

2017-01-01

Noble gases are one of the key elements used in the various processes of the bulbs industry, automotive industry, space industry, lasers industry, display industry as well as the semiconductor industry. Considering continuous growth, the provision of a reliable standard is required for those industries to improve their productivity. In this report, a result of the key comparison, CCQM-K113: noble gas mixture, is presented. Nominal amount-of-substance fractions of argon, neon, krypton, and xenon in helium are 20, 10, 2, and 1 cmol/mol, respectively. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Xenon Recovery at Room Temperature using Metal-Organic Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elsaidi, Sameh K.; Ongari, Daniele; Xu, Wenqian

2017-07-24

Xenon is known to be a very efficient anesthetic gas but its cost prohibits the wider use in medical industry and other potential applications. It has been shown that Xe recovery and recycle from anesthetic gas mixture can significantly reduce its cost as anesthetic. The current technology uses series of adsorbent columns followed by low temperature distillation to recover Xe, which is expensive to use in medical facilities. Herein, we propose much efficient and simpler system to recover and recycle Xe from simulant exhale anesthetic gas mixture at room temperature using metal organic frameworks. Among the MOFs tested, PCN-12 exhibitsmore » unprecedented performance with high Xe capacity, Xe/O2, Xe/N2 and Xe/CO2 selectivity at room temperature. The in-situ synchrotron measurements suggest the Xe is occupied in the small pockets of PCN-12 compared to unsaturated metal centers (UMCs). Computational modeling of adsorption further supports our experimental observation of Xe binding sites in PCN-12.« less

Xenon Recovery at Room Temperature using Metal-Organic Frameworks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elsaidi, Sameh K.; Ongari, Daniele; Xu, Wenqian

2017-07-24

Xenon is known to be a very efficient anesthetic gas but its cost prohibits the wider use in medical industry and other potential applications. It has been shown that Xe recovery and recycle from anesthetic gas mixture can significantly reduce its cost as anesthetic. The current technology uses series of adsorbent columns followed by low temperature distillation to recover Xe, which is expensive to use in medical facilities. Herein, we propose much efficient and simpler system to recover and recycle Xe from simulant exhale anesthetic gas mixture at room temperature using metal organic frameworks. Among the MOFs tested, PCN-12 exhibitsmore » unprecedented performance with high Xe capacity, Xe/N2 and Xe/O2 selectivity at room temperature. The in-situ synchrotron measurements suggest the Xe is occupied in the small pockets of PCN-12 compared to unsaturated metal centers (UMCs). Computational modeling of adsorption further supports our experimental observation of Xe binding sites in PCN-12.« less

An automated multidimensional preparative gas chromatographic system for isolation and enrichment of trace amounts of xenon from ambient air.

PubMed

Larson, Tuula; Östman, Conny; Colmsjö, Anders

2011-04-01

The monitoring of radioactive xenon isotopes is one of the principal methods for the detection of nuclear explosions in order to identify clandestine nuclear testing. In this work, a miniaturized, multiple-oven, six-column, preparative gas chromatograph was constructed in order to isolate trace quantities of radioactive xenon isotopes from ambient air, utilizing nitrogen as the carrier gas. The multidimensional chromatograph comprised preparative stainless steel columns packed with molecular sieves, activated carbon, and synthetic carbon adsorbents (e.g., Anasorb®-747 and Carbosphere®). A combination of purification techniques--ambient adsorption, thermal desorption, back-flushing, thermal focusing, and heart cutting--was selectively optimized to produce a well-defined xenon peak that facilitated reproducible heart cutting and accurate quantification. The chromatographic purification of a sample requires approximately 4 h and provides complete separation of xenon from potentially interfering components (such as water vapor, methane, carbon dioxide, and radon) with recovery and accuracy close to 100%. The preparative enrichment process isolates and concentrates a highly purified xenon gas fraction that is suitable for subsequent ultra-low-level γ-, ß/γ-spectroscopic or high-resolution mass spectrometric measurement (e.g., to monitor the gaseous fission products of nuclear explosions at remote locations). The Xenon Processing Unit is a free-standing, relatively lightweight, and transportable system that can be interfaced to a variety of sampling and detection systems. It has a relatively inexpensive, rugged, and compact modular (19-inch rack) design that provides easy access to all parts for maintenance and has a low power requirement.

Detection of Alpha Particles and Low Energy Gamma Rays by Thermo-Bonded Micromegas in Xenon Gas

NASA Astrophysics Data System (ADS)

Wei, Yuehuan; Guan, Liang; Zhang, Zhiyong; Lin, Qing; Wang, Xiaolian; Ni, Kaixuan; Zhao, Tianchi

2013-08-01

Micromegas is a type of micro-pattern gaseous detector currently under R&D for applications in rare event search experiments. Here we report the performance of a Micromegas structure constructed with a micromesh thermo-bonded to a readout plane, motivated by its potential application in two-phase xenon detectors for dark matter and neutrinoless double beta decay experiments. The study is carried out in pure xenon at room temperature. Measurements with alpha particles from the Americium-241 source showed that gas gains larger than 200 can be obtained at xenon pressure up to 3 atm. Gamma rays down to 8 keV were observed with such a device.

Design and development of radioactive xenon gas purification and analysis system based on molecular sieves.

PubMed

Sabzian, M; Nasrabadi, M N; Haji-Hosseini, M

2018-10-01

The dynamic adsorption of xenon on molecular sieve packed columns was investigated. The modified Wheeler-Jonas equation was used to describe adsorption parameters such as adsorption capacity and adsorption rate coefficient. Different experimental conditions were accomplished to study their effects and to touch appropriate adsorbing circumstances. Respectable consistency was reached between experimental and modeled values. A purification and analysis setup was developed for radioactive xenon gas determination. Standard sample analysis results approved acceptable quantification accuracy. Copyright © 2018. Published by Elsevier Ltd.

Improving Students' Understanding of the Connections between the Concepts of Real-Gas Mixtures, Gas Ideal-Solutions, and Perfect-Gas Mixtures

ERIC Educational Resources Information Center

Privat, Romain; Jaubert, Jean-Noël; Moine, Edouard

2016-01-01

In many textbooks of chemical-engineering thermodynamics, a gas mixture obeying the fundamental law pV[subscript m] = RT is most often called ideal-gas mixture (in some rare cases, the term perfect-gas mixture can be found). These textbooks also define the fundamental concept of ideal solution which in theory, can be applied indifferently to…

A method for calculating the gas volume proportions and inhalation temperature of inert gas mixtures allowing reaching normothermic or hypothermic target body temperature in the awake rat.

PubMed

Abraini, Jacques H; David, Hélène N; Blatteau, Jean-Éric; Risso, Jean Jacques; Vallée, Nicolas

2017-01-01

The noble gases xenon (Xe) and helium (He) are known to possess neuroprotective properties. Xe is considered the golden standard neuroprotective gas. However, Xe has a higher molecular weight and lower thermal conductivity and specific heat than those of nitrogen, the main diluent of oxygen (O2) in air, conditions that could impair or at least reduce the intrinsic neuroprotective properties of Xe by increasing the critical care patient's respiratory workload and body temperature. In contrast, He has a lower molecular weight and higher thermal conductivity and specific heat than those of nitrogen, but is unfortunately far less potent than Xe at providing neuroprotection. Therefore, combining Xe with He could allow obtaining, depending on the gas inhalation temperature and composition, gas mixtures with neutral or hypothermic properties, the latter being advantageous in term of neuroprotection. However, calculating the thermal properties of a mixture, whatever the substances - gases, metals, rubbers, etc . - is not trivial. To answer this question, we provide a graphical method to assess the volume proportions of Xe, He and O2 that a gas mixture should contain, and the inhalation temperature to which it should be administered to allow a clinician to maintain the patient at a target body temperature.

A method for calculating the gas volume proportions and inhalation temperature of inert gas mixtures allowing reaching normothermic or hypothermic target body temperature in the awake rat

PubMed Central

Abraini, Jacques H.; David, Hélène N.; Blatteau, Jean-Éric; Risso, Jean Jacques; Vallée, Nicolas

2017-01-01

The noble gases xenon (Xe) and helium (He) are known to possess neuroprotective properties. Xe is considered the golden standard neuroprotective gas. However, Xe has a higher molecular weight and lower thermal conductivity and specific heat than those of nitrogen, the main diluent of oxygen (O2) in air, conditions that could impair or at least reduce the intrinsic neuroprotective properties of Xe by increasing the critical care patient's respiratory workload and body temperature. In contrast, He has a lower molecular weight and higher thermal conductivity and specific heat than those of nitrogen, but is unfortunately far less potent than Xe at providing neuroprotection. Therefore, combining Xe with He could allow obtaining, depending on the gas inhalation temperature and composition, gas mixtures with neutral or hypothermic properties, the latter being advantageous in term of neuroprotection. However, calculating the thermal properties of a mixture, whatever the substances – gases, metals, rubbers, etc. – is not trivial. To answer this question, we provide a graphical method to assess the volume proportions of Xe, He and O2 that a gas mixture should contain, and the inhalation temperature to which it should be administered to allow a clinician to maintain the patient at a target body temperature. PMID:29152210

Xenon preconditioning: the role of prosurvival signaling, mitochondrial permeability transition and bioenergetics in rats.

PubMed

Mio, Yasushi; Shim, Yon Hee; Richards, Ebony; Bosnjak, Zeljko J; Pagel, Paul S; Bienengraeber, Martin

2009-03-01

Similar to volatile anesthetics, the anesthetic noble gas xenon protects the heart from ischemia/reperfusion injury, but the mechanisms responsible for this phenomenon are not fully understood. We tested the hypothesis that xenon-induced cardioprotection is mediated by prosurvival signaling kinases that target mitochondria. Male Wistar rats instrumented for hemodynamic measurements were subjected to a 30 min left anterior descending coronary artery occlusion and 2 h reperfusion. Rats were randomly assigned to receive 70% nitrogen/30% oxygen (control) or three 5-min cycles of 70% xenon/30% oxygen interspersed with the oxygen/nitrogen mixture administered for 5 min followed by a 15 min memory period. Myocardial infarct size was measured using triphenyltetrazolium staining. Additional hearts from control and xenon-pretreated rats were excised for Western blotting of Akt and glycogen synthase kinase 3 beta (GSK-3beta) phosphorylation and isolation of mitochondria. Mitochondrial oxygen consumption before and after hypoxia/reoxygenation and mitochondrial permeability transition pore opening were determined. Xenon significantly (P < 0.05) reduced myocardial infarct size compared with control (32 +/- 4 and 59% +/- 4% of the left ventricular area at risk; mean +/- sd) and enhanced phosphorylation of Akt and GSK-3beta. Xenon pretreatment preserved state 3 respiration of isolated mitochondria compared with the results obtained in the absence of the gas. The Ca(2+) concentration required to induce mitochondrial membrane depolarization was larger in the presence compared with the absence of xenon pretreatment (78 +/- 17 and 56 +/- 17 microM, respectively). The phosphoinositol-3-kinase-kinase inhibitor wortmannin blocked the effect of xenon on infarct size and respiration. These results indicate that xenon preconditioning reduces myocardial infarct size, phosphorylates Akt, and GSK-3beta, preserves mitochondrial function, and inhibits Ca(2+)-induced mitochondrial permeability

Critical Viscosity of Xenon

NASA Technical Reports Server (NTRS)

2001-01-01

The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Because xenon near the critical point will collapse under its own weight, experiments on Earth (green line) are limited as they get closer (toward the left) to the critical point. CVX in the microgravity of space (red line) moved into unmeasured territory that scientists had not been able to reach.

Xenon in the treatment of panic disorder: an open label study.

PubMed

Dobrovolsky, Alexander; Ichim, Thomas E; Ma, Daqing; Kesari, Santosh; Bogin, Vladimir

2017-06-13

Current treatments of panic disorder (PD) are limited by adverse effects, poor efficacy, and need for chronic administration. The established safety profile of subanesthetic concentrations of xenon gas, which is known to act as a glutamate subtype NMDA receptor antagonist, coupled with preclinical studies demonstrating its effects in other anxiety related conditions, prompted us to evaluate its feasibility and efficacy in treatment of patients with PD. An open-label clinical trial of xenon-oxygen mixture was conducted in 81 patients with PD; group 1 consisting of patients only with PD (N = 42); and group 2 patients with PD and other comorbidities (N = 39). Based on the analysis of the results of a number of psychometric scales used in this study (SAS, HADS, CGI), several conclusions can be made: (1) xenon is a potentially effective modality in acute treatment of PD; (2) an anti-panic effect of xenon administration persists for at least 6 months after the completion of the active phase of treatment; (3) xenon inhalation is well tolerated, with the drop-out rates being much lower than that of conventional pharmacotherapy (5.8% vs. 15%); (4) the severity of depressive disorders that frequently accompany PD can be significantly reduced with the use of xenon; (5) xenon may be considered as an alternative to benzodiazepines in conjunction with cognitive-behavioral therapy as a safe modality in treatment of anxiety disorder. These data support the need for randomized double-blind clinical trials to further study xenon-based interventions. Trial registration This clinical trial was retrospectively registered on April 14th, 2017 as ISRCTN15184285 in the ISRCTN database.

Buffer gas cooling and mixture analysis

DOEpatents

Patterson, David S.; Doyle, John M.

2018-03-06

An apparatus for spectroscopy of a gas mixture is described. Such an apparatus includes a gas mixing system configured to mix a hot analyte gas that includes at least one analyte species in a gas phase into a cold buffer gas, thereby forming a supersaturated mixture to be provided for spectroscopic analysis.

Critical Viscosity of Xenon

NASA Technical Reports Server (NTRS)

2001-01-01

The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of liquid xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Resembling a tiny bit of window screen, the oscillator at the heart of CVX-2 will vibrate between two pairs of paddle-like electrodes. The slight bend in the shape of the mesh has no effect on the data. What counts are the mesh's displacement in the xenon fluid and the rate at which the displacement dampens. The unit shown here is encased in a small test cell and capped with a sapphire windown to contain the xenon at high pressure.

[How xenon works: neuro and cardioprotection mechanisms].

PubMed

Morais, Ricardo; Andrade, Luísa; Lourenço, André; Tavares, Jorge

2014-01-01

The Xenon, a noble gas, has anesthetics properties, associated with remarkable hemodynamic stability as well as cardioprotective, neuroprotective proprieties. Its physicochemical characteristics give him a quick induction and emergence of anesthesia, being free of deleterious effects in all organs and showing no teratogenicity. Such properties have led to a growing interest in improving the knowledge about this noble gas, in order to assess the mechanisms of neuro and cardioprotection induced and to assess the clinical indications for its use. Qualitative review of clinical trials on anesthesia with xenon. Studies were identified from MEDLINE and by hand-searching, using the following keywords: xenon, xenon anestesia, xenon neuroprotection, xenon cradioprotection. After several studies, including two randomized multicenter controlled trials, the use of xenon as an anesthetic in patients ASA I-II was approved in March 2007. However his use in clinical practice has been strongly limited by it's high price. It seems unlikely that the advantages it offers in relation to other anesthetics justify it's use in patients ASA I-II. Although, xenon may be a valuable asset in the reduction of co-morbilities and mortality in anesthesia of patients ASA III-IV, unfortunately, there are no large randomized control studies to prove it. Unfortunately, there are still no randomized or multicentric studies showing a favourable cost-benefit profile of xenon in ASA III-IV patients vs. other anaesthetics. The usefulness of xenon in Anesthesiology requires more studies to be defined.

Recovering Residual Xenon Propellant for an Ion Propulsion System

NASA Technical Reports Server (NTRS)

Ganapathi, Gani; Skakkottai, P.; wu, Jiunn Jeng

2006-01-01

Future nuclear-powered Ion-Propulsion- System-propelled spacecraft such as Jupiter Icy Moon Orbiter (JIMO) will carry more than 10,000 kg of xenon propellant. Typically, a small percentage of this propellant cannot be used towards the end of the mission because of the pressure drop requirements for maintaining flow. For large missions such as JIMO, this could easily translate to over 250 kg of unusable xenon. A proposed system, the Xenon Recovery System (XRS), for recovering almost all of the xenon remaining in the tank, would include a cryopump in the form of a condenser/evaporator that would be alternatively cooled by a radiator, then heated electrically. When the pressure of the xenon in the tank falls below 0.7 MPa (100 psia), the previously isolated XRS will be brought online and the gas from the tank would enter the cryopump that is initially cooled to a temperature below saturation temperature of xenon. This causes xenon liquefaction and further cryopumping from the tank till the cryopump is full of liquid xenon. At this point, the cryopump is heated electrically by small heaters (70 to 80 W) to evaporate the liquid that is collected as high-pressure gas (<7 MPa; 1,000 psia) in an intermediate accumulator. Check valves between the tank and the XRS prevent the reverse flow of xenon during the heating cycle. The accumulator serves as the high-pressure source of xenon gas to the Xenon Feed System (XFS) downstream of the XRS. This cycle is repeated till almost all the xenon is recovered. Currently, this system is being baselined for JIMO.

Hyperpolarized xenon magnetic resonance of the lung and the brain

NASA Astrophysics Data System (ADS)

Venkatesh, Arvind Krishnamachari

2001-04-01

Hyperpolarized noble gas Magnetic Resonance Imaging (MRI) is a new diagnostic modality that has been used successfully for lung imaging. Xenon is soluble in blood and inhaled xenon is transported to the brain via circulating blood. Xenon also accumulates in the lipid rich white matter of the brain. Hyperpolarized xenon can hence be used as a tissue- sensitive probe of brain function. The goals of this study were to identify the NMR resonances of xenon in the rat brain and evaluate the role of hyperpolarized xenon for brain MRI. We have developed systems to produce sufficient volumes of hyperpolarized xenon for in vivo brain experiments. The specialized instrumentation developed include an apparatus for optical pump-cell manufacture and high purity gas manifolds for filling cells. A hyperpolarized gas delivery system was designed to ventilate small animals with hyperpolarized xenon for transport to the brain. The T1 of xenon dissolved in blood indicates that the lifetime of xenon in the blood is sufficient for significant magnetization to be transferred to distal tissues. A variety of carrier agents for intravenous delivery of hyperpolarized xenon were tested for transport to distal tissues. Using our new gas delivery system, high SNR 129Xe images of rat lungs were obtained. Spectroscopy with hyperpolarized xenon indicated that xenon was transported from the lungs to the blood and tissues with intact magnetization. After preliminary studies that indicated the feasibility for in vivo rat brain studies, experiments were performed with adult rats and young rats with different stages of white matter development. Both in vivo and in vitro experiments showed the prominence of one peak from xenon in the rat brain, which was assigned to brain lipids. Cerebral brain perfusion was calculated from the wash-out of the hyperpolarized xenon signal in the brain. An increase in brain perfusion during maturation was observed. These experiments showed that hyperpolarized xenon MRI

In situ measurement of atmospheric krypton and xenon on Mars with Mars Science Laboratory

DOE PAGES

Conrad, P. G.; Malespin, C. A.; Franz, H. B.; ...

2016-11-01

Mars Science Laboratory's Sample Analysis at Mars (SAM) investigation has measured all of the stable isotopes of the heavy noble gases krypton and xenon in the martian atmosphere, in situ, from the Curiosity Rover at Gale Crater, Mars. Previous knowledge of martian atmospheric krypton and xenon isotope ratios has been based upon a combination of the Viking mission's krypton and xenon detections and measurements of noble gas isotope ratios in martian meteorites. But, the meteorite measurements reveal an impure mixture of atmospheric, mantle, and spallation contributions. The xenon and krypton isotopic measurements reported here include the complete set of stablemore » isotopes, unmeasured by Viking. Our new results generally agree with Mars meteorite measurements but also provide a unique opportunity to identify various non-atmospheric heavy noble gas components in the meteorites. Kr isotopic measurements define a solar-like atmospheric composition, but deviating from the solar wind pattern at 80Kr and 82Kr in a manner consistent with contributions originating from neutron capture in Br. The Xe measurements suggest an intriguing possibility that isotopes lighter than 132Xe have been enriched to varying degrees by spallation and neutron capture products degassed to the atmosphere from the regolith, and a model is constructed to explore this possibility. Such a spallation component, but, is not apparent in atmospheric Xe trapped in the glassy phases of martian meteorites.« less

In situ measurement of atmospheric krypton and xenon on Mars with Mars Science Laboratory

NASA Astrophysics Data System (ADS)

Conrad, P. G.; Malespin, C. A.; Franz, H. B.; Pepin, R. O.; Trainer, M. G.; Schwenzer, S. P.; Atreya, S. K.; Freissinet, C.; Jones, J. H.; Manning, H.; Owen, T.; Pavlov, A. A.; Wiens, R. C.; Wong, M. H.; Mahaffy, P. R.

2016-11-01

Mars Science Laboratory's Sample Analysis at Mars (SAM) investigation has measured all of the stable isotopes of the heavy noble gases krypton and xenon in the martian atmosphere, in situ, from the Curiosity Rover at Gale Crater, Mars. Previous knowledge of martian atmospheric krypton and xenon isotope ratios has been based upon a combination of the Viking mission's krypton and xenon detections and measurements of noble gas isotope ratios in martian meteorites. However, the meteorite measurements reveal an impure mixture of atmospheric, mantle, and spallation contributions. The xenon and krypton isotopic measurements reported here include the complete set of stable isotopes, unmeasured by Viking. The new results generally agree with Mars meteorite measurements but also provide a unique opportunity to identify various non-atmospheric heavy noble gas components in the meteorites. Kr isotopic measurements define a solar-like atmospheric composition, but deviating from the solar wind pattern at 80Kr and 82Kr in a manner consistent with contributions originating from neutron capture in Br. The Xe measurements suggest an intriguing possibility that isotopes lighter than 132Xe have been enriched to varying degrees by spallation and neutron capture products degassed to the atmosphere from the regolith, and a model is constructed to explore this possibility. Such a spallation component, however, is not apparent in atmospheric Xe trapped in the glassy phases of martian meteorites.

In Situ Measurement of Atmospheric Krypton and Xenon on Mars with Mars Science Laboratory

NASA Technical Reports Server (NTRS)

Conrad, P. G.; Malespin, C. A.; Franz, H. B.; Pepin, R. O.; Trainer, M. G.; Schwenzer, S. P.; Atreya, S. K.; Freissinet, C.; Jones, J. H.; Manning, H.;

In situ measurement of atmospheric krypton and xenon on Mars with Mars Science Laboratory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conrad, P. G.; Malespin, C. A.; Franz, H. B.

Mars Science Laboratory's Sample Analysis at Mars (SAM) investigation has measured all of the stable isotopes of the heavy noble gases krypton and xenon in the martian atmosphere, in situ, from the Curiosity Rover at Gale Crater, Mars. Previous knowledge of martian atmospheric krypton and xenon isotope ratios has been based upon a combination of the Viking mission's krypton and xenon detections and measurements of noble gas isotope ratios in martian meteorites. But, the meteorite measurements reveal an impure mixture of atmospheric, mantle, and spallation contributions. The xenon and krypton isotopic measurements reported here include the complete set of stablemore » isotopes, unmeasured by Viking. Our new results generally agree with Mars meteorite measurements but also provide a unique opportunity to identify various non-atmospheric heavy noble gas components in the meteorites. Kr isotopic measurements define a solar-like atmospheric composition, but deviating from the solar wind pattern at 80Kr and 82Kr in a manner consistent with contributions originating from neutron capture in Br. The Xe measurements suggest an intriguing possibility that isotopes lighter than 132Xe have been enriched to varying degrees by spallation and neutron capture products degassed to the atmosphere from the regolith, and a model is constructed to explore this possibility. Such a spallation component, but, is not apparent in atmospheric Xe trapped in the glassy phases of martian meteorites.« less

[Xenon: From rare gaz to doping product].

PubMed

Tassel, Camille; Le Daré, Brendan; Morel, Isabelle; Gicquel, Thomas

2016-04-01

Doping is defined as the use of processes or substances to artificially increase physical or mental performance. Xenon is a noble gas used as an anesthetic and recently as a doping agent. Xenon is neuroprotective as an antagonist of NMDA glutamate receptors. Xenon stimulates the synthesis of erythropoietin (EPO) by increase of hypoxia inducible factor (HIF). Xenon would be a new doping product, maintaining doping methods ahead of detection. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Evaluation of pulmonary function using single-breath-hold dual-energy computed tomography with xenon: Results of a preliminary study.

PubMed

Kyoyama, Hiroyuki; Hirata, Yusuke; Kikuchi, Satoshi; Sakai, Kosuke; Saito, Yuriko; Mikami, Shintaro; Moriyama, Gaku; Yanagita, Hisami; Watanabe, Wataru; Otani, Katharina; Honda, Norinari; Uematsu, Kazutsugu

2017-01-01

Xenon-enhanced dual-energy computed tomography (xenon-enhanced CT) can provide lung ventilation maps that may be useful for assessing structural and functional abnormalities of the lung. Xenon-enhanced CT has been performed using a multiple-breath-hold technique during xenon washout. We recently developed xenon-enhanced CT using a single-breath-hold technique to assess ventilation. We sought to evaluate whether xenon-enhanced CT using a single-breath-hold technique correlates with pulmonary function testing (PFT) results.Twenty-six patients, including 11 chronic obstructive pulmonary disease (COPD) patients, underwent xenon-enhanced CT and PFT. Three of the COPD patients underwent xenon-enhanced CT before and after bronchodilator treatment. Images from xenon-CT were obtained by dual-source CT during a breath-hold after a single vital-capacity inspiration of a xenon-oxygen gas mixture. Image postprocessing by 3-material decomposition generated conventional CT and xenon-enhanced images.Low-attenuation areas on xenon images matched low-attenuation areas on conventional CT in 21 cases but matched normal-attenuation areas in 5 cases. Volumes of Hounsfield unit (HU) histograms of xenon images correlated moderately and highly with vital capacity (VC) and total lung capacity (TLC), respectively (r = 0.68 and 0.85). Means and modes of histograms weakly correlated with VC (r = 0.39 and 0.38), moderately with forced expiratory volume in 1 second (FEV1) (r = 0.59 and 0.56), weakly with the ratio of FEV1 to FVC (r = 0.46 and 0.42), and moderately with the ratio of FEV1 to its predicted value (r = 0.64 and 0.60). Mode and volume of histograms increased in 2 COPD patients after the improvement of FEV1 with bronchodilators. Inhalation of xenon gas caused no adverse effects.Xenon-enhanced CT using a single-breath-hold technique depicted functional abnormalities not detectable on thin-slice CT. Mode, mean, and volume of HU histograms of xenon images reflected

Simultaneous detection of xenon and krypton in equine plasma by gas chromatography-tandem mass spectrometry for doping control.

PubMed

Kwok, Wai Him; Choi, Timmy L S; So, Pui-Kin; Yao, Zhong-Ping; Wan, Terence S M

2017-02-01

Xenon can activate the hypoxia-inducible factors (HIFs). As such, it has been allegedly used in human sports for increasing erythropoiesis. Krypton, another noble gas with reported narcosis effect, can also be expected to be a potential and less expensive erythropoiesis stimulating agent. This has raised concern about the misuse of noble gases as doping agents in equine sports. The aim of the present study is to establish a method for the simultaneous detection of xenon and krypton in equine plasma for the purpose of doping control. Xenon- or krypton-fortified equine plasma samples were prepared according to reported protocols. The target noble gases were simultaneously detected by gas chromatography-triple quadrupole mass spectrometry using headspace injection. Three xenon isotopes at m/z 129, 131, and 132, and four krypton isotopes at m/z 82, 83, 84, and 86 were targeted in selected reaction monitoring mode (with the precursor ions and product ions at identical mass settings), allowing unambiguous identification of the target analytes. Limits of detection for xenon and krypton were about 19 pmol/mL and 98 pmol/mL, respectively. Precision for both analytes was less than 15%. The method has good specificity as background analyte signals were not observed in negative equine plasma samples (n = 73). Loss of analytes under different storage temperatures has also been evaluated. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Critical Viscosity of Xenon

NASA Technical Reports Server (NTRS)

2001-01-01

The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The sample cell at the heart of CVX-2 will sit inside a thermostat providing three layers of insulation. The cell itself comprises a copper body that conducts heat efficiently and smoothes out thermal variations that that would destroy the xenon's uniformity. Inside the cell, the oscillating screen viscometer element is supported between two pairs of electrodes that deflect the screen and then measure screen motion.

Pulsed-field-gradient measurements of time-dependent gas diffusion

NASA Technical Reports Server (NTRS)

Mair, R. W.; Cory, D. G.; Peled, S.; Tseng, C. H.; Patz, S.; Walsworth, R. L.

1998-01-01

Pulsed-field-gradient NMR techniques are demonstrated for measurements of time-dependent gas diffusion. The standard PGSE technique and variants, applied to a free gas mixture of thermally polarized xenon and O2, are found to provide a reproducible measure of the xenon diffusion coefficient (5.71 x 10(-6) m2 s-1 for 1 atm of pure xenon), in excellent agreement with previous, non-NMR measurements. The utility of pulsed-field-gradient NMR techniques is demonstrated by the first measurement of time-dependent (i.e., restricted) gas diffusion inside a porous medium (a random pack of glass beads), with results that agree well with theory. Two modified NMR pulse sequences derived from the PGSE technique (named the Pulsed Gradient Echo, or PGE, and the Pulsed Gradient Multiple Spin Echo, or PGMSE) are also applied to measurements of time dependent diffusion of laser polarized xenon gas, with results in good agreement with previous measurements on thermally polarized gas. The PGMSE technique is found to be superior to the PGE method, and to standard PGSE techniques and variants, for efficiently measuring laser polarized noble gas diffusion over a wide range of diffusion times. Copyright 1998 Academic Press.

Dielectric gas mixtures containing sulfur hexafluoride

DOEpatents

Cooke, Chathan M.

1979-01-01

Electrically insulating gaseous media of unexpectedly high dielectric strength comprised of mixtures of two or more dielectric gases are disclosed wherein the dielectric strength of at least one gas in each mixture increases at less than a linear rate with increasing pressure and the mixture gases are present in such proportions that the sum of their electrical discharge voltages at their respective partial pressures exceeds the electrical discharge voltage of each individual gas at the same temperature and pressure as that of the mixture.

Purging means and method for Xenon arc lamps

NASA Technical Reports Server (NTRS)

Miller, C. G. (Inventor)

1973-01-01

High pressure Xenon short-arc lamp with two reservoirs which are selectively connectable to the lamp's envelope is described. One reservoir contains an absorbent which will absorb both Xenon and contaminant gases such as CO2 and O2. The absorbent temperature is controlled to evacuate the envelope of both the Xenon and the contaminant gases. The temperature of the absorbent is then raised to desorb only clean Xenon while retaining the contaminant gases, thereby clearing the envelope of the contaminant gases. The second reservoir contains a gas whose specific purpose is, to remove the objectional metal film which deposits gradually on the interior surface of the lamp envelope during normal arc operation. The origin of the film is metal transferred from the cathode of the arc lamp by sputtering or other gas transfer processes.

Gas mixtures for spark gap closing switches

DOEpatents

Christophorou, L.G.; McCorkle, D.L.; Hunter, S.R.

1987-02-20

Gas mixtures for use in spark gap closing switches comprised of fluorocarbons and low molecular weight, inert buffer gases. To this can be added a third gas having a low ionization potential relative to the buffer gas. The gas mixtures presented possess properties that optimized the efficiency spark gap closing switches. 6 figs.

Xenon migration behaviour in titanium nitride

NASA Astrophysics Data System (ADS)

Gavarini, S.; Toulhoat, N.; Peaucelle, C.; Martin, P.; Mende, J.; Pipon, Y.; Jaffrezic, H.

2007-05-01

Titanium nitride is one of the inert matrixes proposed to surround the fuel in gas cooled fast reactor (GFR) systems. These reactors operate at high temperature and necessitate refractory materials presenting a high chemical stability and good mechanical properties. A total retention of the most volatile fission products, such as Xe, I or Cs, by the inert matrix is needed during the in pile process. The thermal migration of xenon in TiN was studied by implanting 800 keV Xe++ ions in sintered samples at an ion fluence of 5 × 1015 cm-2. Annealing was performed at temperatures ranging from 1673 to 1923 K for 1 and 3 h. Xenon concentration profiles were studied by Rutherford backscattering spectrometry (RBS) using 2.5 MeV α-particles. The migration behaviour of xenon corresponds to a gas migration model. It is dominated by a surface directed transport with a slight diffusion component. The mean activation energy corresponding to the diffusion component was found to be 2.2 ± 0.3 eV and corresponds to the Brownian motion of xenon bubbles. The directed Xe migration can be interpreted in term of bubble transport using Evans model. This last process is mostly responsible for xenon release from TiN.

The feasibility of using a portable xenon delivery device to permit earlier xenon ventilation with therapeutic cooling of neonates during ambulance retrieval.

PubMed

Dingley, John; Liu, Xun; Gill, Hannah; Smit, Elisa; Sabir, Hemmen; Tooley, James; Chakkarapani, Ela; Windsor, David; Thoresen, Marianne

2015-06-01

Therapeutic hypothermia is the standard of care after perinatal asphyxia. Preclinical studies show 50% xenon improves outcome, if started early. During a 32-patient study randomized between hypothermia only and hypothermia with xenon, 5 neonates were given xenon during retrieval using a closed-circuit incubator-mounted system. Without xenon availability during retrieval, 50% of eligible infants exceeded the 5-hour treatment window. With the transportable system, 100% were recruited. Xenon delivery lasted 55 to 120 minutes, using 174 mL/h (117.5-193.2) (median [interquartile range]), after circuit priming (1300 mL). Xenon delivery during ambulance retrieval was feasible, reduced starting delays, and used very little gas.

Critical Viscosity of Xenon

NASA Technical Reports Server (NTRS)

2001-01-01

The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Shear thirning will cause a normally viscous fluid -- such as pie filling or whipped cream -- to deform and flow more readily under high shear conditions. In shear thinning, a pocket of fluid will deform and move one edge forward, as depicted here.

Critical Viscosity of Xenon investigators

NASA Technical Reports Server (NTRS)

2001-01-01

Dr. Dr. Robert F. Berg (right), principal investigator and Dr. Micheal R. Moldover (left), co-investigator, for the Critical Viscosity of Xenon (CVX/CVX-2) experiment. They are with the National Institutes of Standards and Technology, Gaithersburg, MD. The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Although it does not easily combine with other chemicals, its viscosity at the critical point can be used as a model for a range of chemicals.

New approach in direct-simulation of gas mixtures

NASA Technical Reports Server (NTRS)

Chung, Chan-Hong; De Witt, Kenneth J.; Jeng, Duen-Ren

1991-01-01

Results are reported for an investigation of a new direct-simulation Monte Carlo method by which energy transfer and chemical reactions are calculated. The new method, which reduces to the variable cross-section hard sphere model as a special case, allows different viscosity-temperature exponents for each species in a gas mixture when combined with a modified Larsen-Borgnakke phenomenological model. This removes the most serious limitation of the usefulness of the model for engineering simulations. The necessary kinetic theory for the application of the new method to mixtures of monatomic or polyatomic gases is presented, including gas mixtures involving chemical reactions. Calculations are made for the relaxation of a diatomic gas mixture, a plane shock wave in a gas mixture, and a chemically reacting gas flow along the stagnation streamline in front of a hypersonic vehicle. Calculated results show that the introduction of different molecular interactions for each species in a gas mixture produces significant differences in comparison with a common molecular interaction for all species in the mixture. This effect should not be neglected for accurate DSMC simulations in an engineering context.

XENON100 Dark Matter Search: Scintillation Response of Liquid Xenon to Electronic Recoils

NASA Astrophysics Data System (ADS)

Lim, Kyungeun Elizabeth

Dark matter is one of the missing pieces necessary to complete the puzzle of the universe. Numerous astrophysical observations at all scales suggest that 23 % of the universe is made of nonluminous, cold, collisionless, nonbaryonic, yet undiscovered dark matter. Weakly Interacting Massive Particles (WIMPs) are the most well-motivated dark matter candidates and significant efforts have been made to search for WIMPs. The XENON100 dark matter experiment is currently the most sensitive experiment in the global race for the first direct detection of WIMP dark matter. XENON100 is a dual-phase (liquid-gas) time projection chamber containing a total of 161 kg of liquid xenon (LXe) with a 62kg WIMP target mass. It has been built with radiopure materials to achieve an ultra-low electromagnetic background and operated at the Laboratori Nazionali del Gran Sasso in Italy. WIMPs are expected to scatter off xenon nuclei in the target volume. Simultaneous measurement of ionization and scintillation produced by nuclear recoils allows for the detection of WIMPs in XENON100. Data from the XENON100 experiment have resulted in the most stringent limits on the spin-independent elastic WIMP-nucleon scattering cross sections for most of the significant WIMP masses. As the experimental precision increases, a better understanding of the scintillation and ionization response of LXe to low energy (< 10 keV) particles is crucial for the interpretation of data from LXe based WIMP searches. A setup has been built and operated at Columbia University to measure the scintillation response of LXe to both electronic and nuclear recoils down to energies of a few keV, in particular for the XENON100 experiment. In this thesis, I present the research carried out in the context of the XENON100 dark matter search experiment. For the theoretical foundation of the XENON100 experiment, the first two chapters are dedicated to the motivation for and detection medium choice of the XENON100 experiment

The noble gas xenon induces pharmacological preconditioning in the rat heart in vivo via induction of PKC-ɛ and p38 MAPK

PubMed Central

Weber, Nina C; Toma, Octavian; Wolter, Jessica I; Obal, Detlef; Müllenheim, Jost; Preckel, Benedikt; Schlack, Wolfgang

2004-01-01

Xenon is an anesthetic with minimal hemodynamic side effects, making it an ideal agent for cardiocompromised patients. We investigated if xenon induces pharmacological preconditioning (PC) of the rat heart and elucidated the underlying molecular mechanisms. For infarct size measurements, anesthetized rats were subjected to 25 min of coronary artery occlusion followed by 120 min of reperfusion. Rats received either the anesthetic gas xenon, the volatile anesthetic isoflurane or as positive control ischemic preconditioning (IPC) during three 5-min periods before 25-min ischemia. Control animals remained untreated for 45 min. To investigate the involvement of protein kinase C (PKC) and p38 mitogen-activated protein kinase (MAPK), rats were pretreated with the PKC inhibitor calphostin C (0.1 mg kg−1) or the p38 MAPK inhibitor SB203580 (1 mg kg−1). Additional hearts were excised for Western blot and immunohistochemistry. Infarct size was reduced from 50.9±16.7% in controls to 28.1±10.3% in xenon, 28.6±9.9% in isoflurane and to 28.5±5.4% in IPC hearts. Both, calphostin C and SB203580, abolished the observed cardioprotection after xenon and isoflurane administration but not after IPC. Immunofluorescence staining and Western blot assay revealed an increased phosphorylation and translocation of PKC-ɛ in xenon treated hearts. This effect could be blocked by calphostin C but not by SB203580. Moreover, the phosphorylation of p38 MAPK was induced by xenon and this effect was blocked by calphostin C. In summary, we demonstrate that xenon induces cardioprotection by PC and that activation of PKC-ɛ and its downstream target p38 MAPK are central molecular mechanisms involved. Thus, the results of the present study may contribute to elucidate the beneficial cardioprotective effects of this anesthetic gas. PMID:15644876

Sensor for oxygen-combustibles gas mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Isenberg, A.O.

1981-08-25

A molten carbonate electrochemical cell is described which operates at a temperature between 400/sup 0/ and 700/sup 0/ C. It used to remove O/sub 2/ in combination with CO/sub 2/ from an oxygen/combustibles gas mixture to provide a low temperature measurement of the oxygen content of the gas mixture.

Xenon Fractionation and Archean Hydrogen Escape

NASA Technical Reports Server (NTRS)

Zahnle, K. J.

2015-01-01

Xenon is the heaviest gas found in significant quantities in natural planetary atmospheres. It would seem the least likely to escape. Yet there is more evidence for xenon escape from Earth than for any element other than helium and perhaps neon. The most straightforward evidence is that most of the radiogenic Xe from the decay of (129)I (half-life 15.7 Myr) and (244)Pu (half-life 81 Myr) that is Earth's birthright is missing. The missing xenon is often attributed to the impact erosion of early atmospheres of Earth and its ancestors. It is obvious that if most of the radiogenic xenon were driven off by impacts, most of the rest of the atmophiles fared the same fate. The other line of evidence is in the nonradiogenic isotopes of xenon and its silent partner, krypton. Atmospheric xenon is strongly mass fractionated (at about 4% per amu) compared to any known solar system source (Figure 1). This is in stark contrast to krypton, which may not be fractionated at all: atmospheric Kr is slightly heavier than solar Kr (at about 0.5% per amu), but it is the same as in carbonaceous chondrites. Nonradiogenic xenon is also under abundant relative to krypton (the so-called "missing xenon" problem). Together these observations imply that xenon has been subject to fractionating escape and krypton not.

Anticonvulsant effect of xenon on neonatal asphyxial seizures.

PubMed

Azzopardi, Denis; Robertson, Nicola J; Kapetanakis, Andrew; Griffiths, James; Rennie, Janet M; Mathieson, Sean R; Edwards, A David

2013-09-01

Xenon, a monoatomic gas with very high tissue solubility, is a non-competitive inhibitor of N-methyl-D-aspartate (NMDA) glutamate receptor, has antiapoptotic effects and is neuroprotective following hypoxic ischaemic injury in animals. Xenon may be expected to have anticonvulsant effects through glutamate receptor blockade, but this has not previously been demonstrated clinically. We examined seizure activity on the real time and amplitude integrated EEG records of 14 full-term infants with perinatal asphyxial encephalopathy treated within 12 h of birth with 30% inhaled xenon for 24 h combined with 72 h of moderate systemic hypothermia. Seizures were identified on 5 of 14 infants. Seizures stopped during xenon therapy but recurred within a few minutes of withdrawing xenon and stopped again after xenon was restarted. Our data show that subanaesthetic levels of xenon may have an anticonvulsant effect. Inhaled xenon may be a valuable new therapy in this hard-to-treat population.

The Genesis solar xenon composition and its relationship to planetary xenon signatures

NASA Astrophysics Data System (ADS)

Crowther, S. A.; Gilmour, J. D.

2013-12-01

The fluence and isotopic composition of solar wind xenon have been determined from silicon collector targets flown on the NASA Genesis mission. A protocol was developed to extract gas quantitatively from samples of ∼9-25 mm2, and xenon measured using the RELAX mass spectrometer. The fluence of implanted solar wind xenon is 1.202(87) × 106 atoms 132Xe cm-2, which equates to a flux of 5.14(21) × 106 atoms 132Xe cm-2 year-1 at the L1 point. This value is in good agreement with those reported in other studies. The isotopic composition of the solar wind is consistent with that extracted from the young lunar regolith and other Genesis collector targets. The more precise xenon isotopic data derived from the Genesis mission confirm models of relationships among planetary xenon signatures. The underlying composition of Xe-Q is mass fractionated solar wind; small, varying contributions of Xe-HL and 129Xe from 129I decay are present in reported meteorite analyses. In contrast, an s-process deficit is apparent in Xe-P3, which appears to have been mass fractionated to the same extent as Xe-Q from a precursor composition, suggesting similar trapping mechanisms. Solar wind xenon later evolved by the addition of ∼1% (at 132Xe) of s-process xenon to this precursor. As an alternative model to a single source reservoir for Xe-P3, we propose that trapping of xenon onto carbonaceous carriers has been an ongoing process across galactic history, and that preparation of the residues in which Xe-P3 has been identified preferentially preserves longer lived host phases; a higher proportion of these sample xenon isotopic compositions from earlier in galactic chemical evolution, allowing the s-process deficit to become apparent. The relationships among SW-Xe, Xe-Q and Xe-P3 predict that the 124Xe/132Xe ratio for the solar wind is 0.00481(6).

Xenon elimination kinetics following brief exposure.

PubMed

Schaefer, Maximilian S; Piper, Thomas; Geyer, Hans; Schneemann, Julia; Neukirchen, Martin; Thevis, Mario; Kienbaum, Peter

2017-05-01

Xenon is a modern inhalative anaesthetic with a very low solubility in tissues providing rapid elimination and weaning from anaesthesia. Besides its anaesthetic properties, Xenon promotes the endogenous erythropoietin biosynthesis and thus has been enlisted as prohibited substance by the World Anti-Doping Agency (WADA). For effective doping controls, knowledge about the elimination kinetics of Xenon and the duration of traceability are of particular importance. Seventy-seven full blood samples were obtained from 7 normal weight patients undergoing routine Xenon-based general anaesthesia with a targeted inspiratory concentration of 60% Xenon in oxygen. Samples were taken before and during Xenon inhalation as well as one, two, 4, 8, 16, 24, 32, 40, and 48 h after exposure. Xenon concentrations were assessed in full blood by gas chromatography and triple quadrupole tandem mass spectrometry with a detection limit of 0.25 µmol/L. The elimination of Xenon was characterized by linear regression of log-transformed Xenon blood concentrations, as well as non-linear regression. Xenon exposure yielded maximum concentrations in arterial blood of 1.3 [1.1; 1.6] mmol/L. Xenon was traceable for 24 to 48 h. The elimination profile was characterized by a biphasic pattern with a rapid alpha phase, followed by a slower beta phase showing a first order kinetics (c[Xe] = 69.1e -0.26x , R 2  = 0.83, t 1/2  = 2.7 h). Time in hours after exposure could be estimated by 50*ln(1.39/c[Xe] 0.077 ). Xenon's elimination kinetics is biphasic with a delayed beta phase following a first order kinetics. Xenon can reliably be detected for at least 24 h after brief exposure. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Online ^{222}Rn removal by cryogenic distillation in the XENON100 experiment

NASA Astrophysics Data System (ADS)

Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Arneodo, F.; Barrow, P.; Baudis, L.; Bauermeister, B.; Benabderrahmane, M. L.; Berger, T.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cervantes, M.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; Gangi, P. Di; Giovanni, A. Di; Diglio, S.; Duchovni, E.; Eurin, G.; Fei, J.; Ferella, A. D.; Fieguth, A.; Franco, D.; Fulgione, W.; Gallo Rosso, A.; Galloway, M.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Grandi, L.; Greene, Z.; Grignon, C.; Hasterok, C.; Hogenbirk, E.; Itay, R.; Kaminsky, B.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Lellouch, D.; Levinson, L.; Calloch, M. Le; Lin, Q.; Lindemann, S.; Lindner, M.; Lopes, J. A. M.; Manfredini, A.; Maris, I.; Undagoitia, T. Marrodán; Masbou, J.; Massoli, F. V.; Masson, D.; Mayani, D.; Meng, Y.; Messina, M.; Micheneau, K.; Miguez, B.; Molinario, A.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Orrigo, S. E. A.; Pakarha, P.; Pelssers, B.; Persiani, R.; Piastra, F.; Pienaar, J.; Piro, M.-C.; Pizzella, V.; Plante, G.; Priel, N.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; Rupp, N.; Saldanha, R.; dos Santos, J. M. F.; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schreiner, J.; Schumann, M.; Lavina, L. Scotto; Selvi, M.; Shagin, P.; Shockley, E.; Silva, M.; Simgen, H.; Sivers, M. v.; Stein, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Upole, N.; Wang, H.; Wei, Y.; Weinheimer, C.; Wulf, J.; Ye, J.; Zhang, Y.; Cristescu, I.

2017-06-01

We describe the purification of xenon from traces of the radioactive noble gas radon using a cryogenic distillation column. The distillation column was integrated into the gas purification loop of the XENON100 detector for online radon removal. This enabled us to significantly reduce the constant ^{222}Rn background originating from radon emanation. After inserting an auxiliary ^{222}Rn emanation source in the gas loop, we determined a radon reduction factor of R > 27 (95% C.L.) for the distillation column by monitoring the ^{222}Rn activity concentration inside the XENON100 detector.

Characterization of Nuclear Recoils in High Pressure Xenon Gas: Towards a Simultaneous Search for WIMP Dark Matter and Neutrinoless Double Beta Decay

DOE PAGES

Renner, J.; Gehman, V. M.; Goldschmidt, A.; ...

2015-03-24

Xenon has recently been the medium of choice in several large scale detectors searching for WIMP dark matter and neutrinoless double beta decay. Though present-day large scale experiments use liquid xenon, the gas phase offers advantages favorable to both types of searches such as improved intrinsic energy resolution and fewer fluctuations in the partition of deposited energy between scintillation and ionization channels. We recently constructed a high pressure xenon gas TPC as a prototype for the NEXT (Neutrino Experiment with a Xenon TPC) neutrinoless double beta decay experiment and have demonstrated the feasibility of 0.5% FWHM energy resolution at themore » 136Xe double beta Q-value with 3-D tracking capabilities. We now present results from this prototype on the simultaneous observation of scintillation and ionization produced by nuclear recoils at approximately 14 bar pressure. The recoils were produced by neutrons of approximately 2-6 MeV emitted from a radioisotope plutonium-beryllium source, and primary scintillation (S1) and electroluminescent photons produced by ionization (S2) were observed. We discuss the potential of gaseous xenon to distinguish between electron and nuclear recoils through the ratio of these two signals S2/S1. From these results combined with the possibility of using columnar recombination to sense nuclear recoil directionality at high pressures we envision a dual-purpose, ton-scale gaseous xenon detector capable of a combined search for WIMP dark matter and neutrinoless double beta decay. This work has been performed within the context of the NEXT collaboration.« less

Mixture optimization for mixed gas Joule-Thomson cycle

NASA Astrophysics Data System (ADS)

Detlor, J.; Pfotenhauer, J.; Nellis, G.

2017-12-01

An appropriate gas mixture can provide lower temperatures and higher cooling power when used in a Joule-Thomson (JT) cycle than is possible with a pure fluid. However, selecting gas mixtures to meet specific cooling loads and cycle parameters is a challenging design problem. This study focuses on the development of a computational tool to optimize gas mixture compositions for specific operating parameters. This study expands on prior research by exploring higher heat rejection temperatures and lower pressure ratios. A mixture optimization model has been developed which determines an optimal three-component mixture based on the analysis of the maximum value of the minimum value of isothermal enthalpy change, ΔhT , that occurs over the temperature range. This allows optimal mixture compositions to be determined for a mixed gas JT system with load temperatures down to 110 K and supply temperatures above room temperature for pressure ratios as small as 3:1. The mixture optimization model has been paired with a separate evaluation of the percent of the heat exchanger that exists in a two-phase range in order to begin the process of selecting a mixture for experimental investigation.

The narrow pulse approximation and long length scale determination in xenon gas diffusion NMR studies of model porous media

NASA Technical Reports Server (NTRS)

Mair, R. W.; Sen, P. N.; Hurlimann, M. D.; Patz, S.; Cory, D. G.; Walsworth, R. L.

2002-01-01

We report a systematic study of xenon gas diffusion NMR in simple model porous media, random packs of mono-sized glass beads, and focus on three specific areas peculiar to gas-phase diffusion. These topics are: (i) diffusion of spins on the order of the pore dimensions during the application of the diffusion encoding gradient pulses in a PGSE experiment (breakdown of the narrow pulse approximation and imperfect background gradient cancellation), (ii) the ability to derive long length scale structural information, and (iii) effects of finite sample size. We find that the time-dependent diffusion coefficient, D(t), of the imbibed xenon gas at short diffusion times in small beads is significantly affected by the gas pressure. In particular, as expected, we find smaller deviations between measured D(t) and theoretical predictions as the gas pressure is increased, resulting from reduced diffusion during the application of the gradient pulse. The deviations are then completely removed when water D(t) is observed in the same samples. The use of gas also allows us to probe D(t) over a wide range of length scales and observe the long time asymptotic limit which is proportional to the inverse tortuosity of the sample, as well as the diffusion distance where this limit takes effect (approximately 1-1.5 bead diameters). The Pade approximation can be used as a reference for expected xenon D(t) data between the short and the long time limits, allowing us to explore deviations from the expected behavior at intermediate times as a result of finite sample size effects. Finally, the application of the Pade interpolation between the long and the short time asymptotic limits yields a fitted length scale (the Pade length), which is found to be approximately 0.13b for all bead packs, where b is the bead diameter. c. 2002 Elsevier Sciences (USA).

The narrow pulse approximation and long length scale determination in xenon gas diffusion NMR studies of model porous media.

PubMed

Mair, R W; Sen, P N; Hürlimann, M D; Patz, S; Cory, D G; Walsworth, R L

2002-06-01

We report a systematic study of xenon gas diffusion NMR in simple model porous media, random packs of mono-sized glass beads, and focus on three specific areas peculiar to gas-phase diffusion. These topics are: (i) diffusion of spins on the order of the pore dimensions during the application of the diffusion encoding gradient pulses in a PGSE experiment (breakdown of the narrow pulse approximation and imperfect background gradient cancellation), (ii) the ability to derive long length scale structural information, and (iii) effects of finite sample size. We find that the time-dependent diffusion coefficient, D(t), of the imbibed xenon gas at short diffusion times in small beads is significantly affected by the gas pressure. In particular, as expected, we find smaller deviations between measured D(t) and theoretical predictions as the gas pressure is increased, resulting from reduced diffusion during the application of the gradient pulse. The deviations are then completely removed when water D(t) is observed in the same samples. The use of gas also allows us to probe D(t) over a wide range of length scales and observe the long time asymptotic limit which is proportional to the inverse tortuosity of the sample, as well as the diffusion distance where this limit takes effect (approximately 1-1.5 bead diameters). The Padé approximation can be used as a reference for expected xenon D(t) data between the short and the long time limits, allowing us to explore deviations from the expected behavior at intermediate times as a result of finite sample size effects. Finally, the application of the Padé interpolation between the long and the short time asymptotic limits yields a fitted length scale (the Padé length), which is found to be approximately 0.13b for all bead packs, where b is the bead diameter. c. 2002 Elsevier Sciences (USA).

A Decade of Xenon Chemistry

ERIC Educational Resources Information Center

Moody, G. J.

1974-01-01

Presents reactions for the formation of xenon compounds and compounds of the other inert gases. Provides bonding and structure theories for noble gas compounds and speculates on possible applications. (GS)

Critical Viscosity of Xenon

NASA Technical Reports Server (NTRS)

2001-01-01

The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2001 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The thermostat for CVX sits inside the white cylinder on a support structure that is placed inside a pressure canister. A similar canister holds the electronics and control systems. The CVX-2 arrangement is identical. The principal investigator is Dr. Robert F. Berg (not shown) of the National Institutes of Standards and Technology, Gaithersburg, MD. This is a detail view of MSFC 0100143.

Devices for the Production of Reference Gas Mixtures.

PubMed

Fijało, Cyprian; Dymerski, Tomasz; Gębicki, Jacek; Namieśnik, Jacek

2016-09-02

For many years there has been growing demand for gaseous reference materials, which is connected with development in many fields of science and technology. As a result, new methodological and instrumental solutions appear that can be used for this purpose. Appropriate quality assurance/quality control (QA/QC) must be used to make sure that measurement data are a reliable source of information. Reference materials are a significant element of such systems. In the case of gas samples, such materials are generally called reference gas mixtures. This article presents the application and classification of reference gas mixtures, which are a specific type of reference materials, and the methods for obtaining them are described. Construction solutions of devices for the production of reference gas mixtures are detailed, and a description of a prototype device for dynamic production of reference gas mixtures containing aroma compounds is presented.

Cryogenic system with GM cryocooler for krypton, xenon separation from hydrogen-helium purge gas

NASA Astrophysics Data System (ADS)

Chu, X. X.; Zhang, M. M.; Zhang, D. X.; Xu, D.; Qian, Y.; Liu, W.

2014-01-01

In the thorium molten salt reactor (TMSR), fission products such as krypton, xenon and tritium will be produced continuously in the process of nuclear fission reaction. A cryogenic system with a two stage GM cryocooler was designed to separate Kr, Xe, and H2 from helium purge gas. The temperatures of two stage heat exchanger condensation tanks were maintained at about 38 K and 4.5 K, respectively. The main fluid parameters of heat transfer were confirmed, and the structural heat exchanger equipment and cold box were designed. Designed concentrations after cryogenic separation of Kr, Xe and H2 in helium recycle gas are less than 1 ppb.

Chromatographic separation of radioactive noble gases from xenon

NASA Astrophysics Data System (ADS)

Akerib, D. S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Bramante, R.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chiller, A. A.; Chiller, C.; Coffey, T.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Ihm, M.; Jacobsen, R. G.; Ji, W.; Kamdin, K.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Palladino, K. J.; Pease, E. K.; Pech, K.; Phelps, P.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Yazdani, K.; Young, S. K.; Zhang, C.

2018-01-01

The Large Underground Xenon (LUX) experiment operates at the Sanford Underground Research Facility to detect nuclear recoils from the hypothetical Weakly Interacting Massive Particles (WIMPs) on a liquid xenon target. Liquid xenon typically contains trace amounts of the noble radioactive isotopes 85Kr and 39Ar that are not removed by the in situ gas purification system. The decays of these isotopes at concentrations typical of research-grade xenon would be a dominant background for a WIMP search experiment. To remove these impurities from the liquid xenon, a chromatographic separation system based on adsorption on activated charcoal was built. 400 kg of xenon was processed, reducing the average concentration of krypton from 130 ppb to 3.5 ppt as measured by a cold-trap assisted mass spectroscopy system. A 50 kg batch spiked to 0.001 g/g of krypton was processed twice and reduced to an upper limit of 0.2 ppt.

Chromatographic separation of radioactive noble gases from xenon

DOE PAGES

Akerib, DS; Araújo, HM; Bai, X; ...

2017-10-31

The Large Underground Xenon (LUX) experiment operates at the Sanford Underground Research Facility to detect nuclear recoils from the hypothetical Weakly Interacting Massive Particles (WIMPs) on a liquid xenon target. Liquid xenon typically contains trace amounts of the noble radioactive isotopesmore » $$^{85}$$Kr and $$^{39}$$Ar that are not removed by the in situ gas purification system. The decays of these isotopes at concentrations typical of research-grade xenon would be a dominant background for a WIMP search exmperiment. To remove these impurities from the liquid xenon, a chromatographic separation system based on adsorption on activated charcoal was built. 400 kg of xenon was processed, reducing the average concentration of krypton from 130 ppb to 3.5 ppt as measured by a cold-trap assisted mass spectroscopy system. A 50 kg batch spiked to 0.001 g/g of krypton was processed twice and reduced to an upper limit of 0.2 ppt.« less

Measuring and Modeling Xenon Uptake in Plastic Beta-Cells

NASA Astrophysics Data System (ADS)

Suarez, R.; Hayes, J. C.; Harper, W. W.; Humble, P.; Ripplinger, M. D.; Stephenson, D. E.; Williams, R. M.

2013-12-01

The precision of the stable xenon volume measurement in atmospheric monitoring radio-xenon systems is a critical parameter used to determine the activity concentration of a radio-xenon sample. Typically these types of systems use a plastic scintillating beta-cell as part of a beta-gamma detection scheme to measure the radioactivity present in the gas sample. Challenges arise when performing the stable xenon calculation during or after radioactive counting of the sample due to xenon uptake into the plastic beta-cells. Plastic beta cells can adsorb as much as 5% of the sample during counting. If quantification is performed after counting, the uptake of xenon into the plastic results in an underestimation of the xenon volume measurement. This behavior also causes what is typically known as 'memory effect' in the cell. Experiments were conducted using a small volume low pressure range thermal conductivity sensor to quantify the amount of xenon uptake into the cell over a given period of time. Understanding the xenon uptake in the cell provides a better estimate of the stable volume which improves the overall measurement capability of the system. The results from these experiments along with modeling will be presented.

SPALAX new generation: New process design for a more efficient xenon production system for the CTBT noble gas network.

PubMed

Topin, Sylvain; Greau, Claire; Deliere, Ludovic; Hovesepian, Alexandre; Taffary, Thomas; Le Petit, Gilbert; Douysset, Guilhem; Moulin, Christophe

2015-11-01

The SPALAX (Système de Prélèvement Automatique en Ligne avec l'Analyse du Xénon) is one of the systems used in the International Monitoring System of the Comprehensive Nuclear Test Ban Treaty (CTBT) to detect radioactive xenon releases following a nuclear explosion. Approximately 10 years after the industrialization of the first system, the CEA has developed the SPALAX New Generation, SPALAX-NG, with the aim of increasing the global sensitivity and reducing the overall size of the system. A major breakthrough has been obtained by improving the sampling stage and the purification/concentration stage. The sampling stage evolution consists of increasing the sampling capacity and improving the gas treatment efficiency across new permeation membranes, leading to an increase in the xenon production capacity by a factor of 2-3. The purification/concentration stage evolution consists of using a new adsorbent Ag@ZSM-5 (or Ag-PZ2-25) with a much larger xenon retention capacity than activated charcoal, enabling a significant reduction in the overall size of this stage. The energy consumption of the system is similar to that of the current SPALAX system. The SPALAX-NG process is able to produce samples of almost 7 cm(3) of xenon every 12 h, making it the most productive xenon process among the IMS systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Inferential determination of various properties of a gas mixture

DOEpatents

Morrow, Thomas B.; Behring, II, Kendricks A.

2007-03-27

Methods for inferentially determining various properties of a gas mixture, when the speed of sound in the gas is known at an arbitrary temperature and pressure. The method can be applied to natural gas mixtures, where the known parameters are the sound speed, temperature, pressure, and concentrations of any dilute components of the gas. The method uses a set of reference gases and their calculated density and speed of sound values to estimate the density of the subject gas. Additional calculations can be made to estimate the molecular weight of the subject gas, which can then be used as the basis for heating value calculations. The method may also be applied to inferentially determine density and molecular weight for gas mixtures other than natural gases.

Cryogenic system with GM cryocooler for krypton, xenon separation from hydrogen-helium purge gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chu, X. X.; Zhang, D. X.; Qian, Y.

2014-01-29

In the thorium molten salt reactor (TMSR), fission products such as krypton, xenon and tritium will be produced continuously in the process of nuclear fission reaction. A cryogenic system with a two stage GM cryocooler was designed to separate Kr, Xe, and H{sub 2} from helium purge gas. The temperatures of two stage heat exchanger condensation tanks were maintained at about 38 K and 4.5 K, respectively. The main fluid parameters of heat transfer were confirmed, and the structural heat exchanger equipment and cold box were designed. Designed concentrations after cryogenic separation of Kr, Xe and H{sub 2} in heliummore » recycle gas are less than 1 ppb.« less

Ethane and Xenon mixing: density functional theory (DFT) simulations and experiments on Sandia's Z machine

NASA Astrophysics Data System (ADS)

Magyar, Rudolph; Root, Seth; Mattsson, Thomas; Cochrane, Kyle

2012-02-01

The combination of ethane and xenon is one of the simplest binary mixtures in which bond breaking is expected to play a role under shock conditions. At cryogenic conditions, xenon is often understood to mix with alkanes such as Ethane as if it were also an alkane, but this model is expected to break down at higher temperatures and pressures. To investigate the breakdown, we have performed density functional theory (DFT) calculations on several xenon/ethane mixtures. Additionally, we have performed shock compression experiments on Xenon-Ethane using the Sandia Z - accelerator. The DFT and experimental results are compared to hydrodynamic simulations using different mixing models in the equation of state. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of the Lockheed Martin company, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Critical Viscosity of Xenon team

NASA Technical Reports Server (NTRS)

2001-01-01

The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The thermostat for CVX sits inside the white cylinder on a support structure (at left) that is placed inside a pressure canister. A similar canister (right) holds the electronics and control systems. The CVX-2 arrangement is identical. The principal investigator is Dr. Robert F. Berg (left) of the National Institutes of Standards and Technology, Gaithersburg, MD.

Critical Viscosity of Xenon team

NASA Technical Reports Server (NTRS)

2001-01-01

The Critical Viscosity of Xenon Experiment (CVX-2) on the STS-107 Research 1 mission in 2002 will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. The thermostat for CVX sits inside the white cylinder on a support structure (at left) that is placed inside a pressure canister. A similar canister (right) holds the electronics and control systems. The CVX-2 arrangement is identical. The principal investigator is Dr. Robert F. Berg (not shown) of the National Institutes of Standards and Technology, Gaithersburg, MD.

Solid Xenon Project

NASA Astrophysics Data System (ADS)

Balakishiyeva, Durdana N.; Mahapatra, Rupak; Saab, Tarek; Yoo, Jonghee

2010-08-01

Crystals like Germanium and Silicon need to be grown in specialized facilities which is time and money costly. It takes many runs to test the detector once it's manufactured and mishaps are very probable. It is of a great challenge to grow big germanium crystals and that's why stacking them up in a tower is the only way at the moment to increase testing mass. Liquid Noble gas experiments experiencing contamination problems, their predicted energy resolution at 10 keV and lower energy range is not as good as predicted. Every experiment is targeting one specific purpose, looking for one thing. Why not to design an experiment that is diverse and build a detector that can search for Dark Matter, Solar Axions, Neutrinoless Double Beta decay, etc. Solid Xenon detector is such detector. We designed a simple Xenon crystal growing chamber that was put together at Fermi National Accelerator Laboratory. The first phase of this experiment was to demonstrate that a good, crack free Xenon crystal can be grown (regardless of many failed attempts by various groups) and our first goal, 1 kg crystal, was successful.

Corona inception voltage in statorettes with various gas-solid dielectric systems

NASA Technical Reports Server (NTRS)

Bollenbacher, G.; Kempke, E. E., Jr.

1972-01-01

Corona inception voltage was calculated and measured for three statorettes in several gases and gas mixtures at pressures from 50.8 to 1270 torr. In helium the corona inception voltage was lowest, and in air it was highest. In argon and mixtures of helium and xenon the corona inception voltage was between that of air and helium. Correlation between experimental and calculated data was good.

Noble Gas Xenon Is a Novel Adenosine Triphosphate-sensitive Potassium Channel Opener

PubMed Central

Bantel, Carsten; Maze, Mervyn; Trapp, Stefan

2010-01-01

Background Adenosine triphosphate-sensitive potassium (KATP) channels in brain are involved in neuroprotective mechanisms. Pharmacologic activation of these channels is seen as beneficial, but clinical exploitation by using classic K+ channel openers is hampered by their inability to cross the blood–brain barrier. This is different with the inhalational anesthetic xenon, which recently has been suggested to activate KATP channels; it partitions freely into the brain. Methods To evaluate the type and mechanism of interaction of xenon with neuronal-type KATP channels, these channels, consisting of Kir6.2 pore-forming subunits and sulfonylurea receptor-1 regulatory subunits, were expressed in HEK293 cells and whole cell, and excised patch-clamp recordings were performed. Results Xenon, in contrast to classic KATP channel openers, acted directly on the Kir6.2 subunit of the channel. It had no effect on the closely related, adenosine triphosphate (ATP)-regulated Kir1.1 channel and failed to activate an ATP-insensitive mutant version of Kir6.2. Furthermore, concentration–inhibition curves for ATP obtained from inside-out patches in the absence or presence of 80% xenon revealed that xenon reduced the sensitivity of the KATP channel to ATP. This was reflected in an approximately fourfold shift of the concentration causing half-maximal inhibition (IC50) from 26 ± 4 to 96 ± 6 μm. Conclusions Xenon represents a novel KATP channel opener that increases KATP currents independently of the sulfonylurea receptor-1 subunit by reducing ATP inhibition of the channel. Through this action and by its ability to readily partition across the blood–brain barrier, xenon has considerable potential in clinical settings of neuronal injury, including stroke. PMID:20179498

Xenon Blocks Neuronal Injury Associated with Decompression

PubMed Central

Blatteau, Jean-Eric; David, Hélène N.; Vallée, Nicolas; Meckler, Cedric; Demaistre, Sebastien; Lambrechts, Kate; Risso, Jean-Jacques; Abraini, Jacques H.

2015-01-01

Despite state-of-the-art hyperbaric oxygen (HBO) treatment, about 30% of patients suffering neurologic decompression sickness (DCS) exhibit incomplete recovery. Since the mechanisms of neurologic DCS involve ischemic processes which result in excitotoxicity, it is likely that HBO in combination with an anti-excitotoxic treatment would improve the outcome in patients being treated for DCS. Therefore, in the present study, we investigated the effect of the noble gas xenon in an ex vivo model of neurologic DCS. Xenon has been shown to provide neuroprotection in multiple models of acute ischemic insults. Fast decompression compared to slow decompression induced an increase in lactate dehydrogenase (LDH), a well-known marker of sub-lethal cell injury. Post-decompression administration of xenon blocked the increase in LDH release induced by fast decompression. These data suggest that xenon could be an efficient additional treatment to HBO for the treatment of neurologic DCS. PMID:26469983

Xenon Blocks Neuronal Injury Associated with Decompression.

PubMed

Blatteau, Jean-Eric; David, Hélène N; Vallée, Nicolas; Meckler, Cedric; Demaistre, Sebastien; Lambrechts, Kate; Risso, Jean-Jacques; Abraini, Jacques H

2015-10-15

Despite state-of-the-art hyperbaric oxygen (HBO) treatment, about 30% of patients suffering neurologic decompression sickness (DCS) exhibit incomplete recovery. Since the mechanisms of neurologic DCS involve ischemic processes which result in excitotoxicity, it is likely that HBO in combination with an anti-excitotoxic treatment would improve the outcome in patients being treated for DCS. Therefore, in the present study, we investigated the effect of the noble gas xenon in an ex vivo model of neurologic DCS. Xenon has been shown to provide neuroprotection in multiple models of acute ischemic insults. Fast decompression compared to slow decompression induced an increase in lactate dehydrogenase (LDH), a well-known marker of sub-lethal cell injury. Post-decompression administration of xenon blocked the increase in LDH release induced by fast decompression. These data suggest that xenon could be an efficient additional treatment to HBO for the treatment of neurologic DCS.

The Xenon record of Earth's early differentiaiton

NASA Astrophysics Data System (ADS)

Peto, M. K.; Mukhopadhyay, S.; Kelley, K. A.

2011-12-01

Xenon isotopes in mantle derived rocks provide information on the early differentiation of the silicate mantle of our planet. {131,132 134,136}Xe isotopes are produced by the spontaneous fission of two different elements: the now extinct radionuclide 244Pu, and the long-lived 238U. These two parent nuclides, however, yield rather different proportion of fissiogenic Xenon isotopes. Hence, the proportion of Pu- to U-derived fission xenon is indicative of the degree and rate of outgassing of a mantle reservoir. Recent data obtained from Iceland in our lab confirm that the Xenon isotopic composition of the plume source(s) is characterized by lower 136Xe/130Xe ratios than the MORB source and the Iceland plume is more enriched in the Pu-derived Xenon component. These features are interpreted as reflecting different degrees of outgassing and appear not to be the result of preferential recycling of Xenon to the deep mantle. To further investigate how representative the Icelandic measurements might be of other mantle plumes, we measured noble gases (He, Ne, Ar, Xe) in gas-rich basalt glasses from the Rochambeau Ridge (RR) in the Northern Lau Basin. Recent work suggests the presence of a "Samoan-like" OIB source in the northern Lau Basin and our measurements were performed on samples with plume-like 3He/4He ratios (15-28 RA) [1]. The Xenon isotopic measurements indicate that the maximum measured 136Xe/130Xe ratios in the Rochambeau samples are similar to Iceland. In particular, for one of the gas rich samples we were able to obtain 77 different isotopic measurements through step-crushing. Preliminary investigation of this sample suggests higher Pu- to U-derived fission Xenon than in MORBs. To quantitatively evaluate the degree and rate of outgassing of the plume and MORB reservoirs, particularly during the first few hundred million years of Earth's history, we have modified a geochemical reservoir model that was previously developed to investigate mantle overturn and mixing

Measurements and modeling of charge carrier lifetime in compressed xenon

NASA Astrophysics Data System (ADS)

Pudov, A. O.; Abyzov, A. S.; Sokolov, S. A.; Davydov, L. N.; Rybka, A. V.; Kutny, V. E.; Melnikov, S. I.; Kholomyeyev, G. A.; Leonov, S. A.; Turchin, A. A.

2018-06-01

Gamma-spectrometers based on high-pressure xenon gas (HPXe) are proving themselves as a great potential alternative to the spectrometers based on high-purity germanium crystals and scintillators. The working medium for the high-resolution HPXe detectors, that is, xenon gas compressed up to pressure ∼50 bar and sometimes doped with hydrogen, methane or others gases, needs to be of very high purity. The gas purity level can be determined by direct measurements or, alternatively, its usability in gamma-spectrometers can be evaluated indirectly through the charge carrier (electron) lifetime measurements. Different approaches and specific setups have been used for the lifetime determination, most of those methods involve the measurement and analyses of individual pulses from ionizing particles registered in an ionization chamber filled with Xe. In the present paper, we report on the HPXe electron lifetime study carried out by using measurements in a cylindrical ionization chamber and the respective analytical charge transport model. Our results support the possibility of carrier lifetime determination in the cylindrical configuration. In addition, the voltage regimes for the use of the chamber in the spectroscopic mode were determined. The measurements were conducted in a two-electrode configuration for a range of pressure values (5 to 50 bar) for the Xe+0.25%H2 gas mixture of ∼6N purity. It is shown that in gases with relatively high values of the electron drift velocity and the electron lifetime, for example low-density gases, the charge collection time measurements can give significantly underestimated lifetime assessment. On the other hand, for the low drift velocity gases, they give much more accurate results. With the use of the analytical model, the electron lifetime was determined more precisely.

Hyperpolarized xenon-129 production and applications

NASA Astrophysics Data System (ADS)

Ruset, Iulian C.

Hyperpolarized 3He and 129Xe were initially developed and used in the nuclear physics community. Lately they are primarily used in Medical Resonance Imaging (MRI). Although first MRI polarized gas images were acquired using 129Xe, the research community has focused mostly on 3He, due to the well-known polarizing methods and higher polarization numbers achieved. The main purpose of this thesis is to present a novel design of a large-scale SEOP polarizer for producing large quantities of highly polarized 129Xe. High Rb-Xe spin-exchange rates through long-lived van de Waals molecules at low total pressure, implemented in a novel counterflow polarizer design, resulted in xenon polarization as high as 50% for 1.2 liters/hour, with a maximum of 64% for 0.3 l/h. We characterized and improved the polarization process by finding the optimum operating parameters of the polarizer. Two new methods to efficiently use high-power diode lasers are described: a new optical arrangement for a better beam shaping of fiber coupled lasers and the first external-cavity spectrum narrowing of a stack of laser diode arrays. A new accumulation technique for the hyperpolarized xenon was developed and full recovery of polarization after a freeze-thaw cycle was demonstrated for the first time. Two approaches for xenon delivery, frozen and gas states, were developed. Hyperpolarized xenon transportation to Brigham and Women's Hospital was successfully accomplished for collaborative research. First MRI images using hyperpolarized xenon acquired at BWH are presented. Final chapter is focused on describing a low field human MRI scanner using hyperpolarized 3He. We built a human scale imager with open access for orientational studies of the lung functionality. Horizontal and vertical human lung images were acquired as a first stage of this project.

Hyperpolarized Xenon-129 Gas-Exchange Imaging of Lung Microstructure: First Case Studies in Subjects with Obstructive Lung Disease

PubMed Central

Dregely, Isabel; Mugler, John P.; Ruset, Iulian C.; Altes, Talissa A.; Mata, Jaime F.; Miller, G. Wilson; Ketel, Jeffrey; Ketel, Steve; Distelbrink, Jan; Hersman, F.W.; Ruppert, Kai

2011-01-01

Purpose To develop and test a method to non-invasively assess the functional lung microstructure. Materials and Methods The Multiple exchange time Xenon polarization Transfer Contrast technique (MXTC) encodes xenon gas-exchange contrast at multiple delay times permitting two lung-function parameters to be derived: 1) MXTC-F, the long exchange-time depolarization value, which is proportional to the tissue to alveolar-volume ratio and 2) MXTC-S, the square root of the xenon exchange-time constant, which characterizes thickness and composition of alveolar septa. Three healthy volunteers, one asthmatic and two COPD (GOLD stage I and II) subjects were imaged with MXTC MRI. In a subset of subjects, hyperpolarized xenon-129 ADC MRI and CT imaging were also performed. Results The MXTC-S parameter was found to be elevated in subjects with lung disease (p-value = 0.018). In the MXTC-F parameter map it was feasible to identify regional loss of functional tissue in a COPD patient. Further, the MXTC-F map showed excellent regional correlation with CT and ADC (ρ ≥ 0.90) in one COPD subject. Conclusion The functional tissue-density parameter MXTC-F showed regional agreement with other imaging techniques. The newly developed parameter MXTC-S, which characterizes the functional thickness of alveolar septa, has potential as a novel biomarker for regional parenchymal inflammation or thickening. PMID:21509861

Ternary gas mixture for diffuse discharge switch

DOEpatents

Christophorou, Loucas G.; Hunter, Scott R.

1988-01-01

A new diffuse discharge gas switch wherein a mixture of gases is used to take advantage of desirable properties of the respective gases. There is a conducting gas, an insulating gas, and a third gas that has low ionization energy resulting in a net increase in the number of electrons available to produce a current.

Internal structure of shock waves in disparate mass mixtures

NASA Technical Reports Server (NTRS)

Chung, Chan-Hong; De Witt, Kenneth J.; Jeng, Duen-Ren; Penko, Paul F.

1992-01-01

The detailed flow structure of a normal shock wave for a gas mixture is investigated using the direct-simulation Monte Carlo method. A variable diameter hard-sphere (VDHS) model is employed to investigate the effect of different viscosity temperature exponents (VTE) for each species in a gas mixture. Special attention is paid to the irregular behavior in the density profiles which was previously observed in a helium-xenon experiment. It is shown that the VTE can have substantial effects in the prediction of the structure of shock waves. The variable hard-sphere model of Bird shows good agreement, but with some limitations, with the experimental data if a common VTE is chosen properly for each case. The VDHS model shows better agreement with the experimental data without adjusting the VTE. The irregular behavior of the light-gas component in shock waves of disparate mass mixtures is observed not only in the density profile, but also in the parallel temperature profile. The strength of the shock wave, the type of molecular interactions, and the mole fraction of heavy species have substantial effects on the existence and structure of the irregularities.

Detonation velocity in poorly mixed gas mixtures

NASA Astrophysics Data System (ADS)

Prokhorov, E. S.

2017-10-01

The technique for computation of the average velocity of plane detonation wave front in poorly mixed mixture of gaseous hydrocarbon fuel and oxygen is proposed. Here it is assumed that along the direction of detonation propagation the chemical composition of the mixture has periodic fluctuations caused, for example, by layered stratification of gas charge. The technique is based on the analysis of functional dependence of ideal (Chapman-Jouget) detonation velocity on mole fraction (with respect to molar concentration) of the fuel. It is shown that the average velocity of detonation can be significantly (by more than 10%) less than the velocity of ideal detonation. The dependence that permits to estimate the degree of mixing of gas mixture basing on the measurements of average detonation velocity is established.

Hugoniot measurements of double-shocked precompressed dense xenon plasmas

NASA Astrophysics Data System (ADS)

Zheng, J.; Chen, Q. F.; Gu, Y. J.; Chen, Z. Y.

2012-12-01

The current partially ionized plasmas models for xenon show substantial differences since the description of pressure and thermal ionization region becomes a formidable task, prompting the need for an improved understanding of dense xenon plasmas behavior at above 100 GPa. We performed double-shock compression experiments on dense xenon to determine accurately the Hugoniot up to 172 GPa using a time-resolved optical radiation method. The planar strong shock wave was produced using a flyer plate impactor accelerated up to ˜6 km/s with a two-stage light-gas gun. The time-resolved optical radiation histories were acquired by using a multiwavelength channel optical transience radiance pyrometer. Shock velocity was measured and mass velocity was determined by the impedance-matching methods. The experimental equation of state of dense xenon plasmas are compared with the self-consistent fluid variational calculations of dense xenon in the region of partial ionization over a wide range of pressures and temperatures.

A dual-phase xenon TPC for scintillation and ionisation yield measurements in liquid xenon

NASA Astrophysics Data System (ADS)

Baudis, Laura; Biondi, Yanina; Capelli, Chiara; Galloway, Michelle; Kazama, Shingo; Kish, Alexander; Pakarha, Payam; Piastra, Francesco; Wulf, Julien

2018-05-01

A small-scale, two-phase (liquid/gas) xenon time projection chamber ( Xurich II) was designed, constructed and is under operation at the University of Zürich. Its main purpose is to investigate the microphysics of particle interactions in liquid xenon at energies below 50 keV, which are relevant for rare event searches using xenon as target material. Here we describe in detail the detector, its associated infrastructure, and the signal identification algorithm developed for processing and analysing the data. We present the first characterisation of the new instrument with calibration data from an internal ^83{m} Kr source. The zero-field light yield is 15.0 and 14.0 photoelectrons/keV at 9.4 and 32.1 keV, respectively, and the corresponding values at an electron drift field of 1 kV/cm are 10.8 and 7.9 photoelectrons/keV. The charge yields at these energies are 28 and 31 electrons/keV, with the proportional scintillation yield of 24 photoelectrons per one electron extracted into the gas phase, and an electron lifetime of 200 μ s. The relative energy resolution, σ /E, is 11.9 and 5.8% at 9.4 and 32.1 keV, respectively using a linear combination of the scintillation and ionisation signals. We conclude with measurements of the electron drift velocity at various electric fields, and compare these to literature values.

Inference and analysis of xenon outflow curves under multi-pulse injection in two-dimensional chromatography.

PubMed

Shu-Jiang, Liu; Zhan-Ying, Chen; Yin-Zhong, Chang; Shi-Lian, Wang; Qi, Li; Yuan-Qing, Fan

2013-10-11

Multidimensional gas chromatography is widely applied to atmospheric xenon monitoring for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). To improve the capability for xenon sampling from the atmosphere, sampling techniques have been investigated in detail. The sampling techniques are designed by xenon outflow curves which are influenced by many factors, and the injecting condition is one of the key factors that could influence the xenon outflow curves. In this paper, the xenon outflow curves of single-pulse injection in two-dimensional gas chromatography has been tested and fitted as a function of exponential modified Gaussian distribution. An inference formula of the xenon outflow curve for six-pulse injection is derived, and the inference formula is also tested to compare with its fitting formula of the xenon outflow curve. As a result, the curves of both the one-pulse and six-pulse injections obey the exponential modified Gaussian distribution when the temperature of the activated carbon column's temperature is 26°C and the flow rate of the carrier gas is 35.6mLmin(-1). The retention time of the xenon peak for one-pulse injection is 215min, and the peak width is 138min. For the six-pulse injection, however, the retention time is delayed to 255min, and the peak width broadens to 222min. According to the inferred formula of the xenon outflow curve for the six-pulse injection, the inferred retention time is 243min, the relative deviation of the retention time is 4.7%, and the inferred peak width is 225min, with a relative deviation of 1.3%. Copyright © 2013 Elsevier B.V. All rights reserved.

On studies of 3He and isobutane mixture as neutron proportional counter gas

NASA Astrophysics Data System (ADS)

Desai, S. S.; Shaikh, A. M.

2006-02-01

The performance of neutron detectors filled with 3He+iC 4H 10 (isobutane) gas mixtures has been studied and compared with the performance of detectors filled with 3He+Kr gas mixtures. The investigations are made to determine suitable concentration of isobutane in the gas mixture to design neutron proportional counters and linear position sensitive neutron detectors (1-D PSDs). Energy resolution, range of proportionality, plateau and gas gain characteristics are studied for various gas mixtures of 3He and isobutane. The values for various gas constants are determined by fitting the gas gains to Diethorn and Bateman's equations and their variation with isobutane concentration in the fill gas mixture is studied.

Novel Sorbent Development and Evaluation for the Capture of Krypton and Xenon from Nuclear Fuel Reprocessing Off-Gas Streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Troy G. Garn; Mitchell R. Greenhalgh; Jack D. Law

2013-10-01

The release of volatile radionuclides generated during Used Nuclear Fuel reprocessing in the US will most certainly need to be controlled to meet US regulatory emission limits. A US DOE sponsored Off-Gas Sigma Team has been tasked with a multi-lab collaborative research and development effort to investigate and evaluate emissions and immobilization control technologies for the volatile radioactive species generated from commercial Used Nuclear Fuel (UNF) Reprocessing. Physical Adsorption technology is a simpler and potential economical alternative to cryogenic distillation processes that can be used for the capture of krypton and xenon and has resulted in a novel composite sorbentmore » development procedure using synthesized mordenite as the active material. Utilizing the sorbent development procedure, INL sigma team members have developed two composite sorbents that have been evaluated for krypton and xenon capacities at ambient and 191 K temperature using numerous test gas compositions. Adsorption isotherms have been generated to predict equilibration and maximum capacities enabling modeling to support process equipment scale-up.« less

Novel Sorbent Development and Evaluation for the Capture of Krypton and Xenon from Nuclear Fuel Reprocessing Off-Gas Streams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Troy G. Garn; Mitchell R. Greenhalgh; Jack D. Law

2013-09-01

The release of volatile radionuclides generated during Used Nuclear Fuel reprocessing in the US will most certainly need to be controlled to meet US regulatory emission limits. A US DOE sponsored Off-Gas Sigma Team has been tasked with a multi-lab collaborative research and development effort to investigate and evaluate emissions and immobilization control technologies for the volatile radioactive species generated from commercial Used Nuclear Fuel (UNF) Reprocessing. Physical Adsorption technology is a simpler and potential economical alternative to cryogenic distillation processes that can be used for the capture of krypton and xenon and has resulted in a novel composite sorbentmore » development procedure using synthesized mordenite as the active material. Utilizing the sorbent development procedure, INL sigma team members have developed two composite sorbents that have been evaluated for krypton and xenon capacities at ambient and 191 K temperature using numerous test gas compositions. Adsorption isotherms have been generated to predict equilibration and maximum capacities enabling modeling to support process equipment scale-up.« less

XENON-133 IN CALIFORNIA, NEVADA, AND UTAH FROM THE CHERNOBYL ACCIDENT (JOURNAL VERSION)

EPA Science Inventory

The accident at the Chernobyl nuclear reactor in the USSR introduced numerous radioactive nuclides into the atmosphere, including the noble gas xenon-133. EPA's Environmental Monitoring Systems Laboratory, Las Vegas, NV, detected xenon-133 from the Chernobyl accident in air sampl...

Heat capacity of xenon adsorbed on nanobundle grooves

NASA Astrophysics Data System (ADS)

Chishko, K. A.; Sokolova, E. S.

2016-02-01

A model of a one-dimensional nonideal gas in an external transverse force field is used to interpret the experimentally observed thermodynamic properties of xenon deposited in grooves on the surface of carbon nanobundles. A nonideal gas model with pairwise interactions is not entirely adequate for describing dense adsorbates (at low temperatures), but makes it easy to account for the exchange of particles between the 1D adsorbate and the 3D atmosphere, which is an important factor at intermediate (on the order of 35 K for xenon) and, especially, high (˜100 K) temperatures. In this paper, we examine a 1D real gas taking only the one-dimensional Lennard-Jones interaction into account, but under exact equilibrium with respect to the number of particles between the 1D adsorbate and the 3D atmosphere of the measurement cell. The low-temperature branch of the specific heat is fitted independently by an elastic chain model so as to obtain the best agreement between theory and experiment over the widest possible region, beginning at zero temperature. The gas approximation sets in after temperatures for which the phonon specific heat of the chain essentially transforms to a one-dimensional equipartition law. Here the basic parameters of both models can be chosen so that the heat capacity C(T) of the chain transforms essentially continuously into the corresponding curve for the gas approximation. Thus, it can be expected that an adequate interpretation of the real temperature dependences of the specific heat of low-dimensionality atomic adsorbates can be obtained through a reasonable combination of the phonon and gas approximations. The main parameters of the gas approximation (such as the desorption energy) obtained by fitting the theory to experiments on the specific heat of xenon correlate well with published data.

Radon background in liquid xenon detectors

NASA Astrophysics Data System (ADS)

Rupp, N.

2018-02-01

The radioactive daughters isotope of 222Rn are one of the highest risk contaminants in liquid xenon detectors aiming for a small signal rate. The noble gas is permanently emanated from the detector surfaces and mixed with the xenon target. Because of its long half-life 222Rn is homogeneously distributed in the target and its subsequent decays can mimic signal events. Since no shielding is possible this background source can be the dominant one in future large scale experiments. This article provides an overview of strategies used to mitigate this source of background by means of material selection and on-line radon removal techniques.

Calculation and characteristic analysis on synergistic effect of CF3I gas mixtures

NASA Astrophysics Data System (ADS)

Su, ZHAO; Yunkun, DENG; Yuhao, GAO; Dengming, XIAO

2018-06-01

CF3I is a potential SF6 alternative gas. In order to study the insulation properties and synergistic effects of CF3I/N2 and CF3I/CO2 gas mixtures, two-term approximate Boltzmann equations were used to obtain the ionization coefficient α, attachment coefficient η and the critical equivalent electrical field strength (E/N)cr. The results show that the (E/N)cr of CF3I gas at 300 K is 1.2 times that of SF6 gas, and CF3I/N2 and CF3I/CO2 gas mixtures both have synergistic effect occurred. The synergistic effect coefficient of CF3I/CO2 gas mixture was higher than that of CF3I/N2 gas mixture. But the (E/N)cr of CF3I/N2 is higher than that of CF3I/CO2 under the same conditions. When the content of CF3I exceeds 20%, the (E/N)cr of CF3I/N2 and CF3I/CO2 gas mixture increase linearly with the increasing of CF3I gas content. The breakdown voltage of CF3I/N2 gas mixture is also higher than that of CF3I/CO2 gas mixture in slightly non-uniform electrical field under power frequency voltage, but the synergistic effect coefficients of the two gas mixtures are basically the same.

Isolation and Purification of the Xenon Fraction of 252Cf Spontaneous Fission Products for the Production of Radio Xenon Calibration Standards

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGrath, Christopher A.

2015-04-01

The presence of radioactive xenon isotopes indicates that fission events have occurred, and is used to help enforce the Comprehensive Test Ban Treaty. Idaho National Laboratory (INL) produces 135Xe, 133mXe, 133Xe, and 131mXe standards used for the calibration and testing of collection equipment and analytical techniques used to monitor radio xenon emissions. At INL, xenon is produced and collected as one of several spontaneous fission products from a 252Cf source. Further chromatographic purification of the fission gases ensures the separations of the xenon fraction for selective collection. An explanation of the fission gas collection, separation and purification is presented. Additionally,more » the range of 135Xe to 133Xe ratio that can be isolated is explained. This is an operational update on the work introduced previously, now that it is in operation and has been recharged with a second 252Cf source.« less

Electron temperature and density measurement of tungsten inert gas arcs with Ar-He shielding gas mixture

NASA Astrophysics Data System (ADS)

Kühn-Kauffeldt, M.; Marques, J.-L.; Forster, G.; Schein, J.

2013-10-01

The diagnostics of atmospheric welding plasma is a well-established technology. In most cases the measurements are limited to processes using pure shielding gas. However in many applications shielding gas is a mixture of various components including metal vapor in gas metal arc welding (GMAW). Shielding gas mixtures are intentionally used for tungsten inert gas (TIG) welding in order to improve the welding performance. For example adding Helium to Argon shielding gas allows the weld geometry and porosity to be influenced. Yet thermal plasmas produced with gas mixtures or metal vapor still require further experimental investigation. In this work coherent Thomson scattering is used to measure electron temperature and density in these plasmas, since this technique allows independent measurements of electron and ion temperature. Here thermal plasmas generated by a TIG process with 50% Argon and 50% Helium shielding gas mixture have been investigated. Electron temperature and density measured by coherent Thomson scattering have been compared to the results of spectroscopic measurements of the plasma density using Stark broadening of the 696.5 nm Argon spectral line. Further investigations of MIG processes using Thomson scattering technique are planned.

Xenon ventilation computed tomography and the management of asthma in the elderly.

PubMed

Park, Heung-Woo; Jung, Jae-Woo; Kim, Kyung-Mook; Kim, Tae-Wan; Lee, So-Hee; Lee, Chang Hyun; Goo, Jin Mo; Min, Kyung-Up; Cho, Sang-Heon

2014-04-01

Xenon ventilation computed tomography (CT) has shown potential in assessing the regional ventilation status in subjects with asthma. The purpose of this study was to evaluate the usefulness of xenon ventilation CT in the management of asthma in the elderly. Treatment-naïve asthmatics aged 65 years or older were recruited. Before initiation of medication, spirometry with bronchodilator (BD) reversibility, questionnaires to assess the severity of symptoms including a visual analogue scale (VAS), tests to evaluate cognitive function and mood, and xenon ventilation CT were performed. Xenon gas trapping (XT) on xenon ventilation CT represents an area where inhaled xenon gas was not expired and was trapped. Symptoms and lung functions were measured again after the 12-week treatment. A total of 30 elderly asthmatics were enrolled. The severity of dyspnoea measured by the VAS showed a significant correlation with the total number of areas of XT on the xenon ventilation CT taken in the pre-BD wash-out phase (r = -0.723, P < 0.001). The total number of areas of XT significantly decreased after BD inhalation, and differences in the total number of areas of XT (between the pre- and post-BD wash-out phases) at baseline showed significant correlations with the per cent increases in forced expiratory volume in 1 s after subsequent anti-asthma treatment (r = -0.775, P < 0.001). Xenon ventilation CT may be an objective and promising tool in the measurement of dyspnoea and prediction of the treatment response in elderly asthmatics. © 2014 The Authors. Respirology © 2014 Asian Pacific Society of Respirology.

Detection of lipoid tumors by xenon-133

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, E.E.; DeLand, F.H.; Maruyama, Y.

1978-01-01

Three patients with biopsy-proven liposarcoma were studied with inhalation of xenon-133, a gas highly soluble in fat. Increased concentration of radioactivity in the region of the tumor suggested the potential usefulness of radioxenon for the detection of lipomatous tumors.

In vivo detection of cucurbit[6]uril, a hyperpolarized xenon contrast agent for a xenon magnetic resonance imaging biosensor

PubMed Central

Hane, Francis T.; Li, Tao; Smylie, Peter; Pellizzari, Raiili M.; Plata, Jennifer A.; DeBoef, Brenton; Albert, Mitchell S.

2017-01-01

The Hyperpolarized gas Chemical Exchange Saturation Transfer (HyperCEST) Magnetic Resonance (MR) technique has the potential to increase the sensitivity of a hyperpolarized xenon-129 MRI contrast agent. Signal enhancement is accomplished by selectively depolarizing the xenon within a cage molecule which, upon exchange, reduces the signal in the dissolved phase pool. Herein we demonstrate the in vivo detection of the cucurbit[6]uril (CB6) contrast agent within the vasculature of a living rat. Our work may be used as a stepping stone towards using the HyperCEST technique as a molecular imaging modality. PMID:28106110

Chondritic xenon in the Earth's mantle.

PubMed

Caracausi, Antonio; Avice, Guillaume; Burnard, Peter G; Füri, Evelyn; Marty, Bernard

2016-05-05

Noble gas isotopes are powerful tracers of the origins of planetary volatiles, and the accretion and evolution of the Earth. The compositions of magmatic gases provide insights into the evolution of the Earth's mantle and atmosphere. Despite recent analytical progress in the study of planetary materials and mantle-derived gases, the possible dual origin of the planetary gases in the mantle and the atmosphere remains unconstrained. Evidence relating to the relationship between the volatiles within our planet and the potential cosmochemical end-members is scarce. Here we show, using high-precision analysis of magmatic gas from the Eifel volcanic area (in Germany), that the light xenon isotopes identify a chondritic primordial component that differs from the precursor of atmospheric xenon. This is consistent with an asteroidal origin for the volatiles in the Earth's mantle, and indicates that the volatiles in the atmosphere and mantle originated from distinct cosmochemical sources. Furthermore, our data are consistent with the origin of Eifel magmatism being a deep mantle plume. The corresponding mantle source has been isolated from the convective mantle since about 4.45 billion years ago, in agreement with models that predict the early isolation of mantle domains. Xenon isotope systematics support a clear distinction between mid-ocean-ridge and continental or oceanic plume sources, with chemical heterogeneities dating back to the Earth's accretion. The deep reservoir now sampled by the Eifel gas had a lower volatile/refractory (iodine/plutonium) composition than the shallower mantle sampled by mid-ocean-ridge volcanism, highlighting the increasing contribution of volatile-rich material during the first tens of millions of years of terrestrial accretion.

Using chromatography – desorption method of manufacturing gas mixtures for analytical instruments calibration

NASA Astrophysics Data System (ADS)

Platonov, I. A.; Kolesnichenko, I. N.; Lange, P. K.

2018-05-01

In this paper, the chromatography desorption method of obtaining gas mixtures of known compositions stable for a time sufficient to calibrate analytical instruments is considered. The comparative analysis results of the preparation accuracy of gas mixtures with volatile organic compounds using diffusion, polyabarbotage and chromatography desorption methods are presented. It is shown that the application of chromatography desorption devices allows one to obtain gas mixtures that are stable for 10...60 hours in a dynamic condition. These gas mixtures contain volatile aliphatic and aromatic hydrocarbons with a concentration error of no more than 7%. It is shown that it is expedient to use such gas mixtures for analytical instruments calibration (chromatographs, spectrophotometers, etc.)

Quantitative analysis of multi-component gas mixture based on AOTF-NIR spectroscopy

NASA Astrophysics Data System (ADS)

Hao, Huimin; Zhang, Yong; Liu, Junhua

2007-12-01

Near Infrared (NIR) spectroscopy analysis technology has attracted many eyes and has wide application in many domains in recent years because of its remarkable advantages. But the NIR spectrometer can only be used for liquid and solid analysis by now. In this paper, a new quantitative analysis method of gas mixture by using new generation NIR spectrometer is explored. To collect the NIR spectra of gas mixtures, a vacuumable gas cell was designed and assembled to Luminar 5030-731 Acousto-Optic Tunable Filter (AOTF)-NIR spectrometer. Standard gas samples of methane (CH 4), ethane (C IIH 6) and propane (C 3H 8) are diluted with super pure nitrogen via precision volumetric gas flow controllers to obtain gas mixture samples of different concentrations dynamically. The gas mixtures were injected into the gas cell and the spectra of wavelength between 1100nm-2300nm were collected. The feature components extracted from gas mixture spectra by using Partial Least Squares (PLS) were used as the inputs of the Support Vector Regress Machine (SVR) to establish the quantitative analysis model. The effectiveness of the model is tested by the samples of predicting set. The prediction Root Mean Square Error (RMSE) of CH 4, C IIH 6 and C 3H 8 is respectively 1.27%, 0.89%, and 1.20% when the concentrations of component gas are over 0.5%. It shows that the AOTF-NIR spectrometer with gas cell can be used for gas mixture analysis. PLS combining with SVR has a good performance in NIR spectroscopy analysis. This paper provides the bases for extending the application of NIR spectroscopy analysis to gas detection.

Numerical study on xenon positive column discharges of mercury-free lamp

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ouyang, Jiting; He, Feng; Miao, Jinsong

2007-02-15

In this paper, the numerical study has been performed on the xenon positive column discharges of mercury-free fluorescent lamp. The plasma discharge characteristics are analyzed by numerical simulation based on two-dimensional fluid model. The effects of cell geometry, such as the dielectric layer, the electrode width, the electrode gap, and the cell height, and the filling gas including the pressure and the xenon percentage are investigated in terms of discharge current and discharge efficiency. The results show that a long transient positive column will form in the xenon lamp when applying ac sinusoidal power and the lamp can operate inmore » a large range of voltage and frequency. The front dielectric layer of the cell plays an important role in the xenon lamp while the back layer has little effect. The ratio of electrode gap to cell height should be large to achieve a long positive column xenon lamp and higher efficiency. Increase of pressure or xenon concentration results in an increase of discharge efficiency and voltage. The discussions will be helpful for the design of commercial xenon lamp cells.« less

Urine analysis concerning xenon for doping control purposes.

PubMed

Thevis, Mario; Piper, Thomas; Geyer, Hans; Schaefer, Maximilian S; Schneemann, Julia; Kienbaum, Peter; Schänzer, Wilhelm

2015-01-15

On September 1(st) 2014, a modified Prohibited List as established by the World Anti-Doping Agency (WADA) became effective featuring xenon as a banned substance categorized as hypoxia-inducible factor (HIF) activator. Consequently, the analysis of xenon from commonly provided doping control specimens such as blood and urine is desirable, and first data on the determination of xenon from urine in the context of human sports drug testing, are presented. In accordance to earlier studies utilizing plasma as doping control matrix, urine was enriched to saturation with xenon, sequentially diluted, and the target analyte was detected as supported by the internal standard d6 -cyclohexanone by means of gas chromatography/triple quadrupole mass spectrometry (GC/MS/MS) using headspace injection. Three major xenon isotopes at m/z 128.9, 130.9 and 131.9 were targeted in (pseudo) selected reaction monitoring mode enabling the unambiguous identification of the prohibited substance. Assay characteristics including limit of detection (LOD), intraday/interday precision, and specificity as well as analyte recovery under different storage conditions were determined. Proof-of-concept data were generated by applying the established method to urine samples collected from five patients before, during and after (up to 48 h) xenon-based general anesthesia. Xenon was traceable in enriched human urine samples down to the detection limit of approximately 0.5 nmol/mL. The intraday and interday imprecision values of the method were found below 25%, and specificity was demonstrated by analyzing 20 different blank urine samples that corroborated the fitness-for-purpose of the analytical approach to unequivocally detect xenon at non-physiological concentrations in human urine. The patients' urine specimens returned 'xenon-positive' test results up to 40 h post-anesthesia, indicating the limits of the expected doping control detection window. Since xenon has been considered a prohibited substance

Extreme Confinement of Xenon by Cryptophane-111 in the Solid State

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joseph, Akil I.; Lapidus, Saul H.; Kane, Christopher M.

2014-12-11

Solids that sorb, capture and/or store the heavier noble gases are of interest because of their potential for transformative rare gas separation/production, storage, or recovery technologies. Herein, we report the isolation, crystal structures, and thermal stabilities of a series of xenon and krypton clathrates of (±)-cryptophane-111 (111). One trigonal crystal form, Xe@111•y(solvent), is exceptionally stable, retaining xenon at temperatures of up to about 300 °C. The high kinetic stability is attributable not only to the high xenon affinity and cage-like nature of the host, but also to the crystal packing of the clathrate, wherein each window of the molecular containermore » is blocked by the bridges of adjacent containers, effectively imprisoning the noble gas in the solid state. The results highlight the potential of discrete molecule materials exhibiting intrinsic microcavities or zero-dimensional pores.« less

Slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures

DOEpatents

Aines, Roger D.; Bourcier, William L.; Viani, Brian

2013-01-29

A slurried solid media for simultaneous water purification and carbon dioxide removal from gas mixtures includes the steps of dissolving the gas mixture and carbon dioxide in water providing a gas, carbon dioxide, water mixture; adding a porous solid media to the gas, carbon dioxide, water mixture forming a slurry of gas, carbon dioxide, water, and porous solid media; heating the slurry of gas, carbon dioxide, water, and porous solid media producing steam; and cooling the steam to produce purified water and carbon dioxide.

On thermal conductivity of gas mixtures containing hydrogen

NASA Astrophysics Data System (ADS)

Zhukov, Victor P.; Pätz, Markus

2017-06-01

A brief review of formulas used for the thermal conductivity of gas mixtures in CFD simulations of rocket combustion chambers is carried out in the present work. In most cases, the transport properties of mixtures are calculated from the properties of individual components using special mixing rules. The analysis of different mixing rules starts from basic equations and ends by very complex semi-empirical expressions. The formulas for the thermal conductivity are taken for the analysis from the works on modelling of rocket combustion chambers. \\hbox {H}_2{-}\\hbox {O}_2 mixtures are chosen for the evaluation of the accuracy of the considered mixing rules. The analysis shows that two of them, of Mathur et al. (Mol Phys 12(6):569-579, 1967), and of Mason and Saxena (Phys Fluids 1(5):361-369, 1958), have better agreement with the experimental data than other equations for the thermal conductivity of multicomponent gas mixtures.

Gas Foil Bearings for Space Propulsion Nuclear Electric Power Generation

NASA Technical Reports Server (NTRS)

Howard, Samuel A.; DellaCorte, Christopher

2006-01-01

The choice of power conversion technology is critical in directing the design of a space vehicle for the future NASA mission to Mars. One candidate design consists of a foil bearing supported turbo alternator driven by a helium-xenon gas mixture heated by a nuclear reactor. The system is a closed-loop, meaning there is a constant volume of process fluid that is sealed from the environment. Therefore, foil bearings are proposed due to their ability to use the process gas as a lubricant. As such, the rotor dynamics of a foil bearing supported rotor is an important factor in the eventual design. The current work describes a rotor dynamic analysis to assess the viability of such a system. A brief technology background, assumptions, analyses, and conclusions are discussed in this report. The results indicate that a foil bearing supported turbo alternator is possible, although more work will be needed to gain knowledge about foil bearing behavior in helium-xenon gas.

Superconducting cable cooling system by helium gas and a mixture of gas and liquid helium

DOEpatents

Dean, John W.

1977-01-01

Thermally contacting, oppositely streaming cryogenic fluid streams in the same enclosure in a closed cycle that changes from a cool high pressure helium gas to a cooler reduced pressure helium fluid comprised of a mixture of gas and boiling liquid so as to be near the same temperature but at different pressures respectively in go and return legs that are in thermal contact with each other and in thermal contact with a longitudinally extending superconducting transmission line enclosed in the same cable enclosure that insulates the line from the ambient at a temperature T.sub.1. By first circulating the fluid in a go leg from a refrigerator at one end of the line as a high pressure helium gas near the normal boiling temperature of helium; then circulating the gas through an expander at the other end of the line where the gas becomes a mixture of reduced pressure gas and boiling liquid at its boiling temperature; then by circulating the mixture in a return leg that is separated from but in thermal contact with the gas in the go leg and in the same enclosure therewith; and finally returning the resulting low pressure gas to the refrigerator for compression into a high pressure gas at T.sub.2 is a closed cycle, where T.sub.1 >T.sub.2, the temperature distribution is such that the line temperature is nearly constant along its length from the refrigerator to the expander due to the boiling of the liquid in the mixture. A heat exchanger between the go and return lines removes the gas from the liquid in the return leg while cooling the go leg.

Xenon Defects in Uranium Dioxide From First Principles and Interatomic Potentials

NASA Astrophysics Data System (ADS)

Thompson, Alexander

In this thesis, we examine the defect energetics and migration energies of xenon atoms in uranium dioxide (UO2) from first principles and interatomic potentials. We also parameterize new, accurate interatomic potentials for xenon and uranium dioxide. To achieve accurate energetics and provide a foundation for subsequent calculations, we address difficulties in finding consistent energetics within Hubbard U corrected density functional theory (DFT+U). We propose a method of slowly ramping the U parameter in order to guide the calculation into low energy orbital occupations. We find that this method is successful for a variety of materials. We then examine the defect energetics of several noble gas atoms in UO2 for several different defect sites. We show that the energy to incorporate large noble gas atoms into interstitial sites is so large that it is energetically favorable for a Schottky defect cluster to be created to relieve the strain. We find that, thermodynamically, xenon will rarely ever be in the interstitial site of UO2. To study larger defects associated with the migration of xenon in UO 2, we turn to interatomic potentials. We benchmark several previously published potentials against DFT+U defect energetics and migration barriers. Using a combination of molecular dynamics and nudged elastic band calculations, we find a new, low energy migration pathway for xenon in UO2. We create a new potential for xenon that yields accurate defect energetics. We fit this new potential with a method we call Iterative Potential Refinement that parameterizes potentials to first principles data via a genetic algorithm. The potential finds accurate energetics for defects with relatively low amounts of strain (xenon in defect clusters). It is important to find accurate energetics for these sorts of low-strain defects because they essentially represent small xenon bubbles. Finally, we parameterize a new UO2 potential that simultaneously yields accurate vibrational properties

Chemical recognition of gases and gas mixtures with terahertz waves.

PubMed

Jacobsen, R H; Mittleman, D M; Nuss, M C

1996-12-15

A time-domain chemical-recognition system for classifying gases and analyzing gas mixtures is presented. We analyze the free induction decay exhibited by gases excited by far-infrared (terahertz) pulses in the time domain, using digital signal-processing techniques. A simple geometric picture is used for the classif ication of the waveforms measured for unknown gas species. We demonstrate how the recognition system can be used to determine the partial pressures of an ammonia-water gas mixture.

Chemical recognition of gases and gas mixtures with terahertz waves

NASA Astrophysics Data System (ADS)

Jacobsen, R. H.; Mittleman, D. M.; Nuss, M. C.

1996-12-01

A time-domain chemical-recognition system for classifying gases and analyzing gas mixtures is presented. We analyze the free induction decay exhibited by gases excited by far-infrared (terahertz) pulses in the time domain, using digital signal-processing techniques. A simple geometric picture is used for the classification of the waveforms measured for unknown gas species. We demonstrate how the recognition system can be used to determine the partial pressures of an ammonia-water gas mixture.

Reduced viscosity interpreted for fluid/gas mixtures

NASA Technical Reports Server (NTRS)

Lewis, D. H.

1981-01-01

Analysis predicts decrease in fluid viscosity by comparing pressure profile of fluid/gas mixture with that of power-law fluid. Fluid is taken to be viscous, non-Newtonian, and incompressible; the gas to be ideal; the flow to be inertia-free, isothermal, and one dimensional. Analysis assists in design of flow systems for petroleum, coal, polymers, and other materials.

Assessing the depth of hypnosis of xenon anaesthesia with the EEG.

PubMed

Stuttmann, Ralph; Schultz, Arthur; Kneif, Thomas; Krauss, Terence; Schultz, Barbara

2010-04-01

Xenon was approved as an inhaled anaesthetic in Germany in 2005 and in other countries of the European Union in 2007. Owing to its low blood/gas partition coefficient, xenons effects on the central nervous system show a fast onset and offset and, even after long xenon anaesthetics, the wake-up times are very short. The aim of this study was to examine which electroencephalogram (EEG) stages are reached during xenon application and whether these stages can be identified by an automatic EEG classification. Therefore, EEG recordings were performed during xenon anaesthetics (EEG monitor: Narcotrend®). A total of 300 EEG epochs were assessed visually with regard to the EEG stages. These epochs were also classified automatically by the EEG monitor Narcotrend® using multivariate algorithms. There was a high correlation between visual and automatic classification (Spearman's rank correlation coefficient r=0.957, prediction probability Pk=0.949). Furthermore, it was observed that very deep stages of hypnosis were reached which are characterised by EEG activity in the low frequency range (delta waves). The burst suppression pattern was not seen. In deep hypnosis, in contrast to the xenon EEG, the propofol EEG was characterised by a marked superimposed higher frequency activity. To ensure an optimised dosage for the single patient, anaesthetic machines for xenon should be combined with EEG monitoring. To date, only a few anaesthetic machines for xenon are available. Because of the high price of xenon, new and further developments of machines focus on optimizing xenon consumption.

Xenon ventilation during therapeutic hypothermia in neonatal encephalopathy: a feasibility study.

PubMed

Dingley, John; Tooley, James; Liu, Xun; Scull-Brown, Emma; Elstad, Maja; Chakkarapani, Ela; Sabir, Hemmen; Thoresen, Marianne

2014-05-01

Therapeutic hypothermia has become standard of care in newborns with moderate and severe neonatal encephalopathy; however, additional interventions are needed. In experimental models, breathing xenon gas during cooling offers long-term additive neuroprotection. This is the first xenon feasibility study in cooled infants. Xenon is expensive, requiring a closed-circuit delivery system. Cooled newborns with neonatal encephalopathy were eligible for this single-arm, dose-escalation study if clinically stable, under 18 hours of age and requiring less than 35% oxygen. Xenon duration increased stepwise from 3 to 18 hours in 14 subjects; 1 received 25% xenon and 13 received 50%. Respiratory, cardiovascular, neurologic (ie, amplitude-integrated EEG, seizures), and inflammatory (C-reactive protein) effects were examined. The effects of starting or stopping xenon rapidly or slowly were studied. Three matched control subjects per xenon treated subject were selected from our cooling database. Follow-up was at 18 months using mental developmental and physical developmental indexes of the Bayley Scales of Infant Development II. No adverse respiratory or cardiovascular effects, including post-extubation stridor, were seen. Xenon increased sedation and suppressed seizures and background electroencephalographic activity. Seizures sometimes occurred during rapid weaning of xenon but not during slow weaning. C-reactive protein levels were similar between groups. Hourly xenon consumption was 0.52 L. Three died, and 7 of 11 survivors had mental and physical developmental index scores ≥70 at follow-up. Breathing 50% xenon for up to 18 hours with 72 hours of cooling was feasible, with no adverse effects seen with 18 months' follow-up. Copyright © 2014 by the American Academy of Pediatrics.

Venus, Earth, Xenon

NASA Astrophysics Data System (ADS)

Zahnle, K. J.

2013-12-01

Xenon has been regarded as an important goal of many proposed missions to Venus. This talk is intended to explain why. Despite its being the heaviest gas found in natural planetary atmospheres, there is more evidence that Xe escaped from Earth than for any element apart from helium: (i) Atmospheric Xe is very strongly mass fractionated (at about 4% per amu) from any known solar system source. This suggests fractionating escape that preferentially left the heavy Xe isotopes behind. (ii) Xe is underabundant compared to Kr, a lighter noble gas that is not strongly mass fractionated in air. (iii) Radiogenic Xe is strongly depleted by factors of several to ~100 compared to the quantities expected from radioactive decay of primordial solar system materials. In these respects Xe on Mars is similar to Xe on Earth, but with one key difference: Xe on Mars is readily explained by a simple process like hydrodynamic escape that acts on an initially solar or meteoritic Xe. This is not so for Earth. Earth's Xe cannot be derived by an uncontrived mass fractionating process acting on any known type of Solar System Xe. Earth is a stranger, made from different stuff than any known meteorite or Mars or even the Sun. Who else is in Earth's family? Comets? We know nothing. Father Zeus? Data from Jupiter are good enough to show that jovian Xe is not strongly mass-fractionated but not good enough to determine whether Jupiter resembles the Earth or the Sun. Sister Venus? Noble gas data from Venus are incomplete, with Kr uncertain and Xe unmeasured. Krypton was measured by several instruments on several spacecraft. The reported Kr abundances are discrepant and were once highly controversial. These discrepancies appear to have been not so much resolved as forgotten. Xenon was not detected on Venus. Upper limits were reported for the two most abundant xenon isotopes 129Xe and 132Xe. From the limited data it is not possible to tell whether Venus's affinities lie with the solar wind, or with

Xenon decreases cell migration and secretion of a pro-angiogenesis factor in breast adenocarcinoma cells: comparison with sevoflurane.

PubMed

Ash, S A; Valchev, G I; Looney, M; Ni Mhathuna, A; Crowley, P D; Gallagher, H C; Buggy, D J

2014-07-01

While volatile agents have been implicated in metastasis-enhancing effects on cancer cells, the effects of xenon are unknown. We investigated xenon- and sevoflurane-mediated effects on migration and expression of angiogenesis biomarkers in human breast adenocarcinoma cells. MDA-MB-231 and MCF-7 cells were exposed to xenon 70% with O2 25%, CO2 5%; control gas containing O2 25%, CO2 5%, N2 70%; or sevoflurane 2.5 vol% administered in O2 60%, N2 37%, or control gas. Cell viability was determined by the MTT assay. Migration at 24 h was determined using the Oris™ Cell Migration Assay. Secretion of angiogenesis factors was measured using a membrane-based immunoassay array. Xenon reduced MDA-MB-231 migration to 59 (13%) after 1-h exposure (P=0.02), 64 (10%) after 3 h (P=0.01), and 71 (9%) after 5 h (P=0.04) compared with control gas, without affecting viability. Similarly, MCF-7 migration was significantly reduced at all timepoints [to 58 (12%) at 1 h, 65 (12%) at 3 h, and 65% (12%) at 5 h]. Sevoflurane did not affect migration when delivered in control gas. Glycine, an N-methyl-d-aspartate receptor co-agonist, antagonized the effects of xenon on migration. Expression of the pro-angiogenesis factor regulated on activation, normal T cell expressed and secreted (RANTES) was reduced in conditioned medium from xenon-exposed MDA-MB-231 cells compared with cells exposed to either control gas or sevoflurane [mean dot density 2.0 (0.2) compared with 3.0 (0.1) and 3.1 (0.3), respectively (P=0.02)]. Xenon, but not sevoflurane, inhibited migration in both oestrogen receptor positive and negative breast adenocarcinoma cells. Furthermore, xenon decreased release of the pro-angiogenic factor RANTES from MDA-MB-231 cells. © The Author [2014]. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Binary and ternary gas mixtures for use in glow discharge closing switches

DOEpatents

Hunter, Scott R.; Christophorou, Loucas G.

1990-01-01

Highly efficient binary and ternary gas mixtures for use in diffuse glow discharge closing switches are disclosed. The binary mixtures are combinations of helium or neon and selected perfluorides. The ternary mixtures are combinations of helium, neon, or argon, a selected perfluoride, and a small amount of gas that exhibits enhanced ionization characteristics. These mixtures are shown to be the optimum choices for use in diffuse glow discharge closing switches by virtue of the combined physio-electric properties of the mixture components.

Terrestrial and Martian weathering signatures of xenon components in shergottite mineral separates

NASA Astrophysics Data System (ADS)

Cartwright, J. A.; Ocker, K. D.; Crowther, S. A.; Burgess, R.; Gilmour, J. D.

2010-08-01

Xenon-isotopic ratios, step-heating release patterns, and gas concentrations of mineral separates from Martian shergottites Roberts Massif (RBT) 04262, Dar al Gani (DaG) 489, Shergotty, and Elephant Moraine (EET) 79001 lithology B are reported. Concentrations of Martian atmospheric xenon are similar in mineral separates from all meteorites, but more weathered samples contain more terrestrial atmospheric xenon. The distributions of xenon from the Martian and terrestrial atmospheres among minerals in any one sample are similar, suggesting similarities in the processes by which they were acquired. However, in opaque and maskelynite fractions, Martian atmospheric xenon is released at higher temperatures than terrestrial atmospheric xenon. It is suggested that both Martian and terrestrial atmospheric xenon were initially introduced by weathering (low temperature alteration processes). However, the Martian component was redistributed by shock, accounting for its current residence in more retentive sites. The presence or absence of detectable 129Xe from the Martian atmosphere in mafic minerals may correspond to the extent of crustal contamination of the rock's parent melt. Variable contents of excess 129Xe contrast with previously reported consistent concentrations of excess 40Ar, suggesting distinct sources contributed these gases to the parent magma.

Gas adsorption and gas mixture separations using mixed-ligand MOF material

DOEpatents

Hupp, Joseph T [Northfield, IL; Mulfort, Karen L [Chicago, IL; Snurr, Randall Q [Evanston, IL; Bae, Youn-Sang [Evanston, IL

2011-01-04

A method of separating a mixture of carbon dioxiode and hydrocarbon gas using a mixed-ligand, metal-organic framework (MOF) material having metal ions coordinated to carboxylate ligands and pyridyl ligands.

Binary and ternary gas mixtures for use in glow discharge closing switches

DOEpatents

Hunter, S.R.; Christophorou, L.G.

1988-04-27

Highly efficient binary and ternary gas mixtures for use in diffuse glow discharge closing switches are disclosed. The binary mixtures are combinations of helium or neon and selected perfluorides. The ternary mixtures are combinations of helium, neon, or argon, a selected perfluoride, and a small amount of gas that exhibits enhanced ionization characteristics. These mixtures are shown to be the optimum choices for use in diffuse glow discharge closing switches by virtue if the combines physio-electric properties of the mixture components. 9 figs.

Genetically encoded reporters for hyperpolarized xenon magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Shapiro, Mikhail G.; Ramirez, R. Matthew; Sperling, Lindsay J.; Sun, George; Sun, Jinny; Pines, Alexander; Schaffer, David V.; Bajaj, Vikram S.

2014-07-01

Magnetic resonance imaging (MRI) enables high-resolution non-invasive observation of the anatomy and function of intact organisms. However, previous MRI reporters of key biological processes tied to gene expression have been limited by the inherently low molecular sensitivity of conventional 1H MRI. This limitation could be overcome through the use of hyperpolarized nuclei, such as in the noble gas xenon, but previous reporters acting on such nuclei have been synthetic. Here, we introduce the first genetically encoded reporters for hyperpolarized 129Xe MRI. These expressible reporters are based on gas vesicles (GVs), gas-binding protein nanostructures expressed by certain buoyant microorganisms. We show that GVs are capable of chemical exchange saturation transfer interactions with xenon, which enables chemically amplified GV detection at picomolar concentrations (a 100- to 10,000-fold improvement over comparable constructs for 1H MRI). We demonstrate the use of GVs as heterologously expressed indicators of gene expression and chemically targeted exogenous labels in MRI experiments performed on living cells.

Chondritic xenon in the Earth’s mantle

NASA Astrophysics Data System (ADS)

Caracausi, Antonio; Avice, Guillaume; Burnard, Peter G.; Füri, Evelyn; Marty, Bernard

2016-05-01

Noble gas isotopes are powerful tracers of the origins of planetary volatiles, and the accretion and evolution of the Earth. The compositions of magmatic gases provide insights into the evolution of the Earth’s mantle and atmosphere. Despite recent analytical progress in the study of planetary materials and mantle-derived gases, the possible dual origin of the planetary gases in the mantle and the atmosphere remains unconstrained. Evidence relating to the relationship between the volatiles within our planet and the potential cosmochemical end-members is scarce. Here we show, using high-precision analysis of magmatic gas from the Eifel volcanic area (in Germany), that the light xenon isotopes identify a chondritic primordial component that differs from the precursor of atmospheric xenon. This is consistent with an asteroidal origin for the volatiles in the Earth’s mantle, and indicates that the volatiles in the atmosphere and mantle originated from distinct cosmochemical sources. Furthermore, our data are consistent with the origin of Eifel magmatism being a deep mantle plume. The corresponding mantle source has been isolated from the convective mantle since about 4.45 billion years ago, in agreement with models that predict the early isolation of mantle domains. Xenon isotope systematics support a clear distinction between mid-ocean-ridge and continental or oceanic plume sources, with chemical heterogeneities dating back to the Earth’s accretion. The deep reservoir now sampled by the Eifel gas had a lower volatile/refractory (iodine/plutonium) composition than the shallower mantle sampled by mid-ocean-ridge volcanism, highlighting the increasing contribution of volatile-rich material during the first tens of millions of years of terrestrial accretion.

Secondary scintillation yield of xenon with sub-percent levels of CO 2 additive for rare-event detection

DOE PAGES

Henriques, C. A. O.; Freitas, E. D. C.; Azevedo, C. D. R.; ...

2017-09-12

Xe–CO 2 mixtures are important alternatives to pure xenon in Time Projection Chambers (TPC) based on secondary scintillation (electroluminescence) signal amplification with applications in the important field of rare event detection such as directional dark matter, double electron capture and double beta decay detection. The addition of CO 2 to pure xenon at the level of 0.05–0.1% can reduce significantly the scale of electron diffusion from 10 mm / √m to 2.5mm / √m, with high impact on the discrimination efficiency of the events through pattern recognition of the topology of primary ionization trails. We have measured the electroluminescence (EL)more » yield of Xe–CO 2 mixtures, with sub-percent CO 2 concentrations. We demonstrate that the EL production is still high in these mixtures, 70% and 35% relative to that produced in pure xenon, for CO 2 concentrations around 0.05% and 0.1%, respectively. In conclusion, the contribution of the statistical fluctuations in EL production to the energy resolution increases with increasing CO 2 concentration, being smaller than the contribution of the Fano factor for concentrations below 0.1% CO 2.« less

Secondary scintillation yield of xenon with sub-percent levels of CO2 additive for rare-event detection

NASA Astrophysics Data System (ADS)

Henriques, C. A. O.; Freitas, E. D. C.; Azevedo, C. D. R.; González-Díaz, D.; Mano, R. D. P.; Jorge, M. R.; Fernandes, L. M. P.; Monteiro, C. M. B.; Gómez-Cadenas, J. J.; Álvarez, V.; Benlloch-Rodríguez, J. M.; Borges, F. I. G. M.; Botas, A.; Cárcel, S.; Carríon, J. V.; Cebrían, S.; Conde, C. A. N.; Díaz, J.; Diesburg, M.; Esteve, R.; Felkai, R.; Ferrario, P.; Ferreira, A. L.; Goldschmidt, A.; Gutiérrez, R. M.; Hauptman, J.; Hernandez, A. I.; Hernando Morata, J. A.; Herrero, V.; Jones, B. J. P.; Labarga, L.; Laing, A.; Lebrun, P.; Liubarsky, I.; López-March, N.; Losada, M.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; McDonald, A. D.; Monrabal, F.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Musti, M.; Nebot-Guinot, M.; Novella, P.; Nygren, D. R.; Palmeiro, B.; Para, A.; Pérez, J.; Querol, M.; Renner, J.; Ripoll, L.; Rodríguez, J.; Rogers, L.; Santos, F. P.; dos Santos, J. M. F.; Simón, A.; Sofka, C.; Sorel, M.; Stiegler, T.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Webb, R.; White, J. T.; Yahlali, N.; NEXT Collaboration

2017-10-01

Xe-CO2 mixtures are important alternatives to pure xenon in Time Projection Chambers (TPC) based on secondary scintillation (electroluminescence) signal amplification with applications in the important field of rare event detection such as directional dark matter, double electron capture and double beta decay detection. The addition of CO2 to pure xenon at the level of 0.05-0.1% can reduce significantly the scale of electron diffusion from 10 mm /√{m} to 2.5 mm /√{m}, with high impact on the discrimination efficiency of the events through pattern recognition of the topology of primary ionization trails. We have measured the electroluminescence (EL) yield of Xe-CO2 mixtures, with sub-percent CO2 concentrations. We demonstrate that the EL production is still high in these mixtures, 70% and 35% relative to that produced in pure xenon, for CO2 concentrations around 0.05% and 0.1%, respectively. The contribution of the statistical fluctuations in EL production to the energy resolution increases with increasing CO2 concentration, being smaller than the contribution of the Fano factor for concentrations below 0.1% CO2.

Secondary scintillation yield of xenon with sub-percent levels of CO 2 additive for rare-event detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henriques, C. A. O.; Freitas, E. D. C.; Azevedo, C. D. R.

Xe–CO 2 mixtures are important alternatives to pure xenon in Time Projection Chambers (TPC) based on secondary scintillation (electroluminescence) signal amplification with applications in the important field of rare event detection such as directional dark matter, double electron capture and double beta decay detection. The addition of CO 2 to pure xenon at the level of 0.05–0.1% can reduce significantly the scale of electron diffusion from 10 mm / √m to 2.5mm / √m, with high impact on the discrimination efficiency of the events through pattern recognition of the topology of primary ionization trails. We have measured the electroluminescence (EL)more » yield of Xe–CO 2 mixtures, with sub-percent CO 2 concentrations. We demonstrate that the EL production is still high in these mixtures, 70% and 35% relative to that produced in pure xenon, for CO 2 concentrations around 0.05% and 0.1%, respectively. In conclusion, the contribution of the statistical fluctuations in EL production to the energy resolution increases with increasing CO 2 concentration, being smaller than the contribution of the Fano factor for concentrations below 0.1% CO 2.« less

Two-phase turbine engines. [using gas-liquid mixture accelerated in nozzles

NASA Technical Reports Server (NTRS)

Elliott, D. G.; Hays, L. G.

1976-01-01

A description is given of a two-phase turbine which utilizes a uniform mixture of gas and liquid accelerated in nozzles of the types reported by Elliott and Weinberg (1968). The mixture acts directly on an axial flow or tangential impulse turbine or is separated into gas and liquid streams which operate separately on a gas turbine and a hydraulic turbine. The basic two-phase cycles are examined, taking into account working fluids, aspects of nozzle expansion, details of turbine cycle operation, and the effect of mixture ratio variation. Attention is also given to two-phase nozzle efficiency, two-phase turbine operating characteristics and efficiencies, separator turbines, and impulse turbine experiments.

Monitoring xenon purity in the LUX detector with a mass spectrometry system

NASA Astrophysics Data System (ADS)

Balajthy, Jon; LUX Experiment Collaboration

2015-04-01

The LUX dark matter search experiment is a 350 kg two-phase liquid/gas xenon time projection chamber located at the 4850 ft level of the Sanford Underground Research Facility in Lead, SD. To monitor for radioactive impurities such as krypton and impurities which limit charge yield such as oxygen, LUX uses a xenon sampling system consisting of a mass spectrometer and a liquid nitrogen cold trap. The cold trap separates the gaseous impurities from a small sample of xenon and allows them to pass to the mass spectrometer for analysis. We report here on results from the LUX xenon sampling program. We also report on methods to enhance the sensitivity of the cold trap technique in preparation for the next-generation LUX-ZEPLIN experiment which will have even more stringent purity requirements.

Method of detecting leakage of reactor core components of liquid metal cooled fast reactors

DOEpatents

Holt, Fred E.; Cash, Robert J.; Schenter, Robert E.

1977-01-01

A method of detecting the failure of a sealed non-fueled core component of a liquid-metal cooled fast reactor having an inert cover gas. A gas mixture is incorporated in the component which includes Xenon-124; under neutron irradiation, Xenon-124 is converted to radioactive Xenon-125. The cover gas is scanned by a radiation detector. The occurrence of 188 Kev gamma radiation and/or other identifying gamma radiation-energy level indicates the presence of Xenon-125 and therefore leakage of a component. Similarly, Xe-126, which transmutes to Xe-127 and Kr-84, which produces Kr-85.sup.m can be used for detection of leakage. Different components are charged with mixtures including different ratios of isotopes other than Xenon-124. On detection of the identifying radiation, the cover gas is subjected to mass spectroscopic analysis to locate the leaking component.

Modeling Xenon Purification Systems in a Laser Inertial Fusion Engine

NASA Astrophysics Data System (ADS)

Hopkins, Ann; Gentile, Charles

2011-10-01

A Laser Inertial Fusion Engine (LIFE) is a proposed method to employ fusion energy to produce electricity for consumers. However, before it can be built and used as such, each aspect of a LIFE power plant must first be meticulously planned. We are in the process of developing and perfecting models for an exhaust processing and fuel recovery system. Such a system is especially essential because it must be able to recapture and purify expensive materials involved in the reaction so they may be reused. One such material is xenon, which is to be used as an intervention gas in the target chamber. Using Aspen HYSYS, we have modeled several subsystems for exhaust processing, including a subsystem for xenon recovery and purification. After removing hydrogen isotopes using lithium bubblers, we propose to use cryogenic distillation to purify the xenon from remaining contaminants. Aspen HYSYS allows us to analyze predicted flow rates, temperatures, pressures, and compositions within almost all areas of the xenon purification system. Through use of Aspen models, we hope to establish that we can use xenon in LIFE efficiently and in a practical manner.

Application of Two Phase (Liquid/Gas) Xenon Gamma-Camera for the Detection of Special Nuclear Material and PET Medical Imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKinsey, Daniel Nicholas

The McKinsey group at Yale has been awarded a grant from DTRA for the building of a Liquid Xenon Gamma Ray Color Camera (LXe-GRCC), which combines state-of-the-art detection of LXe scintillation light and time projection chamber (TPC) charge readout. The DTRA application requires a movable detector and hence only a single phase (liquid) xenon detector can be considered in this case. We propose to extend the DTRA project to applications that allow a two phase (liquid/gas) xenon TPC. This entails additional (yet minimal) hardware and extension of the research effort funded by DTRA. The two phase detector will have bettermore » energy and angular resolution. Such detectors will be useful for PET medical imaging and detection of special nuclear material in stationary applications (e.g. port of entry). The expertise of the UConn group in gas phase TPCs will enhance the capabilities of the Yale group and the synergy between the two groups will be very beneficial for this research project as well as the education and research projects of the two universities. The LXe technology to be used in this project has matured rapidly over the past few years, developed for use in detectors for nuclear physics and astrophysics. This technology may now be applied in a straightforward way to the imaging of gamma rays. According to detailed Monte Carlo simulations recently performed at Yale University, energy resolution of 1% and angular resolution of 3 degrees may be obtained for 1.0 MeV gamma rays, using existing technology. With further research and development, energy resolution of 0.5% and angular resolution of 1.3 degrees will be possible at 1.0 MeV. Because liquid xenon is a high density, high Z material, it is highly efficient for scattering and capturing gamma rays. In addition, this technology scales elegantly to large detector areas, with several square meter apertures possible. The Yale research group is highly experienced in the development and use of noble liquid

Measuring Sound Speed in Gas Mixtures Using a Photoacoustic Generator

NASA Astrophysics Data System (ADS)

Suchenek, Mariusz; Borowski, Tomasz

2018-01-01

We present a new method which allows us to percentage distinction of gas composition with a fast response time. This system uses the speed of sound in a resonant cell along with temperature to determine the gas mixture composition. The gas mixtures contain two gases with an unknown combination. In our experiment, the acoustic waves were excited inside the acoustic longitudinal resonator with the use of a positive feedback. This feedback provides fast tracking of a resonance frequency of the cell and causes fast tracking changes in the speed of sound. The presented method corresponds to the theoretical description of this topic. Two gas mixtures—carbon dioxide and argon mixed with nitrogen—were tested.

Crystallographic studies with xenon and nitrous oxide provide evidence for protein-dependent processes in the mechanisms of general anesthesia.

PubMed

Abraini, Jacques H; Marassio, Guillaume; David, Helene N; Vallone, Beatrice; Prangé, Thierry; Colloc'h, Nathalie

2014-11-01

The mechanisms by which general anesthetics, including xenon and nitrous oxide, act are only beginning to be discovered. However, structural approaches revealed weak but specific protein-gas interactions. To improve knowledge, we performed x-ray crystallography studies under xenon and nitrous oxide pressure in a series of 10 binding sites within four proteins. Whatever the pressure, we show (1) hydrophobicity of the gas binding sites has a screening effect on xenon and nitrous oxide binding, with a threshold value of 83% beyond which and below which xenon and nitrous oxide, respectively, binds to their sites preferentially compared to each other; (2) xenon and nitrous oxide occupancies are significantly correlated respectively to the product and the ratio of hydrophobicity by volume, indicating that hydrophobicity and volume are binding parameters that complement and oppose each other's effects; and (3) the ratio of occupancy of xenon to nitrous oxide is significantly correlated to hydrophobicity of their binding sites. These data demonstrate that xenon and nitrous oxide obey different binding mechanisms, a finding that argues against all unitary hypotheses of narcosis and anesthesia, and indicate that the Meyer-Overton rule of a high correlation between anesthetic potency and solubility in lipids of general anesthetics is often overinterpreted. This study provides evidence that the mechanisms of gas binding to proteins and therefore of general anesthesia should be considered as the result of a fully reversible interaction between a drug ligand and a receptor as this occurs in classical pharmacology.

Xenon Feed System Progress

DTIC Science & Technology

2006-01-01

From - To) 13-06-2006 Technical Paper 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER F04611-00-C-0055 Xenon Feed System Progress (Preprint) 5b. GRANT...propulsion xenon feed system for a flight technology demonstration program. Major accomplishments include: 1) Utilization of the Moog...successfully fed xenon to a 200 watt Hall Effect Thruster in a Technology Demonstration Program. The feed system has demonstrated throttling of xenon

Xenon-Ion Drilling of Tungsten Films

NASA Technical Reports Server (NTRS)

Garner, C. E.

1986-01-01

High-velocity xenon ions used to drill holes of controlled size and distribution through tungsten layer that sheaths surface of controlled-porosity dispenser cathode of traveling wave-tube electron emitter. Controlled-porosity dispenser cathode employs barium/calcium/ aluminum oxide mixture that migrates through pores in cathode surface, thus coating it and reducing its work function. Rapid, precise drilling technique applied to films of other metals and used in other applications where micron-scale holes required. Method requires only few hours, as opposed to tens of hours by prior methods.

Volumetric direct nuclear pumped laser

NASA Technical Reports Server (NTRS)

Jalufka, N. W.; Hohl, F.; Deyoung, R. J.; Williams, M. D. (Inventor)

1978-01-01

A volumetric direct nuclear pumped laser was developed in which the gas is a mixture of He-3 and a minority gas from the group of argon, krypton, xenon, chlorine and fluorine. The mixture of He-3 and the minority gas produces lasing with a minority gas concentration of from 0.01 to 10 percent argon, 1 percent krypton, 0.01 to 5 percent xenon and small concentrations of chlorine or fluorine.

Dark matter directionality revisited with a high pressure xenon gas detector

DOE PAGES

Mohlabeng, Gopolang; Kong, Kyoungchul; Li, Jin; ...

2015-07-20

An observation of the anisotropy of dark matter interactions in a direction-sensitive detector would provide decisive evidence for the discovery of galactic dark matter. Directional information would also provide a crucial input to understanding its distribution in the local Universe. Most of the existing directional dark matter detectors utilize particle tracking methods in a low-pressure gas time projection chamber. These low pressure detectors require excessively large volumes in order to be competitive in the search for physics beyond the current limit. In order to avoid these volume limitations, we consider a novel proposal, which exploits a columnar recombination effect inmore » a high-pressure gas time projection chamber. The ratio of scintillation to ionization signals observed in the detector carries the angular information of the particle interactions. In this paper, we investigate the sensitivity of a future directional detector focused on the proposed high-pressure Xenon gas time projection chamber. We study the prospect of detecting an anisotropy in the dark matter velocity distribution. We find that tens of events are needed to exclude an isotropic distribution of dark matter interactions at 95% confidence level in the most optimistic case with head-to-tail information. However, one needs at least 10-20 times more events without head-to-tail information for light dark matter below ~50 GeV. For an intermediate mass range, we find it challenging to observe an anisotropy of the dark matter distribution. Our results also show that the directional information significantly improves precision measurements of dark matter mass and the elastic scattering cross section for a heavy dark matter.« less

Xenon. Now More than Ever.

NASA Astrophysics Data System (ADS)

Zahnle, K. J.

2017-12-01

Xenon is one of the major goals of proposed missions to Venus. This talk explains why xenon is important to understanding the evolution of Venus's atmosphere. Implications for the historic climate of Venus add a new wrinkle in the story. Xenon's 9 stable isotopes can tell us much about the contrasting histories of Earth, Mars, and Venus. Earth's atmospheric Xe is highly mass fractionated compared to any known solar system source. Moreover, Earth's Xe/Kr ratio is low. It would seem that our heaviest gas has been escaping. What is even more remarkable, Xe escape took place for billions of years until the advent of an O2 atmosphere (Srinivasan EPSL 31:129 (1976); Pujol et al. EPSL 308:298 (2011); Avice et al. Nature Comm 8 (2017)). (ii) Earth's original xenon - what Pepin named U-Xe and claimed was the true solar Xe - had not been seen anywhere else until this year, when the secret parent of U-Xe was found hiding in Comet 67P/Churyumov-Gerasimenko by Rosetta (Marty et al. Science 356:1069 (2017)). Apparently 20% of Earth's xenon came from this kind of comet. This has obvious consequences for volatiles in general. Mars's Xe is also strongly mass fractionated, but its original Xe is indistinguishable from solar Xe, which means that Xe escape is a planetary process that operated in parallel on the two planets. (iii) 7% of Earth's 129Xe are radiogenic daughters of extinct 129I, half-life 15.7 Myrs. This is only 1% of the radiogenic 129Xe that Earth would have had had Earth retained its full cosmic birthright. The missing 129Xe can be interpreted as dating the Moon-forming impact to 100 Myrs after the solar system formed. Venus will be different. Xenon loss probably requires escape as an ion, and therefore it likely depends on hydrogen escape and an organized planetary magnetic field. Xenon escape during Earth's Archean implies that hydrogen was abundant and that the planetary magnetic field was strong. Venus will have seen a different history of escape, so that the mass

Xenon Preconditioning Protects against Renal Ischemic-Reperfusion Injury via HIF-1α Activation

PubMed Central

Ma, Daqing; Lim, Ta; Xu, Jing; Tang, Haidy; Wan, Yanjie; Zhao, Hailin; Hossain, Mahmuda; Maxwell, Patrick H.; Maze, Mervyn

2009-01-01

The mortality rate from acute kidney injury after major cardiovascular operations can be as high as 60%, and no therapies have been proved to prevent acute kidney injury in this setting. Here, we show that preconditioning with the anesthetic gas xenon activates hypoxia-inducible factor 1α (HIF-1α) and its downstream effectors erythropoietin and vascular endothelial growth factor in a time-dependent manner in the kidneys of adult mice. Xenon increased the efficiency of HIF-1α translation via modulation of the mammalian target of rapamycin pathway. In a model of renal ischemia-reperfusion injury, xenon provided morphologic and functional renoprotection; hydrodynamic injection of HIF-1α small interfering RNA demonstrated that this protection is HIF-1α dependent. These results suggest that xenon preconditioning is a natural inducer of HIF-1α and that administration of xenon before renal ischemia can prevent acute renal failure. If these data are confirmed in the clinical setting, then preconditioning with xenon may be beneficial before procedures that temporarily interrupt renal perfusion. PMID:19144758

The nonlinear model for emergence of stable conditions in gas mixture in force field

NASA Astrophysics Data System (ADS)

Kalutskov, Oleg; Uvarova, Liudmila

2016-06-01

The case of M-component liquid evaporation from the straight cylindrical capillary into N - component gas mixture in presence of external forces was reviewed. It is assumed that the gas mixture is not ideal. The stable states in gas phase can be formed during the evaporation process for the certain model parameter valuesbecause of the mass transfer initial equationsnonlinearity. The critical concentrations of the resulting gas mixture components (the critical component concentrations at which the stable states occur in mixture) were determined mathematically for the case of single-component fluid evaporation into two-component atmosphere. It was concluded that this equilibrium concentration ratio of the mixture components can be achieved by external force influence on the mass transfer processes. It is one of the ways to create sustainable gas clusters that can be used effectively in modern nanotechnology.

Performance Analysis of Joule-Thomson Cooler Supplied with Gas Mixtures

NASA Astrophysics Data System (ADS)

Piotrowska, A.; Chorowski, M.; Dorosz, P.

2017-02-01

Joule-Thomson (J-T) cryo-coolers working in closed cycles and supplied with gas mixtures are the subject of intensive research in different laboratories. The replacement of pure nitrogen by nitrogen-hydrocarbon mixtures allows to improve both thermodynamic parameters and economy of the refrigerators. It is possible to avoid high pressures in the heat exchanger and to use standard refrigeration compressor instead of gas bottles or high-pressure oil free compressor. Closed cycle and mixture filled Joule-Thomson cryogenic refrigerator providing 10-20 W of cooling power at temperature range 90-100 K has been designed and manufactured. Thermodynamic analysis including the optimization of the cryo-cooler mixture has been performed with ASPEN HYSYS software. The paper describes the design of the cryo-cooler and provides thermodynamic analysis of the system. The test results are presented and discussed.

Chemical Discrimination in Turbulent Gas Mixtures with MOX Sensors Validated by Gas Chromatography-Mass Spectrometry

PubMed Central

Fonollosa, Jordi; Rodríguez-Luján, Irene; Trincavelli, Marco; Vergara, Alexander; Huerta, Ramón

2014-01-01

Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance. PMID:25325339

Chemical discrimination in turbulent gas mixtures with MOX sensors validated by gas chromatography-mass spectrometry.

PubMed

Fonollosa, Jordi; Rodríguez-Luján, Irene; Trincavelli, Marco; Vergara, Alexander; Huerta, Ramón

2014-10-16

Chemical detection systems based on chemo-resistive sensors usually include a gas chamber to control the sample air flow and to minimize turbulence. However, such a kind of experimental setup does not reproduce the gas concentration fluctuations observed in natural environments and destroys the spatio-temporal information contained in gas plumes. Aiming at reproducing more realistic environments, we utilize a wind tunnel with two independent gas sources that get naturally mixed along a turbulent flow. For the first time, chemo-resistive gas sensors are exposed to dynamic gas mixtures generated with several concentration levels at the sources. Moreover, the ground truth of gas concentrations at the sensor location was estimated by means of gas chromatography-mass spectrometry. We used a support vector machine as a tool to show that chemo-resistive transduction can be utilized to reliably identify chemical components in dynamic turbulent mixtures, as long as sufficient gas concentration coverage is used. We show that in open sampling systems, training the classifiers only on high concentrations of gases produces less effective classification and that it is important to calibrate the classification method with data at low gas concentrations to achieve optimal performance.

Surface damage on polycrystalline β-SiC by xenon ion irradiation at high fluence

NASA Astrophysics Data System (ADS)

Baillet, J.; Gavarini, S.; Millard-Pinard, N.; Garnier, V.; Peaucelle, C.; Jaurand, X.; Duranti, A.; Bernard, C.; Rapegno, R.; Cardinal, S.; Escobar Sawa, L.; De Echave, T.; Lanfant, B.; Leconte, Y.

2018-05-01

Polycrystalline β-silicon carbide (β-SiC) pellets were prepared by Spark Plasma Sintering (SPS). These were implanted at room temperature with 800 keV xenon at ion fluences of 5.1015 and 1.1017 cm-2. Microstructural modifications were studied by electronic microscopy (TEM and SEM) and xenon profiles were determined by Rutherford Backscattering Spectroscopy (RBS). A complete amorphization of the implanted area associated with a significant oxidation is observed for the highest fluence. Large xenon bubbles formed in the oxide phase are responsible of surface swelling. No significant gas release has been measured up to 1017 at.cm-2. A model is proposed to explain the different steps of the oxidation process and xenon bubbles formation as a function of ion fluence.

[Correction of the functional state of deck aviation pilots by the course of inhalation of therapeutic doses of xenon during long march].

PubMed

Bubeev, Iu A; Kal'manov, A S; Kotrovskaia, T I

2011-01-01

The article deals with efficiency of the course of O2-Xe inhalation for correction of the functional state of deck aviation pilots in a long march. The course was shown to stabilize vagosympathetic balance in organism, to compensate functioning and to retain reserve of the cardiovascular system that resulted in significant psychoemotional animation attested by self-appreciation, amelioration and cheerfulness, and weakening of reactive anxiety. These observations point to applicability of xenon-based gas mixtures to correction of the pilot's functional state in the most intensive periods of service. Guidelines for broad adoption of the method by military medicine have been developed.

Shock wave induced condensation in fuel-rich gaseous and gas-particles mixtures

NASA Astrophysics Data System (ADS)

Fomin, P. A.

2018-03-01

The possibility of fuel vapor condensation in shock waves in fuel-rich (cyclohexane-oxygen) gaseous mixtures and explosion safety aspects of this effect are discussed. It is shown, that condensation process can essentially change the chemical composition of the gas. For example, the molar fraction of the oxidizer can increase in a few times. As a result, mixtures in which the initial concentration of fuel vapor exceeds the Upper Flammability Limit can, nevertheless, explode, if condensation shifts the composition of the mixture into the ignition region. The rate of the condensation process is estimated. This process can be fast enough to significantly change the chemical composition of the gas and shift it into the flammable range during the compression phase of blast waves, generated by explosions of fuel-vapor clouds or rapture of pressurized chemical reactors, with characteristic size of a few meters. It is shown that the presence of chemically inert microparticles in the gas mixtures under consideration increases the degree of supercooling and the mass of fuel vapors that have passed into the liquid and reduces the characteristic condensation time in comparison with the gas mixture without microparticles. The fuel vapor condensation should be taken into account in estimation the explosion hazard of chemical reactors, industrial and civil constructions, which may contain fuel-rich gaseous mixtures of heavy hydrocarbons with air.

Thermal Conductivity of Gas Mixtures in Chemical Equilibrium

NASA Technical Reports Server (NTRS)

Brokaw, Richard S.

1960-01-01

The expression for the thermal conductivity of gas mixtures in chemical equilibrium is presented in a simpler and less restrictive form. This new form is shown to be equivalent to the previous equations.

Cooling molten salt reactors using "gas-lift"

NASA Astrophysics Data System (ADS)

Zitek, Pavel; Valenta, Vaclav; Klimko, Marek

2014-08-01

This study briefly describes the selection of a type of two-phase flow, suitable for intensifying the natural flow of nuclear reactors with liquid fuel - cooling mixture molten salts and the description of a "Two-phase flow demonstrator" (TFD) used for experimental study of the "gas-lift" system and its influence on the support of natural convection. The measuring device and the application of the TDF device is described. The work serves as a model system for "gas-lift" (replacing the classic pump in the primary circuit) for high temperature MSR planned for hydrogen production. An experimental facility was proposed on the basis of which is currently being built an experimental loop containing the generator, separator bubbles and necessary accessories. This loop will model the removal of gaseous fission products and tritium. The cleaning of the fuel mixture of fluoride salts eliminates problems from Xenon poisoning in classical reactors.

Plasma polymerization of an ethylene-nitrogen gas mixture

NASA Technical Reports Server (NTRS)

Hudis, M.; Wydeven, T.

1975-01-01

A procedure has been developed whereby nitrogen can be incorporated into an organic film from an ethylene-nitrogen gas mixture using an internal electrode capacitively coupled radio frequency reactor. The presence of nitrogen has been shown directly by infrared transmittance spectra and electron spectroscopic chemical analysis data, and further indirect evidence was provided by dielectric measurements and by the reverse osmosis properties of the film. Preparation of a nitrogen containing film did not require vapor from an organic nitrogen containing liquid monomer. Some control over the bonding and stoichiometry of the polymer film was provided by the added degree of freedom of the nitrogen partial pressure in the gas mixture. This new parameter strongly affected the dielectric properties of the plasma polymerized film and could affect the reverse osmosis behavior.

Near-infrared scintillation of xenon by 63Ni beta decay

NASA Astrophysics Data System (ADS)

Yoshimizu, Norimasa; Lal, Amit; Pollock, Clifford R.

2006-07-01

The near-infrared scintillation of xenon gas by the β decay of 37MBq of Ni63 was studied, in the interest of its use in integrated devices for applications such as optical beacons and wavelength calibration. The emission was imaged and analyzed using Spencer's theory of electron penetration using xenon scattering cross sections derived from Thomas-Fermi theory. The total emission was approximately 2×105photons/s at 20kPa and 1×105photons/s at 100kPa. Spectral data show three dominant peaks at 823, 828, and 882nm as well as the formation of metastable states.

Variable-temperature cryogenic trap for the separation of gas mixtures

NASA Technical Reports Server (NTRS)

Des Marais, D. J.

1978-01-01

The paper describes a continuous variable-temperature U-shaped cold trap which can both purify vacuum-line combustion products for subsequent stable isotopic analysis and isolate the methane and ethane constituents of natural gases. The canister containing the trap is submerged in liquid nitrogen, and, as the gas cools, the gas mixture components condense sequentially according to their relative vapor pressures. After the about 12 min required for the bottom of the trap to reach the liquid-nitrogen temperature, passage of electric current through the resistance wire wrapped around the tubing covering the U-trap permits distillation of successive gas components at optimal temperatures. Data on the separation achieved for two mixtures, the first being typical vacuum-line combustion products of geochemical samples such as rocks and the second being natural gas, are presented, and the thermal behavior and power consumption are reported.

Simultaneous magnetic resonance imaging of ventilation distribution and gas uptake in the human lung using hyperpolarized xenon-129

PubMed Central

Mugler, John P.; Altes, Talissa A.; Ruset, Iulian C.; Dregely, Isabel M.; Mata, Jaime F.; Miller, G. Wilson; Ketel, Stephen; Ketel, Jeffrey; Hersman, F. William; Ruppert, Kai

2010-01-01

Despite a myriad of technical advances in medical imaging, as well as the growing need to address the global impact of pulmonary diseases, such as asthma and chronic obstructive pulmonary disease, on health and quality of life, it remains challenging to obtain in vivo regional depiction and quantification of the most basic physiological functions of the lung—gas delivery to the airspaces and gas uptake by the lung parenchyma and blood—in a manner suitable for routine application in humans. We report a method based on MRI of hyperpolarized xenon-129 that permits simultaneous observation of the 3D distributions of ventilation (gas delivery) and gas uptake, as well as quantification of regional gas uptake based on the associated ventilation. Subjects with lung disease showed variations in gas uptake that differed from those in ventilation in many regions, suggesting that gas uptake as measured by this technique reflects such features as underlying pathological alterations of lung tissue or of local blood flow. Furthermore, the ratio of the signal associated with gas uptake to that associated with ventilation was substantially altered in subjects with lung disease compared with healthy subjects. This MRI-based method provides a way to quantify relationships among gas delivery, exchange, and transport, and appears to have significant potential to provide more insight into lung disease. PMID:21098267

Investigation of Dalton and Amagat's laws for gas mixtures with shock propagation

NASA Astrophysics Data System (ADS)

Wayne, Patrick; Trueba Monje, Ignacio; Yoo, Jason H.; Truman, C. Randall; Vorobieff, Peter

2016-11-01

Two common models describing gas mixtures are Dalton's Law and Amagat's Law (also known as the laws of partial pressures and partial volumes, respectively). Our work is focused on determining the suitability of these models to prediction of effects of shock propagation through gas mixtures. Experiments are conducted at the Shock Tube Facility at the University of New Mexico (UNM). To validate experimental data, possible sources of uncertainty associated with experimental setup are identified and analyzed. The gaseous mixture of interest consists of a prescribed combination of disparate gases - helium and sulfur hexafluoride (SF6). The equations of state (EOS) considered are the ideal gas EOS for helium, and a virial EOS for SF6. The values for the properties provided by these EOS are then used used to model shock propagation through the mixture in accordance with Dalton's and Amagat's laws. Results of the modeling are compared with experiment to determine which law produces better agreement for the mixture. This work is funded by NNSA Grant DE-NA0002913.

Slip and barodiffusion phenomena in slow flows of a gas mixture

NASA Astrophysics Data System (ADS)

Zhdanov, V. M.

2017-03-01

The slip and barodiffusion problems for the slow flows of a gas mixture are investigated on the basis of the linearized moment equations following from the Boltzmann equation. We restrict ourselves to the set of the third-order moment equations and state two general relations (resembling conservation equations) for the moments of the distribution function similar to the conditions used by Loyalka [S. K. Loyalka, Phys. Fluids 14, 2291 (1971), 10.1063/1.1693331] in his approximation method (the modified Maxwell method). The expressions for the macroscopic velocities of the gas mixture species, the partial viscous stress tensors, and the reduced heat fluxes for the stationary slow flow of a gas mixture in the semi-infinite space over a plane wall are obtained as a result of the exact solution of the linearized moment equations in the 10- and 13-moment approximations. The general expression for the slip velocity and the simple and accurate expressions for the viscous, thermal, diffusion slip, and baroslip coefficients, which are given in terms of the basic transport coefficients, are derived by using the modified Maxwell method. The solutions of moment equations are also used for investigation of the flow and diffusion of a gas mixture in a channel formed by two infinite parallel plates. A fundamental result is that the barodiffusion factor in the cross-section-averaged expression for the diffusion flux contains contributions associated with the viscous transfer of momentum in the gas mixture and the effect of the Knudsen layer. Our study revealed that the barodiffusion factor is equal to the diffusion slip coefficient (correct to the opposite sign). This result is consistent with the Onsager's reciprocity relations for kinetic coefficients following from nonequilibrium thermodynamics of the discontinuous systems.

Development of a liquid xenon time projection chamber for the XENON dark matter search

NASA Astrophysics Data System (ADS)

Ni, Kaixuan

This thesis describes the research conducted for the XENON dark matter direct detection experiment. The tiny energy and small cross-section, from the interaction of dark matter particle on the target, requires a low threshold and sufficient background rejection capability of the detector. The XENON experiment uses dual phase technology to detect scintillation and ionization simultaneously from an event in liquid xenon (LXe). The distinct ratio, between scintillation and ionization, for nuclear recoil and electron recoil events provides excellent background rejection potential. The XENON detector is designed to have 3D position sensitivity down to mm scale, which provides additional event information for background rejection. Started in 2002, the XENON project made steady progress in the R&D phase during the past few years. Those include developing sensitive photon detectors in LXe, improving the energy resolution and LXe purity for detecting very low energy events. Two major quantities related to the dark matter detection, the scintillation efficiency and ionization yield of nuclear recoils in LXe, have been established. A prototype dual phase detector (XENON3) has been built and tested extensively in above ground laboratory. The 3D position sensitivity, as well as the background discrimination potential demonstrated from the XENON3 prototype, allows the construction of a 10 kg scale detector (XENON10), to be deployed underground in early 2006. With 99.5% electron recoil rejection efficiency and 16 keVr nuclear recoil energy threshold, XENON10 will be able to probe the WIMP-nucleon cross-section down to 2 x 10-44 cm2 in the supersymmetry parameter space, after one month operation in the Gran Sasso underground laboratory.

Improving Spectroscopic Performance of a Coplanar-Anode High-Pressure Xenon Gamma-Ray Spectrometer

NASA Astrophysics Data System (ADS)

Kiff, Scott Douglas; He, Zhong; Tepper, Gary C.

2007-08-01

High-pressure xenon (HPXe) gas is a desirable radiation detection medium for homeland security applications because of its good inherent room-temperature energy resolution, potential for large, efficient devices, and stability over a broad temperature range. Past work in HPXe has produced large-diameter gridded ionization chambers with energy resolution at 662 keV between 3.5 and 4% FWHM. However, one major limitation of these detectors is resolution degradation due to Frisch grid microphonics. A coplanar-anode HPXe detector has been developed as an alternative to gridded chambers. An investigation of this detector's energy resolution is reported in this submission. A simulation package is used to investigate the contributions of important physical processes to the measured photopeak broadening. Experimental data is presented for pure Xe and Xe + 0.2%H2 mixtures, including an analysis of interaction location effects on the energy spectrum.

Stirring Up an Elastic Fluid: Critical Viscosity of Xenon-2 (CVX-2)

NASA Astrophysics Data System (ADS)

Berg, Robert F.; Moldover, Michael R.; Zimmerli, Gregory A.

2002-12-01

Whipped cream stays in place even when turned upside down. Yet it readily flows through the nozzle of a spray can to reach the dessert plate. This demonstrates the phenomenon of shear thinning that is important to many industrial and physical processes. Paints, film emulsions, and other complex solutions that are highly viscous under normal conditions but become thin and flow easily under shear forces. A simple fluid, such as water, does not exhibit shear thinning under normal conditions. Very close to the liquid-vapor critical point, where the distinction between liquid and vapor disappears, the fluid becomes more complex and is predicted to display shear thinning. At the critical point, xenon atoms interact over long distances in a classical model of cooperative phenomena. Physicists rely on this system to learn how long-range order arises. The Critical Viscosity of Xenon Experiment (CVX-2) will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Although it does not easily combine with other chemicals, its viscosity at the critical point can be used as a model for a range of fluids. Viscosity originates from the interactions of individual molecules. It is so complicated that, except for the simplest gas, it cannot be calculated accurately from theory. Tests with critical fluids can provide key data, but are limited on Earth because critical fluids are highly compressed by gravity. CVX-2 employs a tiny metal screen vibrating between two electrodes in a bath of critical xenon. The vibrations and how they dampen are used to measure viscosity. CVX flew on STS-85 (1997), where it revealed that, close to the critical point, the xenon is partly elastic: it can 'stretch' as well as flow. For STS-107, the hardware has been enhanced to determine if critical xenon is a shear-thinning fluid.

Stirring Up an Elastic Fluid: Critical Viscosity of Xenon-2 (CVX-2)

NASA Technical Reports Server (NTRS)

Berg, Robert F.; Moldover, Michael R.; Zimmerli, Gregory A.; Motil, Susan M. (Technical Monitor)

2002-01-01

Whipped cream stays in place even when turned upside down. Yet it readily flows through the nozzle of a spray can to reach the dessert plate. This demonstrates the phenomenon of shear thinning that is important to many industrial and physical processes. Paints, film emulsions, and other complex solutions that are highly viscous under normal conditions but become thin and flow easily under shear forces. A simple fluid, such as water, does not exhibit shear thinning under normal conditions. Very close to the liquid-vapor critical point, where the distinction between liquid and vapor disappears, the fluid becomes more complex and is predicted to display shear thinning. At the critical point, xenon atoms interact over long distances in a classical model of cooperative phenomena. Physicists rely on this system to learn how long-range order arises. The Critical Viscosity of Xenon Experiment (CVX-2) will measure the viscous behavior of xenon, a heavy inert gas used in flash lamps and ion rocket engines, at its critical point. Although it does not easily combine with other chemicals, its viscosity at the critical point can be used as a model for a range of fluids. Viscosity originates from the interactions of individual molecules. It is so complicated that, except for the simplest gas, it cannot be calculated accurately from theory. Tests with critical fluids can provide key data, but are limited on Earth because critical fluids are highly compressed by gravity. CVX-2 employs a tiny metal screen vibrating between two electrodes in a bath of critical xenon. The vibrations and how they dampen are used to measure viscosity. CVX flew on STS-85 (1997), where it revealed that, close to the critical point, the xenon is partly elastic: it can 'stretch' as well as flow. For STS-107, the hardware has been enhanced to determine if critical xenon is a shear-thinning fluid.

Recovery of purified helium or hydrogen from gas mixtures

DOEpatents

Merriman, J.R.; Pashley, J.H.; Stephenson, M.J.; Dunthorn, D.I.

1974-01-15

A process is described for the removal of helium or hydrogen from gaseous mixtures also containing contaminants. The gaseous mixture is contacted with a liquid fluorocarbon in an absorption zone maintained at superatomspheric pressure to preferentially absorb the contaminants in the fluorocarbon. Unabsorbed gas enriched in hydrogen or helium is withdrawn from the absorption zone as product. Liquid fluorocarbon enriched in contaminants is withdrawn separately from the absorption zone. (10 claims)

Evaluation of hemodynamic effects of xenon in dogs undergoing hemorrhagic shock

PubMed Central

Franceschi, Ruben C.; Malbouisson, Luiz; Yoshinaga, Eduardo; Auler, José Otavio Costa; de Figueiredo (in memoriam), Luiz Francisco Poli; Carmona, Maria José C.

2013-01-01

OBJECTIVES: The anesthetic gas xenon is reported to preserve hemodynamic stability during general anesthesia. However, the effects of the gas during shock are unclear. The objective of this study was to evaluate the effect of Xe on hemodynamic stability and tissue perfusion in a canine model of hemorrhagic shock. METHOD: Twenty-six dogs, mechanically ventilated with a fraction of inspired oxygen of 21% and anesthetized with etomidate and vecuronium, were randomized into Xenon (Xe; n = 13) or Control (C; n = 13) groups. Following hemodynamic monitoring, a pressure-driven shock was induced to reach an arterial pressure of 40 mmHg. Hemodynamic data and blood samples were collected prior to bleeding, immediately after bleeding and 5, 20 and 40 minutes following shock. The Xe group was treated with 79% Xe diluted in ambient air, inhaled for 20 minutes after shock. RESULT: The mean bleeding volume was 44 mL.kg−1 in the C group and 40 mL.kg−1 in the Xe group. Hemorrhage promoted a decrease in both the cardiac index (p<0.001) and mean arterial pressure (p<0.001). These changes were associated with an increase in lactate levels and worsening of oxygen transport variables in both groups (p<0.05). Inhalation of xenon did not cause further worsening of hemodynamics or tissue perfusion markers. CONCLUSIONS: Xenon did not alter hemodynamic stability or tissue perfusion in an experimentally controlled hemorrhagic shock model. However, further studies are necessary to validate this drug in other contexts. PMID:23525321

Xenon adsorption on geological media and implications for radionuclide signatures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paul, M. J.; Biegalski, S. R.; Haas, D. A.

Here, the detection of radioactive noble gases is a primary technology for verifying compliance with the pending Comprehensive Nuclear-Test-Ban Treaty. A fundamental challenge in applying this technology for detecting underground nuclear explosions is estimating the timing and magnitude of the radionuclide signatures. While the primary mechanism for transport is advective transport, either through barometric pumping or thermally driven advection, diffusive transport in the surrounding matrix also plays a secondary role. From the study of primordial noble gas signatures, it is known that xenon has a strong physical adsorption affinity in shale formations. Given the unselective nature of physical adsorption, isothermmore » measurements reported here show that non-trivial amounts of xenon adsorb on a variety of media, in addition to shale. A dual-porosity model is then discussed demonstrating that sorption amplifies the diffusive uptake of an adsorbing matrix from a fracture. This effect may reduce the radioxenon signature down to approximately one-tenth, similar to primordial xenon isotopic signatures.« less

Xenon adsorption on geological media and implications for radionuclide signatures

DOE PAGES

Paul, M. J.; Biegalski, S. R.; Haas, D. A.; ...

2018-02-13

Here, the detection of radioactive noble gases is a primary technology for verifying compliance with the pending Comprehensive Nuclear-Test-Ban Treaty. A fundamental challenge in applying this technology for detecting underground nuclear explosions is estimating the timing and magnitude of the radionuclide signatures. While the primary mechanism for transport is advective transport, either through barometric pumping or thermally driven advection, diffusive transport in the surrounding matrix also plays a secondary role. From the study of primordial noble gas signatures, it is known that xenon has a strong physical adsorption affinity in shale formations. Given the unselective nature of physical adsorption, isothermmore » measurements reported here show that non-trivial amounts of xenon adsorb on a variety of media, in addition to shale. A dual-porosity model is then discussed demonstrating that sorption amplifies the diffusive uptake of an adsorbing matrix from a fracture. This effect may reduce the radioxenon signature down to approximately one-tenth, similar to primordial xenon isotopic signatures.« less

Comparison of xenon-based anaesthesia compared with total intravenous anaesthesia in high risk surgical patients.

PubMed

Bein, B; Turowski, P; Renner, J; Hanss, R; Steinfath, M; Scholz, J; Tonner, P H

2005-10-01

Xenon, a noble gas with anaesthetic and analgesic properties, has gained renewed interest due to its favourable physical properties which allow a rapid emergence from anaesthesia. However, high costs limit its use to a subset of patients who may benefit from xenon, thereby offsetting its costs. To date, there are only limited data available on the performance of xenon in high risk patients. We studied 39 patients with ASA physical status III undergoing aortic surgery. The patients were randomly assigned to either a xenon (Xe, n = 20) or a TIVA (T, n = 19) group. Global cardiac performance and myocardial contractility were assessed using transoesophageal echocardiography, and myocardial cell damage with troponin T and CK-MB. Echocardiographic measurements were made prior to xenon administration, following xenon administration, and after clamping of the abdominal aorta, after declamping and at corresponding time points in the TIVA group. Laboratory values were determined repeatedly for up to 72 h. Data were analysed using two-way anova factoring for time and anaesthetic agent or with ancova comparing linear regression lines. No significant differences were found in global myocardial performance, myocardial contractility or laboratory values at any time during the study period. Mean (SEM) duration of stay on the ICU (xenon: 38 +/- 46 vs. TIVA 25 +/- 15 h) or in hospital (xenon: 14 +/- 12 vs. TIVA 10 +/- 6 days) did not differ significantly between the groups. Although xenon has previously been shown to exert superior haemodynamic stability, we were unable to demonstrate an advantage of xenon-based anaesthesia compared to TIVA in high risk surgical patients.

Early treatment with xenon protects against the cold ischemia associated with chronic allograft nephropathy in rats.

PubMed

Zhao, Hailin; Luo, Xianghong; Zhou, Zhaowei; Liu, Juying; Tralau-Stewart, Catherine; George, Andrew J T; Ma, Daqing

2014-01-01

Chronic allograft nephropathy (CAN) is a common finding in kidney grafts with functional impairment. Prolonged hypothermic storage-induced ischemia-reperfusion injury is associated with the early onset of CAN. As the noble gas xenon is clinically used as an anesthetic and has renoprotective properties in a rodent model of ischemia-reperfusion injury, we studied whether early treatment with xenon could attenuate CAN associated with prolonged hypothermic storage. Exposure to xenon enhanced the expression of insulin growth factor-1 (IGF-1) and its receptor in human proximal tubular (HK-2) cells, which, in turn, increased cell proliferation. Xenon treatment before or after hypothermia-hypoxia decreased cell apoptosis and cell inflammation after reoxygenation. The xenon-induced HK-2 cell proliferation was abolished by blocking the IGF-1 receptor, mTOR, and HIF-1α individually. In the Fischer-to-Lewis rat allogeneic renal transplantation model, xenon exposure of donors before graft retrieval or recipients after engraftment enhanced tubular cell proliferation and decreased tubular cell death and cell inflammation associated with ischemia-reperfusion injury. Compared with control allografts, xenon treatment significantly suppressed T-cell infiltration and fibrosis, prevented the development of CAN, and improved renal function. Thus, xenon treatment promoted recovery from ischemia-reperfusion injury and reduced susceptibility to the subsequent development of CAN in allografts.

Status of the Large Underground Xenon (LUX) Detector

NASA Astrophysics Data System (ADS)

Larsen, Nicole

2012-03-01

The LUX (Large Underground Xenon) experiment is a 350-kg xenon-based direct dark matter detection experiment consisting of a two-phase (liquid/gas) xenon time projection chamber with a 100-kg fiducial mass. This technology has many advantages, including scalability, self-shielding, the absence of any long-lived isotopes, high gamma ray stopping power, and the ability to precisely measure the charge-to-light ratio of interactions within the detector, which provides an accurate method for discriminating between electron recoils (gamma rays, beta decays) and nuclear recoils (neutrons, WIMPS) within the detector. LUX's projected sensitivity for 300 days of acquisition is a cross-section of 7 x10-46 cm^2 for a WIMP mass of 100 GeV, representing an increase of nearly an order of magnitude over previous WIMP cross-section limits. From November 2011 through February 2012, LUX was deployed in a surface laboratory at the Homestake Mine in South Dakota for its second surface run. This talk will provide an overview of the LUX design and a report on the status of the experiment after the surface run and before underground deployment.

30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

30 CFR 75.1106-6 - Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Exemption of small low pressure gas cylinders... STANDARDS-UNDERGROUND COAL MINES Fire Protection § 75.1106-6 Exemption of small low pressure gas cylinders containing nonflammable or nonexplosive gas mixtures. Small low pressure gas cylinders containing...

Reduced xenon diffusion for quantitative lung study--the role of SF(6)

NASA Technical Reports Server (NTRS)

Mair, R. W.; Hoffmann, D.; Sheth, S. A.; Wong, G. P.; Butler, J. P.; Patz, S.; Topulos, G. P.; Walsworth, R. L.

2000-01-01

The large diffusion coefficients of gases result in significant spin motion during the application of gradient pulses that typically last a few milliseconds in most NMR experiments. In restricted environments, such as the lung, this rapid gas diffusion can lead to violations of the narrow pulse approximation, a basic assumption of the standard Stejskal-Tanner NMR method of diffusion measurement. We therefore investigated the effect of a common, biologically inert buffer gas, sulfur hexafluoride (SF(6)), on (129)Xe NMR and diffusion. We found that the contribution of SF(6) to (129)Xe T(1) relaxation in a 1:1 xenon/oxygen mixture is negligible up to 2 bar of SF(6) at standard temperature. We also measured the contribution of SF(6) gas to (129)Xe T(2) relaxation, and found it to scale inversely with pressure, with this contribution approximately equal to 1 s for 1 bar SF(6) pressure and standard temperature. Finally, we found the coefficient of (129)Xe diffusion through SF(6) to be approximately 4.6 x 10(-6) m(2)s(-1) for 1 bar pressure of SF(6) and standard temperature, which is only 1.2 times smaller than the (129)Xe self diffusion coefficient for 1 bar (129)Xe pressure and standard temperature. From these measurements we conclude that SF(6) will not sufficiently reduce (129)Xe diffusion to allow accurate surface-area/volume ratio measurements in human alveoli using time-dependent gas diffusion NMR.

Xenon excimer emission from pulsed high-pressure capillary microdischarges

NASA Astrophysics Data System (ADS)

Lee, Byung-Joon; Rahaman, Hasibur; Petzenhauser, Isfried; Frank, Klaus; Giapis, Konstantinos P.

2007-06-01

Intense xenon vacuum ultraviolet (VUV) emission is observed from a high-pressure capillary cathode microdischarge in direct current operation, by superimposing a high-voltage pulse of 50ns duration. Under stagnant gas conditions, the total VUV light intensity increases linearly with pressure from 400 to 1013mbar for a fixed voltage pulse. At fixed pressure, however, the VUV light intensity increases superlinearly with voltage pulse height ranging from 08to2.8kV. Gains in emission intensity are obtained by inducing gas flow through the capillary cathode, presumably because of excimer dimer survival due to gas cooling.

A plan for directional dark matter sensitivity in high-pressure xenon detectors through the addition of wavelength shifting gaseous molecules

NASA Astrophysics Data System (ADS)

Gehman, V. M.; Goldschmidt, A.; Nygren, D.; Oliveira, C. A. B.; Renner, J.

2013-10-01

Xenon is an especially attractive candidate for both direct WIMP and 0νββ decay searches. Although the current trend has exploited the liquid phase, the gas phase xenon offers remarkable performance advantages for: energy resolution, topology visualization, and discrimination between electron and nuclear recoils. The NEXT-100 experiment, now under construction in the Canfranc Underground Laboratory, Spain, will operate at ~ 15 bars with 100 kg of 136Xe for the 0νββ decay search. We will describe recent results with small prototypes, indicating that NEXT-100 can provide about 0.5% FWHM energy resolution at the decay's Q value (2457.83 keV), as well as rejection of γ-rays with topological cuts. However, sensitivity goals for WIMP dark matter and 0νββ decay searches indicate the probable need for ton-scale active masses. NEXT-100 provides the springboard to reach this scale with xenon gas. We describe a scenario for performing both searches in a single, high-pressure, ton-scale xenon gas detector, without significant compromise to either. In addition, even in a single ton-scale, high-pressure xenon gas TPC, an intrinsic sensitivity to the nuclear recoil direction may exist. This plausibly offers an advance of more than two orders of magnitude relative to current low-pressure TPC concepts. We argue that, in an era of deepening fiscal austerity, such a dual-purpose detector may be possible at acceptable cost, within the time frame of interest, and deserves our collective attention.

Scalability study of solid xenon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoo, J.; Cease, H.; Jaskierny, W. F.

2015-04-01

We report a demonstration of the scalability of optically transparent xenon in the solid phase for use as a particle detector above a kilogram scale. We employed a cryostat cooled by liquid nitrogen combined with a xenon purification and chiller system. A modified {\\it Bridgeman's technique} reproduces a large scale optically transparent solid xenon.

10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

Code of Federal Regulations, 2010 CFR

2010-01-01

... natural gas or petroleum. 503.38 Section 503.38 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS... mixtures containing natural gas or petroleum. (a) Eligibility. Section 212(d) of the Act provides for a... proposes to use a mixture of natural gas or petroleum and an alternate fuel as a primary energy source; (2...

Modeling of non-thermal plasma in flammable gas mixtures

NASA Astrophysics Data System (ADS)

Napartovich, A. P.; Kochetov, I. V.; Leonov, S. B.

2008-07-01

An idea of using plasma-assisted methods of fuel ignition is based on non-equilibrium generation of chemically active species that speed up the combustion process. It is believed that gain in energy consumed for combustion acceleration by plasmas is due to the non-equilibrium nature of discharge plasma, which allows radicals to be produced in an above-equilibrium amount. Evidently, the size of the effect is strongly dependent on the initial temperature, pressure, and composition of the mixture. Of particular interest is comparison between thermal ignition of a fuel-air mixture and non-thermal plasma initiation of the combustion. Mechanisms of thermal ignition in various fuel-air mixtures have been studied for years, and a number of different mechanisms are known providing an agreement with experiments at various conditions. The problem is -- how to conform thermal chemistry approach to essentially non-equilibrium plasma description. The electric discharge produces much above-equilibrium amounts of chemically active species: atoms, radicals and ions. The point is that despite excess concentrations of a number of species, total concentration of these species is far below concentrations of the initial gas mixture. Therefore, rate coefficients for reactions of these discharge produced species with other gas mixture components are well known quantities controlled by the translational temperature, which can be calculated from the energy balance equation taking into account numerous processes initiated by plasma. A numerical model was developed combining traditional approach of thermal combustion chemistry with advanced description of the plasma kinetics based on solution of electron Boltzmann equation. This approach allows us to describe self-consistently strongly non-equilibrium electric discharge in chemically unstable (ignited) gas. Equations of pseudo-one-dimensional gas dynamics were solved in parallel with a system of thermal chemistry equations, kinetic equations

Solid xenon radiation detectors

NASA Astrophysics Data System (ADS)

Dolinski, Michelle J.

2014-03-01

Cryogenic liquid xenon detectors have become a popular technology in the search for rare events, such as dark matter interactions and neutrinoless double beta decay. The power of the liquid xenon detector technology is in the combination of the ionization and scintillation signals, resulting in particle discrimination and improved energy resolution over the ionization-only signal. The improved energy resolution results from a unique anti-correlation phenomenon that has not been described from first principles. Solid xenon bolometers, under development at Drexel University, are expected to have excellent counting statistics in the phonon channel, with energy resolution of 0.1% or better. This additional energy channel may offer the final piece of the puzzle in understanding liquid xenon detector energy response. Supported by a grant from the Charles E. Kaufman Foundation.

Toward molecular mechanism of xenon anesthesia: a link to studies of xenon complexes with small aromatic molecules.

PubMed

Andrijchenko, Natalya N; Ermilov, Alexander Yu; Khriachtchev, Leonid; Räsänen, Markku; Nemukhin, Alexander V

2015-03-19

The present study illustrates the steps toward understanding molecular mechanism of xenon anesthesia by focusing on a link to the structures and spectra of intermolecular complexes of xenon with small aromatic molecules. A primary cause of xenon anesthesia is attributed to inhibition of N-methyl-D-aspartate (NMDA) receptors by an unknown mechanism. Following the results of quantum mechanics/molecular mechanics (QM/MM) and molecular dynamics (MD) calculations we report plausible xenon action sites in the ligand binding domain of the NMDA receptor, which are due to interaction of xenon atoms with aromatic amino-acid residues. We rely in these calculations on computational protocols adjusted in combined experimental and theoretical studies of intermolecular complexes of xenon with phenol. Successful reproduction of vibrational shifts in molecular species upon complexation with xenon measured in low-temperature matrices allowed us to select a proper functional form in density functional theory (DFT) approach for use in QM subsystems, as well as to calibrate force field parameters for MD simulations. The results of molecular modeling show that xenon atoms can compete with agonists for a place in the corresponding protein cavity, thus indicating their active role in anesthetic action.

Configuration interaction in charge exchange spectra of tin and xenon

NASA Astrophysics Data System (ADS)

D'Arcy, R.; Morris, O.; Ohashi, H.; Suda, S.; Tanuma, H.; Fujioka, S.; Nishimura, H.; Nishihara, K.; Suzuki, C.; Kato, T.; Koike, F.; O'Sullivan, G.

2011-06-01

Charge-state-specific extreme ultraviolet spectra from both tin ions and xenon ions have been recorded at Tokyo Metropolitan University. The electron cyclotron resonance source spectra were produced from charge exchange collisions between the ions and rare gas target atoms. To identify unknown spectral lines of tin and xenon, atomic structure calculations were performed for Sn14+-Sn17+ and Xe16+-Xe20+ using the Hartree-Fock configuration interaction code of Cowan (1981 The Theory of Atomic Structure and Spectra (Berkeley, CA: University of California Press)). The energies of the capture states involved in the single-electron process that occurs in these slow collisions were estimated using the classical over-barrier model.

Experimental ion mobility measurements in Xe-CF4 mixtures

NASA Astrophysics Data System (ADS)

Cortez, A. F. V.; Kaja, M. A.; Escada, J.; Santos, M. A. G.; Veenhof, R.; Neves, P. N. B.; Santos, F. P.; Borges, F. I. G. M.; Conde, C. A. N.

2018-04-01

In this paper we present the results of the ion mobility measurements made in gaseous mixtures of xenon with carbon tetrafluoride (Xe-CF4) for pressures ranging from 6 to 10 Torr (8-10.6 mbar) and for low reduced electric fields in the 10 to 25 Td range (2.4-6.1 kVṡcm‑1ṡbar‑1), at room temperature. The time-of-arrival spectra revealed one or two peaks depending on the gas relative abundances, which were attributed to CF3+ and to Xe2+ ions. However, for Xe concentrations above 60%, only one peak remains (Xe2+). The reduced mobilities obtained from the peak centroid of the time-of-arrival spectra are presented for Xe concentrations in the 5%-95% range.

A general stagnation-point convective heating equation for arbitrary gas mixtures

NASA Technical Reports Server (NTRS)

Sutton, K.; Graves, R. A., Jr.

1971-01-01

The stagnation-point convective heat transfer to an axisymmetric blunt body for arbitrary gases in chemical equilibrium was investigated. The gases considered were base gases of nitrogen, oxygen, hydrogen, helium, neon, argon, carbon dioxide, ammonia, and methane and 22 gas mixtures composed of the base gases. Enthalpies ranged from 2.3 to 116.2 MJ/kg, pressures ranged from 0.001 to 100 atmospheres, and the wall temperatures were 300 and 1111 K. A general equation for the stagnation-point convective heat transfer in base gases and gas mixtures was derived and is a function of the mass fraction, the molecular weight, and a transport parameter of the base gases. The relation compares well with present boundary-layer computer results and with other analytical and experimental results. In addition, the analysis verified that the convective heat transfer in gas mixtures can be determined from a summation relation involving the heat transfer coefficients of the base gases. The basic technique developed for the prediction of stagnation-point convective heating to an axisymmetric blunt body could be applied to other heat transfer problems.

Gas Control System for HEAO-B

NASA Technical Reports Server (NTRS)

Taylor, B.; Brissette, R.; Humphrey, A.; Morris, J.; Luger, J.; Swift, W.

1978-01-01

The HEAO-B Gas Control System consists of a high pressure gas storage supply together with distribution and regulation assemblies and their associated electronics for management of gas required for HEAO-B X-ray counter experiments. The Gas Control System replenishes a gas mixture (82 percent argon, 12.3 percent carbon dioxide, 5.7 percent xenon) in the counter volumes which is lost by: diffusion through controlled leakage plugs, diffusion through counter windows, and consumption resulting from periodic purges. The gas density in each counter volume is maintained constant to within 0.25 percent by comparison with a sealed reference volume. The system is fully redundant, capable of operating at atmospheric pressure as well as in a vacuum, contains interlocks which shut down gas flow in the event of either leakage or excessive pressure, and is able to shut down counter high voltage if counter pressure is abnormally low. The system is electronically controlled by ground command and self-sustaining in orbit for a period of at least one year.

UTEX modeling of xenon signature sensitivity to geology and explosion cavity characteristics following an underground nuclear explosion

NASA Astrophysics Data System (ADS)

Lowrey, J. D.; Haas, D.

2013-12-01

Underground nuclear explosions (UNEs) produce anthropogenic isotopes that can potentially be used in the verification component of the Comprehensive Nuclear-Test-Ban Treaty. Several isotopes of radioactive xenon gas have been identified as radionuclides of interest within the International Monitoring System (IMS) and in an On-Site Inspection (OSI). Substantial research has been previously undertaken to characterize the geologic and atmospheric mechanisms that can drive the movement of radionuclide gas from a well-contained UNE, considering both sensitivities on gas arrival time and signature variability of xenon due to the nature of subsurface transport. This work further considers sensitivities of radioxenon gas arrival time and signatures to large variability in geologic stratification and generalized explosion cavity characteristics, as well as compares this influence to variability in the shallow surface.

Initial experimental demonstration of the principles of a xenon gas shield designed to protect optical components from soft x-ray induced opacity (blanking) in high energy density experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Swadling, G. F.; Ross, J. S.; Manha, D.

The design principles of a xenon gas shield device that is intended to protect optical components from x-ray induced opacity (“x-ray blanking”) have been experimentally demonstrated at the OMEGA-60 Laser Facility at the Laboratory for Laser Energetics, University of Rochester. A volume of xenon gas placed in front of an optical component absorbs the incoming soft x-ray radiation but transmits optical and ultra-violet radiation. The time-resolved optical (532 nm) transmission of samples was recorded as they were exposed to soft x-rays produced by a gold sphere source (1.5 kJ sr $-$1, 250–300 eV). Blanking of fused silica (SiO 2) wasmore » measured to occur over a range of time-integrated soft x-ray (<3 keV) fluence from ~0.2–2.5 J cm $-$2. A shield test device consisting of a 30 nm silicon nitride (Si 3N 4) and a 10 cm long volume of 0.04 bar xenon gas succeeded in delaying loss of transmission through a magnesium fluoride sample; optical transmission was observed over a longer period than for the unprotected sample. It is hoped that the design of this x-ray shield can be scaled in order to produce a shield device for the National Ignition Facility optical Thomson scattering collection telescope, in order to allow measurements of hohlraum plasma conditions produced in inertial confinement fusion experiments. Finally, if successful, it will also have applications in many other high energy density experiments where optical and ultra-violet measurements are desirable.« less

Initial experimental demonstration of the principles of a xenon gas shield designed to protect optical components from soft x-ray induced opacity (blanking) in high energy density experiments

DOE PAGES

Swadling, G. F.; Ross, J. S.; Manha, D.; ...

2017-03-16

The design principles of a xenon gas shield device that is intended to protect optical components from x-ray induced opacity (“x-ray blanking”) have been experimentally demonstrated at the OMEGA-60 Laser Facility at the Laboratory for Laser Energetics, University of Rochester. A volume of xenon gas placed in front of an optical component absorbs the incoming soft x-ray radiation but transmits optical and ultra-violet radiation. The time-resolved optical (532 nm) transmission of samples was recorded as they were exposed to soft x-rays produced by a gold sphere source (1.5 kJ sr $-$1, 250–300 eV). Blanking of fused silica (SiO 2) wasmore » measured to occur over a range of time-integrated soft x-ray (<3 keV) fluence from ~0.2–2.5 J cm $-$2. A shield test device consisting of a 30 nm silicon nitride (Si 3N 4) and a 10 cm long volume of 0.04 bar xenon gas succeeded in delaying loss of transmission through a magnesium fluoride sample; optical transmission was observed over a longer period than for the unprotected sample. It is hoped that the design of this x-ray shield can be scaled in order to produce a shield device for the National Ignition Facility optical Thomson scattering collection telescope, in order to allow measurements of hohlraum plasma conditions produced in inertial confinement fusion experiments. Finally, if successful, it will also have applications in many other high energy density experiments where optical and ultra-violet measurements are desirable.« less

Electrochemical separation and concentration of hydrogen sulfide from gas mixtures

DOEpatents

Winnick, Jack; Sather, Norman F.; Huang, Hann S.

1984-10-30

A method of removing sulfur oxides of H.sub.2 S from high temperature gas mixtures (150.degree.-1000.degree. C.) is the subject of the present invention. An electrochemical cell is employed. The cell is provided with inert electrodes and an electrolyte which will provide anions compatible with the sulfur containing anions formed at the anode. The electrolyte is also selected to provide inert stable cations at the temperatures encountered. The gas mixture is passed by the cathode where the sulfur gases are converted to SO.sub.4 -- or, in the case of H.sub.2 S, to S--. The anions migrate to the anode where they are converted to a stable gaseous form at much greater concentration levels (>10X). Current flow may be effected by utilizing an external source of electrical energy or by passing a reducing gas such as hydrogen past the anode.

ELECTROCHEMICAL SEPARATION AND CONCENTRATION OF HYDROGEN SULFIDE FROM GAS MIXTURES

DOEpatents

Winnick, Jack; Sather, Norman F.; Huang, Hann S.

1984-10-30

A method of removing sulfur oxides of H.sub.2 S from high temperature gas mixtures (150.degree.-1000.degree. C.) is the subject of the present invention. An electrochemical cell is employed. The cell is provided with inert electrodes and an electrolyte which will provide anions compatible with the sulfur containing anions formed at the anode. The electrolyte is also selected to provide inert stable cations at the temperatures encountered. The gas mixture is passed by the cathode where the sulfur gases are converted to SO.sub.4 -- or, in the case of H.sub.2 S, to S--. The anions migrate to the anode where they are converted to a stable gaseous form at much greater concentration levels (>10X). Current flow may be effected by utilizing an external source of electrical energy or by passing a reducing gas such as hydrogen past the anode.

Measurement of Xenon Viscosity as a Function of Low Temperature and Pressure

NASA Technical Reports Server (NTRS)

Grisnik, Stanley P.

1998-01-01

The measurement of xenon gas viscosity at low temperatures (175-298 K) and low pressures (350 torr-760 torr) has been performed in support of Hall Thruster testing at NASA Lewis Research Center. The measurements were taken using the capillary flow technique. Viscosity measurements were repeatable to within 3%. The results in this paper are in agreement with data from Hanley and Childs and suggest that the data from Clarke and Smith is approximately 2% low. There are no noticeable pressure effects on xenon absolute viscosity for the pressure range from 350 torr to 760 torr.

Gas mixture studies for streamer operated Resistive Plate Chambers

NASA Astrophysics Data System (ADS)

Paoloni, A.; Longhin, A.; Mengucci, A.; Pupilli, F.; Ventura, M.

2016-06-01

Resistive Plate Chambers operated in streamer mode are interesting detectors in neutrino and astro-particle physics applications (like OPERA and ARGO experiments). Such experiments are typically characterized by large area apparatuses with no stringent requirements on detector aging and rate capabilities. In this paper, results of cosmic ray tests performed on a RPC prototype using different gas mixtures are presented, the principal aim being the optimization of the TetraFluoroPropene concentration in Argon-based mixtures. The introduction of TetraFluoroPropene, besides its low Global Warming Power, is helpful because it simplifies safety requirements allowing to remove also isobutane from the mixture. Results obtained with mixtures containing SF6, CF4, CO2, N2 and He are also shown, presented both in terms of detectors properties (efficiency, multiple-streamer probability and time resolution) and in terms of streamer characteristics.

Simultaneous resonant enhanced multiphoton ionization and electron avalanche ionization in gas mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shneider, Mikhail N.; Zhang Zhili; Miles, Richard B.

2008-07-15

Resonant enhanced multiphoton ionization (REMPI) and electron avalanche ionization (EAI) are measured simultaneously in Ar:Xe mixtures at different partial pressures of mixture components. A simple theory for combined REMPI+EAI in gas mixture is developed. It is shown that the REMPI electrons seed the avalanche process, and thus the avalanche process amplifies the REMPI signal. Possible applications are discussed.

Development of Solid Xenon Bolometers

NASA Astrophysics Data System (ADS)

Dolinski, Michelle; Hansen, Erin

2016-09-01

Cryogenic liquid xenon detectors have become a popular technology in the search for rare events, such as dark matter interactions and neutrinoless double beta decay. The power of liquid xenon detector technology is in the combination of ionization and scintillation signals, resulting in particle discrimination and improved energy resolution over the ionization-only signal. The improved energy resolution results from a microscopic anti-correlation phenomenon that has not been described from first principles. Solid xenon bolometers operated at 10 mK are expected to have excellent counting statistics in the phonon channel, with energy resolution of 0.1% or better. This additional energy channel may offer the final piece of the puzzle in understanding liquid xenon detector energy response. We present work toward the development and characterization of solid xenon bolometers at Drexel University. Funding for this project was provided by the Charles E. Kaufman Foundation of The Pittsburgh Foundation.

Evaluation of carrier agents for hyperpolarized xenon MRI

NASA Technical Reports Server (NTRS)

Venkatesh, A. K.; Zhao, L.; Balamore, D.; Jolesz, F. A.; Albert, M. S.

2000-01-01

Several biocompatible carrier agents, in which xenon is highly soluble and has a long T(1), were tested, and injected in living rats. These included saline, Intralipid suspension, perfluorocarbon emulsion and (129)Xe gas-filled liposomes. The T(1) of (129)Xe in these compounds ranged from 47 to 116 s. Vascular injection of these carrier agents was tolerated well, encouraging their use for further experiments in live animals. In vivo spectra, obtained from gas-filled liposomes and perfluorocarbon solutions, suggest that these carrier agents have potential for use in angiography and perfusion imaging. Copyright 2000 John Wiley & Sons, Ltd.

Xenon improves neurological outcome and reduces secondary injury following trauma in an in vivo model of traumatic brain injury

PubMed Central

Luh, Clara; Gruss, Marco; Radyushkin, Konstantin; Hirnet, Tobias; Werner, Christian; Engelhard, Kristin; Franks, Nicholas P; Thal, Serge C; Dickinson, Robert

2015-01-01

Objectives To determine the neuroprotective efficacy of the inert gas xenon following traumatic brain injury, and to determine whether application of xenon has a clinically relevant therapeutic time window. Design Controlled animal study. Setting University research laboratory. Subjects Male C57BL/6N mice (n=196) Interventions 75% xenon, 50% xenon or 30% xenon, with 25% oxygen (balance nitrogen) treatment following mechanical brain lesion by controlled cortical impact. Measurements & Main Results Outcome following trauma was measured using: 1) functional neurological outcome score, 2) histological measurement of contusion volume, 3) analysis of locomotor function and gait. Our study shows that xenon-treatment improves outcome following traumatic brain injury. Neurological outcome scores were significantly (p<0.05) better in xenon-treated groups in the early phase (24 hours) and up to 4 days after injury. Contusion volume was significantly (p<0.05) reduced in the xenon-treated groups. Xenon treatment significantly (p<0.05) reduced contusion volume when xenon was given 15 minutes after injury or when treatment was delayed 1 hour or 3 hours after injury. Neurological outcome was significantly (p<0.05) improved when xenon treatment was given 15 minutes or 1 hour after injury. Improvements in locomotor function (p<0.05) were observed in the xenon-treated group, 1 month after trauma. Conclusions These results show for the first time that xenon improves neurological outcome and reduces contusion volume following traumatic brain injury in mice. In this model, xenon application has a therapeutic time window of up to at least 3 hours. These findings support the idea that xenon may be of benefit as a neuroprotective treatment in brain trauma patients. PMID:25188549

Xenon improves neurologic outcome and reduces secondary injury following trauma in an in vivo model of traumatic brain injury.

PubMed

Campos-Pires, Rita; Armstrong, Scott P; Sebastiani, Anne; Luh, Clara; Gruss, Marco; Radyushkin, Konstantin; Hirnet, Tobias; Werner, Christian; Engelhard, Kristin; Franks, Nicholas P; Thal, Serge C; Dickinson, Robert

2015-01-01

To determine the neuroprotective efficacy of the inert gas xenon following traumatic brain injury and to determine whether application of xenon has a clinically relevant therapeutic time window. Controlled animal study. University research laboratory. Male C57BL/6N mice (n = 196). Seventy-five percent xenon, 50% xenon, or 30% xenon, with 25% oxygen (balance nitrogen) treatment following mechanical brain lesion by controlled cortical impact. Outcome following trauma was measured using 1) functional neurologic outcome score, 2) histological measurement of contusion volume, and 3) analysis of locomotor function and gait. Our study shows that xenon treatment improves outcome following traumatic brain injury. Neurologic outcome scores were significantly (p < 0.05) better in xenon-treated groups in the early phase (24 hr) and up to 4 days after injury. Contusion volume was significantly (p < 0.05) reduced in the xenon-treated groups. Xenon treatment significantly (p < 0.05) reduced contusion volume when xenon was given 15 minutes after injury or when treatment was delayed 1 or 3 hours after injury. Neurologic outcome was significantly (p < 0.05) improved when xenon treatment was given 15 minutes or 1 hour after injury. Improvements in locomotor function (p < 0.05) were observed in the xenon-treated group, 1 month after trauma. These results show for the first time that xenon improves neurologic outcome and reduces contusion volume following traumatic brain injury in mice. In this model, xenon application has a therapeutic time window of up to at least 3 hours. These findings support the idea that xenon may be of benefit as a neuroprotective treatment in patients with brain trauma.

Xenon adsorption on geological media and implications for radionuclide signatures.

PubMed

Paul, M J; Biegalski, S R; Haas, D A; Jiang, H; Daigle, H; Lowrey, J D

2018-07-01

The detection of radioactive noble gases is a primary technology for verifying compliance with the pending Comprehensive Nuclear-Test-Ban Treaty. A fundamental challenge in applying this technology for detecting underground nuclear explosions is estimating the timing and magnitude of the radionuclide signatures. While the primary mechanism for transport is advective transport, either through barometric pumping or thermally driven advection, diffusive transport in the surrounding matrix also plays a secondary role. From the study of primordial noble gas signatures, it is known that xenon has a strong physical adsorption affinity in shale formations. Given the unselective nature of physical adsorption, isotherm measurements reported here show that non-trivial amounts of xenon adsorb on a variety of media, in addition to shale. A dual-porosity model is then discussed demonstrating that sorption amplifies the diffusive uptake of an adsorbing matrix from a fracture. This effect may reduce the radioxenon signature down to approximately one-tenth, similar to primordial xenon isotopic signatures. Copyright © 2018 Elsevier Ltd. All rights reserved.

More environment-friendly and safer working gas mixtures for Bakelite RPCs operated in streamer mode

NASA Astrophysics Data System (ADS)

Zhang, Qingmin; Lv, Zhipeng; Lv, Jinge; Zhang, Jiawen; Xu, Jilei; Ning, Zhe

2017-08-01

This paper presents experimental results of RPCs performances with different working gas mixtures. Owing to Freon's high global warming potential, its threat to RPCs aging and its large consumption in large particle physics experiments, studies to minimize the concentration of HFC-134A, and even its complete replacement, have been undertaken. In addition, the reduction of iso-butane is also a favorable strategy, due to the flammability level of the gas mixture. Freon-less working gas mixture of Ar/HFC-134A/i-C4H10/CO2=20/0/8/72 was chosen with plateau efficiency of 86.3% and noise rate of 0.61 Hz/cm2. For working gas with lower ratio of Freon, Ar/HFC-134A/i-C4H10/CO2=20/20/8/52 was suggested with plateau efficiency of 91.0% and noise rate of 0.19 Hz/cm2, in which Freon was decreased by 22% compared to the BESIII RPC gas mixture. Furthermore, iso-butane was decreased to 6% with RPC's efficiency of 90% and noise rate of 0.20 Hz/cm2 achieved. Finally, the explanation of RPC's different performances at various working gas mixtures has been validated by the investigation of secondary streamers. This study will be helpful for RPC's application in future large particle physics experiments, in which RPCs can run in streamer mode.

Radioactive 133-Xenon gas-filled balloon to prevent restenosis: dosimetry, efficacy, and safety considerations.

PubMed

Apple, Marc; Waksman, Ron; Chan, Rosanna C; Vodovotz, Yoram; Fournadjiev, Jana; Bass, Bill G

2002-08-06

Ionizing radiation administered intraluminally via catheter-based systems using solid beta and gamma sources or liquid-filled balloons has shown reduction in the neointima formation after injury in the porcine model. We propose a novel system that uses a 133-Xenon (133Xe) radioactive gas-filled balloon catheter system. Overstretch balloon injury was performed in the coronary arteries of 33 domestic pigs. A novel 133Xe radioactive gas-filled balloon (3.5/45 mm) was positioned to overlap the injured segment with margins. After vacuum was obtained in the balloon catheter, approximately 2.5 cc of 133Xe gas was injected to fill the balloon. Doses of 0, 7.5, 15, and 30 Gy were delivered to a distance of 0.25 mm from the balloon surface. The dwell time ranged from 1.0 to 4.0 minutes, depending on the dose. Localization of 133Xe in the balloon was verified by a gamma camera. The average activity in a 3.5/45-mm balloon was measured at 67.7+/-12.1 mCi, and the total diffusion loss of the injected dose was 0.26% per minute of the injected dose. Bedside radiation exposure measured between 2 and 6 mR/h, and the shallow dose equivalent was calculated as 0.037 mrem per treatment. Histomorphometric analysis at 2 weeks showed inhibition of the intimal area (intimal area corrected for medial fracture length [IA/FL]) in the irradiated segments of 0.26+/-0.08 with 30 Gy, 0.07+/-0.24 with 15 Gy, and 0.12+/-0.89 with 7.5 Gy versus 0.76+/-0.08 with control P<0.001. 133Xe gas-filled balloon is feasible and effective in the reduction of neointima formation in the porcine model and safe for use in coronary arteries.

Search for WIMP inelastic scattering off xenon nuclei with XENON100

NASA Astrophysics Data System (ADS)

Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Arneodo, F.; Barrow, P.; Baudis, L.; Bauermeister, B.; Benabderrahmane, M. L.; Berger, T.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cervantes, M.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; di Gangi, P.; di Giovanni, A.; Diglio, S.; Eurin, G.; Fei, J.; Ferella, A. D.; Fieguth, A.; Fulgione, W.; Gallo Rosso, A.; Galloway, M.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Greene, Z.; Grignon, C.; Hasterok, C.; Hogenbirk, E.; Itay, R.; Kaminsky, B.; Kazama, S.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Lellouch, D.; Levinson, L.; Lin, Q.; Lindemann, S.; Lindner, M.; Lombardi, F.; Lopes, J. A. M.; Manfredini, A.; Maris, I.; Marrodán Undagoitia, T.; Masbou, J.; Massoli, F. V.; Masson, D.; Mayani, D.; Messina, M.; Micheneau, K.; Molinario, A.; Mora, K.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Pakarha, P.; Pelssers, B.; Persiani, R.; Piastra, F.; Pienaar, J.; Pizzella, V.; Piro, M.-C.; Plante, G.; Priel, N.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; Rupp, N.; Dos Santos, J. M. F.; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schreiner, J.; Schumann, M.; Scotto Lavina, L.; Selvi, M.; Shagin, P.; Silva, M.; Simgen, H.; Sivers, M. V.; Stein, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Vargas, M.; Wang, H.; Wang, Z.; Wei, Y.; Weinheimer, C.; Wulf, J.; Ye, J.; Zhang, Y.; Xenon Collaboration

2017-07-01

We present the first constraints on the spin-dependent, inelastic scattering cross section of weakly interacting massive particles (WIMPs) on nucleons from XENON100 data with an exposure of 7.64 ×103 kg .days . XENON100 is a dual-phase xenon time projection chamber with 62 kg of active mass, operated at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy and designed to search for nuclear recoils from WIMP-nucleus interactions. Here we explore inelastic scattering, where a transition to a low-lying excited nuclear state of Xe 129 is induced. The experimental signature is a nuclear recoil observed together with the prompt deexcitation photon. We see no evidence for such inelastic WIMP-Xe 129 interactions. A profile likelihood analysis allows us to set a 90% C.L. upper limit on the inelastic, spin-dependent WIMP-nucleon cross section of 3.3 ×10-38 cm2 at 100 GeV /c2 . This is the most constraining result to date, and sets the pathway for an analysis of this interaction channel in upcoming, larger dual-phase xenon detectors.

Regional Mapping of Gas Uptake by Blood and Tissue in the Human Lung using Hyperpolarized Xenon-129 MRI

PubMed Central

Qing, Kun; Ruppert, Kai; Jiang, Yun; Mata, Jaime F.; Miller, G. Wilson; Shim, Y. Michael; Wang, Chengbo; Ruset, Iulian C.; Hersman, F. William; Altes, Talissa A.; Mugler, John P.

2013-01-01

Purpose To develop a breath-hold acquisition for regional mapping of ventilation and the fractions of hyperpolarized xenon-129 (Xe129) dissolved in tissue (lung parenchyma and plasma) and red blood cells (RBCs), and to perform an exploratory study to characterize data obtained in human subjects. Materials and Methods A three-dimensional, multi-echo, radial-trajectory pulse sequence was developed to obtain ventilation (gaseous Xe129), tissue and RBC images in healthy subjects, smokers and asthmatics. Signal ratios (total dissolved Xe129 to gas, tissue-to-gas, RBC-to-gas and RBC-to-tissue) were calculated from the images for quantitative comparison. Results Healthy subjects demonstrated generally uniform values within coronal slices, and a gradient in values along the anterior-to-posterior direction. In contrast, images and associated ratio maps in smokers and asthmatics were generally heterogeneous and exhibited values mostly lower than those in healthy subjects. Whole-lung values of total dissolved Xe129 to gas, tissue-to-gas, and RBC-to-gas ratios in healthy subjects were significantly larger than those in diseased subjects. Conclusion Regional maps of tissue and RBC fractions of dissolved Xe129 were obtained from a short breath-hold acquisition, well tolerated by healthy volunteers and subjects with obstructive lung disease. Marked differences were observed in spatial distributions and overall amounts of Xe129 dissolved in tissue and RBCs among healthy subjects, smokers and asthmatics. PMID:23681559

Sub-anesthetic Xenon Increases Erythropoietin Levels in Humans: A Randomized Controlled Trial.

PubMed

Stoppe, Christian; Ney, Julia; Brenke, Martin; Goetzenich, Andreas; Emontzpohl, Christoph; Schälte, Gereon; Grottke, Oliver; Moeller, Manfred; Rossaint, Rolf; Coburn, Mark

2016-11-01

The licensed anesthetic xenon, which exerts organ protective properties, was recently added by the World Anti-Doping Agency to the list of prohibited substances. Xenon is supposed to trigger the production of hypoxia-inducible factor 1α (HIF-1α) and subsequently erythropoietin, but data are limited to in vivo experimental work. Therefore we evaluated the effect of xenon on erythropoietin levels in healthy persons. Twenty-four healthy volunteers were randomly assigned either to a group spontaneously breathing xenon 30 % (Xe/O 2 30 %/60 %) or a group breathing control gas (N 2 /O 2 40 %/60 %) for 45 min. Primary outcome parameters were erythropoietin levels at several time-points after exposure. Secondary outcome parameters were serum levels of testosterone, cytokines, and growth factors as well as concentrations of xenon in blood and exhalation samples measured at several time-points after exposure. In addition, hemodynamic safety parameters were monitored during exposure. The administration of xenon significantly increased erythropoietin levels 8 h after exposure (1.34 [±0.368]; p = 0.008), peaking at 24 h compared to the baseline values (1.45 [±0.498]; p = 0.01) and remained traceable in blood and exhalation probes until 24 h after exposure. In contrast, no significant change was observed in the control group. Measurement of stromal cell-derived factor 1 (SDF-1) revealed a significant increase of SDF-1 levels (p = 0.005), whereas no differences were observed with respect to growth factors, cytokines, or androgens. In an in vitro chemotaxis assay, endothelial progenitor cells (EPCs) showed a trend towards increased migration in serum samples received from participants after xenon exposure (p = 0.080). The present study presents first evidence about a xenon-induced effect on increased erythropoietin levels in healthy volunteers. The study was registered at the European Medicines Agency (EudraCT-number: 2014-000973-38) and at Clinical

Magnetization transfer from laser-polarized xenon to protons located in the hydrophobic cavity of the wheat nonspecific lipid transfer protein

PubMed Central

Landon, Céline; Berthault, Patrick; Vovelle, Françoise; Desvaux, Hervé

2001-01-01

Nonspecific lipid transfer protein from wheat is studied by liquid-state NMR in the presence of xenon. The gas–protein interaction is indicated by the dependence of the protein proton chemical shifts on the xenon pressure and formally confirmed by the first observation of magnetization transfer from laser-polarized xenon to the protein protons. Twenty-six heteronuclear nOes have allowed the characterization of four interaction sites inside the wheat ns-LTP cavity. Their locations are in agreement with the variations of the chemical shifts under xenon pressure and with solvation simulations. The richness of the information obtained by the noble gas with a nuclear polarization multiplied by ∼12,000 makes this approach based on dipolar cross-relaxation with laser-polarized xenon promising for probing protein hydrophobic pockets at ambient pressure. PMID:11274467

Synthesis and investigation of reaction mechanisms of diamondoids produced using plasmas generated inside microcapillaries in supercritical xenon

NASA Astrophysics Data System (ADS)

Oshima, Fumito; Stauss, Sven; Inose, Yoshifumi; Terashima, Kazuo

2014-01-01

We have synthesized diamondoids using dielectric barrier discharge microplasmas generated inside a microcapillary reactor in supercritical xenon. The plasmas were generated near the critical temperature (T_{\\text{crit}} = 389.75\\,\\text{K}) and pressure (p_{\\text{crit}} = 5.84\\,\\text{MPa}) of xenon in the ranges of T/T_{\\text{crit}} = 0.964-0.983 and p/p_{\\text{crit}} = 0.998\\text-1.026 under both batch-type and continuous flow conditions with gas flow rates of 0.01-0.5 mL min-1. Micro-Raman spectra of the synthesized particles showed features characteristic of diamondoids, while gas chromatography-mass spectrometry measurements revealed that diamondoids up to undecamantane were possibly synthesized. Further, the amount of obtained diamantane was greater than those obtained using previously reported diamondoid synthesis processes that involve plasmas in supercritical fluids. This increase is attributed to the higher solubility of the supercritical medium, i.e., xenon, and the higher efficiency of the microreactor. A detailed gas chromatography-mass spectrometry analysis showed that higher diamondoids grow in a stepwise manner via the alternate removal of hydrogen atoms and the addition of methyl groups.

Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

DOEpatents

Aines, Roger D

2015-03-31

A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

Catalyst functionalized buffer sorbent pebbles for rapid separation of carbon dioxide from gas mixtures

DOEpatents

Aines, Roger D.

2013-03-12

A method for separating CO.sub.2 from gas mixtures uses a slurried media impregnated with buffer compounds and coating the solid media with a catalyst or enzyme that promotes the transformation of CO.sub.2 to carbonic acid. Buffer sorbent pebbles with a catalyst or enzyme coating are provided for rapid separation of CO.sub.2 from gas mixtures.

Theoretical Calculation of the Electron Transport Parameters and Energy Distribution Function for CF3I with noble gases mixtures using Monte Carlo simulation program

NASA Astrophysics Data System (ADS)

Jawad, Enas A.

2018-05-01

In this paper, The Monte Carlo simulation program has been used to calculation the electron energy distribution function (EEDF) and electric transport parameters for the gas mixtures of The trif leoroiodo methane (CF3I) ‘environment friendly’ with a noble gases (Argon, Helium, kryptos, Neon and Xenon). The electron transport parameters are assessed in the range of E/N (E is the electric field and N is the gas number density of background gas molecules) between 100 to 2000Td (1 Townsend = 10-17 V cm2) at room temperature. These parameters, namely are electron mean energy (ε), the density –normalized longitudinal diffusion coefficient (NDL) and the density –normalized mobility (μN). In contrast, the impact of CF3I in the noble gases mixture is strongly apparent in the values for the electron mean energy, the density –normalized longitudinal diffusion coefficient and the density –normalized mobility. Note in the results of the calculation agreed well with the experimental results.

High-Rydberg Xenon Submillimeter-Wave Detector

NASA Technical Reports Server (NTRS)

Chutjian, Ara

1987-01-01

Proposed detector for infrared and submillimeter-wavelength radiation uses excited xenon atoms as Rydberg sensors instead of customary beams of sodium, potassium, or cesium. Chemically inert xenon easily stored in pressurized containers, whereas beams of dangerously reactive alkali metals must be generated in cumbersome, unreliable ovens. Xenon-based detector potential for infrared astronomy and for Earth-orbiter detection of terrestrial radiation sources. Xenon atoms excited to high energy states in two stages. Doubly excited atoms sensitive to photons in submillimeter wavelength range, further excited by these photons, then ionized and counted.

Implementation of Ultrasonic Sensing for High Resolution Measurement of Binary Gas Mixture Fractions

PubMed Central

Bates, Richard; Battistin, Michele; Berry, Stephane; Bitadze, Alexander; Bonneau, Pierre; Bousson, Nicolas; Boyd, George; Bozza, Gennaro; Crespo-Lopez, Olivier; Riva, Enrico Da; Degeorge, Cyril; Deterre, Cecile; DiGirolamo, Beniamino; Doubek, Martin; Favre, Gilles; Godlewski, Jan; Hallewell, Gregory; Hasib, Ahmed; Katunin, Sergey; Langevin, Nicolas; Lombard, Didier; Mathieu, Michel; McMahon, Stephen; Nagai, Koichi; Pearson, Benjamin; Robinson, David; Rossi, Cecilia; Rozanov, Alexandre; Strauss, Michael; Vitek, Michal; Vacek, Vaclav; Zwalinski, Lukasz

2014-01-01

We describe an ultrasonic instrument for continuous real-time analysis of the fractional mixture of a binary gas system. The instrument is particularly well suited to measurement of leaks of a high molecular weight gas into a system that is nominally composed of a single gas. Sensitivity < 5 × 10−5 is demonstrated to leaks of octaflouropropane (C3F8) coolant into nitrogen during a long duration (18 month) continuous study. The sensitivity of the described measurement system is shown to depend on the difference in molecular masses of the two gases in the mixture. The impact of temperature and pressure variances on the accuracy of the measurement is analysed. Practical considerations for the implementation and deployment of long term, in situ ultrasonic leak detection systems are also described. Although development of the described systems was motivated by the requirements of an evaporative fluorocarbon cooling system, the instrument is applicable to the detection of leaks of many other gases and to processes requiring continuous knowledge of particular binary gas mixture fractions. PMID:24961217

The ‘ideal selectivity’ vs ‘true selectivity’ for permeation of gas mixture in nanoporous membranes

NASA Astrophysics Data System (ADS)

He, Zhou; Wang, Kean

2018-03-01

In this study, we proposed and validated a novel and non-destructive experimental technology for measuring the permeation of binary gas mixture in nanoporous membranes. The traditional time lag rig was modified to examine the permeation characteristics of each gas component as well as that of the binary gas mixtures. The difference in boiling points of each species were explored. Binary gas mixtures of CO2/He were permeated through the nanoporous carbon molecular sieve membrane (CMSM). The results showed that, due to the strong interaction among different molecules and with the porous network of the membrane, the measured perm-selectivity or ‘true selectivity’ of a binary mixture can significantly deviate from the ‘ideal selectivity’ calculated form the permeation flux of each pure species, and this deviation is a complicated function of the molecular properties and operation conditions.

On the behavior of solutions of xenon in liquid n-alkanes: solubility of xenon in n-pentane and n-hexane.

PubMed

Bonifácio, Rui P M F; Martins, Luís F G; McCabe, Clare; Filipe, Eduardo J M

2010-12-09

The solubility of xenon in liquid n-pentane and n-hexane has been studied experimentally, theoretically, and by computer simulation. Measurements of the solubility are reported for xenon + n-pentane as a function of temperature from 254 to 305 K. The uncertainty in the experimental data is less than 0.15%. The thermodynamic functions of solvation such as the standard Gibbs energy, enthalpy, and entropy of solvation have been calculated from Henry's law coefficients for xenon + n-pentane solutions and also for xenon + n-hexane, which were reported in previous work. The results provide a further example of the similarity between the xenon + n-alkane interaction and the n-alkane + n-alkane interactions. Using the SAFT-VR approach we were able to quantitatively predict the experimental solubility for xenon in n-pentane and semiquantitatively that of xenon in n-hexane using simple Lorentz-Berthelot combining rules to describe the unlikely interaction. Henry's constants at infinite dilution for xenon + n-pentane and xenon + n-hexane were also calculated by Monte Carlo simulation using a united atom force field to describe the n-alkane and the Widom test particle insertion method.

Xenon is an inhibitor of tissue-plasminogen activator: adverse and beneficial effects in a rat model of thromboembolic stroke

PubMed Central

David, Hélène N; Haelewyn, Benoît; Risso, Jean-Jacques; Colloc'h, Nathalie; Abraini, Jacques H

2010-01-01

Preclinical evidence in rodents has proven that xenon may be a very promising neuroprotective agent for treating acute ischemic stroke. This has led to the general thinking that clinical trials with xenon could be initiated in acute stroke patients in a next future. However, an unappreciated physicochemical property of xenon has been that this gas also binds to the active site of a series of serine proteases. Because the active site of serine proteases is structurally conserved, we have hypothesized and investigated whether xenon may alter the catalytic efficiency of tissue-type plasminogen activator (tPA), a serine protease that is the only approved therapy for acute ischemic stroke today. Here, using molecular modeling and in vitro and in vivo studies, we show (1) xenon is a tPA inhibitor; (2) intraischemic xenon dose dependently inhibits tPA-induced thrombolysis and subsequent reduction of ischemic brain damage; (3) postischemic xenon virtually suppresses ischemic brain damage and tPA-induced brain hemorrhages and disruption of the blood–brain barrier. Taken together, these data indicate (1) xenon should not be administered before or together with tPA therapy; (2) xenon could be a golden standard for treating acute ischemic stroke if given after tPA-induced reperfusion, with both unique neuroprotective and antiproteolytic (anti-hemorrhaging) properties. PMID:20087367

Investigation of Dalton and Amagat’s laws for gas mixtures with shock propagation

DOE PAGES

Wayne, Patrick; Cooper, Sean; Simons, Dylan; ...

2017-06-20

Dalton's and Amagat's laws (also known as the law of partial pressures and the law of partial volumes respectively) are two well-known thermodynamic models describing gas mixtures. We focus our current research on determining the suitability of these models in predicting effects of shock propagation through gas mixtures. Experiments are conducted at the Shock Tube Facility at the University of New Mexico (UNM). The gas mixture used in these experiments consists of approximately 50% sulfur hexafluoride (SF6) and 50% helium (He) by mass. Fast response pressure transducers are used to obtain pressure readings both before and after the shock wave;more » these data are then used to determine the velocity of the shock wave. Temperature readings are obtained using an ultra-fast mercury cadmium telluride (MCT) infrared (IR) detector, with a response time on the order of nanoseconds. Coupled with a stabilized broadband infrared light source (operating at 1500 K), the detector provides pre- and post-shock line-of-sight readings of average temperature within the shock tube, which are used to determine the speed of sound in the gas mixture. Paired with the velocity of the shock wave, this information allows us to determine the Mach number. Our experimental results are compared with theoretical predictions of Dalton's and Amagat's laws to determine which one is more suitable.« less

Electrochemical separation and concentration of sulfur containing gases from gas mixtures

DOEpatents

Winnick, Jack

1981-01-01

A method of removing sulfur oxides of H.sub.2 S from high temperature gas mixtures (150.degree.-1000.degree. C.) is the subject of the present invention. An electrochemical cell is employed. The cell is provided with inert electrodes and an electrolyte which will provide anions compatible with the sulfur containing anions formed at the anode. The electrolyte is also selected to provide inert stable cations at the temperatures encountered. The gas mixture is passed by the cathode where the sulfur gases are converted to SO.sub.4.sup.= or, in the case of H.sub.2 S, to S.sup.=. The anions migrate to the anode where they are converted to a stable gaseous form at much greater concentration levels (>10X). Current flow may be effected by utilizing an external source of electrical energy or by passing a reducing gas such as hydrogen past the anode.

Relaxation rates of low-field gas-phase ^129Xe storage cells

NASA Astrophysics Data System (ADS)

Limes, Mark; Saam, Brian

2010-10-01

A study of longitudinal nuclear relaxation rates T1 of ^129Xe and Xe-N2 mixtures in a magnetic field of 3.8 mT is presented. In this regime, intrinsic spin relaxation is dominated by the intramolecular spin-rotation interaction due to persistent xenon dimers, a mechanism that can be quelled by introducing large amounts of N2 into the storage cell. Extrinsic spin relaxation is dominated by the wall-relaxation rate, which is the primary quantity of interest for the various low-field storage cells and coatings that we have tested. Previous group work has shown that extremely long gas-phase relaxation times T1 can be obtained, but only at large magnetic fields and low xenon densities. The current work is motivated by the practical benefits of retaining hyperpolarized ^129Xe for extended periods of time in a small magnetic field.

An experimental approach aiming the production of a gas mixture composed of hydrogen and methane from biomass as natural gas substitute in industrial applications.

PubMed

Kraussler, Michael; Schindler, Philipp; Hofbauer, Hermann

2017-08-01

This work presents an experimental approach aiming the production of a gas mixture composed of H 2 and CH 4 , which should serve as natural gas substitute in industrial applications. Therefore, a lab-scale process chain employing a water gas shift unit, scrubbing units, and a pressure swing adsorption unit was operated with tar-rich product gas extracted from a commercial dual fluidized bed biomass steam gasification plant. A gas mixture with a volumetric fraction of about 80% H 2 and 19% CH 4 and with minor fractions of CO and CO 2 was produced by employing carbon molecular sieve as adsorbent. Moreover, the produced gas mixture had a lower heating value of about 15.5MJ·m -3 and a lower Wobbe index of about 43.4MJ·m -3 , which is similar to the typical Wobbe index of natural gas. Copyright © 2017 Elsevier Ltd. All rights reserved.

ARGON, XENON, HYDROGEN, AND THE OXYGEN CONSUMPTION AND GLYCOLYSIS OF MOUSE TISSUE SLICES

PubMed Central

South, Frank E.; Cook, Sherburne F.

1954-01-01

The effects of xenon, argon, and hydrogen on the aerobic and anaerobic metabolism of mouse liver, brain, and sarcoma slices have been investigated. Xenon was found to alter the rates of metabolism of these tissues in a manner almost identical with helium. The gas increased the rate of oxygen consumption in all three tissues and significantly depressed that of anaerobic glycolysis in brain and liver. The depression of glycolysis in sarcoma was less pronounced and not highly significant. Although both the magnitude and statistical significance of the effects observed with argon were much smaller, there was a seeming adherence to the general pattern established by xenon and helium. Hydrogen while remaining essentially ineffective insofar as oxygen uptake was concerned, depressed glycolysis in both liver and brain slices but did not significantly affect sarcoma slices. The following points are stressed in the Discussion: (1) the magnitude and direction of effects exerted by helium, argon, xenon, hydrogen, and nitrogen do not conform with the relative values of molecular weight, density, and solubility of these gases; (2) the effect of these gases on tissue metabolism does not necessarily parallel that exerted upon the whole organism. PMID:13118104

Chlorine gas toxicity from mixture of bleach with other cleaning products--California.

PubMed

1991-09-13

From October 1987 through November 1989, five episodes of chlorine gas exposure with toxicity to at least 14 persons occurred at two state hospitals in California. Each hospital provides inpatient treatment to approximately 1000 forensic psychiatric patients. As part of their rehabilitation programs, selected patients perform cleaning duties under the supervision of janitors or nursing staff. Each incident occurred during the performance of these duties and involved the mixture of bleach (sodium hypochlorite) and a phosphoric acid cleaner by inpatients. This mixture produced chlorine gas and other chemical byproducts (Figure 1a and 1b) and resulted in temporary illness in exposed persons.

Assessment of regional emphysema, air-trapping and Xenon-ventilation using dual-energy computed tomography in chronic obstructive pulmonary disease patients.

PubMed

Lee, Sang Min; Seo, Joon Beom; Hwang, Hye Jeon; Kim, Namkug; Oh, Sang Young; Lee, Jae Seung; Lee, Sei Won; Oh, Yeon-Mok; Kim, Tae Hoon

2017-07-01

To compare the parenchymal attenuation change between inspiration/expiration CTs with dynamic ventilation change between xenon wash-in (WI) inspiration and wash-out (WO) expiration CTs. 52 prospectively enrolled COPD patients underwent xenon ventilation dual-energy CT during WI and WO periods and pulmonary function tests (PFTs). The parenchymal attenuation parameters (emphysema index (EI), gas-trapping index (GTI) and air-trapping index (ATI)) and xenon ventilation parameters (xenon in WI (Xe-WI), xenon in WO (Xe-WO) and xenon dynamic (Xe-Dyna)) of whole lung and three divided areas (emphysema, hyperinflation and normal) were calculated on virtual non-contrast images and ventilation images. Pearson correlation, linear regression analysis and one-way ANOVA were performed. EI, GTI and ATI showed a significant correlation with Xe-WI, Xe-WO and Xe-Dyna (EI R = -.744, -.562, -.737; GTI R = -.621, -.442, -.629; ATI R = -.600, -.421, -.610, respectively, p < 0.01). All CT parameters showed significant correlation with PFTs except forced vital capacity (FVC). There was a significant difference in GTI, ATI and Xe-Dyna in each lung area (p < 0.01). The parenchymal attenuation change between inspiration/expiration CTs and xenon dynamic change between xenon WI- and WO-CTs correlate significantly. There are alterations in the dynamics of xenon ventilation between areas of emphysema. • The xenon ventilation change correlates with the parenchymal attenuation change. • The xenon ventilation change shows the difference between three lung areas. • The combination of attenuation and xenon can predict more accurate PFTs.

Effective diffusion coefficients of gas mixture in heavy oil under constant-pressure conditions

NASA Astrophysics Data System (ADS)

Li, Huazhou Andy; Sun, Huijuan; Yang, Daoyong

2017-05-01

We develop a method to determine the effective diffusion coefficient for each individual component of a gas mixture in a non-volatile liquid (e.g., heavy oil) at high pressures with compositional analysis. Theoretically, a multi-component one-way diffusion model is coupled with the volume-translated Peng-Robinson equation of state to quantify the mass transfer between gas and liquid (e.g., heavy oil). Experimentally, the diffusion tests have been conducted with a PVT setup for one pure CO2-heavy oil system and one C3H8-CO2-heavy oil system under constant temperature and pressure, respectively. Both the gas-phase volume and liquid-phase swelling effect are simultaneously recorded during the measurement. As for the C3H8-CO2-heavy oil system, the gas chromatography method is employed to measure compositions of the gas phase at the beginning and end of the diffusion measurement, respectively. The effective diffusion coefficients are then determined by minimizing the discrepancy between the measured and calculated gas-phase composition at the end of diffusion measurement. The newly developed technique can quantify the contributions of each component of mixture to the bulk mass transfer from gas into liquid. The effective diffusion coefficient of C3H8 in the C3H8-CO2 mixture at 3945 ± 20 kPa and 293.85 K, i.e., 18.19 × 10^{ - 10} {{m}}^{ 2} / {{s}}, is found to be much higher than CO2 at 3950 ± 18 kPa and 293.85 K, i.e., 8.68 × 10^{ - 10} {{m}}^{ 2} / {{s}}. In comparison with pure CO2, the presence of C3H8 in the C3H8-CO2 mixture contributes to a faster diffusion of CO2 from the gas phase into heavy oil and consequently a larger swelling factor of heavy oil.

Measurement of xenon diffusing capacity in the rat lung by hyperpolarized 129Xe MRI and dynamic spectroscopy in a single breath-hold.

PubMed

Abdeen, Nishard; Cross, Albert; Cron, Gregory; White, Steven; Rand, Thomas; Miller, David; Santyr, Giles

2006-08-01

We used the dual capability of hyperpolarized 129Xe for spectroscopy and imaging to develop new measures of xenon diffusing capacity in the rat lung that (analogously to the diffusing capacity of carbon monoxide or DLCO) are calculated as a product of total lung volume and gas transfer rate constants divided by the pressure gradient. Under conditions of known constant pressure breath-hold, the volume is measured by hyperpolarized 129Xe MRI, and the transfer rate is measured by dynamic spectroscopy. The new quantities (xenon diffusing capacity in lung parenchyma (DLXeLP)), xenon diffusing capacity in RBCs (DLXeRBC), and total lung xenon diffusing capacity (DLXe)) were measured in six normal rats and six rats with lung inflammation induced by instillation of fungal spores of Stachybotrys chartarum. DLXeLP, DLXeRBC, and DLXe were 56 +/- 10 ml/min/mmHg, 64 +/- 35 ml/min/mmHg, and 29 +/- 9 ml/min/mmHg, respectively, for normal rats, and 27 +/- 9 ml/min/mmHg, 42 +/- 27 ml/min/mmHg, and 16 +/- 7 ml/min/mmHg, respectively, for diseased rats. Lung volumes and gas transfer times for LP (TtrLP) were 16 +/- 2 ml and 22 +/- 3 ms, respectively, for normal rats and 12 +/- 2 ml and 35 +/- 8 ms, respectively, for diseased rats. Xenon diffusing capacities may be useful for measuring changes in gas exchange associated with inflammation and other lung diseases. Copyright 2006 Wiley-Liss, Inc.

Reduced-order modellin for high-pressure transient flow of hydrogen-natural gas mixture

NASA Astrophysics Data System (ADS)

Agaie, Baba G.; Khan, Ilyas; Alshomrani, Ali Saleh; Alqahtani, Aisha M.

2017-05-01

In this paper the transient flow of hydrogen compressed-natural gas (HCNG) mixture which is also referred to as hydrogen-natural gas mixture in a pipeline is numerically computed using the reduced-order modelling technique. The study on transient conditions is important because the pipeline flows are normally in the unsteady state due to the sudden opening and closure of control valves, but most of the existing studies only analyse the flow in the steady-state conditions. The mathematical model consists in a set of non-linear conservation forms of partial differential equations. The objective of this paper is to improve the accuracy in the prediction of the HCNG transient flow parameters using the Reduced-Order Modelling (ROM). The ROM technique has been successfully used in single-gas and aerodynamic flow problems, the gas mixture has not been done using the ROM. The study is based on the velocity change created by the operation of the valves upstream and downstream the pipeline. Results on the flow characteristics, namely the pressure, density, celerity and mass flux are based on variations of the mixing ratio and valve reaction and actuation time; the ROM computational time cost advantage are also presented.

Preparation of sterile xenon-133 in saline for tissue perfusion studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

DiPiazza, H.J.; Harbert, J.C.

1983-11-01

A simple, inexpensive method of obtaining Xe-133 in sterile saline is presented. The method uses commercial xenon ampules supplied for pulmonary ventilation studies. As much as 10% of the gas activity can be recovered per aliquot by cooling the saline to 4/sup 0/C. The specific activities obtained are adequate for most tissue perfusion studies.

Xenon lighting adjusted to plant requirements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koefferlein, M.; Doehring, T.; Payer, H.D.

1994-12-31

The high luminous flux and spectral properties of xenon lamps would provide an ideal luminary for plant lighting if not excess IR radiation poses several problems for an application: the required filter systems reduce the irradiance at spectral regions of particular importance for plant development. Most of the economical drawbacks of xenon lamps are related to the difficult handling of that excess IR energy. Furthermore, the temporal variation of the xenon output depending on the oscillations of the applied AC voltage has to be considered for the plant development. However, xenon lamps outperform other lighting systems with respect to spectralmore » stability, immediate response, and maximum luminance. Therefore, despite considerable competition by other lighting techniques, xenon lamps provide a very useful tool for special purposes. In plant lighting however, they seem to play a less important role as other lamp and lighting developments can meet these particular requirements at lower costs.« less

Time-resolved spectroscopic measurements behind incident and reflected shock waves in air and xenon

NASA Technical Reports Server (NTRS)

Yoshinaga, T.

1973-01-01

Time-resolved spectra have been obtained behind incident and reflected shock waves in air and xenon at initial pressures of 0.1 and 1.0 torr using a rotating drum spectrograph and the OSU (The Ohio State University) arc-driven shock tube. These spectra were used to determine the qualitative nature of the flow as well as for making estimates of the available test time. The (n+1,n) and (n,n) band spectra of N2(+) (1st negative) were observed in the test gas behind incident shock waves in air at p1=1.0 torr and Us=9-10 km/sec. Behind reflected shock waves in air, the continuum of spectra appeared to cover almost the entire wavelength of 2,500-7,000 A for the shock-heated test gas. For xenon, the spectra for the incident shock wave cases for p1=0.1 torr show an interesting structure in which two intensely bright regions are witnessed in the time direction. The spectra obtained behind reflected shock waves in xenon were also dominated by continuum radiation but included strong absorption spectra due to FeI and FeII from the moment the reflected shock passed and on.

Xenon Feed System Progress (Postprint)

DTIC Science & Technology

2006-06-13

development, assembly and test of an electric propulsion xenon feed system for a flight technology demonstration program. Major accomplishments...pressure transducer feedback, the PFCV has successfully fed xenon to a 200 watt Hall Effect Thruster in a Technology Demonstration Program. The feed

A study of nonflammable ArCO 2-hydrocarbon gas mixtures for limited streamer tubes

NASA Astrophysics Data System (ADS)

Cartwright, S.; Schneekloth, U.; Alpat, B.; Artemi, C.; Battiston, R.; Bilei, G.; Italiani, M.; Pauluzzi, M.; Servoli, L.; Messner, R.; Wyss, J.; Zdarko, R.; Johnson, J.

1989-04-01

The gas mixtures generally used until now in limited streamer tube detectors (Ar+C 4H 10 or Ar+CO 2+C 5H 12) are very flammable when leaked into air. The safety issues are therefore very relevant for large-volume underground experiments. We have found a set of completely safe (i.e. nonflammable) ternary mixtures of the kind Ar + hydrocarbon + CO 2 containing less than ˜ 5% of Ar and less than ˜ 10% of hydrocarbon. We tested C 4H 10, C 5H 12 and C 6H 14 as quenching agents. The main characteristics of the various mixtures have been measured: singles (untriggered) counting rate versus high voltage and with different dead times, and average charge. The stability of these mixtures is good, and their spurious streamer activity is compared with the standard binary or ternary mixture. We studied in particular the combination Ar(2.5%) + C 4H 10(9.5%) + CO 2(88%). All the data suggest that this or a similar gas mixture can successfully replace standard flammable mixtures both in tracking devices and hadron calorimeters.

Plasma chemistry of NO in complex gas mixtures excited with a surfatron launcher.

PubMed

Hueso, J L; González-Elipe, A R; Cotrino, J; Caballero, A

2005-06-09

The plasma chemistry of NO has been investigated in gas mixtures with oxygen and/or hydrocarbon and Ar as carrier gas. Surface wave discharges operating at microwave frequencies have been used for this study. The different plasma reactions have been analyzed for a pressure range between 30 and 75 Torr. Differences in product concentration and/or reaction yields smaller than 10% were found as a function of this parameter. The following gas mixtures have been considered for investigation: Ar/NO, Ar/NO/O2, Ar/NO/CH4, Ar/CH4/O2, Ar/NO/CH4/O2. It is found that NO decomposes into N2 and O2, whereas other products such as CO, H2, and H2O are also formed when CH4 and O2 are present in the reaction mixture. Depending on the working conditions, other minority products such as HCN, CO2, and C2 or higher hydrocarbons have been also detected. The reaction of an Ar/NO plasma with deposits of solid carbon has also been studied. The experiments have provided useful information with respect to the possible removal of soot particles by this type of plasma. It has been shown that carbon deposits are progressively burned off by interaction with the plasma, and practically 100% decomposition of NO was found. Plasma intermediate species have been studied by optical emission spectroscopy (OES). Bands and/or peaks due to N2*, NO*, OH*, C2*, CN*, CH*, or H* were detected with different relative intensities depending on the gas mixture. From the analysis of both the reaction products and efficiency and the type of intermediate species detected by OES, different plasma reactions and processes are proposed to describe the plasma chemistry of NO in each particular mixture of gases. The results obtained provide interesting insights about the plasma removal of NO in real gas exhausts.

Heat Transfer and Pressure Drop in Concentric Annular Flows of Binary Inert Gas Mixtures

NASA Technical Reports Server (NTRS)

Reid, R. S.; Martin, J. J.; Yocum, D. J.; Stewart, E. T.

2007-01-01

Studies of heat transfer and pressure drop of binary inert gas mixtures flowing through smooth concentric circular annuli, tubes with fully developed velocity profiles, and constant heating rate are described. There is a general lack of agreement among the constant property heat transfer correlations for such mixtures. No inert gas mixture data exist for annular channels. The intent of this study was to develop highly accurate and benchmarked pressure drop and heat transfer correlations that can be used to size heat exchangers and cores for direct gas Brayton nuclear power plants. The inside surface of the annular channel is heated while the outer surface of the channel is insulated. Annulus ratios range 0.5 < r* < 0.83. These smooth tube data may serve as a reference to the heat transfer and pressure drop performance in annuli, tubes, and channels having helixes or spacer ribs, or other surfaces.

WE-AB-202-07: Ventilation CT: Voxel-Level Comparison with Hyperpolarized Helium-3 & Xenon-129 MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tahir, B; Marshall, H; Hughes, P

Purpose: To compare the spatial correlation of ventilation surrogates computed from inspiratory and expiratory breath-hold CT with hyperpolarized Helium-3 & Xenon-129 MRI in a cohort of lung cancer patients. Methods: 5 patients underwent expiration & inspiration breath-hold CT. Xenon-129 & {sup 1}H MRI were also acquired at the same inflation state as inspiratory CT. This was followed immediately by acquisition of Helium-3 & {sup 1}H MRI in the same breath and at the same inflation state as inspiratory CT. Expiration CT was deformably registered to inspiration CT for calculation of ventilation CT from voxel-wise differences in Hounsfield units. Inspiration CTmore » and the Xenon-129’s corresponding anatomical {sup 1}H MRI were registered to Helium-3 MRI via the same-breath anatomical {sup 1}H MRI. This enabled direct comparison of CT ventilation with Helium-3 MRI & Xenon-129 MRI for the median values in corresponding regions of interest, ranging from finer to coarser in-plane dimensions of 10 by 10, 20 by 20, 30 by 30 and 40 by 40, located within the lungs as defined by the same-breath {sup 1}H MRI lung mask. Spearman coefficients were used to assess voxel-level correlation. Results: The median Spearman’s coefficients of ventilation CT with Helium-3 & Xenon-129 MRI for ROIs of 10 by 10, 20 by 20, 30 by 30 and 40 by 40 were 0.52, 0.56, 0.60 and 0.68 and 0.40, 0.42, 0.52 and 0.70, respectively. Conclusion: This work demonstrates a method of acquiring CT & hyperpolarized gas MRI (Helium-3 & Xenon-129 MRI) in similar breath-holds to enable direct spatial comparison of ventilation maps. Initial results show moderate correlation between ventilation CT & hyperpolarized gas MRI, improving for coarser regions which could be attributable to the inherent noise in CT intensity, non-ventilatory effects and registration errors at the voxel-level. Thus, it may be more beneficial to quantify ventilation at a more regional level.« less

Acoustic composition sensor for cryogenic gas mixtures

NASA Technical Reports Server (NTRS)

Shakkottai, P.; Kwack, E. Y.; Luchik, T. S.; Back, L. H.

1991-01-01

An acoustic sensor useful for the determination of the composition of a gaseous binary mixture in cryogenic liquid spills has been characterized. One version of the instrument traps a known mixture of helium and nitrogen at ambient temperature in a tube which is interrogated by sonic pulses to determine the speed of sound and hence the composition. Experimental data shows that this sensor is quite accurate. The second version uses two unconfined microphones which sense sound pulses. Experimental data acquired during mixing when liquid nitrogen is poured into a vessel of gaseous helium is presented. Data during transient cooling of the tubular sensor containing nitrogen when the sensor is dipped into liquid nitrogen and during transient warm-up when the sensor is withdrawn are also presented. This sensor is being developed for use in the mixing of liquid cryogens with gas evolution in the simulation of liquid hydrogen/liquid oxygen explosion hazards.

Acoustic composition sensor for cryogenic gas mixtures

NASA Astrophysics Data System (ADS)

Shakkottai, P.; Kwack, E. Y.; Luchik, T. S.; Back, L. H.

An acoustic sensor useful for the determination of the composition of a gaseous binary mixture in cryogenic liquid spills has been characterized. One version of the instrument traps a known mixture of helium and nitrogen at ambient temperature in a tube which is interrogated by sonic pulses to determine the speed of sound and hence the composition. Experimental data shows that this sensor is quite accurate. The second version uses two unconfined microphones which sense sound pulses. Experimental data acquired during mixing when liquid nitrogen is poured into a vessel of gaseous helium is presented. Data during transient cooling of the tubular sensor containing nitrogen when the sensor is dipped into liquid nitrogen and during transient warm-up when the sensor is withdrawn are also presented. This sensor is being developed for use in the mixing of liquid cryogens with gas evolution in the simulation of liquid hydrogen/liquid oxygen explosion hazards.

Numerical solution of Boltzmann tranport equation for TEA CO 2 laser having nitrogen-lean gas mixtures to predict laser characteristics and gas lifetime

NASA Astrophysics Data System (ADS)

Kumar, Manoj; Khare, Jai; Nath, A. K.

2007-02-01

Selective laser isotope separation by TEA CO 2 laser often needs short tail-free pulses. Using laser mixtures having very little nitrogen almost tail free laser pulses can be generated. The laser pulse characteristics and its gas lifetime is an important issue for long-term laser operation. Boltzmann transport equation is therefore solved numerically for TEA CO 2 laser gas mixtures having very little nitrogen to predict electron energy distribution function (EEDF). The distribution function is used to calculate various excitation and dissociation rate of CO 2 to predict laser pulse characteristics and laser gas lifetime, respectively. Laser rate equations have been solved with the calculated excitation rates for numerically evaluated discharge current and voltage profiles to calculate laser pulse shape. The calculated laser pulse shape and duration are in good agreement with the measured laser characteristics. The gas lifetime is estimated by integrating the equation governing the dissociation of CO 2. An experimental study of gas lifetime was carried out using quadrapole mass analyzer for such mixtures to estimate the O 2 being produced due to dissociation of CO 2 in the pulse discharge. The theoretically calculated O 2 concentration in the laser gas mixture matches with experimentally observed value. In the present TEA CO 2 laser system, for stable discharge the O 2 concentration should be below 0.2%.

Ideal gas solubilities and solubility selectivities in a binary mixture of room-temperature ionic liquids.

PubMed

Finotello, Alexia; Bara, Jason E; Narayan, Suguna; Camper, Dean; Noble, Richard D

2008-02-28

This study focuses on the solubility behaviors of CO2, CH4, and N2 gases in binary mixtures of imidazolium-based room-temperature ionic liquids (RTILs) using 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][Tf2N]) and 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2mim][BF4]) at 40 degrees C and low pressures (approximately 1 atm). The mixtures tested were 0, 25, 50, 75, 90, 95, and 100 mol % [C2mim][BF4] in [C2mim][Tf2N]. Results show that regular solution theory (RST) can be used to describe the gas solubility and selectivity behaviors in RTIL mixtures using an average mixture solubility parameter or an average measured mixture molar volume. Interestingly, the solubility selectivity, defined as the ratio of gas mole fractions in the RTIL mixture, of CO2 with N2 or CH4 in pure [C2mim][BF4] can be enhanced by adding 5 mol % [C2mim][Tf2N].

Adsorption of xenon on vicinal copper and platinum surfaces

NASA Astrophysics Data System (ADS)

Baker, Layton

The adsorption of xenon was studied on Cu(111), Cu(221), Cu(643) and on Pt(111), Pt(221), and Pt(531) using low energy electron diffraction (LEED), temperature programmed desorption (TPD) of xenon, and ultraviolet photoemission of adsorbed xenon (PAX). These experiments were performed to study the atomic and electronic structure of stepped and step-kinked, chiral metal surfaces. Xenon TPD and PAX were performed on each surface in an attempt to titrate terrace, step edge, and kink adsorption sites by adsorption energetics (TPD) and local work function differences (PAX). Due to the complex behavior of xenon on the vicinal copper and platinum metal surfaces, adsorption sites on these surfaces could not be adequately titrated by xenon TPD. On Cu(221) and Cu(643), xenon desorption from step adsorption sites was not apparent leading to the conclusion that the energy difference between terrace and step adsorption is minuscule. On Pt(221) and Pt(531), xenon TPD indicated that xenon prefers to bond at step edges and that the xenon-xenon interaction at step edges in repulsive but no further indication of step-kink adsorption was observed. The Pt(221) and Pt(531) TPD spectra indicated that the xenon overlayer undergoes strong compression near monolayer coverage on these surfaces due to repulsion between step-edge adsorbed xenon and other encroaching xenon atoms. The PAX experiments on the copper and platinum surfaces demonstrated that the step adsorption sites have lower local work functions than terrace adsorption sites and that higher step density leads to a larger separation in the local work function of terrace and step adsorption sites. The PAX spectra also indicated that, for all surfaces studied at 50--70 K, step adsorption is favored at low coverage but the step sites are not saturated until monolayer coverage is reached; this observation is due to the large entropy difference between terrace and step adsorption states and to repulsive interactions between xenon atoms

Influence of atmospheric transport patterns on xenon detections at the CTBTO radionuclide network

NASA Astrophysics Data System (ADS)

Krysta, Monika; Kusmierczyk-Michulec, Jolanta

2016-04-01

In order to fulfil its task of monitoring for signals emanating from nuclear explosions, Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) operates global International Monitoring System (IMS) comprising seismic, infrasound, hydroacoustic and radionuclide measurement networks. At present, 24 among 80 radionuclide stations foreseen by the Comprehensive Nuclear-Test-Ban Treaty (CTBT) are equipped with certified noble gas measurement systems. Over a past couple of years these systems collected a rich set of measurements of radioactive isotopes of xenon. Atmospheric transport modelling simulations are crucial to an assessment of the origin of xenon detected at the IMS stations. Numerous studies undertaken in the past enabled linking these detections to non Treaty-relevant activities and identifying main contributors. Presence and quantity of xenon isotopes at the stations is hence a result of an interplay of emission patterns and atmospheric circulation. In this presentation we analyse the presence or absence of radioactive xenon at selected stations from an angle of such an interplay. We attempt to classify the stations according to similarity of detection patterns, examine seasonality in those patterns and link them to large scale or local meteorological phenomena. The studies are undertaken using crude hypotheses on emission patterns from known sources and atmospheric transport modelling simulations prepared with the FLEXPART model.

Program on the combustion chemistry of low- and intermediate-Btu gas mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1981-11-30

Low and intermediate Btu (LBTU and IBTU) gas mixtures are essentially mixtures of CO, H/sub 2/ and CH/sub 4/ diluted with nitrogen and CO/sub 2/. Although the combustion properties of these three fuels have been extensively investigated and their individual combustion kinetics are reasonably well established, prediction techniques for applying these gas mixtures remain for the most part empirical. This program has aimed to bring together and apply some of the fundamental combustion parameters to the CO-H/sub 2/-CH/sub 4/ flame system with the hope of reducing some of this empiricism. Four topical reports have resulted from this program. This finalmore » report summarizes these reports and other activities undertaken in this program. This program was initiated June 22, 1976 under ERDA Contract No. E(49-18)-2406 and was later continued under DOE/PETC and DOE Contract No. DE-AC22-76ET10653.« less

Laser-induced fluorescence measurements of argon and xenon ion velocities near the sheath boundary in 3 ion species plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yip, Chi-Shung; Hershkowitz, Noah; Severn, Greg

2016-05-15

The Bohm sheath criterion is studied with laser-induced fluorescence in three ion species plasmas using two tunable diode lasers. Krypton is added to a low pressure unmagnetized DC hot filament discharge in a mixture of argon and xenon gas confined by surface multi-dipole magnetic fields. The argon and xenon ion velocity distribution functions are measured at the sheath-presheath boundary near a negatively biased boundary plate. The potential structures of the plasma sheath and presheath are measured by an emissive probe. Results are compared with previous experiments with Ar–Xe plasmas, where the two ion species were observed to reach the sheathmore » edge at nearly the same speed. This speed was the ion sound speed of the system, which is consistent with the generalized Bohm criterion. In such two ion species plasmas, instability enhanced collisional friction was demonstrated [Hershkowitz et al., Phys. Plasmas 18(5), 057102 (2011).] to exist which accounted for the observed results. When three ion species are present, it is demonstrated under most circumstances the ions do not fall out of the plasma at their individual Bohm velocities. It is also shown that under most circumstances the ions do not fall out of the plasma at the system sound speed. These observations are also consistent with the presence of the instabilities.« less

Functionalized xenon as a biosensor

PubMed Central

Spence, Megan M.; Rubin, Seth M.; Dimitrov, Ivan E.; Ruiz, E. Janette; Wemmer, David E.; Pines, Alexander; Yao, Shao Qin; Tian, Feng; Schultz, Peter G.

2001-01-01

The detection of biological molecules and their interactions is a significant component of modern biomedical research. In current biosensor technologies, simultaneous detection is limited to a small number of analytes by the spectral overlap of their signals. We have developed an NMR-based xenon biosensor that capitalizes on the enhanced signal-to-noise, spectral simplicity, and chemical-shift sensitivity of laser-polarized xenon to detect specific biomolecules at the level of tens of nanomoles. We present results using xenon “functionalized” by a biotin-modified supramolecular cage to detect biotin–avidin binding. This biosensor methodology can be extended to a multiplexing assay for multiple analytes. PMID:11535830

Study of thermite mixture consolidated by the cold gas dynamic spray process

NASA Astrophysics Data System (ADS)

Bacciochini, A.; Maines, G.; Poupart, C.; Akbarnejad, H.; Radulescu, M.; Jodoin, B.; Zhang, F.; Lee, J. J.

2014-05-01

The present study focused on the cold gas dynamic spray process for manufacturing porosity free, finely structured energetic materials with high reactivity and structural integrity. The experiments have focused the reaction between the aluminium and metal oxide, such as Al-CuO system. The consolidation of the materials used the cold gas dynamic spray technique, where the particles are accelerated to high speeds and consolidated via plastic deformation upon impact. Reactive composites are formed in arbitrary shapes with close to zero porosity and without any reactions during the consolidation phase. Reactivity of mixtures has been investigated through flame propagation analysis on cold sprayed samples and compacted powder mixture. Deflagration tests showed the influence of porosity on the reactivity.

Adding 5 h delayed xenon to delayed hypothermia treatment improves long-term function in neonatal rats surviving to adulthood.

PubMed

Liu, Xun; Dingley, John; Scull-Brown, Emma; Thoresen, Marianne

2015-06-01

We previously reported that combining immediate hypothermia with immediate or 2 h delayed inhalation of an inert gas, xenon, gave additive neuroprotection in rats after a hypoxic-ischemic insult, compared to hypothermia alone. Defining the therapeutic time window for this new combined intervention is crucial in clinical practice when immediate treatment is not always feasible. The aim of this study is to investigate whether combined hypothermia and xenon still provide neuroprotection in rats after a 5 h delay for both hypothermia and xenon. Seven-day-old Wistar rat pups underwent a unilateral hypoxic-ischemic insult. Pups received 5 h of treatment starting 5 h after the insult randomized between normothermia, hypothermia, or hypothermia with 50% xenon. Surviving pups were tested for fine motor function through weeks 8-10 before being euthanized at week 11. Their hemispheric and hippocampal areas were assessed. Both delayed hypothermia-xenon and hypothermia-only treated groups had significantly less brain tissue loss than those which underwent normothermia. The functional performance after 1 wk and adulthood was significantly better after hypothermia-xenon treatment as compared to the hypothermia-only or normothermia groups. Adding 50% xenon to 5 h delayed hypothermia significantly improved functional outcome as compared to delayed hypothermia alone despite similar reductions in brain area.

Method of testing gas insulated systems for the presence of conducting particles utilizing a gas mixture of nitrogen and sulfur hexafluoride

DOEpatents

Wootton, Roy E.

1979-01-01

A method of testing a gas insulated system for the presence of conducting particles. The method includes inserting a gaseous mixture comprising about 98 volume percent nitrogen and about 2 volume percent sulfur hexafluoride into the gas insulated system at a pressure greater than 60 lb./sq. in. gauge, and then applying a test voltage to the system. If particles are present within the system, the gaseous mixture will break down, providing an indicator of the presence of the particles.

Compressible Flow Phenomena at Inception of Lateral Density Currents Fed by Collapsing Gas-Particle Mixtures

NASA Astrophysics Data System (ADS)

Valentine, Greg A.; Sweeney, Matthew R.

2018-02-01

Many geological flows are sourced by falling gas-particle mixtures, such as during collapse of lava domes, and impulsive eruptive jets, and sustained columns, and rock falls. The transition from vertical to lateral flow is complex due to the range of coupling between particles of different sizes and densities and the carrier gas, and due to the potential for compressible flow phenomena. We use multiphase modeling to explore these dynamics. In mixtures with small particles, and with subsonic speeds, particles follow the gas such that outgoing lateral flows have similar particle concentration and speed as the vertical flows. Large particles concentrate immediately upon impact and move laterally away as granular flows overridden by a high-speed jet of expelled gas. When a falling flow is supersonic, a bow shock develops above the impact zone, and this produces a zone of high pressure from which lateral flows emerge as overpressured wall jets. The jets form complex structures as the mixtures expand and accelerate and then recompress through a recompression zone that mimics a Mach disk shock in ideal gas jets. In mixtures with moderate to high ratios of fine to coarse particles, the latter tend to follow fine particles through the expansion-recompression flow fields because of particle-particle drag. Expansion within the flow fields can lead to locally reduced gas pressure that could enhance substrate erosion in natural flows. The recompression zones form at distances, and have peak pressures, that are roughly proportional to the Mach numbers of impacting flows.

Anticipatory control of xenon in a pressurized water reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Impink, A.J. Jr.

1987-02-10

A method is described for automatically dampening xenon-135 spatial transients in the core of a pressurized water reactor having control rods which regulate reactor power level, comprising the steps of: measuring the neutron flu in the reactor core at a plurality of axially spaced locations on a real-time, on-line basis; repetitively generating from the neutron flux measurements, on a point-by-point basis, signals representative of the current axial distribution of xenon-135, and signals representative of the current rate of change of the axial distribution of xenon-135; generating from the xenon-135 distribution signals and the rate of change of xenon distribution signals,more » control signals for reducing the xenon transients; and positioning the control rods as a function of the control signals to dampen the xenon-135 spatial transients.« less

On-farm euthanasia of broiler chickens: effects of different gas mixtures on behavior and brain activity.

PubMed

Gerritzen, M A; Lambooij, B; Reimert, H; Stegeman, A; Spruijt, B

2004-08-01

The purpose of this study was to investigate the suitability of gas mixtures for euthanasia of groups of broilers in their housing by increasing the percentage of CO2. The suitability was assessed by the level of discomfort before loss of consciousness, and the killing rate. The gas mixtures injected into the housing were 1) 100% CO2, 2) 50% N2 + 50% CO2, and 3) 30% O2 + 40% CO2 + 30% N2, followed by 100% CO2. At 2 and 6 wk of age, groups of 20 broiler chickens per trial were exposed to increasing CO2 percentages due to the injection of these gas mixtures. Behavior and killing rate were examined. At the same time, 2 broilers per trial equipped with brain electrodes were observed for behavior and brain activity. Ten percent of the 2-wk-old broilers survived the increasing CO2 percentage due to the injection of 30% O2 + 40% CO2 + 30% N2 mixture, therefore this mixture was excluded for further testing at 6 wk of age. At 6 wk of age, 30% of the broilers survived in the 50% N2 + 50% CO2 group. The highest level of CO2 in the breathing air (42%) was reached by the injection of the 100% CO2 mixture, vs. 25% for the other 2 mixtures. In all 3 gas mixtures, head shaking, gasping, and convulsions were observed before loss of posture. Loss of posture and suppression of electrical activity of the brain (n = 7) occurred almost simultaneously. The results of this experiment indicate that euthanasia of groups of 2- and 6-wk-old broilers by gradually increasing the percentage of CO2 in the breathing air up to 40% is possible.

Xenon Protects against Blast-Induced Traumatic Brain Injury in an In Vitro Model.

PubMed

Campos-Pires, Rita; Koziakova, Mariia; Yonis, Amina; Pau, Ashni; Macdonald, Warren; Harris, Katie; Edge, Christopher J; Franks, Nicholas P; Mahoney, Peter F; Dickinson, Robert

2018-04-15

The aim of this study was to evaluate the neuroprotective efficacy of the inert gas xenon as a treatment for patients with blast-induced traumatic brain injury in an in vitro laboratory model. We developed a novel blast traumatic brain injury model using C57BL/6N mouse organotypic hippocampal brain-slice cultures exposed to a single shockwave, with the resulting injury quantified using propidium iodide fluorescence. A shock tube blast generator was used to simulate open field explosive blast shockwaves, modeled by the Friedlander waveform. Exposure to blast shockwave resulted in significant (p < 0.01) injury that increased with peak-overpressure and impulse of the shockwave, and which exhibited a secondary injury development up to 72 h after trauma. Blast-induced propidium iodide fluorescence overlapped with cleaved caspase-3 immunofluorescence, indicating that shock-wave-induced cell death involves apoptosis. Xenon (50% atm) applied 1 h after blast exposure reduced injury 24 h (p < 0.01), 48 h (p < 0.05), and 72 h (p < 0.001) later, compared with untreated control injury. Xenon-treated injured slices were not significantly different from uninjured sham slices at 24 h and 72 h. We demonstrate for the first time that xenon treatment after blast traumatic brain injury reduces initial injury and prevents subsequent injury development in vitro. Our findings support the idea that xenon may be a potential first-line treatment for those with blast-induced traumatic brain injury.

Xenon Protects against Blast-Induced Traumatic Brain Injury in an In Vitro Model

PubMed Central

Campos-Pires, Rita; Koziakova, Mariia; Yonis, Amina; Pau, Ashni; Macdonald, Warren; Harris, Katie; Edge, Christopher J.; Franks, Nicholas P.; Mahoney, Peter F.

2018-01-01

Abstract The aim of this study was to evaluate the neuroprotective efficacy of the inert gas xenon as a treatment for patients with blast-induced traumatic brain injury in an in vitro laboratory model. We developed a novel blast traumatic brain injury model using C57BL/6N mouse organotypic hippocampal brain-slice cultures exposed to a single shockwave, with the resulting injury quantified using propidium iodide fluorescence. A shock tube blast generator was used to simulate open field explosive blast shockwaves, modeled by the Friedlander waveform. Exposure to blast shockwave resulted in significant (p < 0.01) injury that increased with peak-overpressure and impulse of the shockwave, and which exhibited a secondary injury development up to 72 h after trauma. Blast-induced propidium iodide fluorescence overlapped with cleaved caspase-3 immunofluorescence, indicating that shock-wave–induced cell death involves apoptosis. Xenon (50% atm) applied 1 h after blast exposure reduced injury 24 h (p < 0.01), 48 h (p < 0.05), and 72 h (p < 0.001) later, compared with untreated control injury. Xenon-treated injured slices were not significantly different from uninjured sham slices at 24 h and 72 h. We demonstrate for the first time that xenon treatment after blast traumatic brain injury reduces initial injury and prevents subsequent injury development in vitro. Our findings support the idea that xenon may be a potential first-line treatment for those with blast-induced traumatic brain injury. PMID:29285980

The XENON1T dark matter experiment

NASA Astrophysics Data System (ADS)

Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Antunes, B.; Arneodo, F.; Balata, M.; Barrow, P.; Baudis, L.; Bauermeister, B.; Benabderrahmane, M. L.; Berger, T.; Breskin, A.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cervantes, M.; Chiarini, A.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Corrieri, R.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; Gangi, P. Di; Giovanni, A. Di; Diglio, S.; Disdier, J.-M.; Doets, M.; Duchovni, E.; Eurin, G.; Fei, J.; Ferella, A. D.; Fieguth, A.; Franco, D.; Front, D.; Fulgione, W.; Rosso, A. Gallo; Galloway, M.; Gao, F.; Garbini, M.; Geis, C.; Giboni, K.-L.; Goetzke, L. W.; Grandi, L.; Greene, Z.; Grignon, C.; Hasterok, C.; Hogenbirk, E.; Huhmann, C.; Itay, R.; James, A.; Kaminsky, B.; Kazama, S.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Lellouch, D.; Levinson, L.; Lin, Q.; Lindemann, S.; Lindner, M.; Lombardi, F.; Lopes, J. A. M.; Maier, R.; Manfredini, A.; Maris, I.; Undagoitia, T. Marrodán; Masbou, J.; Massoli, F. V.; Masson, D.; Mayani, D.; Messina, M.; Micheneau, K.; Molinario, A.; Morå, K.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Orlandi, D.; Othegraven, R.; Pakarha, P.; Parlati, S.; Pelssers, B.; Persiani, R.; Piastra, F.; Pienaar, J.; Pizzella, V.; Piro, M.-C.; Plante, G.; Priel, N.; García, D. Ramírez; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; Rupp, N.; Santos, J. M. F. dos; Saldanha, R.; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schreiner, J.; Schumann, M.; Lavina, L. Scotto; Selvi, M.; Shagin, P.; Shockley, E.; Silva, M.; Simgen, H.; Sivers, M. v.; Stern, M.; Stein, A.; Tatananni, D.; Tatananni, L.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Upole, N.; Vargas, M.; Wack, O.; Walet, R.; Wang, H.; Wang, Z.; Wei, Y.; Weinheimer, C.; Wittweg, C.; Wulf, J.; Ye, J.; Zhang, Y.

2017-12-01

The XENON1T experiment at the Laboratori Nazionali del Gran Sasso (LNGS) is the first WIMP dark matter detector operating with a liquid xenon target mass above the ton-scale. Out of its 3.2 t liquid xenon inventory, 2.0 t constitute the active target of the dual-phase time projection chamber. The scintillation and ionization signals from particle interactions are detected with low-background photomultipliers. This article describes the XENON1T instrument and its subsystems as well as strategies to achieve an unprecedented low background level. First results on the detector response and the performance of the subsystems are also presented.

High pressure and temperature optical flow cell for near-infra-red spectroscopic analysis of gas mixtures.

PubMed

Norton, C G; Suedmeyer, J; Oderkerk, B; Fieback, T M

2014-05-01

A new optical flow cell with a new optical arrangement adapted for high pressures and temperatures using glass fibres to connect light source, cell, and spectrometer has been developed, as part of a larger project comprising new methods for in situ analysis of bio and hydrogen gas mixtures in high pressure and temperature applications. The analysis is based on measurements of optical, thermo-physical, and electromagnetic properties in gas mixtures with newly developed high pressure property sensors, which are mounted in a new apparatus which can generate gas mixtures with up to six components with an uncertainty of composition of as little as 0.1 mol. %. Measurements of several pure components of natural gases and biogases to a pressure of 20 MPa were performed on two isotherms, and with binary mixtures of the same pure gases at pressures to 17.5 MPa. Thereby a new method of analyzing the obtained spectra based on the partial density of methane was investigated.

Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches

DOEpatents

Christophorou, Loucas G.; Hunter, Scott R.

1990-01-01

An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc.

The atmosphere of Mars: detection of krypton and xenon.

PubMed

Owen, T; Biemann, K; Rushneck, D R; Biller, J E; Howarth, D W; Lafleur, A L

1976-12-11

Krypton and xenon have been discovered in the martian atmosphere with the mass spectrometer on the second Viking lander. Krypton is more abundant than xenon. The relative abundances of the krypton isotopes appear normal, but the ratio of xenon-129 to xenon-132 is enhanced on Mars relative to the terrestrial value for this ratio. Some possible implications of these findings are discussed.

Some possibilities of using gas mixtures other than air in aerodynamic research

NASA Technical Reports Server (NTRS)

Chapman, Dean R

1956-01-01

A study is made of the advantages that can be realized in compressible-flow research by employing a substitute heavy gas in place of air. The present report is based on the idea that by properly mixing a heavy monatomic gas with a suitable heavy polyatomic gas, it is possible to obtain a heavy gas mixture which has the correct ratio of specific heats and which is nontoxic, nonflammable, thermally stable, chemically inert, and comprised of commercially available components. Calculations were made of wind-tunnel characteristics for 63 gas pairs comprising 21 different polyatomic gases properly mixed with each of three monatomic gases (argon, krypton, and zenon).

Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches

DOEpatents

Christophorou, L.G.; Hunter, S.R.

1990-06-26

An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc. 11 figs.

Binary and ternary gas mixtures with temperature enhanced diffuse glow discharge characteristics for use in closing switches

DOEpatents

Christophorou, L.G.; Hunter, S.R.

1988-06-28

An improvement to the gas mixture used in diffuse glow discharge closing switches is disclosed which includes binary and ternary gas mixtures which are formulated to exhibit decreasing electron attachment with increasing temperature. This increases the efficiency of the conductance of the glow discharge and further inhibits the formation of an arc. 11 figs.

Development of mass measurement equipment using an electronic mass-comparator for gravimetric preparation of reference gas mixtures

NASA Astrophysics Data System (ADS)

Matsumoto, Nobuhiro; Watanabe, Takuro; Maruyama, Masaaki; Horimoto, Yoshiyuki; Maeda, Tsuneaki; Kato, Kenji

2004-06-01

The gravimetric method is the most popular method for preparing reference gas mixtures with high accuracy. We have designed and manufactured novel mass measurement equipment for gravimetric preparation of reference gas mixtures. This equipment consists of an electronic mass-comparator with a maximum capacity of 15 kg and readability of 1 mg and an automatic cylinder exchanger. The structure of this equipment is simpler and the cost is much lower than a conventional mechanical knife-edge type large balance used for gravimetric preparation of primary gas mixtures in Japan. This cylinder exchanger can mount two cylinders alternatively on the weighing pan of the comparator. In this study, the performance of the equipment has been evaluated. At first, the linearity and repeatability of the mass measurement were evaluated using standard mass pieces. Then, binary gas mixtures of propane and nitrogen were prepared and compared with those prepared with the conventional knife-edge type balance. The comparison resulted in good consistency at the compatibility criterion described in ISO6143:2001.

Theoretical study on some plasma parameters and thermophysical properties of various gas mixtures in gas-discharge lasers

NASA Astrophysics Data System (ADS)

Temelkov, K. A.; Slaveeva, S. I.; Fedchenko, Yu I.; Chernogorova, T. P.

2018-03-01

Using the well-known Wassiljewa equation and a new simple method, the thermal conductivities of various 2- and 3-component gas mixtures were calculated and compared under gas-discharge conditions optimal for two prospective lasers excited in a nanosecond pulsed longitudinal discharge. By solving the non-stationary heat-conduction equation for electrons, a 2D numerical model was also developed for determination of the radial and temporal dependences of the electron temperature Te (r, t).

Transdermal diffusion of xenon in vitro using diffusion cells

NASA Astrophysics Data System (ADS)

Verkhovsky, A.; Petrov, E.

2015-11-01

The aim of this research was to study the diffusion rate of xenon through guinea pig skin and how viscosity of cosmetic component capryl/capric triglyceride (CCT) facilitates to deliver xenon to surface of skin patches. They were placed in Franz cell for 24 hours and diffusion rate and permeability of xenon were calculated. Thus diffusion rate was 0.031 mg/hour*cm2 and permeability was 0.003 cm/hour. Using Brookfield viscometer it was shown that viscosity of CCT decreased upon increasing xenon concentration. Obtained results can be utilized in developing of new xenon containing drugs for topical administration.

78 FR 41768 - Chemical Substances and Mixtures Used in Oil and Gas Exploration or Production; TSCA Section 21...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-11

... Substances and Mixtures Used in Oil and Gas Exploration or Production; TSCA Section 21 Petition; Reasons for... processors of oil and gas exploration and production (E&P) chemical substances and mixtures to maintain... interest to you if you manufacture (including import), process, or distribute chemical substances or...

Xenon isotopic composition of the Mid Ocean Ridge Basalt (MORB) source

NASA Astrophysics Data System (ADS)

Peto, M. K.; Mukhopadhyay, S.

2012-12-01

Although convection models do not preclude preservation of smaller mantle regions with more pristine composition throughout Earth's history, it has been widely assumed that the moon forming giant impact likely homogenizes the whole mantle following a magma ocean that extended all the way to the bottom of the mantle. Recent findings of tungsten and xenon heterogeneities in the mantle [1,2,3,4], however, imply that i) the moon forming giant impact may not have homogenized the whole mantle and ii) plate tectonics was inefficient in erasing early formed compositional differences, particularly for the xenon isotopes. Therefore, the xenon isotope composition in the present day mantle still preserves a memory of early Earth processes. However, determination of the xenon isotopic composition of the mantle source is still scarce, since the mantle composition is overprinted by post-eruptive atmospheric contamination in basalts erupted at ocean islands and mid ocean ridges. The xenon composition of the depleted upper mantle has been defined by the gas rich sample, 2πD43 (also known as "popping rock"), from the North Atlantic (13° 469`N). However, the composition of a single sample is not likely to define the composition of the upper mantle, especially since popping rock has an "enriched" trace element composition. We will present Ne, Ar and Xe isotope data on MORB glass samples with "normal" helium isotope composition (8±1 Ra) from the Southeast Indian Ridge, the South Atlantic Ridge, the Sojourn Ridge, the Juan de Fuca, the East Pacific Rise, and the Gakkel Ridge. Following the approach of [1], we correct for syn- and post-eruptive atmosphere contamination, and determine the variation of Ar and Xe isotope composition of the "normal" MORB source. We investigate the effect of atmospheric recycling in the variation of MORB mantle 40Ar/36Ar and 129Xe/130Xe ratios, and attempt to constrain the average upper mantle argon and xenon isotopic compositions. [1] Mukhopadhyay, Nature

Xenon for tunnelling analysis of the efflux pump component OprN.

PubMed

Ntsogo Enguéné, Yvette Véronique; Phan, Gilles; Garnier, Cyril; Ducruix, Arnaud; Prangé, Thierry; Broutin, Isabelle

2017-01-01

Tripartite efflux pumps are among the main actors responsible for antibiotics resistance in Gram-negative bacteria. In the last two decades, structural studies gave crucial information about the assembly interfaces and the mechanistic motions. Thus rigidifying the assembly seems to be an interesting way to hamper the drug efflux. In this context, xenon is a suitable probe for checking whether small ligands could act as conformational lockers by targeting hydrophobic cavities. Here we focus on OprN, the outer membrane channel of the MexEF efflux pump from Pseudomonas aeruginosa. After exposing OprN crystals to xenon gas pressure, 14 binding sites were observed using X-ray crystallography. These binding sites were unambiguously characterized in hydrophobic cavities of OprN. The major site is observed in the sensitive iris-like region gating the channel at the periplasmic side, built by the three key-residues Leu 405, Asp 109, and Arg 412. This arrangement defines along the tunnel axis a strong hydrophobic/polar gradient able to enhance the passive efflux mechanism of OprN. The other xenon atoms reveal strategic hydrophobic regions of the channel scaffold to target, with the aim to freeze the dynamic movements responsible of the open/close conformational equilibrium in OprN.

Xenon for tunnelling analysis of the efflux pump component OprN

PubMed Central

Garnier, Cyril; Ducruix, Arnaud; Broutin, Isabelle

2017-01-01

Tripartite efflux pumps are among the main actors responsible for antibiotics resistance in Gram-negative bacteria. In the last two decades, structural studies gave crucial information about the assembly interfaces and the mechanistic motions. Thus rigidifying the assembly seems to be an interesting way to hamper the drug efflux. In this context, xenon is a suitable probe for checking whether small ligands could act as conformational lockers by targeting hydrophobic cavities. Here we focus on OprN, the outer membrane channel of the MexEF efflux pump from Pseudomonas aeruginosa. After exposing OprN crystals to xenon gas pressure, 14 binding sites were observed using X-ray crystallography. These binding sites were unambiguously characterized in hydrophobic cavities of OprN. The major site is observed in the sensitive iris-like region gating the channel at the periplasmic side, built by the three key-residues Leu 405, Asp 109, and Arg 412. This arrangement defines along the tunnel axis a strong hydrophobic/polar gradient able to enhance the passive efflux mechanism of OprN. The other xenon atoms reveal strategic hydrophobic regions of the channel scaffold to target, with the aim to freeze the dynamic movements responsible of the open/close conformational equilibrium in OprN. PMID:28886086

Measurements of the equations of state and spectrum of nonideal xenon plasma under shock compression

NASA Astrophysics Data System (ADS)

Zheng, J.; Gu, Y. J.; Chen, Z. Y.; Chen, Q. F.

2010-08-01

Experimental equations of state on generation of nonideal xenon plasma by intense shock wave compression was presented in the ranges of pressure of 2-16 GPa and temperature of 31-50 kK, and the xenon plasma with the nonideal coupling parameter Γ range from 0.6-2.1 was generated. The shock wave was produced using the flyer plate impact and accelerated up to ˜6km/s with a two-stage light gas gun. Gaseous specimens were shocked from two initial pressures of 0.80 and 4.72 MPa at room temperature. Time-resolved spectral radiation histories were recorded by using a multiwavelength channel pyrometer. The transient spectra with the wavelength range of 460-700 nm were recorded by using a spectrometer to evaluate the shock temperature. Shock velocity was measured and particle velocity was determined by the impedance matching methods. The equations of state of xenon plasma and ionization degree have been discussed in terms of the self-consistent fluid variational theory.

Measurements of the equations of state and spectrum of nonideal xenon plasma under shock compression.

PubMed

Zheng, J; Gu, Y J; Chen, Z Y; Chen, Q F

2010-08-01

Experimental equations of state on generation of nonideal xenon plasma by intense shock wave compression was presented in the ranges of pressure of 2-16 GPa and temperature of 31-50 kK, and the xenon plasma with the nonideal coupling parameter Γ range from 0.6-2.1 was generated. The shock wave was produced using the flyer plate impact and accelerated up to ∼6 km/s with a two-stage light gas gun. Gaseous specimens were shocked from two initial pressures of 0.80 and 4.72 MPa at room temperature. Time-resolved spectral radiation histories were recorded by using a multiwavelength channel pyrometer. The transient spectra with the wavelength range of 460-700 nm were recorded by using a spectrometer to evaluate the shock temperature. Shock velocity was measured and particle velocity was determined by the impedance matching methods. The equations of state of xenon plasma and ionization degree have been discussed in terms of the self-consistent fluid variational theory.

Clinical efficacy of xenon versus propofol: A systematic review and meta-analysis.

PubMed

Xia, Yimeng; Fang, Hongwei; Xu, Jindong; Jia, Chenfei; Tao, Guorong; Yu, Buwei

2018-05-01

Interest in the anesthetic use of xenon, a noble gas, has waxed and waned for decades, and the clinical effects of xenon are still debated. We performed a meta-analysis to compare the clinical efficacy of xenon with that of propofol. Electronic searches were performed through December 2017 using various databases, including PubMed, Embase, and the Cochrane Library. We identified thirteen trials that included a total of 817 patients. Patients treated with xenon had a lower bispectral index (BIS) (weighted mean difference (WMD): -6.26, 95% confidence interval (CI): -11.33 to -1.18, P = .02), a higher mean arterial blood pressure (MAP) (WMD: 7.00, 95% CI: 2.32-11.68, P = .003) and a lower heart rate (HR) (WMD: -9.45, 95% CI: -12.28 to -6.63, P < 0.00001) than propofol-treated patients. However, there were no significant differences between the 2 treatment groups in the effects of nondepolarizing muscular relaxants, the duration spent in the postanesthesia care unit (PACU) (WMD: -0.94, 95% CI: -8.79-6.91, P = .81), or the incidence of perioperative complications [assessed using the outcomes of postoperative nausea and vomiting (PONV) (relative risk (RR): 2.01, 95% CI: 0.79-5.11, P = .14), hypotension (RR: 0.62, 95% CI: 0.27 to 1.40, P = .25), hypertension (RR: 1.27, 95% CI: 0.73-2.21, P = .39) and bradycardia (RR: 1.00, 95% CI: 0.36-2.74, P = 1.00)]. In this meta-analysis of randomized controlled trials, we found that xenon treatment resulted in a higher MAP, a lower HR, and a smaller BIS index than treatment with propofol.

Electron drift in a large scale solid xenon

DOE PAGES

Yoo, J.; Jaskierny, W. F.

2015-08-21

A study of charge drift in a large scale optically transparent solid xenon is reported. A pulsed high power xenon light source is used to liberate electrons from a photocathode. The drift speeds of the electrons are measured using a 8.7 cm long electrode in both the liquid and solid phase of xenon. In the liquid phase (163 K), the drift speed is 0.193 ± 0.003 cm/μs while the drift speed in the solid phase (157 K) is 0.397 ± 0.006 cm/μs at 900 V/cm over 8.0 cm of uniform electric fields. Furthermore, it is demonstrated that a factor twomore » faster electron drift speed in solid phase xenon compared to that in liquid in a large scale solid xenon.« less

Supersonic Flow of Chemically Reacting Gas-Particle Mixtures. Volume 2: RAMP - A Computer Code for Analysis of Chemically Reacting Gas-Particle Flows

NASA Technical Reports Server (NTRS)

Penny, M. M.; Smith, S. D.; Anderson, P. G.; Sulyma, P. R.; Pearson, M. L.

1976-01-01

A computer program written in conjunction with the numerical solution of the flow of chemically reacting gas-particle mixtures was documented. The solution to the set of governing equations was obtained by utilizing the method of characteristics. The equations cast in characteristic form were shown to be formally the same for ideal, frozen, chemical equilibrium and chemical non-equilibrium reacting gas mixtures. The characteristic directions for the gas-particle system are found to be the conventional gas Mach lines, the gas streamlines and the particle streamlines. The basic mesh construction for the flow solution is along streamlines and normals to the streamlines for axisymmetric or two-dimensional flow. The analysis gives detailed information of the supersonic flow and provides for a continuous solution of the nozzle and exhaust plume flow fields. Boundary conditions for the flow solution are either the nozzle wall or the exhaust plume boundary.

Neuroprotection and neurotoxicity in the developing brain: an update on the effects of dexmedetomidine and xenon.

PubMed

Alam, Azeem; Suen, Ka Chun; Hana, Zac; Sanders, Robert D; Maze, Mervyn; Ma, Daqing

Growing and consistent preclinical evidence, combined with early clinical epidemiological observations, suggest potentially neurotoxic effects of commonly used anesthetic agents in the developing brain. This has prompted the FDA to issue a safety warning for all sedatives and anesthetics approved for use in children under three years of age. Recent studies have identified dexmedetomidine, the potent α2-adrenoceptor agonist, and xenon, the noble gas, as effective anesthetic adjuvants that are both less neurotoxic to the developing brain, and also possess neuroprotective properties in neonatal and other settings of acute ongoing neurologic injury. Dexmedetomidine and xenon are effective anesthetic adjuvants that appear to be less neurotoxic than other existing agents and have the potential to be neuroprotective in the neonatal and pediatric settings. Although results from recent clinical trials and case reports have indicated the neuroprotective potential of xenon and dexmedetomidine, additional randomized clinical trials corroborating these studies are necessary. By reviewing both the existing preclinical and clinical evidence on the neuroprotective effects of dexmedetomidine and xenon, we hope to provide insight into the potential clinical efficacy of these agents in the management of pediatric surgical patients. Copyright © 2017 Elsevier Inc. All rights reserved.

Xenon lighting adjusted to plant requirements

NASA Technical Reports Server (NTRS)

Koefferlein, M.; Doehring, T.; Payer, Hans D.; Seidlitz, H. K.

1994-01-01

Xenon lamps are available as low and high power lamps with relatively high efficiency and a relatively long lifetime up to several thousand hours. Different construction types of short-arc and long-arc lamps permit a good adaptation to various applications in projection and illumination techniques without substantial changes of the spectral quality. Hence, the xenon lamp was the best choice for professional technical purposes where high power at simultaneously good spectral quality of the light was required. However, technical development does not stand still. Between the luminous efficacy of xenon lamps of 25-50 lm/W and the theoretical limit for 'white light' of 250 lm/W is still much room for improvement. The present development mainly favors other lamp types, like metal halide lamps and fluorescent lamps for commercial lighting purposes. The enclosed sections deal with some of the properties of xenon lamps relevant to plant illumination; particularly the spectral aspects, the temporal characteristics of the emission, and finally the economy of xenon lamps will be addressed. Due to radiation exceeding the natural global radiation in both the ultraviolet (UV) and the infrared (IR) regions, filter techniques have to be included into the discussion referring to the requirements of plant illumination. Most of the presented results were obtained by investigations in the GSF phytotron or in the closed Phytocell chambers of the University of Erlangen. As our experiences are restricted to area plant illumination rather than spot lights our discussion will concentrate on low pressure long-arc xenon lamps which are commonly used for such plant illuminations. As the spectral properties of short-arc lamps do not differ much from those of long-arc lamps most of our conclusions will be valid for high pressure xenon lamps too. These lamps often serve as light sources for small sun simulators and for monochromators which are used for action spectroscopy of plant responses.

Neuroprotection against traumatic brain injury by xenon, but not argon, is mediated by inhibition at the N-methyl-D-aspartate receptor glycine site.

PubMed

Harris, Katie; Armstrong, Scott P; Campos-Pires, Rita; Kiru, Louise; Franks, Nicholas P; Dickinson, Robert

2013-11-01

Xenon, the inert anesthetic gas, is neuroprotective in models of brain injury. The authors investigate the neuroprotective mechanisms of the inert gases such as xenon, argon, krypton, neon, and helium in an in vitro model of traumatic brain injury. The authors use an in vitro model using mouse organotypic hippocampal brain slices, subjected to a focal mechanical trauma, with injury quantified by propidium iodide fluorescence. Patch clamp electrophysiology is used to investigate the effect of the inert gases on N-methyl-D-aspartate receptors and TREK-1 channels, two molecular targets likely to play a role in neuroprotection. Xenon (50%) and, to a lesser extent, argon (50%) are neuroprotective against traumatic injury when applied after injury (xenon 43±1% protection at 72 h after injury [N=104]; argon 30±6% protection [N=44]; mean±SEM). Helium, neon, and krypton are devoid of neuroprotective effect. Xenon (50%) prevents development of secondary injury up to 48 h after trauma. Argon (50%) attenuates secondary injury, but is less effective than xenon (xenon 50±5% reduction in secondary injury at 72 h after injury [N=104]; argon 34±8% reduction [N=44]; mean±SEM). Glycine reverses the neuroprotective effect of xenon, but not argon, consistent with competitive inhibition at the N-methyl-D-aspartate receptor glycine site mediating xenon neuroprotection against traumatic brain injury. Xenon inhibits N-methyl-D-aspartate receptors and activates TREK-1 channels, whereas argon, krypton, neon, and helium have no effect on these ion channels. Xenon neuroprotection against traumatic brain injury can be reversed by increasing the glycine concentration, consistent with inhibition at the N-methyl-D-aspartate receptor glycine site playing a significant role in xenon neuroprotection. Argon and xenon do not act via the same mechanism.

Methods to produce calibration mixtures for anesthetic gas monitors and how to perform volumetric calculations on anesthetic gases.

PubMed

Christensen, P L; Nielsen, J; Kann, T

1992-10-01

A simple procedure for making calibration mixtures of oxygen and the anesthetic gases isoflurane, enflurane, and halothane is described. One to ten grams of the anesthetic substance is evaporated in a closed, 11,361-cc glass bottle filled with oxygen gas at atmospheric pressure. The carefully mixed gas is used to calibrate anesthetic gas monitors. By comparison of calculated and measured volumetric results it is shown that at atmospheric conditions the volumetric behavior of anesthetic gas mixtures can be described with reasonable accuracy using the ideal gas law. A procedure is described for calculating the deviation from ideal gas behavior in cases in which this is needed.

Radioactive plume from the Three Mile Island accident: xenon-133 in air at a distance of 375 kilometers.

PubMed

Wahlen, M; Kunz, C O; Matuszek, J M; Mahoney, W E; Thompson, R C

1980-02-08

The transit of an air mass containing radioactive gas released from the Three Mile Island reactor was recorded in Albany, New York, by measuring xenon-133. These measurements provide an evaluation of Three Mile Island effluents to distances greater than 100 kilometers. Two independent techniques identified xenon-133 in ambient air at concentrations as high as 3900 picocuries per cubic meter. The local gamma-ray whole-body dose from the passing radioactivity amounted to 0.004 millirem, or 0.004 percent of the annual dose from natural sources.

The influence of surface-active agents in gas mixture on the intensity of jet condensation

NASA Astrophysics Data System (ADS)

Yezhov, YV; Okhotin, VS

2017-11-01

The report presents: the methodology of calculation of contact condensation of steam from the steam-gas mixture into the stream of water, taking into account: the mass flow of steam through the boundary phase, particularly the change in turbulent transport properties near the interface and their connection to the interface perturbations due to the surface tension of the mixture; the method of calculation of the surface tension at the interface water - a mixture of fluorocarbon vapor and water, based on the previously established analytical methods we calculate the surface tension for simple one - component liquid-vapor systems. The obtained analytical relation to calculate the surface tension of the mixture is a function of temperature and volume concentration of the fluorocarbon gas in the mixture and is true for all sizes of gas molecules. On the newly created experimental stand is made verification of experimental studies to determine the surface tension of pure substances: water, steam, C3F8 pair C3F8, produced the first experimental data on surface tension at the water - a mixture of water vapor and fluorocarbon C3F8. The obtained experimental data allow us to refine the values of the two constants used in the calculated model of the surface tension of the mixture. Experimental study of jet condensation was carried out with the flow in the zone of condensation of different gases. The condensation process was monitored by measurement of consumption of water flowing from the nozzle, and the formed condensate. When submitting C3F8, there was a noticeable, intensification condensation process compared with the condensation of pure water vapor. The calculation results are in satisfactory agreement with the experimental data on surface tension of the mixture and steam condensation from steam-gas mixture. Analysis of calculation results shows that the presence of surfactants in the condensation zone affects the partial vapor pressure on the interfacial surface, and

Steady-state temperature distribution within a Brayton rotating unit operating in a power conversion system using helium-xenon gas

NASA Technical Reports Server (NTRS)

Johnsen, R. L.; Namkoong, D.; Edkin, R. A.

1971-01-01

The Brayton rotating unit (BRU), consisting of a turbine, an alternator, and a compressor, was tested as part of a Brayton cycle power conversion system over a side range of steady state operating conditions. The working fluid in the system was a mixture of helium-xenon gases. Turbine inlet temperature was varied from 1200 to 1600 F, compressor inlet temperature from 60 to 120 F, compressor discharge pressure from 20 to 45 psia, rotative speed from 32 400 to 39 600 rpm, and alternator liquid-coolant flow rate from 0.01 to 0.27 pound per second. Test results indicated that the BRU internal temperatures were highly sensitive to alternator coolant flow below the design value of 0.12 pound per second but much less so at higher values. The armature winding temperature was not influenced significantly by turbine inlet temperature, but was sensitive, up to 20 F per kVA alternator output, to varying alternator output. When only the rotational speed was changed (+ or - 10% of rated value), the BRU internal temperatures varied directly with the speed.

Study of thermite mixtures consolidated by cold gas dynamic spray process

NASA Astrophysics Data System (ADS)

Bacciochini, Antoine; Maines, Geoffrey; Poupart, Christian; Radulescu, Matei; Jodoin, Bertrand; Lee, Julian

2013-06-01

The present study focused on the cold gas dynamic spray process for manufacturing finely structured energetic materials with high reactivity, vanishing porosity, as well as structural integrity and arbitrary shape. The experiments have focused the reaction between the aluminum and metal oxides, such as Al-CuO and Al-MoO3 systems. To increase the reactivity, an initial mechanical activation was achieved through interrupted ball milling. The consolidation of the materials used the supersonic cold gas spray technique, where the particles are accelerated to high speeds and consolidated via plastic deformation upon impact, forming activated nano-composites in arbitrary shapes with close to zero porosity. This technique permits to retain the feedstock powder micro-structure and prevents any reactions during the consolidation phase. Reactivity of mixtures has been investigated through flame propagation analysis on cold sprayed samples and compacted powder mixture. Deflagration tests showed the influence of porosity on the reactivity.

Pairwise additivity in the nuclear magnetic resonance interactions of atomic xenon.

PubMed

Hanni, Matti; Lantto, Perttu; Vaara, Juha

2009-04-14

Nuclear magnetic resonance (NMR) of atomic (129/131)Xe is used as a versatile probe of the structure and dynamics of various host materials, due to the sensitivity of the Xe NMR parameters to intermolecular interactions. The principles governing this sensitivity can be investigated using the prototypic system of interacting Xe atoms. In the pairwise additive approximation (PAA), the binary NMR chemical shift, nuclear quadrupole coupling (NQC), and spin-rotation (SR) curves for the xenon dimer are utilized for fast and efficient evaluation of the corresponding NMR tensors in small xenon clusters Xe(n) (n = 2-12). If accurate, the preparametrized PAA enables the analysis of the NMR properties of xenon clusters, condensed xenon phases, and xenon gas without having to resort to electronic structure calculations of instantaneous configurations for n > 2. The binary parameters for Xe(2) at different internuclear distances were obtained at the nonrelativistic Hartree-Fock level of theory. Quantum-chemical (QC) calculations at the corresponding level were used to obtain the NMR parameters of the Xe(n) (n = 2-12) clusters at the equilibrium geometries. Comparison of PAA and QC data indicates that the direct use of the binary property curves of Xe(2) can be expected to be well-suited for the analysis of Xe NMR in the gaseous phase dominated by binary collisions. For use in condensed phases where many-body effects should be considered, effective binary property functions were fitted using the principal components of QC tensors from Xe(n) clusters. Particularly, the chemical shift in Xe(n) is strikingly well-described by the effective PAA. The coordination number Z of the Xe site is found to be the most important factor determining the chemical shift, with the largest shifts being found for high-symmetry sites with the largest Z. This is rationalized in terms of the density of virtual electronic states available for response to magnetic perturbations.

The Xenon1T Dark Matter Search Experiment

NASA Astrophysics Data System (ADS)

Aprile, Elena

The worldwide race towards direct dark matter detection in the form of Weakly Interacting Massive Particles (WIMPs) has been dramatically accelerated by the remarkable progress and evolution of liquid xenon time projection chambers (LXeTPCs). With a realistic discovery potential, Xenon100 has already reached a sensitivity of 7 × 10-45 cm2, and continues to accrue data at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy towards its ultimate sensitivity reach at the σ SI ˜ 2 × 10-45 cm2 level for the spin-independent WIMP-nucleon cross-section. To fully explore the favoured parameter space for WIMP dark matter in search of a first robust and statistically significant discovery, or to confirm any hint of a signal from Xenon100, the next phase of the Xenon program will be a detector at the ton scale - Xenon1T. The Xenon1T detector, based on 2.2 ton of LXe viewed by low radioactivity photomultiplier tubes and housed in a water Cherenkov muon veto at LNGS, is presented. With an experimental aim of probing WIMP interaction cross-sections above of order σ SI ˜ 2 × 10-47 cm2 within 2 years of operation, Xenon1T will provide the sensitivity to probe a particularly favourable region of electroweak physics on a timescale compatible with complementary ground and satellite based indirect searches and with accelerator dark matter searches at the LHC. Indeed, for a σ SI ˜ 10-45 cm2 and 100 GeV/c2 WIMP mass, Xenon1T could detect of order 100 events in this exposure, providing statistics for placing significant constraints on the WIMP mass.

Inflammable Gas Mixture Detection with a Single Catalytic Sensor Based on the Electric Field Effect

PubMed Central

Tong, Ziyuan; Tong, Min-Ming; Meng, Wen; Li, Meng

2014-01-01

This paper introduces a new way to analyze mixtures of inflammable gases with a single catalytic sensor. The analysis technology was based on a new finding that an electric field on the catalytic sensor can change the output sensitivity of the sensor. The analysis of mixed inflammable gases results from processing the output signals obtained by adjusting the electric field parameter of the catalytic sensor. For the signal process, we designed a group of equations based on the heat balance of catalytic sensor expressing the relationship between the output signals and the concentration of gases. With these equations and the outputs of different electric fields, the gas concentration in a mixture could be calculated. In experiments, a mixture of methane, butane and ethane was analyzed by this new method, and the results showed that the concentration of each gas in the mixture could be detected with a single catalytic sensor, and the maximum relative error was less than 5%. PMID:24717635

Xenon migration in UO2 under irradiation studied by SIMS profilometry

NASA Astrophysics Data System (ADS)

Marchand, B.; Moncoffre, N.; Pipon, Y.; Bérerd, N.; Garnier, C.; Raimbault, L.; Sainsot, P.; Epicier, T.; Delafoy, C.; Fraczkiewicz, M.; Gaillard, C.; Toulhoat, N.; Perrat-Mabilon, A.; Peaucelle, C.

2013-09-01

During Pressurized Water Reactor operation, around 25% of the created Fission Products (FP) are Xenon and Krypton. They have a low solubility in the nuclear fuel and can either (i) agglomerate into bubbles which induce mechanical stress in the fuel pellets or (ii) be released from the pellets, increasing the pressure within the cladding and decreasing the thermal conductivity of the gap between pellets and cladding. After fifty years of studies on the nuclear fuel, all mechanisms of Fission Gas Release (FGR) are still not fully understood. This paper aims at studying the FGR mechanisms by decoupling thermal and irradiation effects and by assessing the Xenon behavior for the first time by profilometry. Samples are first implanted with 136Xe at 800 keV corresponding to a projected range of 140 nm. They are then either annealed in the temperature range 1400-1600 °C, or irradiated with heavy energy ions (182 MeV Iodine) at Room Temperature (RT), 600 °C or 1000 °C. Depth profiles of implanted Xenon in UO2 are determined by Secondary Ion Mass Spectrometry (SIMS). It is shown that Xenon is mobile during irradiation at 1000 °C. In contrast, thermal treatments do not induce any Xenon migration process: these results are correlated to the formation of Xenon bubbles observed by Transmission Electron Microscopy. At depths lower than about 40 nm (zone 1), no bubbles are observed, At depths in between 40 nm and 110 nm (zone 2), a large number of small bubbles (around 2 nm in diameter) can be observed. By comparing with the SRIM profile, it appears that this area corresponds to the maximum of the defect profile, The third zone displays two bubble populations. The first population has the same size than the bubbles present in zone 2. The bubble size of the second population is significantly larger (up to around 10 nm). A STEM micrograph is presented in Fig. 4. It highlights the Xenon bubbles more clearly. It appears that the largest bubbles are located mainly near dislocations

Equation of state of mixtures: density functional theory (DFT) simulations and experiments on Sandia's Z machine

NASA Astrophysics Data System (ADS)

Magyar, R. J.; Root, S.; Haill, T. A.; Schroen, D. G.; Mattsson, T. R.; Flicker, D. G.; Sandia National Laboratories Collaboration

2011-06-01

Mixtures of materials are expected to behave quite differently from their isolated constituents, particularly when the constituents atomic numbers differ significantly. To investigate the mixture behavior, we performed density functional theory (DFT) calculations on xenon/hydrogen, xenon/ethane, and platinum/hydrocarbon mixtures. In addition, we performed shock compression experiments on platinum-doped hydrocarbon foams up to 480 GPa using the Sandia Z-accelerator. Since the DFT simulations treat electrons and nuclei generically, simulations of pure and mix systems are expected to be of comparable accuracy. The DFT and experimental results are compared to hydrodynamic simulations using different mixing models in the equation of state. The role of de-mixing and the relative contributions of the enthalpy of mixing are explored. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of the Lockheed Martin company, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Heat transfer during condensation of steam from steam-gas mixtures in the passive safety systems of nuclear power plants

NASA Astrophysics Data System (ADS)

Portnova, N. M.; Smirnov, Yu B.

2017-11-01

A theoretical model for calculation of heat transfer during condensation of multicomponent vapor-gas mixtures on vertical surfaces, based on film theory and heat and mass transfer analogy is proposed. Calculations were performed for the conditions implemented in experimental studies of heat transfer during condensation of steam-gas mixtures in the passive safety systems of PWR-type reactors of different designs. Calculated values of heat transfer coefficients for condensation of steam-air, steam-air-helium and steam-air-hydrogen mixtures at pressures of 0.2 to 0.6 MPa and of steam-nitrogen mixture at the pressures of 0.4 to 2.6 MPa were obtained. The composition of mixtures and vapor-to-surface temperature difference were varied within wide limits. Tube length ranged from 0.65 to 9.79m. The condensation of all steam-gas mixtures took place in a laminar-wave flow mode of condensate film and turbulent free convection in the diffusion boundary layer. The heat transfer coefficients obtained by calculation using the proposed model are in good agreement with the considered experimental data for both the binary and ternary mixtures.

Diffusion of gas mixtures in the sI hydrate structure

NASA Astrophysics Data System (ADS)

Waage, Magnus H.; Trinh, Thuat T.; van Erp, Titus S.

2018-06-01

Replacing methane with carbon dioxide in gas hydrates has been suggested as a way of harvesting methane, while at the same time storing carbon dioxide. Experimental evidence suggests that this process is facilitated if gas mixtures are used instead of pure carbon dioxide. We studied the free energy barriers for diffusion of methane, carbon dioxide, nitrogen, and hydrogen in the sI hydrate structure using molecular simulation techniques. Cage hops between neighboring cages were considered with and without a water vacancy and with a potential inclusion of an additional gas molecule in either the initial or final cage. Our results give little evidence for enhanced methane and carbon dioxide diffusion if nitrogen is present as well. However, the inclusion of hydrogen seems to have a substantial effect as it diffuses rapidly and can easily enter occupied cages, which reduces the barriers of diffusion for the gas molecules that co-occupy a cage with hydrogen.

Cardiac Mitochondria l Membrane Stability after Deep Hypothermia using a Xenon Clathrate Cryostasis Protocol – an Electron Microscopy Study

PubMed Central

Sheleg, Sergey; Hixon, Hugh; Cohen, Bruce; Lowry, David; Nedzved, Mikhail

2008-01-01

We investigated a new cryopreservation method using xenon, a clathrate-forming gas, under medium pressure (100psi). The objective of the study was to determine whether this cryostasis protocol could protect cardiac mitochondria at cryogenic temperatures (below 100 degrees Celsius).We analyzed transmission electron microscopy images to obtain information about changes in mitochondrial morphology induced by cryopreservation of the hearts. Our data showed absence of mitochondrial swelling, rupture of inner and outer membranes, and leakage of mitochondrial matrix into the cytoplasm after applying this cryostasis protocol. The electron microscopy results provided the first evidence that a cryostasis protocol using xenon as a clathrate-forming gas under pressure may have protective effects on intracellular membranes. This cryostasis technology may find applications in developing new approaches for long-term cryopreservation protocols. PMID:18787624

10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

Code of Federal Regulations, 2011 CFR

2011-01-01

... mixture of solar energy (including wind, tide, and other intermittent sources) and petroleum or natural gas, where: (1) Solar energy will account for at least 20 percent of the total annual Btu heat input... 10 Energy 4 2011-01-01 2011-01-01 false Permanent exemption for certain fuel mixtures containing...

10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

Code of Federal Regulations, 2012 CFR

2012-01-01

... mixture of solar energy (including wind, tide, and other intermittent sources) and petroleum or natural gas, where: (1) Solar energy will account for at least 20 percent of the total annual Btu heat input... 10 Energy 4 2012-01-01 2012-01-01 false Permanent exemption for certain fuel mixtures containing...

10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

Code of Federal Regulations, 2013 CFR

2013-01-01

... mixture of solar energy (including wind, tide, and other intermittent sources) and petroleum or natural gas, where: (1) Solar energy will account for at least 20 percent of the total annual Btu heat input... 10 Energy 4 2013-01-01 2013-01-01 false Permanent exemption for certain fuel mixtures containing...

10 CFR 503.38 - Permanent exemption for certain fuel mixtures containing natural gas or petroleum.

Code of Federal Regulations, 2014 CFR

2014-01-01

... mixture of solar energy (including wind, tide, and other intermittent sources) and petroleum or natural gas, where: (1) Solar energy will account for at least 20 percent of the total annual Btu heat input... 10 Energy 4 2014-01-01 2014-01-01 false Permanent exemption for certain fuel mixtures containing...

A study for health hazard evaluation of methylene chloride evaporated from the tear gas mixture.

PubMed

Park, Seung-Hyun; Chung, Eun-Kyo; Yi, Gwang-Yong; Chung, Kwang-Jae; Shin, Jung-Ah; Lee, In-Seop

2010-09-01

This study explored the health hazard of those exposed to methylene chloride by assessing its atmospheric concentration when a tear gas mixture was aerially dispersed. The concentration of methylene chloride ranged from 311.1-980.3 ppm (geometric mean, 555.8 ppm), 30 seconds after the dispersion started. However, the concentration fell rapidly to below 10 ppm after dispersion was completed. The concentration during the dispersion did not surpass the National Institute for Occupational Safety and Health 'immediately dangerous to life or health' value of 2,300 ppm, but did exceed the American Conference of Governmental Industrial Hygienists excursion limit of 250 ppm. Since methylene chloride is highly volatile (vapor pressure, 349 mmHg at 20℃), the postdispersion atmospheric concentration can rise instantaneously. Moreover, the o-chlorobenzylidenemalononitrile formulation of tear gas (CS gas) is an acute upper respiratory tract irritant. Therefore, tear gas mixtures should be handled with delicate care.

Two generators to produce SI-traceable reference gas mixtures for reactive compounds at atmospheric levels

NASA Astrophysics Data System (ADS)

Pascale, C.; Guillevic, M.; Ackermann, A.; Leuenberger, D.; Niederhauser, B.

2017-12-01

To answer the needs of air quality and climate monitoring networks, two new gas generators were developed and manufactured at METAS in order to dynamically generate SI-traceable reference gas mixtures for reactive compounds at atmospheric concentrations. The technical features of the transportable generators allow for the realization of such gas standards for reactive compounds (e.g. NO2, volatile organic compounds) in the nmol · mol-1 range (ReGaS2), and fluorinated gases in the pmol ṡ mol-1 range (ReGaS3). The generation method is based on permeation and dynamic dilution. The transportable generators have multiple individual permeation chambers allowing for the generation of mixtures containing up to five different compounds. This mixture is then diluted using mass flow controllers, thus making the production process adaptable to generate the required amount of substance fraction. All parts of ReGaS2 in contact with the gas mixture are coated to reduce adsorption/desorption processes. Each input parameter required to calculate the generated amount of substance fraction is calibrated with SI-primary standards. The stability and reproducibility of the generated amount of substance fractions were tested with NO2 for ReGaS2 and HFC-125 for ReGaS3. They demonstrate stability over 1-4 d better than 0.4% and 0.8%, respectively, and reproducibility better than 0.7% and 1%, respectively. Finally, the relative expanded uncertainty of the generated amount of substance fraction is smaller than 3% with the major contributions coming from the uncertainty of the permeation rate and/or of the purity of the matrix gas. These relative expanded uncertainties meet then the needs of the data quality objectives fixed by the World Meteorological Organization.

Xenon Acquisition Strategies for High-Power Electric Propulsion NASA Missions

NASA Technical Reports Server (NTRS)

Herman, Daniel A.; Unfried, Kenneth G.

2015-01-01

The benefits of high-power solar electric propulsion (SEP) for both NASA's human and science exploration missions combined with the technology investment from the Space Technology Mission Directorate have enabled the development of a 50kW-class SEP mission. NASA mission concepts developed, including the Asteroid Redirect Robotic Mission, and those proposed by contracted efforts for the 30kW-class demonstration have a range of xenon propellant loads from 100's of kg up to 10,000 kg. A xenon propellant load of 10 metric tons represents greater than 10% of the global annual production rate of xenon. A single procurement of this size with short-term delivery can disrupt the xenon market, driving up pricing, making the propellant costs for the mission prohibitive. This paper examines the status of the xenon industry worldwide, including historical xenon supply and pricing. The paper discusses approaches for acquiring on the order of 10 MT of xenon propellant considering realistic programmatic constraints to support potential near-term NASA missions. Finally, the paper will discuss acquisitions strategies for mission campaigns utilizing multiple high-power solar electric propulsion vehicles requiring 100's of metric tons of xenon over an extended period of time where a longer term acquisition approach could be implemented.

CO2 Capture by Injection of Flue Gas or CO2-N2 Mixtures into Hydrate Reservoirs: Dependence of CO2 Capture Efficiency on Gas Hydrate Reservoir Conditions.

PubMed

Hassanpouryouzband, Aliakbar; Yang, Jinhai; Tohidi, Bahman; Chuvilin, Evgeny; Istomin, Vladimir; Bukhanov, Boris; Cheremisin, Alexey

2018-04-03

Injection of flue gas or CO 2 -N 2 mixtures into gas hydrate reservoirs has been considered as a promising option for geological storage of CO 2 . However, the thermodynamic process in which the CO 2 present in flue gas or a CO 2 -N 2 mixture is captured as hydrate has not been well understood. In this work, a series of experiments were conducted to investigate the dependence of CO 2 capture efficiency on reservoir conditions. The CO 2 capture efficiency was investigated at different injection pressures from 2.6 to 23.8 MPa and hydrate reservoir temperatures from 273.2 to 283.2 K in the presence of two different saturations of methane hydrate. The results showed that more than 60% of the CO 2 in the flue gas was captured and stored as CO 2 hydrate or CO 2 -mixed hydrates, while methane-rich gas was produced. The efficiency of CO 2 capture depends on the reservoir conditions including temperature, pressure, and hydrate saturation. For a certain reservoir temperature, there is an optimum reservoir pressure at which the maximum amount of CO 2 can be captured from the injected flue gas or CO 2 -N 2 mixtures. This finding suggests that it is essential to control the injection pressure to enhance CO 2 capture efficiency by flue gas or CO 2 -N 2 mixtures injection.

Adiabatic temperature changes of magma-gas mixtures during ascent and eruption

USGS Publications Warehouse

Mastin, L.G.; Ghiorso, M.S.

2001-01-01

Most quantitative studies of flow dynamics in eruptive conduits during volcanic eruptions use a simplified energy equation that ignores either temperature changes, or the thermal effects of gas exsolution. In this paper we assess the effects of those simplifications by analyzing the influence of equilibrium gas exsolution and expansion on final temperatures, velocities, and liquid viscosities of magma-gas mixtures during adiabatic decompression. For a given initial pressure (p1), temperature (T1) and melt composition, the final temperature (Tf) and velocity (Umax) will vary depending on the degree to which friction and other irreversible processes reduce mechanical energy within the conduit. The final conditions range between two thermodynamic end members: (1) Constant enthalpy (dh=0), in which Tf is maximal and no energy goes into lifting or acceleration; and (2) constant entropy (ds=0), in which Tf is minimal and maximum energy goes into lifting and acceleration. For ds=0, T1=900 ??C and p1=200 MPa, a water-saturated albitic melt cools by ???200 ??C during decompression, but only about 250 ??C of this temperature decrease can be attributed to the energy of gas exsolution per se: The remainder results from expansion of gas that has already exsolved. For the same T1 and p1, and dh=0, Tf is 10-15 ??C hotter than T1 but is about 10-25 ??C cooler than Tf in similar calculations that ignore the energy of gas exsolution. For ds=0, p1=200 MPa and T1= 9,000 ??C, assuming that all the enthalpy change of decompression goes into kinetic energy, a water-saturated albitic mixture can theoretically accelerate to ???800 m/s. Similar calculations that ignore gas exsolution (but take into account gas expansion) give velocities about 10-15% higher. For the same T1, p1 = 200 MPa, and ds = 0, the cooling associated with gas expansion and exsolution increases final melt viscosity more than 2.5 orders of magnitude. For dh = 0, isenthalpic heating decreases final melt viscosity by about

Relaxation channels of multi-photon excited xenon clusters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Serdobintsev, P. Yu.; Melnikov, A. S.; Department of Physics, St. Petersburg State University, Saint Petersburg 198904

2015-09-21

The relaxation processes of the xenon clusters subjected to multi-photon excitation by laser radiation with quantum energies significantly lower than the thresholds of excitation of atoms and ionization of clusters were studied. Results obtained by means of the photoelectron spectroscopy method showed that desorption processes of excited atoms play a significant role in the decay of two-photon excited xenon clusters. A number of excited states of xenon atoms formed during this process were discovered and identified.

DFT-MD simulations of shocked Xenon

NASA Astrophysics Data System (ADS)

Magyar, Rudolph J.; Mattsson, Thomas R.

2009-03-01

Xenon is not only a technologically important element used in laser technologies, jet propulsion and dental anesthesia, but it is also arguably the simplest material in which to study the metal-insulator transition at high pressure. Because of its closed shell electronic configuration, Xenon is often assumed to be chemically inert, interacting almost entirely through the van der Waals interaction, and at liquid density, is typically modeled well using Leonard-Jones potentials. However, such modeling has a limited range of validity as Xenon is known to form compounds at normal conditions and likely exhibits considerably more chemistry at higher densities when hybridization of occupied orbitals becomes significant. In this talk, we present DFT-MD simulations of shocked liquid Xenon with the goal of developing an improved equation of state. The relative importance of the van der Waals interaction compared to other Coulomb interactions is considered, and estimates of the relative accuracy of various density functionals are quantified. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Evidence of charge exchange pumping in calcium-xenon system

NASA Technical Reports Server (NTRS)

Chubb, D. L.

1973-01-01

Charge exchange between xenon ions and calcium atoms may produce an inversion between the 5s or 4d and 4p energy levels of the calcium ions. A low power flowing xenon plasma seeded with calcium was utilized to determine if charge exchange or electron collisions populate the 5s and 4d levels Ca(+). Line intensity ratios proportional to the density ratios n5s/n4p and n4d/n4p were measured. From the dependence of these intensity ratios on power input to the xenon plasma it was concluded that charge exchange pumping of the 5s and 4d levels predominates over electron collisional pumping of these levels. Also, by comparing intensity ratios obtained using argon and krypton in place of xenon with those obtained in xenon the same conclusion was made.

Effects of superparamagnetic iron oxide nanoparticles on the longitudinal and transverse relaxation of hyperpolarized xenon gas

NASA Astrophysics Data System (ADS)

Burant, Alex; Antonacci, Michael; McCallister, Drew; Zhang, Le; Branca, Rosa Tamara

2018-06-01

SuperParamagnetic Iron Oxide Nanoparticles (SPIONs) are often used in magnetic resonance imaging experiments to enhance Magnetic Resonance (MR) sensitivity and specificity. While the effect of SPIONs on the longitudinal and transverse relaxation time of 1H spins has been well characterized, their effect on highly diffusive spins, like those of hyperpolarized gases, has not. For spins diffusing in linear magnetic field gradients, the behavior of the magnetization is characterized by the relative size of three length scales: the diffusion length, the structural length, and the dephasing length. However, for spins diffusing in non-linear gradients, such as those generated by iron oxide nanoparticles, that is no longer the case, particularly if the diffusing spins experience the non-linearity of the gradient. To this end, 3D Monte Carlo simulations are used to simulate the signal decay and the resulting image contrast of hyperpolarized xenon gas near SPIONs. These simulations reveal that signal loss near SPIONs is dominated by transverse relaxation, with little contribution from T1 relaxation, while simulated image contrast and experiments show that diffusion provides no appreciable sensitivity enhancement to SPIONs.

The XENON100 Dark Matter Experiment: Design, Construction, Calibration and 2010 Search Results with Improved Measurement of the Scintillation Response of Liquid Xenon to Low-Energy Nuclear Recoils

NASA Astrophysics Data System (ADS)

Plante, Guillaume

An impressive array of astrophysical observations suggest that 83% of the matter in the universe is in a form of non-luminous, cold, collisionless, non-baryonic dark matter. Several extensions of the Standard Model of particle physics aimed at solving the hierarchy problem predict stable weakly interacting massive particles (WIMPs) that could naturally have the right cosmological relic abundance today to compose most of the dark matter if their interactions with normal matter are on the order of a weak scale cross section. These candidates also have the added benefit that their properties and interaction rates can be computed in a well defined particle physics model. A considerable experimental effort is currently under way to uncover the nature of dark matter. One method of detecting WIMP dark matter is to look for its interactions in terrestrial detectors where it is expected to scatter off nuclei. In 2007, the XENON10 experiment took the lead over the most sensitive direct detection dark matter search in operation, the CDMS II experiment, by probing spin-independent WIMP-nucleon interaction cross sections down to sigmachi N ˜ 5 x 10-44 cm 2 at 30 GeV/c2. Liquefied noble gas detectors are now among the technologies at the forefront of direct detection experiments. Liquid xenon (LXe), in particular, is a well suited target for WIMP direct detection. It is easily scalable to larger target masses, allows discrimination between nuclear recoils and electronic recoils, and has an excellent stopping power to shield against external backgrounds. A particle losing energy in LXe creates both ionization electrons and scintillation light. In a dual-phase LXe time projection chamber (TPC) the ionization electrons are drifted and extracted into the gas phase where they are accelerated to amplify the charge signal into a proportional scintillation signal. These two signals allow the three-dimensional localization of events with millimeter precision and the ability to

SI-traceable and dynamic reference gas mixtures for water vapour at polar and high troposphere atmospheric levels

NASA Astrophysics Data System (ADS)

Guillevic, Myriam; Pascale, Céline; Mutter, Daniel; Wettstein, Sascha; Niederhauser, Bernhard

2017-04-01

In the framework of METAS' AtmoChem-ECV project, new facilities are currently being developed to generate reference gas mixtures for water vapour at concentrations measured in the high troposphere and polar regions, in the range 1-20 µmol/mol (ppm). The generation method is dynamic (the mixture is produced continuously over time) and SI-traceable (i.e. the amount of substance fraction in mole per mole is traceable to the definition of SI-units). The generation process is composed of three successive steps. The first step is to purify the matrix gas, nitrogen or synthetic air. Second, this matrix gas is spiked with the pure substance using a permeation technique: a permeation device contains a few grams of pure water in liquid form and loses it linearly over time by permeation through a membrane. In a third step, to reach the desired concentration, the first, high concentration mixture exiting the permeation chamber is then diluted with a chosen flow of matrix gas with one or two subsequent dilution steps. All flows are piloted by mass flow controllers. All parts in contact with the gas mixture are passivated using coated surfaces, to reduce adsorption/desorption processes as much as possible. The mixture can eventually be directly used to calibrate an analyser. The standard mixture produced by METAS' dynamic setup was injected into a chilled mirror from MBW Calibration AG, the designated institute for absolute humidity calibration in Switzerland. The used chilled mirror, model 373LX, is able to measure frost point and sample pressure and therefore calculate the water vapour concentration. This intercomparison of the two systems was performed in the range 4-18 ppm water vapour in synthetic air, at two different pressure levels, 1013.25 hPa and 2000 hPa. We present here METAS' dynamic setup, its uncertainty budget and the first results of the intercomparison with MBW's chilled mirror.

Fluid modeling of a high-voltage nanosecond pulsed xenon microdischarge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levko, Dmitry; Raja, Laxminarayan L.

2016-07-15

A computational modeling study of high-voltage nanosecond pulsed microdischarge in xenon gas at 10 atm is presented. The discharge is observed to develop as two streamers originating from the cathode and the anode, and propagating toward each other until they merge to form a single continuous discharge channel. The peak plasma density obtained in the simulations is ∼10{sup 24 }m{sup −3}, i.e., the ionization degree of plasma does not exceed 1%. The influence of the initial gas pre-ionization is established. It is seen that an increase in the seeded plasma density results in an increase in the streamer propagation velocity andmore » an increase in the plasma density obtained after the merging of two streamers.« less

Steady state fractionation of heavy noble gas isotopes in a deep unsaturated zone

USGS Publications Warehouse

Seltzer, Alan M.; Severinghaus, Jeffrey P.; Andraski, Brian J.; Stonestrom, David A.

2017-01-01

To explore steady state fractionation processes in the unsaturated zone (UZ), we measured argon, krypton, and xenon isotope ratios throughout a ∼110 m deep UZ at the United States Geological Survey (USGS) Amargosa Desert Research Site (ADRS) in Nevada, USA. Prior work has suggested that gravitational settling should create a nearly linear increase in heavy-to-light isotope ratios toward the bottom of stagnant air columns in porous media. Our high-precision measurements revealed a binary mixture between (1) expected steady state isotopic compositions and (2) unfractionated atmospheric air. We hypothesize that the presence of an unsealed pipe connecting the surface to the water table allowed for direct inflow of surface air in response to extensive UZ gas sampling prior to our first (2015) measurements. Observed isotopic resettling in deep UZ samples collected a year later, after sealing the pipe, supports this interpretation. Data and modeling each suggest that the strong influence of gravitational settling and weaker influences of thermal diffusion and fluxes of CO2 and water vapor accurately describe steady state isotopic fractionation of argon, krypton, and xenon within the UZ. The data confirm that heavy noble gas isotopes are sensitive indicators of UZ depth. Based on this finding, we outline a potential inverse approach to quantify past water table depths from noble gas isotope measurements in paleogroundwater, after accounting for fractionation during dissolution of UZ air and bubbles.

Viscous slip coefficients for binary gas mixtures measured from mass flow rates through a single microtube

NASA Astrophysics Data System (ADS)

Yamaguchi, H.; Takamori, K.; Perrier, P.; Graur, I.; Matsuda, Y.; Niimi, T.

2016-09-01

The viscous slip coefficient for helium-argon binary gas mixture is extracted from the experimental values of the mass flow rate through a microtube. The mass flow rate is measured by the constant-volume method. The viscous slip coefficient was obtained by identifying the measured mass flow rate through a microtube with the corresponding analytical expression, which is a function of the Knudsen number. The measurements were carried out in the slip flow regime where the first-order slip boundary condition can be applied. The measured viscous slip coefficients of binary gas mixtures exhibit a concave function of the molar ratio of the mixture, showing a similar profile with numerical results. However, from the detailed comparison between the measured and numerical values with the complete and incomplete accommodation at a surface, it is inappropriate to estimate the viscous slip coefficient for the mixture numerically by employing separately measured tangential momentum accommodation coefficient for each component. The time variation of the molar ratio in the downstream chamber was measured by sampling the gas from the chamber using the quadrupole mass spectrometer. In our measurements, it is indicated that the volume flow rate of argon is larger than that of helium because of the difference in the tangential momentum accommodation coefficient.

The Development of the improved equipment for the measurement radionuclides of xenon in atmospheric air

NASA Astrophysics Data System (ADS)

Pakhomov, S. A.; Dubasov, Y. V.

2009-04-01

The Radium Khlopin Institute have developed the mobile (vehicle based) equipment attended for the providing of the monitoring of radioactive xenon isotopes in atmospheric air on territories, neighboring with NPP. This equipment comprises the improved sampling installation with sample-processing unit and specialized spectrometer of β-γ-coincidences. The principal specificity of sampling installation is the using of the gas-cooling machine attended for the reaching of the cryogenic temperatures, which works without helium, using for cooling the processed air itself. The capacity of sampling reaches 20 cubic meters per hour with the xenon extraction factor of 75%. The duration of the sampling cycle forms 3 - 7 hours depending of the xenon volume requirements. The sample-processing unit is designed on preparative gas chromatograph scheme. Duration of sample-processing procedure does not exceed one and half hour. The volume of the prepared sample is around half liter, it contains 3 - 7 cubic centimeters of the xenon, depending of sampling cycle time. For measurements of xenon radioisotopes containing in obtained sample, was developed a β-γ-coincidences spectrometer on the base of the "ORTEC" HP Ge detector equipped with scintillation β-detector designed as Marinelli chamber of 700 cm3 volume. This spectrometer allows to reduce the ambient background more than in 20 times, with γ-channel efficiency reduction not more than in 1.5 times. The minimum detectable activity of 133Хе (MDA), evaluated by Currie formula for probability 95 % is 0.05 Bq at the exposition of 20 hours. Spectrometer is also intended for determination of the stable krypton and xenon concentrations in β-chamber by X-ray-fluorescent method. Therefore, in a shield of the spectrometer collimating pinhole is made and 241Am source is installed. To improve the sensitivity of the analysis beryllium window is made in β-chamber wall, adjoining to the HPGe detector. X-ray-fluorescent analysis allows to

Effect of Channel Geometry and Properties of a Vapor-Gas Mixture on Volume Condensation in a Flow through a Nozzle

NASA Astrophysics Data System (ADS)

Sidorov, A. A.; Yastrebov, A. K.

2018-01-01

A method of direct numerical solution of the kinetic equation for the droplet size distribution function was used for the numerical investigation of volume condensation in a supersonic vapor-gas flow. Distributions of temperature for the gas phase and droplets, degree of supersaturation, pressure, fraction of droplets by weight, the number of droplets per unit mass, and of the nucleation rate along the channel were determined. The influence of nozzle geometry, mixture composition, and temperature dependence of the mixture properties on the investigated process was evaluated. It has been found that the nozzle divergence angle determines the vapor-gas mixture expansion rate: an increase in the divergence angle enhances the temperature decrease rate and the supersaturation degree raise rate. With an increase or decrease in the partial pressure of incondensable gas, the droplet temperature approaches the gas phase temperature or the saturation temperature at the partial gas pressure, respectively. A considerable effect of the temperature dependence of the liquid surface tension and properties on gas phase parameters and the integral characteristics of condensation aerosol was revealed. However, the difference in results obtained with or without considering the temperature dependence of evaporation heat is negligible. The predictions are compared with experimental data of other investigations for two mixtures: a mixture of heavy water vapor with nitrogen (incondensable gas) or n-nonane vapor with nitrogen. The predictions agree quite well qualitatively and quantitatively with the experiment. The comparison of the predictions with numerical results from other publications obtained using the method of moments demonstrates the usefulness of the direct numerical solution method and the method of moments in a wide range of input data.

Plutonium-fission xenon found in Earth's mantle

PubMed

Kunz; Staudacher; Allegre

1998-05-08

Data from mid-ocean ridge basalt glasses indicate that the short-lived radionuclide plutonium-244 that was present during an early stage of the development of the solar system is responsible for roughly 30 percent of the fissiogenic xenon excesses in the interior of Earth today. The rest of the fissiogenic xenon can be ascribed to the spontaneous fission of still live uranium-238. This result, in combination with the refined determination of xenon-129 excesses from extinct iodine-129, implies that the accretion of Earth was finished roughly 50 million to 70 million years after solar system formation and that the atmosphere was formed by mantle degassing.

MiX: a position sensitive dual-phase liquid xenon detector

NASA Astrophysics Data System (ADS)

Stephenson, S.; Haefner, J.; Lin, Q.; Ni, K.; Pushkin, K.; Raymond, R.; Schubnell, M.; Shutty, N.; Tarlé, G.; Weaverdyck, C.; Lorenzon, W.

2015-10-01

The need for precise characterization of dual-phase xenon detectors has grown as the technology has matured into a state of high efficacy for rare event searches. The Michigan Xenon detector was constructed to study the microphysics of particle interactions in liquid xenon across a large energy range in an effort to probe aspects of radiation detection in liquid xenon. We report the design and performance of a small 3D position sensitive dual-phase liquid xenon time projection chamber with high light yield (Ly122=15.2 pe/keV at zero field), long electron lifetime (τ > 200 μs), and excellent energy resolution (σ/E = 1% for 1,333 keV gamma rays in a drift field of 200 V/cm). Liquid xenon time projection chambers with such high energy resolution may find applications not only in dark matter direct detection searches, but also in neutrinoless double beta decay experiments and other applications.

Observation of fast sound in disparate-mass gas mixtures by light scattering

NASA Astrophysics Data System (ADS)

Wegdam, G. H.; Bot, Arjen; Schram, R. P. C.; Schaink, H. M.

1989-12-01

We performed light-scattering experiments on a mixture of hydrogen and argon. By varying the density of the sample, we can probe the range of reduced wave vectors in which Campa and Cohen [Phys. Rev. A 39, 4909 (1989)] predicted, in dilute disparate-mass gas mixtures, the onset of a mode supported by the light particles: the fast sound mode. The presence of the additional sound mode can be established most conveniently by analyzing ω2I(k,ω) rather than I(k,ω). Our results for the shift of fast and slow sound match the theoretical predictions very well.

Second law of thermodynamics in volume diffusion hydrodynamics in multicomponent gas mixtures

NASA Astrophysics Data System (ADS)

Dadzie, S. Kokou

2012-10-01

We presented the thermodynamic structure of a new continuum flow model for multicomponent gas mixtures. The continuum model is based on a volume diffusion concept involving specific species. It is independent of the observer's reference frame and enables a straightforward tracking of a selected species within a mixture composed of a large number of constituents. A method to derive the second law and constitutive equations accompanying the model is presented. Using the configuration of a rotating fluid we illustrated an example of non-classical flow physics predicted by new contributions in the entropy and constitutive equations.

Pretreatment with xenon protected immature rabbit heart from ischaemia/reperfusion injury by opening of the mitoKATP channel.

PubMed

Li, Qian; Lian, Chunwei; Zhou, Ronghua; Li, Tao; Xiang, Xujin; Liu, Bin

2013-04-01

The noble gas anaesthetic, xenon has previously been shown to protect the adult myocardium from ischaemia/reperfusion (I/R) injury, however its effect on immature myocardium is unclear. The aim of this study was to investigate the effect of xenon on the isolated immature heart. Isolated, immature (2-3weeks old) New Zealand rabbit hearts were perfused with Krebs-Henseleit buffer via Langendorff-mode. After 20min of baseline equilibration, hearts were pretreated with 75% xenon, 75% xenon+100μM diazoxide, or 75% xenon+100μM 5-hydroxydecanoate, and then subjected to 1h of global ischaemia and 3h of reperfusion. Pretreatment with 75% xenon significantly improved cardiac function (P<0.01 vs. the I/R group, respectively), limited myocardial infarct size (20.83±2.16%, P<0.01 vs. 35.82±2.14% of the I/R group), reduced cardiac enzyme release (CK-MB, 1.00±0.19IU/L, P<0.01 vs. 0.44±0.14IU/L of the I/R group; LDH, 6.15±1.06IU/L P<0.01 vs. 3.49±0.37IU/L of the I/R group) and decreased apoptosis (6.17±0.56%, P<0.01 vs. 11.31±0.93% of the I/R group). In addition, the mitochondrial structure changes caused by I/R injury were largely prevented by 75% xenon pretreatment (1.37±0.16, P<0.01 vs. 2.32±0.13 of the I/R group). The mitochondrial adenosine triphosphate-sensitive potassium (mitoKATP) channel opener diazoxide did not influence the effect of xenon, but the specific mitoKATP channel blocker 5-hydroxydecanoate completely abolished this effect. Our study demonstrated that pretreatment with 75% xenon protected immature heart from I/R injury, and this protection was probably mediated by preservation of myocardial mitochondria and opening of mitoKATP channel. Copyright © 2012 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

Discrete unified gas kinetic scheme for all Knudsen number flows. III. Binary gas mixtures of Maxwell molecules

NASA Astrophysics Data System (ADS)

Zhang, Yue; Zhu, Lianhua; Wang, Ruijie; Guo, Zhaoli

2018-05-01

Recently a discrete unified gas kinetic scheme (DUGKS) in a finite-volume formulation based on the Boltzmann model equation has been developed for gas flows in all flow regimes. The original DUGKS is designed for flows of single-species gases. In this work, we extend the DUGKS to flows of binary gas mixtures of Maxwell molecules based on the Andries-Aoki-Perthame kinetic model [P. Andries et al., J. Stat. Phys. 106, 993 (2002), 10.1023/A:1014033703134. A particular feature of the method is that the flux at each cell interface is evaluated based on the characteristic solution of the kinetic equation itself; thus the numerical dissipation is low in comparison with that using direct reconstruction. Furthermore, the implicit treatment of the collision term enables the time step to be free from the restriction of the relaxation time. Unlike the DUGKS for single-species flows, a nonlinear system must be solved to determine the interaction parameters appearing in the equilibrium distribution function, which can be obtained analytically for Maxwell molecules. Several tests are performed to validate the scheme, including the shock structure problem under different Mach numbers and molar concentrations, the channel flow driven by a small gradient of pressure, temperature, or concentration, the plane Couette flow, and the shear driven cavity flow under different mass ratios and molar concentrations. The results are compared with those from other reliable numerical methods. The results show that the proposed scheme is an effective and reliable method for binary gas mixtures in all flow regimes.

Tortuosity measurement and the effects of finite pulse widths on xenon gas diffusion NMR studies of porous media

NASA Technical Reports Server (NTRS)

Mair, R. W.; Hurlimann, M. D.; Sen, P. N.; Schwartz, L. M.; Patz, S.; Walsworth, R. L.

2001-01-01

We have extended the utility of NMR as a technique to probe porous media structure over length scales of approximately 100-2000 microm by using the spin 1/2 noble gas 129Xe imbibed into the system's pore space. Such length scales are much greater than can be probed with NMR diffusion studies of water-saturated porous media. We utilized Pulsed Gradient Spin Echo NMR measurements of the time-dependent diffusion coefficient, D(t), of the xenon gas filling the pore space to study further the measurements of both the pore surface-area-to-volume ratio, S/V(p), and the tortuosity (pore connectivity) of the medium. In uniform-size glass bead packs, we observed D(t) decreasing with increasing t, reaching an observed asymptote of approximately 0.62-0.65D(0), that could be measured over diffusion distances extending over multiple bead diameters. Measurements of D(t)/D(0) at differing gas pressures showed this tortuosity limit was not affected by changing the characteristic diffusion length of the spins during the diffusion encoding gradient pulse. This was not the case at the short time limit, where D(t)/D(0) was noticeably affected by the gas pressure in the sample. Increasing the gas pressure, and hence reducing D(0) and the diffusion during the gradient pulse served to reduce the previously observed deviation of D(t)/D(0) from the S/V(p) relation. The Pade approximation is used to interpolate between the long and short time limits in D(t). While the short time D(t) points lay above the interpolation line in the case of small beads, due to diffusion during the gradient pulse on the order of the pore size, it was also noted that the experimental D(t) data fell below the Pade line in the case of large beads, most likely due to finite size effects.

Vertical and bevel-structured SiC etching techniques incorporating different gas mixture plasmas for various microelectronic applications.

PubMed

Sung, Ho-Kun; Qiang, Tian; Yao, Zhao; Li, Yang; Wu, Qun; Lee, Hee-Kwan; Park, Bum-Doo; Lim, Woong-Sun; Park, Kyung-Ho; Wang, Cong

2017-06-20

This study presents a detailed fabrication method, together with validation, discussion, and analysis, for state-of-the-art silicon carbide (SiC) etching of vertical and bevelled structures by using inductively coupled plasma reactive ion etching (ICP-RIE) for microelectronic applications. Applying different gas mixtures, a maximum bevel angle of 87° (almost vertical), large-angle bevels ranging from 40° to 80°, and small-angel bevels ranging from 7° to 17° were achieved separately using distinct gas mixtures at different ratios. We found that SF 6 with additive O 2 was effective for vertical etching, with a best etching rate of 3050 Å/min. As for the large-angle bevel structures, BCl 3  + N 2 gas mixtures show better characteristics, exhibiting a controllable and large etching angle range from 40° to 80° through the adjustment of the mixture ratio. Additionally, a Cl 2  + O 2 mixture at different ratios is applied to achieve a small-angel bevels ranging from 7° to 17°. A minimum bevel angel of approximately 7° was achieved under the specific volume of 2.4 sccm Cl 2 and 3.6 sccm O 2 . These results can be used to improve performance in various microelectronic applications including MMIC via holes, PIN diodes, Schottky diodes, JFETs' bevel mesa, and avalanche photodiode fabrication.

Exploring the plasma chemistry in microwave chemical vapor deposition of diamond from C/H/O gas mixtures.

PubMed

Kelly, Mark W; Richley, James C; Western, Colin M; Ashfold, Michael N R; Mankelevich, Yuri A

2012-09-27

Microwave (MW)-activated CH(4)/CO(2)/H(2) gas mixtures operating under conditions relevant to diamond chemical vapor deposition (i.e., X(C/Σ) = X(elem)(C)/(X(elem)(C) + X(elem)(O)) ≈ 0.5, H(2) mole fraction = 0.3, pressure, p = 150 Torr, and input power, P = 1 kW) have been explored in detail by a combination of spatially resolved absorption measurements (of CH, C(2)(a), and OH radicals and H(n = 2) atoms) within the hot plasma region and companion 2-dimensional modeling of the plasma. CO and H(2) are identified as the dominant species in the plasma core. The lower thermal conductivity of such a mixture (cf. the H(2)-rich plasmas used in most diamond chemical vapor deposition) accounts for the finding that CH(4)/CO(2)/H(2) plasmas can yield similar maximal gas temperatures and diamond growth rates at lower input powers than traditional CH(4)/H(2) plasmas. The plasma chemistry and composition is seen to switch upon changing from oxygen-rich (X(C/Σ) < 0.5) to carbon-rich (X(C/Σ) > 0.5) source gas mixtures and, by comparing CH(4)/CO(2)/H(2) (X(C/Σ) = 0.5) and CO/H(2) plasmas, to be sensitive to the choice of source gas (by virtue of the different prevailing gas activation mechanisms), in contrast to C/H process gas mixtures. CH(3) radicals are identified as the most abundant C(1)H(x) [x = 0-3] species near the growing diamond surface within the process window for successful diamond growth (X(C/Σ) ≈ 0.5-0.54) identified by Bachmann et al. (Diamond Relat. Mater.1991, 1, 1). This, and the findings of similar maximal gas temperatures (T(gas) ~2800-3000 K) and H atom mole fractions (X(H)~5-10%) to those found in MW-activated C/H plasmas, points to the prevalence of similar CH(3) radical based diamond growth mechanisms in both C/H and C/H/O plasmas.

Fundamental equations of a mixture of gas and small spherical solid particles from simple kinetic theory.

NASA Technical Reports Server (NTRS)

Pai, S. I.

1973-01-01

The fundamental equations of a mixture of a gas and pseudofluid of small spherical solid particles are derived from the Boltzmann equation of two-fluid theory. The distribution function of the gas molecules is defined in the same manner as in the ordinary kinetic theory of gases, but the distribution function for the solid particles is different from that of the gas molecules, because it is necessary to take into account the different size and physical properties of solid particles. In the proposed simple kinetic theory, two additional parameters are introduced: one is the radius of the spheres and the other is the instantaneous temperature of the solid particles in the distribution of the solid particles. The Boltzmann equation for each species of the mixture is formally written, and the transfer equations of these Boltzmann equations are derived and compared to the well-known fundamental equations of the mixture of a gas and small solid particles from continuum theory. The equations obtained reveal some insight into various terms in the fundamental equations. For instance, the partial pressure of the pseudofluid of solid particles is not negligible if the volume fraction of solid particles is not negligible as in the case of lunar ash flow.

Breakdown and Limit of Continuum Diffusion Velocity for Binary Gas Mixtures from Direct Simulation

NASA Astrophysics Data System (ADS)

Martin, Robert Scott; Najmabadi, Farrokh

2011-05-01

This work investigates the breakdown of the continuum relations for diffusion velocity in inert binary gas mixtures. Values of the relative diffusion velocities for components of a gas mixture may be calculated using of Chapman-Enskog theory and occur not only due to concentration gradients, but also pressure and temperature gradients in the flow as described by Hirschfelder. Because Chapman-Enskog theory employs a linear perturbation around equilibrium, it is expected to break down when the velocity distribution deviates significantly from equilibrium. This breakdown of the overall flow has long been an area of interest in rarefied gas dynamics. By comparing the continuum values to results from Bird's DS2V Monte Carlo code, we propose a new limit on the continuum approach specific to binary gases. To remove the confounding influence of an inconsistent molecular model, we also present the application of the variable hard sphere (VSS) model used in DS2V to the continuum diffusion velocity calculation. Fitting sample asymptotic curves to the breakdown, a limit, Vmax, that is a fraction of an analytically derived limit resulting from the kinetic temperature of the mixture is proposed. With an expected deviation of only 2% between the physical values and continuum calculations within ±Vmax/4, we suggest this as a conservative estimate on the range of applicability for the continuum theory.

Discovery potential of xenon-based neutrinoless double beta decay experiments in light of small angular scale CMB observations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gómez-Cadenas, J.J.; Martín-Albo, J.; Vidal, J. Muñoz

2013-03-01

The South Pole Telescope (SPT) has probed an expanded angular range of the CMB temperature power spectrum. Their recent analysis of the latest cosmological data prefers nonzero neutrino masses, with Σm{sub ν} = (0.32±0.11) eV. This result, if confirmed by the upcoming Planck data, has deep implications on the discovery of the nature of neutrinos. In particular, the values of the effective neutrino mass m{sub ββ} involved in neutrinoless double beta decay (ββ0ν) are severely constrained for both the direct and inverse hierarchy, making a discovery much more likely. In this paper, we focus in xenon-based ββ0ν experiments, on themore » double grounds of their good performance and the suitability of the technology to large-mass scaling. We show that the current generation, with effective masses in the range of 100 kg and conceivable exposures in the range of 500 kg·year, could already have a sizeable opportunity to observe ββ0ν events, and their combined discovery potential is quite large. The next generation, with an exposure in the range of 10 ton·year, would have a much more enhanced sensitivity, in particular due to the very low specific background that all the xenon technologies (liquid xenon, high-pressure xenon and xenon dissolved in liquid scintillator) can achieve. In addition, a high-pressure xenon gas TPC also features superb energy resolution. We show that such detector can fully explore the range of allowed effective Majorana masses, thus making a discovery very likely.« less

Adsorption of binary gas mixtures in heterogeneous carbon predicted by density functional theory: on the formation of adsorption azeotropes.

PubMed

Ritter, James A; Pan, Huanhua; Balbuena, Perla B

2010-09-07

Classical density functional theory (DFT) was used to predict the adsorption of nine different binary gas mixtures in a heterogeneous BPL activated carbon with a known pore size distribution (PSD) and in single, homogeneous, slit-shaped carbon pores of different sizes. By comparing the heterogeneous results with those obtained from the ideal adsorbed solution theory and with those obtained in the homogeneous carbon, it was determined that adsorption nonideality and adsorption azeotropes are caused by the coupled effects of differences in the molecular size of the components in a gas mixture and only slight differences in the pore sizes of a heterogeneous adsorbent. For many binary gas mixtures, selectivity was found to be a strong function of pore size. As the width of a homogeneous pore increases slightly, the selectivity for two different sized adsorbates may change from being greater than unity to less than unity. This change in selectivity can be accompanied by the formation of an adsorption azeotrope when this same binary mixture is adsorbed in a heterogeneous adsorbent with a PSD, like in BPL activated carbon. These results also showed that the selectivity exhibited by a heterogeneous adsorbent can be dominated by a small number of pores that are very selective toward one of the components in the gas mixture, leading to adsorption azeotrope formation in extreme cases.

Process and catalyst for converting synthesis gas to liquid hydrocarbon mixture

DOEpatents

Rao, V. Udaya S.; Gormley, Robert J.

1987-01-01

Synthesis gas containing CO and H.sub.2 is converted to a high-octane hydrocarbon liquid in the gasoline boiling point range by bringing the gas into contact with a heterogeneous catalyst including, in physical mixture, a zeolite molecular sieve, cobalt at 6-20% by weight, and thoria at 0.5-3.9% by weight. The contacting occurs at a temperature of 250.degree.-300.degree. C., and a pressure of 10-30 atmospheres. The conditions can be selected to form a major portion of the hydrocarbon product in the gasoline boiling range with a research octane of more than 80 and less than 10% by weight aromatics.

Laser-polarized xenon-129 magnetic resonance spectroscopy and imaging. The development of a method for in vivo perfusion measurement

NASA Astrophysics Data System (ADS)

Rosen, Matthew Scot

2001-07-01

This thesis presents in vivo nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) studies with laser-polarized 129Xe delivered to living rats by inhalation and transported to tissue via blood flow. The results presented herein include the observation, assignment, and dynamic measurement of 129Xe resonances in the brain and body, the first one- and two-dimensional chemical-shift-resolved images of 129Xe in blood, tissue, and gas in the thorax, and the first images of 129Xe in brain tissue. These results establish that laser-polarized 129Xe can be used as a magnetic resonance tracer in vivo. NMR resonances at 0, 191, 198, and 209 ppm relative to the 129 Xe gas resonance are observed in the rat thorax and assigned to 129Xe in gas, fat, tissue, and blood respectively. Resonances at 189, 192, 195, 198, and 209 ppm are observed in the brain, and the 195 and 209 ppm resonances are assigned to 129Xe in grey matter, and blood, respectively. The design and construction of a laser-polarized 129Xe production and delivery system is described. This system produces liter-volumes of laser- polarized 129Xe by spin-exchange optical- pumping. It represented an order of magnitude increase over previously reported production volumes of polarized 129Xe. At approximately 3-7% polarization, 157 cc-atm of xenon is produced and stored as ice every 5 minutes. This reliable, effective, and simple production method for large volumes of 129Xe can be applied to other areas of research involving the use of laser-polarized noble gases. A model of the in vivo transport of laser polarized 129Xe to tissue under realistic experimental NMR conditions is described. Appropriate control of the NMR parameters is shown to allow tissue perfasion and 129Xe tissue T1 to be extracted from measurement of the steady-state 129Xe tissue signal. In vivo rodent 129Xe NMR results are used to estimate the signal-to-noise ratio of this technique, and an inhaled 30% xenon/70% O2 mixture polarized to 5

Mechanistic Insights into Xenon Inhibition of NMDA Receptors from MD Simulations

PubMed Central

Liu, Lu Tian; Xu, Yan; Tang, Pei

2010-01-01

Inhibition of N-methyl-D-aspartate (NMDA) receptors has been viewed as a primary cause of xenon anesthesia, yet the mechanism is unclear. Here, we investigated interactions between xenon and the ligand-binding domain (LBD) of a NMDA receptor and examined xenon-induced structural and dynamical changes that are relevant to functional changes of the NMDA receptor. Several comparative molecular dynamics simulations were performed on two X-ray structures representing the open- and closed-cleft LBD of the NMDA receptor. We identified plausible xenon action sites in the LBD, including those nearby agonist sites, in the hinge region, and at the interface between two subunits. The xenon binding energy varies from −5.3 to −0.7 kcal/mol. Xenon's effect on the NMDA receptor is conformation-dependent and is produced through both competitive and non-competitive mechanisms. Xenon can promote cleft opening in the absence of agonists and consequently stabilizes the closed channel. Xenon can also bind at the interface of two subunits, alter the inter-subunit interaction, and lead to a reduction of the distance between GT-links. This reduction corresponds to a rearrangement of the channel toward a direction of pore size decreasing, implying a closed or desensitized channel. In addition to these non-competitive actions, xenon was found to weaken the glutamate binding, which could lead to low agonist efficacy and appear as competitive inhibition. PMID:20560662

10 CFR 504.7 - Prohibition against excessive use of petroleum or natural gas in mixtures-electing powerplants.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) ALTERNATE FUELS EXISTING POWERPLANTS § 504.7 Prohibition against excessive use of petroleum or natural gas... technically and financially feasible for a unit to use a mixture of petroleum or natural gas and an alternate... natural gas, or both, in amounts exceeding the minimum amount necessary to maintain reliability of...

WE-FG-206-07: Assessing the Lung Function of Patients with Non-Small Cell Lung Cancer Using Hyperpolarized Xenon-129 Dissolved-Phase MRI

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qing, K; Mugler, J; Chen, Q

Purpose: Hyperpolarized xenon-129 dissolved-phase MRI is the first imaging technique that allows 3-dimensional regional mapping of ventilation and gas uptake by tissue and blood the in human lung. Multiple outcome measures can be produced from this method. Existing studies in subjects with major lung diseases compared to healthy controls demonstrated high sensitivities of this method to pulmonary physiological factors including ventilation, alveolar tissue density, surface-to-volume ratio, pulmonary perfusion and gas-blood barrier thickness. The purpose of this study is to evaluate the utility of this new imaging tool to assess the lung function in patients with non-small cell lung cancer (NSCLC).more » Methods: Ten healthy controls (age: 63±10) and five patients (age: 62±13) with NSCLC underwent the xenon-129 dissolved-phase MRI, pulmonary function test (PFT) and CT for clinical purpose. Three outcome measures were produced from xenon-129 dissolved-phase MRI, including ventilation defect fraction (Vdef%) reflecting the airflow obstruction, tissue-to-gas ratio reflecting lung tissue density, and RBC-to-tissue ratio reflecting pulmonary perfusion and gas exchange. Results: Compared to healthy controls, patients with NSCLC showed more ventilation defects (NSCLC: 22±6%; control: 40±18%; P=0.01), lower tissue-to-gas (NSCLC: 0.82±0.31%; control: 1.07±0.13%; P=0.05) and RBC-to-tissue ratios (NSCLC: 0.82±0.31%; control: 1.07±0.13%; P=0.01). Maps for ventilation and gas uptake by tissue and blood were highly heterogeneous in the lungs of patients. Vdef% and RBC-to-tissue ratios in all 15 subjects correlated with corresponding global lung functional measures from PFT: FEV1/FVC (R=−0.91, P<0.001) and DLCO % predicted (R=0.54, P=0.03), respectively. The tissue-to-gas ratios correlated with tissue density (HU) measured by CT (R=0.88, P<0.001). Conclusion: With the unique ability to provide detailed information about lung function including ventilation, tissue

Synthesis of the missing oxide of xenon, XeO2, and its implications for Earth's missing xenon.

PubMed

Brock, David S; Schrobilgen, Gary J

2011-04-27

The missing Xe(IV) oxide, XeO(2), has been synthesized at 0 °C by hydrolysis of XeF(4) in water and 2.00 M H(2)SO(4(aq)). Raman spectroscopy and (16/18)O isotopic enrichment studies indicate that XeO(2) possesses an extended structure in which Xe(IV) is oxygen bridged to four neighboring oxygen atoms to give a local square-planar XeO(4) geometry based on an AX(4)E(2) valence shell electron pair repulsion (VSEPR) arrangement. The vibrational spectra of Xe(16)O(2) and Xe(18)O(2) amend prior vibrational assignments of xenon doped SiO(2) and are in accordance with prior speculation that xenon depletion from the Earth's atmosphere may occur by xenon insertion at high temperatures and high pressures into SiO(2) in the Earth's crust.

Xenon Acquisition Strategies for High-Power Electric Propulsion NASA Missions

NASA Technical Reports Server (NTRS)

Herman, Daniel A.; Unfried, Kenneth G.

2015-01-01

Solar electric propulsion (SEP) has been used for station-keeping of geostationary communications satellites since the 1980s. Solar electric propulsion has also benefitted from success on NASA Science Missions such as Deep Space One and Dawn. The xenon propellant loads for these applications have been in the 100s of kilograms range. Recent studies performed for NASA's Human Exploration and Operations Mission Directorate (HEOMD) have demonstrated that SEP is critically enabling for both near-term and future exploration architectures. The high payoff for both human and science exploration missions and technology investment from NASA's Space Technology Mission Directorate (STMD) are providing the necessary convergence and impetus for a 30-kilowatt-class SEP mission. Multiple 30-50- kilowatt Solar Electric Propulsion Technology Demonstration Mission (SEP TDM) concepts have been developed based on the maturing electric propulsion and solar array technologies by STMD with recent efforts focusing on an Asteroid Redirect Robotic Mission (ARRM). Xenon is the optimal propellant for the existing state-of-the-art electric propulsion systems considering efficiency, storability, and contamination potential. NASA mission concepts developed and those proposed by contracted efforts for the 30-kilowatt-class demonstration have a range of xenon propellant loads from 100s of kilograms up to 10,000 kilograms. This paper examines the status of the xenon industry worldwide, including historical xenon supply and pricing. The paper will provide updated information on the xenon market relative to previous papers that discussed xenon production relative to NASA mission needs. The paper will discuss the various approaches for acquiring on the order of 10 metric tons of xenon propellant to support potential near-term NASA missions. Finally, the paper will discuss acquisitions strategies for larger NASA missions requiring 100s of metric tons of xenon will be discussed.

Removing krypton from xenon by cryogenic distillation to the ppq level

NASA Astrophysics Data System (ADS)

Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Arneodo, F.; Barrow, P.; Baudis, L.; Bauermeister, B.; Benabderrahmane, M. L.; Berger, T.; Breur, P. A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cervantes, M.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; Di Gangi, P.; Di Giovanni, A.; Diglio, S.; Duchovni, E.; Eurin, G.; Fei, J.; Ferella, A. D.; Fieguth, A.; Franco, D.; Fulgione, W.; Gallo Rosso, A.; Galloway, M.; Gao, F.; Garbini, M.; Geis, C.; Goetzke, L. W.; Grandi, L.; Greene, Z.; Grignon, C.; Hasterok, C.; Hogenbirk, E.; Huhmann, C.; Itay, R.; Kaminsky, B.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Lellouch, D.; Levinson, L.; Calloch, M. Le; Lin, Q.; Lindemann, S.; Lindner, M.; Lopes, J. A. M.; Manfredini, A.; Maris, I.; Undagoitia, T. Marrodán; Masbou, J.; Massoli, F. V.; Masson, D.; Mayani, D.; Meng, Y.; Messina, M.; Micheneau, K.; Miguez, B.; Molinario, A.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Orrigo, S. E. A.; Pakarha, P.; Pelssers, B.; Persiani, R.; Piastra, F.; Pienaar, J.; Piro, M.-C.; Pizzella, V.; Plante, G.; Priel, N.; Rauch, L.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; Rupp, N.; Saldanha, R.; Santos, J. M. F. dos; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schreiner, J.; Schumann, M.; Lavina, L. Scotto; Selvi, M.; Shagin, P.; Shockley, E.; Silva, M.; Simgen, H.; Sivers, M. v.; Stein, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Upole, N.; Wang, H.; Wei, Y.; Weinheimer, C.; Wulf, J.; Ye, J.; Zhang, Y.; Cristescu, I.

2017-05-01

The XENON1T experiment aims for the direct detection of dark matter in a detector filled with 3.3 tons of liquid xenon. In order to achieve the desired sensitivity, the background induced by radioactive decays inside the detector has to be sufficiently low. One major contributor is the β -emitter ^{85}Kr which is present in the xenon. For XENON1T a concentration of natural krypton in xenon ^{nat}Kr/Xe < 200 ppq (parts per quadrillion, 1 ppq =10^{-15} mol/mol) is required. In this work, the design, construction and test of a novel cryogenic distillation column using the common McCabe-Thiele approach is described. The system demonstrated a krypton reduction factor of 6.4\\cdot 10^5 with thermodynamic stability at process speeds above 3 kg/h. The resulting concentration of ^{nat}Kr/Xe<26 ppq is the lowest ever achieved, almost one order of magnitude below the requirements for XENON1T and even sufficient for future dark matter experiments using liquid xenon, such as XENONnT and DARWIN.

First Dark Matter Search Results from the XENON1T Experiment

NASA Astrophysics Data System (ADS)

Aprile, E.; Aalbers, J.; Agostini, F.; Alfonsi, M.; Amaro, F. D.; Anthony, M.; Arneodo, F.; Barrow, P.; Baudis, L.; Bauermeister, B.; Benabderrahmane, M. L.; Berger, T.; Breur, P. A.; Brown, A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Bütikofer, L.; Calvén, J.; Cardoso, J. M. R.; Cervantes, M.; Cichon, D.; Coderre, D.; Colijn, A. P.; Conrad, J.; Cussonneau, J. P.; Decowski, M. P.; de Perio, P.; di Gangi, P.; di Giovanni, A.; Diglio, S.; Eurin, G.; Fei, J.; Ferella, A. D.; Fieguth, A.; Fulgione, W.; Gallo Rosso, A.; Galloway, M.; Gao, F.; Garbini, M.; Gardner, R.; Geis, C.; Goetzke, L. W.; Grandi, L.; Greene, Z.; Grignon, C.; Hasterok, C.; Hogenbirk, E.; Howlett, J.; Itay, R.; Kaminsky, B.; Kazama, S.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Lellouch, D.; Levinson, L.; Lin, Q.; Lindemann, S.; Lindner, M.; Lombardi, F.; Lopes, J. A. M.; Manfredini, A.; Mariş, I.; Marrodán Undagoitia, T.; Masbou, J.; Massoli, F. V.; Masson, D.; Mayani, D.; Messina, M.; Micheneau, K.; Molinario, A.; Morâ, K.; Murra, M.; Naganoma, J.; Ni, K.; Oberlack, U.; Pakarha, P.; Pelssers, B.; Persiani, R.; Piastra, F.; Pienaar, J.; Pizzella, V.; Piro, M.-C.; Plante, G.; Priel, N.; Rauch, L.; Reichard, S.; Reuter, C.; Riedel, B.; Rizzo, A.; Rosendahl, S.; Rupp, N.; Saldanha, R.; Dos Santos, J. M. F.; Sartorelli, G.; Scheibelhut, M.; Schindler, S.; Schreiner, J.; Schumann, M.; Scotto Lavina, L.; Selvi, M.; Shagin, P.; Shockley, E.; Silva, M.; Simgen, H.; Sivers, M. V.; Stein, A.; Thapa, S.; Thers, D.; Tiseni, A.; Trinchero, G.; Tunnell, C.; Vargas, M.; Upole, N.; Wang, H.; Wang, Z.; Wei, Y.; Weinheimer, C.; Wulf, J.; Ye, J.; Zhang, Y.; Zhu, T.; Xenon Collaboration

2017-11-01

We report the first dark matter search results from XENON1T, a ˜2000 -kg -target-mass dual-phase (liquid-gas) xenon time projection chamber in operation at the Laboratori Nazionali del Gran Sasso in Italy and the first ton-scale detector of this kind. The blinded search used 34.2 live days of data acquired between November 2016 and January 2017. Inside the (1042 ±12 )-kg fiducial mass and in the [5 ,40 ] keVnr energy range of interest for weakly interacting massive particle (WIMP) dark matter searches, the electronic recoil background was (1.93 ±0.25 )×10-4 events /(kg ×day ×keVee) , the lowest ever achieved in such a dark matter detector. A profile likelihood analysis shows that the data are consistent with the background-only hypothesis. We derive the most stringent exclusion limits on the spin-independent WIMP-nucleon interaction cross section for WIMP masses above 10 GeV /c2 , with a minimum of 7.7 ×10-47 cm2 for 35 -GeV /c2 WIMPs at 90% C.L.

10 CFR 504.8 - Prohibitions against excessive use of petroleum or natural gas in mixtures-certifying powerplants.

Code of Federal Regulations, 2010 CFR

2010-01-01

...) ALTERNATE FUELS EXISTING POWERPLANTS § 504.8 Prohibitions against excessive use of petroleum or natural gas... use of petroleum or natural gas in such powerplant in amounts exceeding the minimum amount necessary... feasible for the unit to use a mixture of petroleum or natural gas and coal or another alternate fuel as a...

Postconditioning effects of argon or xenon on early graft function in a porcine model of kidney autotransplantation.

PubMed

De Deken, J; Rex, S; Lerut, E; Martinet, W; Monbaliu, D; Pirenne, J; Jochmans, I

2018-07-01

Ischaemia-reperfusion injury is inevitable during renal transplantation and can lead to delayed graft function and primary non-function. Preconditioning, reconditioning and postconditioning with argon and xenon protects against renal ischaemia-reperfusion injury in rodent models. The hypothesis that postconditioning with argon or xenon inhalation would improve graft function in a porcine renal autotransplant model was tested. Pigs (n = 6 per group) underwent left nephrectomy after 60 min of warm ischaemia (renal artery and vein clamping). The procured kidney was autotransplanted in a separate procedure after 18 h of cold storage, immediately after a right nephrectomy. Upon reperfusion, pigs were randomized to inhalation of control gas (70 per cent nitrogen and 30 per cent oxygen), argon (70 per cent and 30 per cent oxygen) or xenon (70 per cent and 30 per cent oxygen) for 2 h. The primary outcome parameter was peak plasma creatinine; secondary outcome parameters included further markers of graft function (creatinine course, urine output), graft injury (aspartate aminotransferase, heart-type fatty acid-binding protein, histology), apoptosis and autophagy (western blot, terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) staining), inflammatory mediators and markers of cell survival/growth (mRNA and tissue protein quantification), and animal survival. Results are presented as median (i.q.r.). ANOVA and Kruskal-Wallis tests were used where indicated. Peak plasma creatinine levels were similar between the groups: control 20·8 (16·4-23·1) mg/dl, argon 21·4 (17·1-24·9) mg/dl and xenon 19·4 (17·5-21·0) mg/dl (P = 0·607). Xenon was associated with an increase in autophagy and proapoptotic markers. Creatinine course, urine output, injury markers, histology, survival and inflammatory mediators were not affected by the intervention. Postconditioning with argon or xenon did not improve kidney graft function in this

Observation of a barium xenon exciplex within a large argon cluster.

PubMed

Briant, M; Gaveau, M-A; Mestdagh, J-M

2010-07-21

Spectroscopic measurements provide fluorescence and excitation spectra of a single barium atom codeposited with xenon atoms on argon clusters of average size approximately 2000. The spectra are studied as a function of the number of xenon atoms per cluster. The excitation spectrum with approximately 10 xenon atoms per cluster is qualitatively similar to that observed when no xenon atom is present on the cluster. It consists of two bands located on each side of the 6s6p (1)P-6s(2) (1)S resonance line of the free barium. In contrast, the fluorescence spectrum differs qualitatively since a barium-xenon exciplex is observed, which has no counterpart in xenon free clusters. In particular an emission is observed, which is redshifted by 729 cm(-1) with respect to the Ba(6s6p (1)P-6s(2) (1)S) resonance line.

Molecular dynamics investigation of separation of hydrogen sulfide from acidic gas mixtures inside metal-doped graphite micropores.

PubMed

Huang, Pei-Hsing

2015-09-21

The separation of poisonous compounds from various process fluids has long been highly intractable, motivating the present study on the dynamic separation of H2S in acidic-gas-mixture-filled micropores. The molecular dynamics approach, coupled with the isothermal-isochoric ensemble, was used to model the molecular interactions and adsorption of H2S/CO2/CO/H2O mixtures inside metal-doped graphite slits. Due to the difference in the adsorption characteristics between the two distinct adsorbent materials, the metal dopant in the graphitic micropores leads to competitive adsorption, i.e. the Au and graphite walls compete to capture free adsorbates. The effects of competitive adsorption, coupled with changes in the gas temperature, concentration, constituent ratio and slit width on the constituent separation of mixtures were systematically studied. The molecule-wall binding energies calculated in this work (those of H2S, H2O and CO on Au walls and those of H2O, CO and CO2 on graphite walls) show good agreement with those obtained using density functional theory (DFT) and experimental results. The z-directional self-diffusivities (Dz) for adsorbates inside the slit ranged from 10(-9) to 10(-7) m(2) s(-1) as the temperature was increased from 10 to 500 K. The values are comparable with those for a typical microporous fluid (10(-8)-10(-9) m(2) s(-1) in a condensed phase and 10(-6)-10(-7) m(2) s(-1) in the gaseous state). The formation of H-bonding networks and hydrates of H2S is disadvantageous for the separation of mixtures. The results indicate that H2S can be efficiently separated from acidic gas mixtures onto the Au(111) surface by (i) reducing the mole fraction of H2S and H2O in the mixtures, (ii) raising the gas temperature to the high temperature limit (≥400 K), and (iii) lowering the slit width to below the threshold dimension (≤23.26 Å).

Transport coefficients in nonequilibrium gas-mixture flows with electronic excitation.

PubMed

Kustova, E V; Puzyreva, L A

2009-10-01

In the present paper, a one-temperature model of transport properties in chemically nonequilibrium neutral gas-mixture flows with electronic excitation is developed. The closed set of governing equations for the macroscopic parameters taking into account electronic degrees of freedom of both molecules and atoms is derived using the generalized Chapman-Enskog method. The transport algorithms for the calculation of the thermal-conductivity, diffusion, and viscosity coefficients are proposed. The developed theoretical model is applied for the calculation of the transport coefficients in the electronically excited N/N(2) mixture. The specific heats and transport coefficients are calculated in the temperature range 50-50,000 K. Two sets of data for the collision integrals are applied for the calculations. An important contribution of the excited electronic states to the heat transfer is shown. The Prandtl number of atomic species is found to be substantially nonconstant.

[Intracranial and cerebral perfusion pressure in neurosurgical patients during anaesthesia with xenon].

PubMed

Rylova, A V; Gavrilov, A G; Lubnin, A Iu; Potapov, A A

2014-01-01

Despite difficulties in providing xenon anaesthesia, xenon still seems to be attractive for neurosurgical procedures. But data upon its effect on intracranial (ICP) and cerebral perfusion pressure (CPP) remains controversial. We monitored ICP and CPP in patients with or without intracranial hypertension during xenon inhalation in different concentrations. Our results suggest that caution should be used while inhaling xenon in high anaesthetic concentration in patients wiith known intracranial hypertension. We also address new possibilities of xenon use, e.g., for sedation in neurosurgery. The study was supported by Russian Fund for Fundamental Research, grant number 13-04-01640.

Computational investigation of noble gas adsorption and separation by nanoporous materials.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allendorf, Mark D.; Sanders, Joseph C.; Greathouse, Jeffery A.

2008-10-01

Molecular simulations are used to assess the ability of metal-organic framework (MOF) materials to store and separate noble gases. Specifically, grand canonical Monte Carlo simulation techniques are used to predict noble gas adsorption isotherms at room temperature. Experimental trends of noble gas inflation curves of a Zn-based material (IRMOF-1) are matched by the simulation results. The simulations also predict that IRMOF-1 selectively adsorbs Xe atoms in Xe/Kr and Xe/Ar mixtures at total feed gas pressures of 1 bar (14.7 psia) and 10 bar (147 psia). Finally, simulations of a copper-based MOF (Cu-BTC) predict this material's ability to selectively adsorb Xemore » and Kr atoms when present in trace amounts in atmospheric air samples. These preliminary results suggest that Cu-BTC may be an ideal candidate for the pre-concentration of noble gases from air samples. Additional simulations and experiments are needed to determine the saturation limit of Cu-BTC for xenon, and whether any krypton atoms would remain in the Cu-BTC pores upon saturation.« less

10 CFR 504.8 - Prohibitions against excessive use of petroleum or natural gas in mixtures-certifying powerplants.

Code of Federal Regulations, 2013 CFR

2013-01-01

... primary energy source. In assessing whether the unit is technically capable of using a mixture of petroleum or natural gas and coal or another alternate fuel as a primary energy source, for purposes of this... technically capable of using the mixture as a primary energy source under § 504.6(c), this certification...

10 CFR 504.8 - Prohibitions against excessive use of petroleum or natural gas in mixtures-certifying powerplants.

Code of Federal Regulations, 2014 CFR

2014-01-01

... primary energy source. In assessing whether the unit is technically capable of using a mixture of petroleum or natural gas and coal or another alternate fuel as a primary energy source, for purposes of this... technically capable of using the mixture as a primary energy source under § 504.6(c), this certification...

10 CFR 504.8 - Prohibitions against excessive use of petroleum or natural gas in mixtures-certifying powerplants.

Code of Federal Regulations, 2012 CFR

2012-01-01

... primary energy source. In assessing whether the unit is technically capable of using a mixture of petroleum or natural gas and coal or another alternate fuel as a primary energy source, for purposes of this... technically capable of using the mixture as a primary energy source under § 504.6(c), this certification...

Signal yields, energy resolution, and recombination fluctuations in liquid xenon

NASA Astrophysics Data System (ADS)

Akerib, D. S.; Alsum, S.; Araújo, H. M.; Bai, X.; Bailey, A. J.; Balajthy, J.; Beltrame, P.; Bernard, E. P.; Bernstein, A.; Biesiadzinski, T. P.; Boulton, E. M.; Bramante, R.; Brás, P.; Byram, D.; Cahn, S. B.; Carmona-Benitez, M. C.; Chan, C.; Chiller, A. A.; Chiller, C.; Currie, A.; Cutter, J. E.; Davison, T. J. R.; Dobi, A.; Dobson, J. E. Y.; Druszkiewicz, E.; Edwards, B. N.; Faham, C. H.; Fiorucci, S.; Gaitskell, R. J.; Gehman, V. M.; Ghag, C.; Gibson, K. R.; Gilchriese, M. G. D.; Hall, C. R.; Hanhardt, M.; Haselschwardt, S. J.; Hertel, S. A.; Hogan, D. P.; Horn, M.; Huang, D. Q.; Ignarra, C. M.; Ihm, M.; Jacobsen, R. G.; Ji, W.; Kamdin, K.; Kazkaz, K.; Khaitan, D.; Knoche, R.; Larsen, N. A.; Lee, C.; Lenardo, B. G.; Lesko, K. T.; Lindote, A.; Lopes, M. I.; Manalaysay, A.; Mannino, R. L.; Marzioni, M. F.; McKinsey, D. N.; Mei, D.-M.; Mock, J.; Moongweluwan, M.; Morad, J. A.; Murphy, A. St. J.; Nehrkorn, C.; Nelson, H. N.; Neves, F.; O'Sullivan, K.; Oliver-Mallory, K. C.; Palladino, K. J.; Pease, E. K.; Phelps, P.; Reichhart, L.; Rhyne, C.; Shaw, S.; Shutt, T. A.; Silva, C.; Solmaz, M.; Solovov, V. N.; Sorensen, P.; Stephenson, S.; Sumner, T. J.; Szydagis, M.; Taylor, D. J.; Taylor, W. C.; Tennyson, B. P.; Terman, P. A.; Tiedt, D. R.; To, W. H.; Tripathi, M.; Tvrznikova, L.; Uvarov, S.; Verbus, J. R.; Webb, R. C.; White, J. T.; Whitis, T. J.; Witherell, M. S.; Wolfs, F. L. H.; Xu, J.; Yazdani, K.; Young, S. K.; Zhang, C.; LUX Collaboration

2017-01-01

This work presents an analysis of monoenergetic electronic recoil peaks in the dark-matter-search and calibration data from the first underground science run of the Large Underground Xenon (LUX) detector. Liquid xenon charge and light yields for electronic recoil energies between 5.2 and 661.7 keV are measured, as well as the energy resolution for the LUX detector at those same energies. Additionally, there is an interpretation of existing measurements and descriptions of electron-ion recombination fluctuations in liquid xenon as limiting cases of a more general liquid xenon recombination fluctuation model. Measurements of the standard deviation of these fluctuations at monoenergetic electronic recoil peaks exhibit a linear dependence on the number of ions for energy deposits up to 661.7 keV, consistent with previous LUX measurements between 2 and 16 keV with 3H. We highlight similarities in liquid xenon recombination for electronic and nuclear recoils with a comparison of recombination fluctuations measured with low-energy calibration data.

Kinetic model for the vibrational energy exchange in flowing molecular gas mixtures. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Offenhaeuser, F.

1987-01-01

The present study is concerned with the development of a computational model for the description of the vibrational energy exchange in flowing gas mixtures, taking into account a given number of energy levels for each vibrational degree of freedom. It is possible to select an arbitrary number of energy levels. The presented model uses values in the range from 10 to approximately 40. The distribution of energy with respect to these levels can differ from the equilibrium distribution. The kinetic model developed can be employed for arbitrary gaseous mixtures with an arbitrary number of vibrational degrees of freedom for each type of gas. The application of the model to CO2-H2ON2-O2-He mixtures is discussed. The obtained relations can be utilized in a study of the suitability of radiation-related transitional processes, involving the CO2 molecule, for laser applications. It is found that the computational results provided by the model agree very well with experimental data obtained for a CO2 laser. Possibilities for the activation of a 16-micron and 14-micron laser are considered.

Reduced gas seepages in ophiolitic complexes: Evidences for multiple origins of the H2-CH4-N2 gas mixtures

NASA Astrophysics Data System (ADS)

Vacquand, Christèle; Deville, Eric; Beaumont, Valérie; Guyot, François; Sissmann, Olivier; Pillot, Daniel; Arcilla, Carlo; Prinzhofer, Alain

2018-02-01

This paper proposes a comparative study of reduced gas seepages occurring in ultrabasic to basic rocks outcropping in ophiolitic complexes based on the study of seepages from Oman, the Philippines, Turkey and New Caledonia. This study is based on analyses of the gas chemical composition, noble gases contents, stable isotopes of carbon, hydrogen and nitrogen. These seepages are mostly made of mixtures of three main components which are H2, CH4 and N2 in various proportions. The relative contents of the three main gas components show 4 distinct types of gas mixtures (H2-rich, N2-rich, N2-H2-CH4 and H2-CH4). These types are interpreted as reflecting different zones of gas generation within or below the ophiolitic complexes. In the H2-rich type, associated noble gases display signatures close to the value of air. In addition to the atmospheric component, mantle and crustal contributions are present in the N2-rich, N2-H2-CH4 and H2-CH4 types. H2-bearing gases are either associated with ultra-basic (pH 10-12) spring waters or they seep directly in fracture systems from the ophiolitic rocks. In ophiolitic contexts, ultrabasic rocks provide an adequate environment with available Fe2+ and alkaline conditions that favor H2 production. CH4 is produced either directly by reaction of dissolved CO2 with basic-ultrabasic rocks during the serpentinization process or in a second step by H2-CO2 interaction. H2 is present in the gas when no more carbon is available in the system to generate CH4. The N2-rich type is notably associated with relatively high contents of crustal 4He and in this gas type N2 is interpreted as issued mainly from sediments located below the ophiolitic units.

Adsorption process to recover hydrogen from feed gas mixtures having low hydrogen concentration

DOEpatents

Golden, Timothy Christopher; Weist, Jr., Edward Landis; Hufton, Jeffrey Raymond; Novosat, Paul Anthony

2010-04-13

A process for selectively separating hydrogen from at least one more strongly adsorbable component in a plurality of adsorption beds to produce a hydrogen-rich product gas from a low hydrogen concentration feed with a high recovery rate. Each of the plurality of adsorption beds subjected to a repetitive cycle. The process comprises an adsorption step for producing the hydrogen-rich product from a feed gas mixture comprising 5% to 50% hydrogen, at least two pressure equalization by void space gas withdrawal steps, a provide purge step resulting in a first pressure decrease, a blowdown step resulting in a second pressure decrease, a purge step, at least two pressure equalization by void space gas introduction steps, and a repressurization step. The second pressure decrease is at least 2 times greater than the first pressure decrease.

Abatement of Xenon and Iodine Emissions from Medical Isotope Production Facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doll, Charles G.; Sorensen, Christina M.; Bowyer, Ted W.

2014-04-01

The capability of the International Monitoring System (IMS) to detect xenon from underground nuclear explosions is dependent on the radioactive xenon background. Adding to the background, medical isotope production (MIP) by fission releases several important xenon isotopes including xenon-133 and iodine-133 that decays to xenon-133. The amount of xenon released from these facilities may be equivalent to or exceed that released from an underground nuclear explosion. Thus the release of gaseous fission products within days of irradiation makes it difficult to distinguish MIP emissions from a nuclear explosion. In addition, recent shortages in molybdenum-99 have created interest and investment opportunitiesmore » to design and build new MIP facilities in the United States and throughout the world. Due to the potential increase in the number of MIP facilities, a discussion of abatement technologies provides insight into how the problem of emission control from MIP facilities can be tackled. A review of practices is provided to delineate methods useful for abatement of medical isotopes.« less

Analytical Modeling of Weld Bead Shape in Dry Hyperbaric GMAW Using Ar-He Chamber Gas Mixtures

NASA Astrophysics Data System (ADS)

Azar, Amin S.; Ås, Sigmund K.; Akselsen, Odd M.

2013-03-01

Hyperbaric arc welding is a special application of joining the pipeline steels under seawater. In order to analyze the behavior of the arc under ambient pressure, a model is required to estimate the arc efficiency. A distributed point heat source model was employed. The simulated isotherms were calibrated iteratively to fit the actual bead cross section. Basic gas mixture rules and models were used to calculate the thermal properties of the low-temperature shielding gas under the ambient pressure of 10 bar. Nine bead-on-plate welds were deposited each of which under different Ar-He chamber gas compositions. The well-known correlation between arc efficiency (delivered heat) and the thermal conductivity was established for different gas mixtures. The arc efficiency was considered separately for the transverse and perpendicular heat sources. It was found that assigning single heat efficiency factor for the entire arc, which is usually below unity, causes a noticeable underestimation for the heat transfer in the perpendicular direction and a little overestimation in the transverse direction.

First proof of topological signature in the high pressure xenon gas TPC with electroluminescence amplification for the NEXT experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferrario, P.

2016-01-19

The NEXT experiment aims to observe the neutrinoless double beta decay of xenon in a high-pressure 136Xe gas TPC using electroluminescence (EL) to amplify the signal from ionization. One of the main advantages of this technology is the possibility to reconstruct the topology of events with energies close to Q ββ. This paper presents the first demonstration that the topology provides extra handles to reject background events using data obtained with the NEXT-DEMO prototype. Single electrons resulting from the interactions of 22Na 1275 keV gammas and electron-positron pairs produced by conversions of gammas from the 228Th decay chain were usedmore » to represent the background and the signal in a double beta decay. Furthermore, these data were used to develop algorithms for the reconstruction of tracks and the identification of the energy deposited at the end-points, providing an extra background rejection factor of 24.3 ± 1.4 (stat.)%, while maintaining an efficiency of 66.7 ± 1% for signal events.« less

Obtaining the cumulative k-distribution of a gas mixture from those of its components. [radiative transfer in stratosphere

NASA Technical Reports Server (NTRS)

Gerstell, M. F.

1993-01-01

A review of the convolution theorem for obtaining the cumulative k-distribution of a gas mixture proven in Goody et al. (1989) and a discussion of its application to natural spectra are presented. Computational optimizations for use in analyzing high-altitude gas mixtures are introduced. Comparisons of the results of the optimizations, and criteria for deciding what altitudes are 'high' in this context are given. A few relevant features of the testing support software are examined. Some spectrally integrated results, and the circumstances the might permit substituting the method of principal absorbers are examined.

Tunable integration of absorption-membrane-adsorption for efficiently separating low boiling gas mixtures near normal temperature

PubMed Central

Liu, Huang; Pan, Yong; Liu, Bei; Sun, Changyu; Guo, Ping; Gao, Xueteng; Yang, Lanying; Ma, Qinglan; Chen, Guangjin

2016-01-01

Separation of low boiling gas mixtures is widely concerned in process industries. Now their separations heavily rely upon energy-intensive cryogenic processes. Here, we report a pseudo-absorption process for separating low boiling gas mixtures near normal temperature. In this process, absorption-membrane-adsorption is integrated by suspending suitable porous ZIF material in suitable solvent and forming selectively permeable liquid membrane around ZIF particles. Green solvents like water and glycol were used to form ZIF-8 slurry and tune the permeability of liquid membrane surrounding ZIF-8 particles. We found glycol molecules form tighter membrane while water molecules form looser membrane because of the hydrophobicity of ZIF-8. When using mixing solvents composed of glycol and water, the permeability of liquid membrane becomes tunable. It is shown that ZIF-8/water slurry always manifests remarkable higher separation selectivity than solid ZIF-8 and it could be tuned to further enhance the capture of light hydrocarbons by adding suitable quantity of glycol to water. Because of its lower viscosity and higher sorption/desorption rate, tunable ZIF-8/water-glycol slurry could be readily used as liquid absorbent to separate different kinds of low boiling gas mixtures by applying a multistage separation process in one traditional absorption tower, especially for the capture of light hydrocarbons. PMID:26892255

Acoustic wave propagation in bubbly flow with gas, vapor or their mixtures.

PubMed

Zhang, Yuning; Guo, Zhongyu; Gao, Yuhang; Du, Xiaoze

2018-01-01

Presence of bubbles in liquids could significantly alter the acoustic waves in terms of wave speed and attenuation. In the present paper, acoustic wave propagation in bubbly flows with gas, vapor and gas/vapor mixtures is theoretically investigated in a wide range of parameters (including frequency, bubble radius, void fraction, and vapor mass fraction). Our finding reveals two types of wave propagation behavior depending on the vapor mass fraction. Furthermore, the minimum wave speed (required for the closure of cavitation modelling in the sonochemical reactor design) is analyzed and the influences of paramount parameters on it are quantitatively discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

First Dark Matter Search Results from the XENON1T Experiment.

PubMed

Aprile, E; Aalbers, J; Agostini, F; Alfonsi, M; Amaro, F D; Anthony, M; Arneodo, F; Barrow, P; Baudis, L; Bauermeister, B; Benabderrahmane, M L; Berger, T; Breur, P A; Brown, A; Brown, A; Brown, E; Bruenner, S; Bruno, G; Budnik, R; Bütikofer, L; Calvén, J; Cardoso, J M R; Cervantes, M; Cichon, D; Coderre, D; Colijn, A P; Conrad, J; Cussonneau, J P; Decowski, M P; de Perio, P; Di Gangi, P; Di Giovanni, A; Diglio, S; Eurin, G; Fei, J; Ferella, A D; Fieguth, A; Fulgione, W; Gallo Rosso, A; Galloway, M; Gao, F; Garbini, M; Gardner, R; Geis, C; Goetzke, L W; Grandi, L; Greene, Z; Grignon, C; Hasterok, C; Hogenbirk, E; Howlett, J; Itay, R; Kaminsky, B; Kazama, S; Kessler, G; Kish, A; Landsman, H; Lang, R F; Lellouch, D; Levinson, L; Lin, Q; Lindemann, S; Lindner, M; Lombardi, F; Lopes, J A M; Manfredini, A; Mariş, I; Marrodán Undagoitia, T; Masbou, J; Massoli, F V; Masson, D; Mayani, D; Messina, M; Micheneau, K; Molinario, A; Morå, K; Murra, M; Naganoma, J; Ni, K; Oberlack, U; Pakarha, P; Pelssers, B; Persiani, R; Piastra, F; Pienaar, J; Pizzella, V; Piro, M-C; Plante, G; Priel, N; Rauch, L; Reichard, S; Reuter, C; Riedel, B; Rizzo, A; Rosendahl, S; Rupp, N; Saldanha, R; Dos Santos, J M F; Sartorelli, G; Scheibelhut, M; Schindler, S; Schreiner, J; Schumann, M; Scotto Lavina, L; Selvi, M; Shagin, P; Shockley, E; Silva, M; Simgen, H; Sivers, M V; Stein, A; Thapa, S; Thers, D; Tiseni, A; Trinchero, G; Tunnell, C; Vargas, M; Upole, N; Wang, H; Wang, Z; Wei, Y; Weinheimer, C; Wulf, J; Ye, J; Zhang, Y; Zhu, T

2017-11-03

We report the first dark matter search results from XENON1T, a ∼2000-kg-target-mass dual-phase (liquid-gas) xenon time projection chamber in operation at the Laboratori Nazionali del Gran Sasso in Italy and the first ton-scale detector of this kind. The blinded search used 34.2 live days of data acquired between November 2016 and January 2017. Inside the (1042±12)-kg fiducial mass and in the [5,40]  keV_{nr} energy range of interest for weakly interacting massive particle (WIMP) dark matter searches, the electronic recoil background was (1.93±0.25)×10^{-4}  events/(kg×day×keV_{ee}), the lowest ever achieved in such a dark matter detector. A profile likelihood analysis shows that the data are consistent with the background-only hypothesis. We derive the most stringent exclusion limits on the spin-independent WIMP-nucleon interaction cross section for WIMP masses above 10  GeV/c^{2}, with a minimum of 7.7×10^{-47}  cm^{2} for 35-GeV/c^{2} WIMPs at 90% C.L.

Xenon International Automated Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

2016-08-05

The Xenon International Automated Control software monitors, displays status, and allows for manual operator control as well as fully automatic control of multiple commercial and PNNL designed hardware components to generate and transmit atmospheric radioxenon concentration measurements every six hours.

Controlling the position of a stabilized detonation wave in a supersonic gas mixture flow in a plane channel

NASA Astrophysics Data System (ADS)

Levin, V. A.; Zhuravskaya, T. A.

2017-03-01

Stabilization of a detonation wave in a stoichiometric hydrogen-air mixture flowing at a supersonic velocity into a plane symmetric channel with constriction has been studied in the framework of a detailed kinetic mechanism of the chemical interaction. Conditions ensuring the formation of a thrust-producing f low with a stabilized detonation wave in the channel are determined. The inf luence of the inf low Mach number, dustiness of the combustible gas mixture supplied to the channel, and output cross-section size on the position of a stabilized detonation wave in the f low has been analyzed with a view to increasing the efficiency of detonation combustion of the gas mixture. It is established that thrust-producing flow with a stabilized detonation wave can be formed in the channel without any energy consumption.

Signal yields, energy resolution, and recombination fluctuations in liquid xenon

DOE PAGES

Akerib, D. ?S.; Alsum, S.; Ara?jo, H. ?M.; ...

2017-01-19

This study presents an analysis of monoenergetic electronic recoil peaks in the dark-matter-search and calibration data from the first underground science run of the Large Underground Xenon (LUX) detector. Liquid xenon charge and light yields for electronic recoil energies between 5.2 and 661.7 keV are measured, as well as the energy resolution for the LUX detector at those same energies. Additionally, there is an interpretation of existing measurements and descriptions of electron-ion recombination fluctuations in liquid xenon as limiting cases of a more general liquid xenon recombination fluctuation model. Measurements of the standard deviation of these fluctuations at monoenergetic electronicmore » recoil peaks exhibit a linear dependence on the number of ions for energy deposits up to 661.7 keV, consistent with previous LUX measurements between 2 and 16 keV with 3H. We highlight similarities in liquid xenon recombination for electronic and nuclear recoils with a comparison of recombination fluctuations measured with low-energy calibration data.« less

Design of a portable gas chromatography with a conducting polymer nanocomposite detector device and a method to analyze a gas mixture.

PubMed

Pirsa, Sajad

2017-04-01

A portable chromatography device and a method were developed to analyze a gas mixture. The device comprises a chromatographic column for separating components of a sample of the gas mixture. It has an air pump coupled to the inlet of a chromatographic column for pumping air and an injector coupled to the inlet of chromatographic column for feeding the sample using the air as a carrier gas. A detector is arranged downstream from and coupled to the outlet of the chromatographic column. The detector is a nanostructure semiconductive microfiber. The device further comprises an evaluation unit arranged and configured to evaluate each detected component to determine the concentration. The designed portable system was used for simultaneous detection of amines. The possibility of applying dispersive liquid-liquid microextraction for the determination of analytes in trace levels is demonstrated. The reproducibility of this method is acceptable, and good standard deviations were obtained. The relative standard deviation value is less than 6% for all analytes. Finally, the method was successfully applied to the extraction and determination of analytes in water samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Measurement of nitrogen content in a gas mixture by transforming the nitrogen into a substance detectable with nondispersive infrared detection

DOEpatents

Owen, Thomas E.; Miller, Michael A.

2010-08-24

A method of determining the amount of nitrogen in a gas mixture. The constituent gases of the mixture are dissociated and transformed to create a substance that may measured using nondispersive infrared adsorption techniques.

Measurement of nitrogen content in a gas mixture by transforming the nitrogen into a substance detectable with nondispersive infrared detection

DOEpatents

Owen, Thomas E.; Miller, Michael A.

2007-03-13

A method of determining the amount of nitrogen in a gas mixture. The constituent gases of the mixture are dissociated and transformed to create a substance that may measured using nondispersive infrared adsorption techniques.

Density Functional Theory (DFT) Simulations of Shocked Liquid Xenon

NASA Astrophysics Data System (ADS)

Mattsson, Thomas R.; Magyar, Rudolph J.

2009-06-01

Xenon is not only a technologically important element used in laser technologies and jet propulsion, but it is also one of the most accessible materials in which to study the metal-insulator transition with increasing pressure. Because of its closed shell electronic configuration, Xenon is often assumed to be chemically inert, interacting almost entirely through the van der Waals interaction, and at liquid density, is typically modeled well using Leonard-Jones potentials. However, such modeling has a limited range of validity as Xenon is known to form compounds at normal conditions and likely exhibits considerably more chemistry at higher densities when hybridization of occupied orbitals becomes significant. In this talk, we present DFT-MD simulations of shocked liquid Xenon with the goal of developing an improved equation of state. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Coherent soft X-ray high-order harmonics using tight-focusing laser pulses in the gas mixture.

PubMed

Lu, Faming; Xia, Yuanqin; Zhang, Sheng; Chen, Deying; Zhao, Yang; Liu, Bin

2014-01-01

We experimentally study the harmonics from a Xe-He gas mixture using tight-focusing femtosecond laser pulses. The spectrum in the mixed gases exhibits an extended cutoff region from the harmonic H21 to H27. The potential explanation is that the harmonics photons from Xe contribute the electrons of He atoms to transmit into the excited-state. Therefore, the harmonics are emitted from He atoms easily. Furthermore, we show that there are the suppressed harmonics H15 and H17 in the mixed gases. The underlying mechanism is the destructive interference between harmonics generated from different atoms. Our results indicate that HHG from Xe-He gas mixture is an efficient method of obtaining the coherent soft X-ray source.

Method of and apparatus for measuring the mean concentration of thoron and/or radon in a gas mixture

DOEpatents

Lucas, Henry

1990-01-01

A method of and an apparatus for detecting and accurately measuring the mean concentrations of .sup.222 Rn and .sup.220 Tn in a gas mixture, such as the ambient atmosphere in a mine, is provided. The apparatus includes an alpha target member which defines at least one operative target surface and which is preferably fabricated from a single piece of an alpha particle sensitive material. At least one portion of the operative target surface is covered with an alpha particle filter. The uncovered and filter covered operative surface is exposed to the gas mixture containing the .sup.222 Rn and .sup.220 Tn. In the radioactive decay series of these isotopes the maximum kinetic energy emitted by the alpha decay of .sup.222 Rn is about 1.1 MeV less than the maximum kinetic energy emitted by the alpha decay of a .sup.220 Tn. The alpha particle filter has a predetermined mass per unit area of the covered portion of the operative target surface that prevents penetration of alpha particles which originate from .sup.222 Rn decay, but which allows passage therethrough of the maximum kinetic energy alpha particles from .sup.220 Tn decay. Thus, a count of the alpha particle tracks in the uncovered portion of the target member is proportional to the mean concentration of sum of .sup.222 Rn and .sup.220 Tn in the gas mixture, while the count of alpha tracks in the target member under the filter is proportional to the concentration of only the .sup.220 Tn in the gas mixture.

NWA 8114: Analysis of Xenon in this Unique Martian Meteorite

NASA Astrophysics Data System (ADS)

Crowther, S. A.; Jastrzebski, N. D.; Nottingham, M.; Theis, K. J.; Gilmour, J. D.

2014-09-01

The Xe composition of NWA 8114 is dominated by martian atmospheric xenon, with contributions from terrestrial atmospheric contamination at low temperature and fissiogenic xenon at high temperature. The overall systematics are similar to Nakhla.

Reduced gas seepages in serpentinized peridotite complexes: Evidences for multiple origins of the H2-CH4-N2 gas mixtures

NASA Astrophysics Data System (ADS)

Deville, E.; Vacquand, C.; Beaumont, V.; Francois, G.; Sissmann, O.; Pillot, D.; Arcilla, C. A.; Prinzhofer, A.

2017-12-01

A comparative study of reduced gas seepages associated to serpentinized ultrabasic rocks was conducted in the ophiolitic complexes of Oman, the Philippines, Turkey and New Caledonia. This study is based on analyzes of the gas chemical composition, noble gases contents, and stable isotopes of carbon, hydrogen and nitrogen. These gas seepages are mostly made of mixtures of three main components which are H2, CH4 and N2 in various proportions. The relative contents of the three main gas components show 4 distinct families of gas mixtures (H2-rich, N2-rich, N2-H2-CH4 and H2-CH4). These families are interpreted as reflecting different zones of gas generation within or below the ophiolitic complexes. In the H2-rich family associated noble gases display signatures close to the value of air. In addition to the atmospheric component, mantle and crustal contributions are present in the N2-rich, N2-H2-CH4 and H2-CH4 families. H2-bearing gases are either associated to ultra-basic (pH 10-12) spring waters or they seep directly in fracture systems from the ophiolitic rocks. In ophiolitic contexts, ultrabasic rocks provide an adequate environment with available Fe2+ and high pH conditions that favor H2 production. CH4 is produced either directly by reaction of dissolved CO2 with basic-ultrabasic rocks during the serpentinization process or in a second step by H2-CO2 interaction. H2 is present in the gas when no more carbon is available in the system to generate CH4 (conditions of strong carbon restriction). The N2-rich family is associated with relatively high contents of crustal 4He. In this family N2 is interpreted as issued mainly from sediments located below the ophiolitic units.

Multipoint Ignition of a Gas Mixture by a Microwave Subcritical Discharge with an Extended Streamer Structure

NASA Astrophysics Data System (ADS)

Aleksandrov, K. V.; Busleev, N. I.; Grachev, L. P.; Esakov, I. I.; Ravaev, A. A.

2018-02-01

The results of experimental studies on using an electrical discharge with an extended streamer structure in a quasioptical microwave beam in the multipoint ignition of a propane-air mixture have been reported. The pulsed microwave discharge was initiated at the interior surface of a quartz tube that was filled with the mentioned flammable mixture and introduced into a microwave beam with a subbreakdown initial field. Gas breakdown was initiated by an electromagnetic vibrator. The dependence of the type of discharge on the microwave field strength was examined, the lower concentration threshold of ignition of the propane-air mixture by the studied discharge was determined, and the dynamics of combustion of the flammable mixture with local and multipoint ignition were compared.

GraXe, graphene and xenon for neutrinoless double beta decay searches

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gómez-Cadenas, J.J.; Martín-Albo, J.; Monrabal, F.

2012-02-01

We propose a new detector concept, GraXe (to be pronounced as grace), to search for neutrinoless double beta decay in {sup 136}XE. GraXe combines a popular detection medium in rare-event searches, liquid xenon, with a new, background-free material, graphene. In our baseline design of GraXe, a sphere made of graphene-coated titanium mesh and filled with liquid xenon (LXe) enriched in the {sup 136}XE isotope is immersed in a large volume of natural LXe instrumented with photodetectors. Liquid xenon is an excellent scintillator, reasonably transparent to its own light. Graphene is transparent over a large frequency range, and impermeable to themore » xenon. Event position could be deduced from the light pattern detected in the photosensors. External backgrounds would be shielded by the buffer of natural LXe, leaving the ultra-radiopure internal volume virtually free of background. Industrial graphene can be manufactured at a competitive cost to produce the sphere. Enriching xenon in the isotope {sup 136}XE is easy and relatively cheap, and there is already near one ton of enriched xenon available in the world (currently being used by the EXO, KamLAND-Zen and NEXT experiments). All the cryogenic know-how is readily available from the numerous experiments using liquid xenon. An experiment using the GraXe concept appears realistic and affordable in a short time scale, and its physics potential is enormous.« less

10 CFR 504.7 - Prohibition against excessive use of petroleum or natural gas in mixtures-electing powerplants.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 4 2011-01-01 2011-01-01 false Prohibition against excessive use of petroleum or natural...) ALTERNATE FUELS EXISTING POWERPLANTS § 504.7 Prohibition against excessive use of petroleum or natural gas... technically and financially feasible for a unit to use a mixture of petroleum or natural gas and an alternate...

Chondritic Xenon in the Earth's mantle: new constrains on a mantle plume below central Europe

NASA Astrophysics Data System (ADS)

Caracausi, Antonio; Avice, Guillaume; Bernard, Peter; Furi, Evelin; Marty, Bernard

2016-04-01

data support the notion that the fraction of plutonium-derived Xe in plume sources (oceanic as well as continental) is higher than in the MORB source reservoir. Hence, the MORB - type reservoirs appear to be well distinguished and more degassed than the plume sources (oceanic as well as continental) supporting the heterogeneity of Earth's mantle. Finally this study highlights that xenon isotopes in the Eifel gas have preserved a chemical signature that is characteristic of other mantle plume sources. This is very intriguing because the presence of a mantle plume in this sector of Central Europe was already inferred from geophysical and geochemical studies(Buikin et al., 2005; Goes et al., 1999). Notably, tomographic images show a low-velocity structure down to 2000 km depth, representing deep mantle upwelling under central Europe, that may feed smaller upper-mantle plumes (Eifel volcanic district-Germany). References Buikin A., Trieloff M., HoppJ., Althaus T., Korochantseva E., Schwarz W.H. &Altherr R., (2005), Noble gas isotopessuggestdeepmantleplume source of late Cenozoicmaficalkalinevolcanism in Europe, Earth Planet. Sci. Lett. 230, 143-162. Goes S., Spakman W. &BijwaardH., (1999), A lowermantle source for centraleuropeanvolcanism, Science, 286, 1928-1931.G. Holland, M. Cassidy, C.J. Ballentine, Meteorite Kr in the Earth's mantle suggests a late accretionary source for the atmosphere, Science, 326, 1522-1525, (2009). Marty, B. Neon and xenon isotopes in MORB: implications for the Earth-atmosphere evolution. Earth Planet. Sci. Lett. 94, 45-56 (1989). Mukhopadhyay S., Early differentiation and volatile accretion recorded in deep-mantle neon and xenon Nature, 486, 101-106, (2013).

A method for direct, semi-quantitative analysis of gas phase samples using gas chromatography-inductively coupled plasma-mass spectrometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carter, Kimberly E; Gerdes, Kirk

2013-07-01

A new and complete GC–ICP-MS method is described for direct analysis of trace metals in a gas phase process stream. The proposed method is derived from standard analytical procedures developed for ICP-MS, which are regularly exercised in standard ICP-MS laboratories. In order to implement the method, a series of empirical factors were generated to calibrate detector response with respect to a known concentration of an internal standard analyte. Calibrated responses are ultimately used to determine the concentration of metal analytes in a gas stream using a semi-quantitative algorithm. The method was verified using a traditional gas injection from a GCmore » sampling valve and a standard gas mixture containing either a 1 ppm Xe + Kr mix with helium balance or 100 ppm Xe with helium balance. Data collected for Xe and Kr gas analytes revealed that agreement of 6–20% with the actual concentration can be expected for various experimental conditions. To demonstrate the method using a relevant “unknown” gas mixture, experiments were performed for continuous 4 and 7 hour periods using a Hg-containing sample gas that was co-introduced into the GC sample loop with the xenon gas standard. System performance and detector response to the dilute concentration of the internal standard were pre-determined, which allowed semi-quantitative evaluation of the analyte. The calculated analyte concentrations varied during the course of the 4 hour experiment, particularly during the first hour of the analysis where the actual Hg concentration was under predicted by up to 72%. Calculated concentration improved to within 30–60% for data collected after the first hour of the experiment. Similar results were seen during the 7 hour test with the deviation from the actual concentration being 11–81% during the first hour and then decreasing for the remaining period. The method detection limit (MDL) was determined for the mercury by injecting the sample gas into the system following

Collision-induced light scattering in a thin xenon layer between graphite slabs - MD study.

PubMed

Dawid, A; Górny, K; Wojcieszyk, D; Dendzik, Z; Gburski, Z

2014-08-14

The collision-induced light scattering many-body correlation functions and their spectra in thin xenon layer located between two parallel graphite slabs have been investigated by molecular dynamics computer simulations. The results have been obtained at three different distances (densities) between graphite slabs. Our simulations show the increased intensity of the interaction-induced light scattering spectra at low frequencies for xenon atoms in confined space, in comparison to the bulk xenon sample. Moreover, we show substantial dependence of the interaction-induced light scattering correlation functions of xenon on the distances between graphite slabs. The dynamics of xenon atoms in a confined space was also investigated by calculating the mean square displacement functions and related diffusion coefficients. The structural property of confined xenon layer was studied by calculating the density profile, perpendicular to the graphite slabs. Building of a fluid phase of xenon in the innermost part of the slot was observed. The nonlinear dependence of xenon diffusion coefficient on the separation distance between graphite slabs has been found. Copyright © 2014. Published by Elsevier B.V.

Numerical Prediction of Radiation Measurements Taken in the X2 Facility for Mars and Titan Gas Mixtures

NASA Technical Reports Server (NTRS)

Palmer, Grant; Prabhu, Dinesh; Brandis, Aaron; McIntyre, Timothy J.

2011-01-01

Thermochemical relaxation behind a normal shock in Mars and Titan gas mixtures is simulated using a CFD solver, DPLR, for a hemisphere of 1 m radius; the thermochemical relaxation along the stagnation streamline is considered equivalent to the flow behind a normal shock. Flow simulations are performed for a Titan gas mixture (98% N2, 2% CH4 by volume) for shock speeds of 5.7 and 7.6 km/s and pressures ranging from 20 to 1000 Pa, and a Mars gas mixture (96% CO2, and 4% N2 by volume) for a shock speed of 8.6 km/s and freestream pressure of 13 Pa. For each case, the temperatures and number densities of chemical species obtained from the CFD flow predictions are used as an input to a line-by-line radiation code, NEQAIR. The NEQAIR code is then used to compute the spatial distribution of volumetric radiance starting from the shock front to the point where thermochemical equilibrium is nominally established. Computations of volumetric spectral radiance assume Boltzmann distributions over radiatively linked electronic states of atoms and molecules. The results of these simulations are compared against experimental data acquired in the X2 facility at the University of Queensland, Australia. The experimental measurements were taken over a spectral range of 310-450 nm where the dominant contributor to radiation is the CN violet band system. In almost all cases, the present approach of computing the spatial variation of post-shock volumetric radiance by applying NEQAIR along a stagnation line computed using a high-fidelity flow solver with good spatial resolution of the relaxation zone is shown to replicate trends in measured relaxation of radiance for both Mars and Titan gas mixtures.

Start-up, performance and optimization of a compost biofilter treating gas-phase mixture of benzene and toluene.

PubMed

Rene, Eldon R; Kar, Saurajyoti; Krishnan, Jagannathan; Pakshirajan, K; López, M Estefanía; Murthy, D V S; Swaminathan, T

2015-08-01

The performance of a compost biofilter inoculated with mixed microbial consortium was optimized for treating a gas-phase mixture of benzene and toluene. The biofilter was acclimated to these VOCs for a period of ∼18d. The effects of concentration and flow rate on the removal efficiency (RE) and elimination capacity (EC) were investigated by varying the inlet concentration of benzene (0.12-0.95g/m(3)), toluene (0.14-1.48g/m(3)) and gas-flow rate (0.024-0.072m(3)/h). At comparable loading rates, benzene removal in the mixture was reduced in the range of 6.6-41% in comparison with the individual benzene degradation. Toluene removal in mixture was even more affected as observed from the reductions in REs, ranging from 18.4% to 76%. The results were statistically interpreted by performing an analysis of variance (ANOVA) to elucidate the main and interaction effects. Copyright © 2015 Elsevier Ltd. All rights reserved.

Reflectance of polytetrafluoroethylene for xenon scintillation light

NASA Astrophysics Data System (ADS)

Silva, C.; Pinto da Cunha, J.; Pereira, A.; Chepel, V.; Lopes, M. I.; Solovov, V.; Neves, F.

2010-03-01

Gaseous and liquid xenon particle detectors are being used in a number of applications including dark matter search and neutrino-less double beta decay experiments. Polytetrafluoroethylene (PTFE) is often used in these detectors both as electrical insulator and as a light reflector to improve the efficiency of detection of scintillation photons. However, xenon emits in the vacuum ultraviolet (VUV) wavelength region (λ ≃175 nm) where the reflecting properties of PTFE are not sufficiently known. In this work, we report on measurements of PTFE reflectance, including its angular distribution, for the xenon scintillation light. Various samples of PTFE, manufactured by different processes (extruded, expanded, skived, and pressed) have been studied. The data were interpreted with a physical model comprising both specular and diffuse reflections. The reflectance obtained for these samples ranges from about 47% to 66% for VUV light. Other fluoropolymers, namely, ethylene tetrafluoroethylene (ETFE), fluorinated ethylene propylene (FEP), and perfluoro-alkoxyalkane (PFA) were also measured.

Gravity assisted recovery of liquid xenon at large mass flow rates

NASA Astrophysics Data System (ADS)

Virone, L.; Acounis, S.; Beaupère, N.; Beney, J.-L.; Bert, J.; Bouvier, S.; Briend, P.; Butterworth, J.; Carlier, T.; Chérel, M.; Crespi, P.; Cussonneau, J.-P.; Diglio, S.; Manzano, L. Gallego; Giovagnoli, D.; Gossiaux, P.-B.; Kraeber-Bodéré, F.; Ray, P. Le; Lefèvre, F.; Marty, P.; Masbou, J.; Morteau, E.; Picard, G.; Roy, D.; Staempflin, M.; Stutzmann, J.-S.; Visvikis, D.; Xing, Y.; Zhu, Y.; Thers, D.

2018-06-01

We report on a liquid xenon gravity assisted recovery method for nuclear medical imaging applications. The experimental setup consists of an elevated detector enclosed in a cryostat connected to a storage tank called ReStoX. Both elements are part of XEMIS2 (XEnon Medical Imaging System): an innovative medical imaging facility for pre-clinical research that uses pure liquid xenon as detection medium. Tests based on liquid xenon transfer from the detector to ReStoX have been successfully performed showing that an unprecedented mass flow rate close to 1 ton per hour can be reached. This promising achievement as well as future areas of improvement will be discussed in this paper.

Effect of stratified inequality of blood flow on gas exchange in liquid-filled lungs.

NASA Technical Reports Server (NTRS)

West, J. B.; Maloney, J. E.; Castle, B. L.

1972-01-01

This investigation set out to answer two questions: (1) are the distal alveoli in the terminal lung units less well perfused than the proximal alveoli, i.e., is there stratification of blood flow; and (2) if so, does this enhance gas exchange in the presence of stratified inequality of ventilation. Excised dog lungs were ventilated with saline and perfused with blood. Following single inspirations of xenon 133 in saline and various periods of breath holding, the expired xenon concentration against volume was measured and it confirmed marked stratified inequality of ventilation under these conditions. By measuring the rate of depletion of xenon from alveoli during a period of blood flow, we showed that the alveoli which emptied at the end of expiration had 16% less blood flow than those exhaling earlier. However, by measuring the xenon concentration in pulmonary venous blood, we found that about 10% less tracer was transferred from the alveoli into the blood when the inspired xenon was stratified within the respiratory zone. Thus while stratification of blood flow was confirmed, it was shown to impair rather than enhance the efficiency of gas transfer.

Perceptual Characterization and Analysis of Aroma Mixtures Using Gas Chromatography Recomposition-Olfactometry

PubMed Central

Johnson, Arielle J.; Hirson, Gregory D.; Ebeler, Susan E.

2012-01-01

This paper describes the design of a new instrumental technique, Gas Chromatography Recomposition-Olfactometry (GC-R), that adapts the reconstitution technique used in flavor chemistry studies by extracting volatiles from a sample by headspace solid-phase microextraction (SPME), separating the extract on a capillary GC column, and recombining individual compounds selectively as they elute off of the column into a mixture for sensory analysis (Figure 1). Using the chromatogram of a mixture as a map, the GC-R instrument allows the operator to “cut apart" and recombine the components of the mixture at will, selecting compounds, peaks, or sections based on retention time to include or exclude in a reconstitution for sensory analysis. Selective recombination is accomplished with the installation of a Deans Switch directly in-line with the column, which directs compounds either to waste or to a cryotrap at the operator's discretion. This enables the creation of, for example, aroma reconstitutions incorporating all of the volatiles in a sample, including instrumentally undetectable compounds as well those present at concentrations below sensory thresholds, thus correcting for the “reconstitution discrepancy" sometimes noted in flavor chemistry studies. Using only flowering lavender (Lavandula angustifola ‘Hidcote Blue’) as a source for volatiles, we used the instrument to build mixtures of subsets of lavender volatiles in-instrument and characterized their aroma qualities with a sensory panel. We showed evidence of additive, masking, and synergistic effects in these mixtures and of “lavender' aroma character as an emergent property of specific mixtures. This was accomplished without the need for chemical standards, reductive aroma models, or calculation of Odor Activity Values, and is broadly applicable to any aroma or flavor. PMID:22912722

Perceptual characterization and analysis of aroma mixtures using gas chromatography recomposition-olfactometry.

PubMed

Johnson, Arielle J; Hirson, Gregory D; Ebeler, Susan E

2012-01-01

This paper describes the design of a new instrumental technique, Gas Chromatography Recomposition-Olfactometry (GC-R), that adapts the reconstitution technique used in flavor chemistry studies by extracting volatiles from a sample by headspace solid-phase microextraction (SPME), separating the extract on a capillary GC column, and recombining individual compounds selectively as they elute off of the column into a mixture for sensory analysis (Figure 1). Using the chromatogram of a mixture as a map, the GC-R instrument allows the operator to "cut apart" and recombine the components of the mixture at will, selecting compounds, peaks, or sections based on retention time to include or exclude in a reconstitution for sensory analysis. Selective recombination is accomplished with the installation of a Deans Switch directly in-line with the column, which directs compounds either to waste or to a cryotrap at the operator's discretion. This enables the creation of, for example, aroma reconstitutions incorporating all of the volatiles in a sample, including instrumentally undetectable compounds as well those present at concentrations below sensory thresholds, thus correcting for the "reconstitution discrepancy" sometimes noted in flavor chemistry studies. Using only flowering lavender (Lavandula angustifola 'Hidcote Blue') as a source for volatiles, we used the instrument to build mixtures of subsets of lavender volatiles in-instrument and characterized their aroma qualities with a sensory panel. We showed evidence of additive, masking, and synergistic effects in these mixtures and of "lavender' aroma character as an emergent property of specific mixtures. This was accomplished without the need for chemical standards, reductive aroma models, or calculation of Odor Activity Values, and is broadly applicable to any aroma or flavor.

Liquid xenon purification, de-radonation (and de-kryptonation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pocar, Andrea, E-mail: pocar@umass.edu; Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94550

Liquid xenon detectors are at the forefront of rare event physics, including searches for neutrino-less double beta decay and WIMP dark matter. The xenon for these experiments needs to be purified from chemical impurities such as electronegative atoms and molecules, which absorb ionization electrons, and VUV (178 nm) scintillation light-absorbing chemical species. In addition, superb purification from radioactive impurities is required. Particularly challenging are radioactive noble isotopes ({sup 85}Kr,{sup 39,42}Ar,{sup 220,222}Rn). Radon is a particularly universal problem, due to the extended decay sequence of its daughters and its ubiquitous presence in detector materials. Purification and de-radonation of liquid xenon aremore » addressed with particular focus on the experience gained with the EXO-200 neutrino-less double beta decay detector.« less

Long-term stability measurements of low concentration Volatile Organic Compound gas mixtures

NASA Astrophysics Data System (ADS)

Allen, Nick; Amico di Meane, Elena; Brewer, Paul; Ferracci, Valerio; Corbel, Marivon; Worton, David

2017-04-01

VOCs (Volatile Organic Compounds) are a class of compounds with significant influence on the atmosphere due to their large anthropogenic and biogenic emission sources. VOC emissions have a significant impact on the atmospheric hydroxyl budget and nitrogen reservoir species, while also contributing indirectly to the production of tropospheric ozone and secondary organic aerosol. However, the global budget of many of these species are poorly constrained. Moreover, the World Meteorological Organization's (WMO) Global Atmosphere Watch (GAW) have set challenging data quality objectives for atmospheric monitoring programmes for these classes of traceable VOCs, despite the lack of available stable gas standards. The Key-VOCs Joint Research Project is an ongoing three-year collaboration with the aim of improving the measurement infrastructure of important atmospheric VOCs by providing traceable and comparable reference gas standards and by validating new measurement systems in support of the air monitoring networks. It focuses on VOC compounds that are regulated by European legislation, that are relevant for indoor air monitoring and for air quality and climate monitoring programmes like the VOC programme established by the WMO GAW and the European Monitoring and Evaluation Programme (EMEP). These VOCs include formaldehyde, oxy[genated]-VOCs (acetone, ethanol and methanol) and terpenes (a-pinene, 1,8-cineole, δ-3-carene and R-limonene). Here we present the results of a novel long term stability study for low concentration formaldehyde, oxy-VOC and terpenes gas mixtures produced by the Key-VOCs consortium with discussion regarding the implementation of improved preparation techniques and the use of novel cylinder passivation chemistries to guarantee mixture stability.

Final report on EURAMET.QM-S10/1274: supplementary comparison of preparative capabilities for automotive gas mixtures

NASA Astrophysics Data System (ADS)

Val'ková, M.; Ďurišová, Z.; Szilágyi, Z. N.; Büki, T.; Fükű, J.

2016-01-01

This bilateral supplementary preparative comparison involves standard gas mixtures of automotive gas containing carbon monoxide, carbon dioxide and propane in nitrogen. Two laboratories (SMU, Slovakia and MKEH, Hungary) participated in this supplementary comparison. SMU was the coordinating laboratory, responsible for collecting and reporting measurement results. The participants have established facilities for automotive gas gravimetric preparation and analysis. The agreement of the results in this supplementary comparison is good. All the results with their reported uncertainties are in agreement with the reference values for the participants. SMU participated and obtained good results in the previous preparative comparison organised within EURAMET in this field. Both laboratories have existing claims for their Calibration and Measurement Capabilities (CMCs) for automotive gas mixtures. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Binary gas mixture adsorption-induced deformation of microporous carbons by Monte Carlo simulation.

PubMed

Cornette, Valeria; de Oliveira, J C Alexandre; Yelpo, Víctor; Azevedo, Diana; López, Raúl H

2018-07-15

Considering the thermodynamic grand potential for more than one adsorbate in an isothermal system, we generalize the model of adsorption-induced deformation of microporous carbons developed by Kowalczyk et al. [1]. We report a comprehensive study of the effects of adsorption-induced deformation of carbonaceous amorphous porous materials due to adsorption of carbon dioxide, methane and their mixtures. The adsorption process is simulated by using the Grand Canonical Monte Carlo (GCMC) method and the calculations are then used to analyze experimental isotherms for the pure gases and mixtures with different molar fraction in the gas phase. The pore size distribution determined from an experimental isotherm is used for predicting the adsorption-induced deformation of both pure gases and their mixtures. The volumetric strain (ε) predictions from the GCMC method are compared against relevant experiments with good agreement found in the cases of pure gases. Copyright © 2018 Elsevier Inc. All rights reserved.

Compressible Convection Experiment using Xenon Gas in a Centrifuge

NASA Astrophysics Data System (ADS)

Menaut, R.; Alboussiere, T.; Corre, Y.; Huguet, L.; Labrosse, S.; Deguen, R.; Moulin, M.

2017-12-01

We present here an experiment especially designed to study compressible convection in the lab. For significant compressible convection effects, the parameters of the experiment have to be optimized: we use xenon gaz in a cubic cell. This cell is placed in a centrifuge to artificially increase the apparent gravity and heated from below. With these choices, we are able to reach a dissipation number close to Earth's outer core value. We will present our results for different heating fluxes and rotation rates. We success to observe an adiabatic gradient of 3K/cm in the cell. Studies of pressure and temperature fluctuations lead us to think that the convection takes place under the form of a single roll in the cell for high heating flux. Moreover, these fluctuations show that the flow is geostrophic due to the high rotation speed. This important role of rotation, via Coriolis force effects, in our experimental setup leads us to develop a 2D quasigeostrophic compressible model in the anelastic liquid approximation. We test numerically this model with the finite element solver FreeFem++ and compare its results with our experimental data. In conclusion, we will present our project for the next experiment in which the cubic cell will be replace by a annulus cell. We will discuss the new expected effects due to this geometry as Rossby waves and zonal flows.

Effect of relativity on the ionization spectra of the xenon fluorides XeFn (n=2, 4, 6).

PubMed

Pernpointner, Markus; Cederbaum, Lorenz S

2005-06-01

Noble gas compounds exhibit special chemical bonding situations and have been investigated by various spectroscopic and theoretical techniques. In this work we calculate the ionization spectra of the xenon fluorides (XeF2,XeF4, and XeF6) in the valence and subvalence (down to Xe 4d) areas by application of the recently developed Dirac-Hartree-Fock one-particle propagator technique. In this technique, the relativistic (four-component) and electron correlation effects are computed simultaneously. The xenon compounds show considerable spin-orbit splitting strongly influencing the photoelectron spectrum not reproducible in prior calculations. Comparison to one-component methods is made and the occurring satellite structures are interpreted. The satellite structures can be attributed either to the breakdown of the one-particle picture or to a reflection of intra-atomic and interatomic Auger decay processes within the molecule.

Density Functional Theory (dft) Simulations of Shocked Liquid Xenon

NASA Astrophysics Data System (ADS)

Mattsson, Thomas R.; Magyar, Rudolph J.

2009-12-01

Xenon is not only a technologically important element used in laser technologies and jet propulsion, but it is also one of the most accessible materials in which to study the metal-insulator transition with increasing pressure. Because of its closed shell electronic configuration, xenon is often assumed to be chemically inert, interacting almost entirely through the van der Waals interaction, and at liquid density, is typically modeled well using Leonard-Jones potentials. However, such modeling has a limited range of validity as xenon is known to form compounds under normal conditions and likely exhibits considerably more chemistry at higher densities when hybridization of occupied orbitals becomes significant. We present DFT-MD simulations of shocked liquid xenon with the goal of developing an improved equation of state. The calculated Hugoniot to 2 MPa compares well with available experimental shock data. Sandia is a mul-tiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Topological signature in the NEXT high pressure xenon TPC

NASA Astrophysics Data System (ADS)

Ferrario, Paola; NEXT Collaboration

2017-09-01

The NEXT experiment aims to observe the neutrinoless double beta decay of 136Xe in a high-pressure xenon gas TPC using electroluminescence to amplify the signal from ionization. One of the main advantages of this technology is the possibility to use the topology of events with energies close to Qββ as an extra tool to reject background. In these proceedings we show with data from prototypes that an extra background rejection factor of 24.3 ± 1.4 (stat.)% can be achieved, while maintaining an efficiency of 66.7 ± 1.% for signal events. The performance expected in NEW, the next stage of the experiment, is to improve to 12.9% ± 0.6% background acceptance for 66.9% ± 0.6% signal efficiency.

Experimental studies of a zeeman-tuned xenon laser differential absorption apparatus.

PubMed

Linford, G J

1973-06-01

A Zeeman-tuned cw xenon laser differential absorption device is described. The xenon laser was tuned by axial magnetic fields up to 5500 G generated by an unusually large water-cooled dc solenoid. Xenon laser lines at 3.37 micro, 3.51 micro, and 3.99 micro were tuned over ranges of 6 A, 6 A, and 11 A, respectively. To date, this apparatus has been used principally to study the details of formaldehyde absorption lines lying near the 3 .508-micro xenon laser transition. These experiments revealed that the observed absorption spectrum of formaldehyde exhibits a sufficiently unique spectral structure that the present technique may readily be used to measure relative concentrations of formaldehyde in samples of polluted air.

Xenon for the prevention of postoperative delirium in cardiac surgery: study protocol for a randomized controlled clinical trial.

PubMed

Al Tmimi, Layth; Van de Velde, Marc; Herijgers, Paul; Meyns, Bart; Meyfroidt, Geert; Milisen, Koen; Fieuws, Steffen; Coburn, Mark; Poesen, Koen; Rex, Steffen

2015-10-09

Postoperative delirium (POD) is a manifestation of acute postoperative brain dysfunction that is frequently observed after cardiac surgery. POD is associated with short-term complications such as an increase in mortality, morbidity, costs and length of stay, but can also have long-term sequelae, including persistent cognitive deficits, loss of independence, and increased mortality for up to 2 years. The noble gas xenon has been demonstrated in various models of neuronal injury to exhibit remarkable neuroprotective properties. We therefore hypothesize that xenon anesthesia reduces the incidence of POD in elderly patients undergoing cardiac surgery with the use of cardiopulmonary bypass. One hundred and ninety patients, older than 65 years, and scheduled for elective cardiac surgery, will be enrolled in this prospective, randomized, controlled trial. Patients will be randomized to receive general anesthesia with either xenon or sevoflurane. Primary outcome parameter will be the incidence of POD in the first 5 postoperative days. The occurrence of POD will be assessed by trained research personnel, blinded to study group, with the validated 3-minute Diagnostic Confusion Assessment Method (3D-CAM) (on the intensive care unit in its version specifically adapted for the ICU), in addition to chart review and the results of delirium screening tools that will be performed by the bedside nurses). Secondary outcome parameters include duration and severity of POD, and postoperative cognitive function as assessed with the Mini-Mental State Examination. Older patients undergoing cardiac surgery are at particular risk to develop POD. Xenon provides remarkable hemodynamic stability and has been suggested in preclinical studies to exhibit neuroprotective properties. The present trial will assess whether the promising profile of xenon can be translated into a better outcome in the geriatric population. EudraCT Identifier: 2014-005370-11 (13 May 2015).

Structural Basis for Xenon Inhibition in a Cationic Pentameric Ligand-Gated Ion Channel