Tag gases [17 articles]

Abstract

With increasing sophistication of products, there is a general trend towards higher purity (lower tolerances) in materials and parts. The purification of input materials and the need to create low-entropy environments in manufacturing lead to significant energy and materials use - referred to as secondary materialization. In this article we explore secondary materialization in semiconductor manufacturing by characterizing energy use trends for three cases: cleanrooms, producing ultrapure water (UPW), and purifying elemental gases. For purification of water and elemental gases, increasing ...

Abstract

10.1098/rsnr.2009.0058 In 1741–42, William Brownrigg prepared five papers on fire-damps for the Royal Society in which he articulated a theory of a gaseous state of matter, argued that different sorts of elastic fluid existed, and claimed that atmospheric air was a heterogeneous mixture of various elastic fluids with different properties that had only their elasticity in common. Although these papers were never published, there is a strong possibility that they influenced the later development of pneumatic chemistry, because Henry Cavendish was ...

Abstract

Experiments that use cold atoms in optical lattices to simulate the behaviour of strongly correlated solid-state systems promise to provide insight into a range of long-standing problems in many-body physics1, 2, 3, 4, 5, 6, 7, 8, 9, 10. The goal of such ‘quantum simulations’ is to obtain information about homogeneous systems. Cold-gas experiments, however, are carried out in spatially inhomogeneous confining traps, which leads inevitably to different phases in the sample. This makes it difficult to deduce the properties of ...

Abstract

The applicability of the Principle of Corresponding States (PCS) for the noble fluids is discussed. We give the thermodynamic evidence for the dimerization of the liquid phase in heavy noble gases like argon, krypton etc. which manifests itself in deviations from the PCS. The behavior of the diameter of the entropy and the density is analyzed. It is shown that these characteristics are very sensitive to the dimerization process which takes place in the liquid phase of heavy noble gases. ...

Abstract

The transport of gaseous compounds across biological membranes is essential in all forms of life. Although it was generally accepted that gases freely penetrate the lipid matrix of biological membranes, a number of studies challenged this doctrine as they found biological membranes to have extremely low gas-permeability values. These observations led to the identification of several membrane-embedded ldquogasrdquo channels, which facilitate the transport of biological active gases, such as carbon dioxide, nitric oxide, and ammonia. However, some of these findings are ...

Abstract

Fluid Vortices is a comprehensive, up-to-date, research-level overview covering all salient flows in which fluid vortices play a significant role. The various chapters have been written by specialists from North America, Europe and Asia, making for unsurpassed depth and breadth of coverage. Topics addressed include fundamental vortex flows (mixing layer vortices, vortex rings, wake vortices, vortex stability, etc.), industrial and environmental vortex flows (aero-propulsion system vortices, vortex-structure interaction, atmospheric vortices, computational methods with vortices, etc.), and multiphase vortex flows (free-surface effects, vortex cavitation, and bubble and particle interactions with vortices). ...

Abstract

Objective To investigate the influence of l-methadone on medetomidine-induced changes in arterial blood gases and clinical sedation in dogs.Study design  Prospective experimental cross-over study (Latin square design).Animals  Five 1-year-old purpose bred laboratory beagle dogs of both sexes.Methods  Each dog was treated three times: medetomidine (20 03BCg kg22121 IV), l-methadone (0.1 mg kg22121 IV) and their combination. Arterial blood was collected for blood gas analysis. Heart and respiratory rates were recorded, and clinical sedation and reaction to a painful stimulus were scored before drug administration and ...

Abstract

A positive pulsed corona discharge process was applied to the removal of sulfur dioxide and nitric oxide from a simulated flue gas stream, and a mathematical model was proposed to describe this process theoretically. The proposed model takes into account generation of radicals by pulsed corona discharge, followed by radical utilization for the removal of the pollutants. Radicals such as O, OH, N, H, etc. may be concerned in the removal of the pollutants. Their concentrations were derived by considering direct ...

Abstract

It is known that the action of general anesthetics is proportional to their partition coefficient in lipid membranes (Meyer-Overton rule). This solubility is, however, directly related to the depression of the temperature of the melting transition found close to body temperature in biomembranes. We propose a thermodynamic extension of the Meyer-Overton rule, which is based on free energy changes in the system and thus automatically incorporates the effects of melting point depression. This model accounts for the pressure reversal of anesthesia ...

Abstract

Volatile anesthetics at concentrations that are used in clinical practice to induce anesthesia selectively inhibit activity of the plasma membrane Ca[IMG]-transport ATPase (Kosk-Kosicka, D., and Roszczynska, G.(1993) Anesthesiology 79, 774-780). We have investigated the mechanism of the inhibitory action of several anesthetics on the purified erythrocyte Ca[IMG]-ATPase by employing fluorescence spectroscopy measurements that report changes in the environment of intrinsic tryptophans and of an extrinsic probe attached in the active site of the enzyme. We have shown that the observed inhibition ...

Abstract

The current use of South Asian palm oil as biofuel is far from climate neutral. Dependent on assumptions, losses of biogenic carbon associated with ecosystems, emission of CO2 due to the use of fossil fuels and the anaerobic conversion of palm oil mill effluent currently correspond in South Asia with an emission of about 2.8-19.7 kg CO2 equivalent per kg of palm oil. Using oil palm and palm oil processing wastes for the generation of energy and preventing further conversion of ...

Abstract

We review recent developments in the physics of ultracold atomic and molecular gases in optical lattices. Such systems are nearly perfect realisations of various kinds of Hubbard models, and as such may very well serve to mimic condensed matter phenomena. We show how these systems may be employed as <i>quantum simulators</i> to answer some challenging open questions of condensed matter, and even high energy physics. After a short presentation of the models and the methods of treatment of such systems, we ...

Abstract

Abstract: Free energy profiles associated with moving atmospheric gases or radicals across the air/water interface were calculated as potentials of mean force by classical molecular dynamics simulations. With the employed force field, the experimental hydration free energies are satisfactorily reproduced. The main finding is that both hydrophobic gases (nitrogen, oxygen, and ozone) and hydrophilic species (hydroxyl radical, hydroperoxy radical, or hydrogen peroxide) have a free energy minimum at the air/water interface. As a consequence, it is inferred that atmospheric gases, with ...

Abstract

Abstract: Measurements of the temperature- and concentration-dependent surface tensions of aqueous solutions of methanol, 1- and 2-propanol, 1- and 2-butanol, acetic, propionic, and butanoic acids, and acetone were used to determine the standard free energies, enthalpies, and entropies of adsorption from the vapor phase onto a water surface. The saturated surface coverage of all these species is approximately 1014 molecules cm-2. The standard enthalpies of adsorption are correlated to the enthalpies of solution, suggesting that these molecules are partially solvated in ...