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1

Free energy landscape for glucose condensation and dehydration reactions in dimethyl sulfoxide and the effects of solvent.  

PubMed

The mechanisms and free energy surfaces (FES) for the initial critical steps during proton-catalyzed glucose condensation and dehydration reactions were elucidated in dimethyl sulfoxide (DMSO) using Car-Parrinello molecular dynamics (CPMD) coupled with metadynamics (MTD) simulations. Glucose condensation reaction is initiated by protonation of C1--OH whereas dehydration reaction is initiated by protonation of C2--OH. The mechanisms in DMSO are similar to those in aqueous solution. The DMSO molecules closest to the C1--OH or C2--OH on glucose are directly involved in the reactions and act as proton acceptors during the process. However, the energy barriers are strongly solvent dependent. Moreover, polarization from the long-range electrostatic interaction affects the mechanisms and energetics of glucose reactions. Experimental measurements conducted in various DMSO/Water mixtures also show that energy barriers are solvent dependent in agreement with our theoretical results. PMID:24631668

Qian, Xianghong; Liu, Dajiang

2014-03-31

2

Implications of dehydration reactions on the earthquake mechanics and faulting  

NASA Astrophysics Data System (ADS)

Dehydration reactions are inferred to occur along subduction zones where rocks from the oceanic crust undergo a series of metamorphic reactions during their burial. Metamorphic dehydration reactions of hydrous minerals such as clays and serpentines have been suggested as a possible origin for intermediate depth earthquakes in subducting slabs. Indeed, fluid releasing and mechanical compaction of pores during dehydration reactions may induce fault instabilities. However, our understanding of the feedbacks between dehydration reaction, fluid flow properties and mechanical behavior is not yet integrated into a single unified model. In this study, we try to unravel the behavior of dehydration reactions from laboratory experiments conducted on gypsum with a triaxial deformation rigs under controlled temperature (30-140°C) and confining pressure (0-300 MPa). The aim of our set of experiments is to understand the coupling and feedbacks between the state of stress, the mechanical and hydraulic properties of gypsum and the metamorphic reactions. We monitor fluid expulsion, fluid pressure and strain evolution for a given confining pressure, differential stress and temperature during all experiments. In parallel, SEM observations and EBSD analyses are used to constrain reaction and deformation mechanisms occurring at grain scale during each experiment. These analyses conducted at grain scale allow us to discriminate the mechanism of deformation occurring in parallel of dehydration reaction and give information about the rheological laws and behavior of the material for the tested conditions. Llana Funez et al. (2012) focused on the link between fluid pressure and reaction rate. The samples, being porous, compacted, and in new work we examine that process in more detail. The results of laboratory experiments and microstructural analyses are then used to estimate the implications of dehydration reaction on earthquake mechanics and faulting in seismogenic geological contexts such as subduction zones or crustal fault zones composed of hydrous minerals.

Wheeler, J.; LECLÈRE, H.; Faulkner, D. R.; Mariani, E.

2013-12-01

3

Seismic evidence for thermally-controlled dehydration reaction in subducting oceanic crust  

E-print Network

Seismic evidence for thermally-controlled dehydration reaction in subducting oceanic crust Junichi of the Philippine Sea slab immediately above it. These observations suggest that dehydration reactions accompanied-controlled dehydration reaction in subducting oceanic crust, Geophys. Res. Lett., 36, L03303, doi:10.1029/2008GL036865. 1

Rawlinson, Nick

4

Direct dehydrative pyridylthio-glycosidation of unprotected sugars in aqueous media using 2-chloro-1,3-dimethylimidazolinium chloride as a condensing agent.  

PubMed

Various 2-pyridyl 1-thioglycosides, important synthetic intermediates and enzyme inhibitors in sugar chemistry, have been synthesized directly from the corresponding unprotected sugars in good yields by using 2-chloro-1,3-dimethylimidazolinium chloride (DMC) as dehydrative condensing agent. The reaction proceeds in aqueous media without using any protecting groups, affording 2-pyridyl 1-thioglycosides with ?-configuration selectively. According to the present method, not only unprotected monosaccharides but also unprotected oligosaccharides, such as cello-oligosaccharides, chito-oligo-saccharides, malto-oligosaccharides, and glucosamine oligomers, can be converted to the corresponding 2-pyridylthio derivatives, which would greatly expand the utility of aryl 1-thioglycosides in sugar chemistry. PMID:21604376

Yoshida, Naoki; Noguchi, Masato; Tanaka, Tomonari; Matsumoto, Takeshi; Aida, Naoya; Ishihara, Masaki; Kobayashi, Atsushi; Shoda, Shin-ichiro

2011-07-01

5

(100) facets of ?-Al2O3: the active surfaces for alcohol dehydration reactions  

SciTech Connect

Temperature programmed desorption (TPD) of ethanol, and methanol dehydration reaction were studied on ?-Al2O3 in order to identify the catalytic active sites for alcohol dehydration reactions. Two high temperature (> 473 K) desorption features were observed following ethanol adsorption. Samples calcined at T?473 K displayed a desorption feature in the 523-533 K temperature range, while those calcined at T ? 673 K showed a single desorption feature at 498 K. The switch from the high to low temperature ethanol desorption correlated well with the dehydroxylation of the (100) facets of ?-Al2O3 that was predicted at 550 K DFT calculations. Theoretical DFT simulations of the mechanism of dehydration. on clean and hydroxylated ?-Al2O3(100) surfaces, find that a concerted elimination of ethylene from an ethanol molecule chemisorbed at an Al3+ pentacoordinated site is the rate limiting step for catalytic cycle on both surfaces. Furthermore, titration of the pentacoordinate Al3+ sites on the (100) facets of ?-Al2O3 by BaO completely turned off the methanol dehydration reaction activity. These results unambiguously demonstrate that only the (100) facets on ?-Al2O3 are the catalytic active surfaces for alcohol dehydration.

Kwak, Ja Hun; Mei, Donghai; Peden, Charles HF; Rousseau, Roger J.; Szanyi, Janos

2011-05-01

6

Energetics of Electron-Transfer Reactions in Soft Condensed  

E-print Network

Energetics of Electron-Transfer Reactions in Soft Condensed Media DMITRY V. MATYUSHOV Department condensed solvents such as supercooled liquids, liquid crystals, and photosynthetic reaction centers soft condensed media such as liquid crystals,5 proteins,6 and structural glass formers.7

Matyushov, Dmitry

7

Heat-transfer characteristics in tert-butanol dehydration reaction used for heat transport  

SciTech Connect

The reaction system of tert-butanol/isobutene/water was considered for use in chemical heat transport. In this study, the heat-transfer characteristics in an endothermic tert-butanol dehydration reaction which occurred in the heat-supply side of this reaction system was investigated. The heat flow was obtained by measuring the reactant composition change and temperature change in the catalyst bed. The heat flow consists of reaction heat, the latent heat of isobutene, and sensible heat in this reaction system. Numerical calculations based on a two-dimensional model were carried out and the results showed good agreement with experiment. It was noticed that the heat flow with chemical reaction was much higher than without reaction. These results indicated that the dehydration reaction promoted the heat-transfer rate, because of the increase in temperature difference between the heating medium and the wall by making use of chemical reaction for a heat transport. The apparent local heat-transfer coefficient with chemical reaction was higher than without reaction. The possibility of a high efficiency heat transport which used this reaction system was suggested.

Kiguchi, Yuji; Watanabe, Takayuki; Kanzawa, Atsushi [Tokyo Inst. of Tech. (Japan). Dept. of Chemical Engineering

1996-07-01

8

Will water act as a photocatalyst for cluster phase chemical reactions? Vibrational overtone-induced dehydration reaction of methanediol  

SciTech Connect

The possibility of water catalysis in the vibrational overtone-induced dehydration reaction of methanediol is investigated using ab initio dynamical simulations of small methanediol-water clusters. Quantum chemistry calculations employing clusters with one or two water molecules reveal that the barrier to dehydration is lowered by over 20 kcal/mol because of hydrogen-bonding at the transition state. Nevertheless, the simulations of the reaction dynamics following OH-stretch excitation show little catalytic effect of water and, in some cases, even show an anticatalytic effect. The quantum yield for the dehydration reaction exhibits a delayed threshold effect where reaction does not occur until the photon energy is far above the barrier energy. Unlike thermally induced reactions, it is argued that competition between reaction and the irreversible dissipation of photon energy may be expected to raise the dynamical threshold for the reaction above the transition state energy. It is concluded that quantum chemistry calculations showing barrier lowering are not sufficient to infer water catalysis in photochemical reactions, which instead require dynamical modeling.

Kramer, Zeb C.; Takahashi, Kaito; Skodje, Rex T. [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215 (United States); Vaida, Veronica [Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215 (United States); CIRES, University of Colorado, Boulder, Colorado 80309 (United States)

2012-04-28

9

Will water act as a photocatalyst for cluster phase chemical reactions? Vibrational overtone-induced dehydration reaction of methanediol  

NASA Astrophysics Data System (ADS)

The possibility of water catalysis in the vibrational overtone-induced dehydration reaction of methanediol is investigated using ab initio dynamical simulations of small methanediol-water clusters. Quantum chemistry calculations employing clusters with one or two water molecules reveal that the barrier to dehydration is lowered by over 20 kcal/mol because of hydrogen-bonding at the transition state. Nevertheless, the simulations of the reaction dynamics following OH-stretch excitation show little catalytic effect of water and, in some cases, even show an anticatalytic effect. The quantum yield for the dehydration reaction exhibits a delayed threshold effect where reaction does not occur until the photon energy is far above the barrier energy. Unlike thermally induced reactions, it is argued that competition between reaction and the irreversible dissipation of photon energy may be expected to raise the dynamical threshold for the reaction above the transition state energy. It is concluded that quantum chemistry calculations showing barrier lowering are not sufficient to infer water catalysis in photochemical reactions, which instead require dynamical modeling.

Kramer, Zeb C.; Takahashi, Kaito; Vaida, Veronica; Skodje, Rex T.

2012-04-01

10

Reversion and dehydration reactions of glucose during the dilute sulfuric acid hydrolysis of cellulose  

SciTech Connect

The inaccessibility of all glycosidic bonds necessitates industrial conversion schemes which employ a dilute acid catalyst at high temperatures. Process conditions also promote further reactions of glucose via the reversion and dehydration pathways. Quantitative determination of the yields of the major reversion and dehydration products is important for understanding and predicting the amounts of these materials expected under envisioned industrial operating conditions. Microcrystalline cellulose (Avicel) was hydrolyzed with sulfuric acid (0.0-1.25 wt.%), at high temperatures (160-250/sup 0/C), and at a 3:1 liquid-to-solid ratio. The hydrolysis was monitored by evaluating the amount of cellulose remaining and the yields of glucose, solid humin, levulinic acid, formic acid, hydroxymethylfurfural (HMF), and reversion products as a function of the aforementioned reaction conditions. Analysis of the reversion products required the development of a technique for the quantitation of trace carbohydrates in complex mixtures and led to the development of a reduction/permethylation gas chromatographic procedure. Cellulose hydrolysis followed pseudo-homogeneous first-order kinetics. Glucose yield was adequately described as consecutive first-order reactions. Anhydrosugars formed via reversion followed equilibrium reaction kinetics whereas the disaccharides did not. Total reversion product yields approached 10% at 250/sup 0/C. Quantitative determination of the major dehydration products provided important information concerning the destruction of glucose. HMF was produced in up to 12% yields based on the theoretical amount of glucose available, and furfural was detected in up to 5% yields. A carbon mass balance based on the determined product yields revealed that approximately 90% of all carbon was accounted for at maximum glucose yields.

Helm, R.F.

1987-01-01

11

Theoretical study of dehydration-carbonation reaction on brucite surface based on ab initio quantum mechanic calculations  

NASA Astrophysics Data System (ADS)

The carbonation of brucite (Mg(OH)2) has been considered as a potential technology for cleaning industrial carbon dioxide waste. The kinetics of the reaction Mg(OH)2 + CO2 -> MgCO3 + H2O have been studied experimentally at 573°C by Bearat at al. [1]. Their experiments suggest that the carbonation of magnesium hydroxide proceeds by the reaction Mg(OH)2 -> MgO + H2O followed by the adsorption of CO2 molecules on the dehydrated brucite surface. Due to the large difference in volumes between Mg(OH)2 and MgO, dehydration causes the formation of dislocations and cracks, allowing water molecules to leave the brucite surface and facilitating the advance of the carbonation front in the bulk solid. The detailed mechanism of this process is however unknown. We used the Car-Parrinello ab initio molecular dynamics method to study the structure and dynamics of the (0001), (1-100) and (11-20) surfaces of brucit and calculated the enthalpy and activation barrier of H2O nucleation and dehydration on different surfaces. The results obtained are in agreement with previous studies of brucite dehydration by Masini and Bernasconi [2]. The reactive Car-Parrinello molecular dynamics method [3] has been applied to investigate the detailed mechanism of the dehydration-carbonation reaction at the (1-100) interface of brucite with the gas phase. Based on the results of our MD simulations and the calculated enthalpy of CO2 adsorption on the dehydrated brucite surfaces we propose a mechanism for the dehydration/carbonation reaction. [1] Bearat H, McKelvy MJ, Chizmeshya AVG, Sharma R, Carpenter RW (2002) J. Amer. Ceram. Soc. 85(4):742 [2] Masini P and Bernasconi M (2001) J. Phys. Cond. Mat. 13: 1-12 [3] Iannuzzi M, Laio A and Parrinello M (2003) Phys. Rev. Lett. (submitted)

Churakov, S. V.; Parrinello, M.

2003-04-01

12

Modeling the controls on excess pore pressure by dehydration reactions in the slow-slip region of subduction zones  

NASA Astrophysics Data System (ADS)

Slow slip and tremor in subduction zones take place where there is abundant evidence for elevated, near lithostatic, pore pressures along the plate interface. In Japan and Cascadia, these depths (~30-45 km) are such that the main source of fluids must be attributed to chemical dehydration reactions. Here we model the consolidation of low porosity (~5%) oceanic crust subducting through the slow slip and tremor zone, and participating in pressure and temperature-dependent dehydration reactions. Pore pressures in excess of lithostatic values, and hence negative effective stresses, are a robust feature of preliminary work that employs parameters consistent with the geometry of the Cascadia subduction margin, and bulk permeabilities in the range 10-25 ? k ? 10-21 m2. In these calculations, the dehydration fluid source is parameterized using the predictions of previous studies that have calculated the amount of bound H2O lost from subducting oceanic crust as a result of broad metamorphic facies transitions. We also report the predictions of a revised model that includes a general kinetic law, which governs the rate of dehydration as a function of temperature and pressure, and provides constraints on the parameters necessary for such kinetic effects to be relevant for the fluid supply by dehydration reactions in the subducting crust. Finally, we investigate the role of lateral fluid migration by including a fluid sink term that is proportional to modeled horizontal pressure gradients. Our results indicate that processes must be active in the slow slip region of subduction zones that are responsible, perhaps periodically, for alleviating excess pore pressures generated by dehydration reactions. Candidate mechanisms include hydraulic fracturing within or below the plate interface, lateral and/or focused fluid migration, or increases in permeability during slow slip events.

Skarbek, R. M.; Rempel, A. W.

2013-12-01

13

High-resolution models of subduction zones: Implications for mineral dehydration reactions and the transport of water  

E-print Network

are used to reevaluate the thermal structure of the Honshu and Cascadia subduction zones using the more. The thermal structure of the Cascadia subduction zone is markedly different because of the age of the incomingHigh-resolution models of subduction zones: Implications for mineral dehydration reactions

van Keken, Peter

14

The kinetics of phosphotriester condensation reactions on solid support.  

PubMed Central

A study has been made of the kinetics of condensation reactions in phosphotriester synthesis of oligonucleotides on polystyrene copolymer resin support, using monomers, dimers, and trimers as the coupling units. The condensations follow pseudo first order kinetics, with a rate constant that decreases from monomers to dimers to trimers. Arrhenius plots indicate a nearly constant activation energy of around 10.4 kcal mol-1. Extrapolation to find the Arrhenius preexponential factor, A, is inaccurate because of the limited temperature range studied. But if the assumption is made that Ea is the same for monomer, dimer, and trimer reactions, then the A values are inversely proportional to the surface areas of the coupling units, reinforcing the interpretation of A as a collision efficiency factor. PMID:6473109

Ikuta, S; Chattopadhyaya, R; Dickerson, R E

1984-01-01

15

Effects of Reaction Gel Dehydration on the Synthesis of Cu(NC5H5)4VOF4 and  

E-print Network

Effects of Reaction Gel Dehydration on the Synthesis of Cu(NC5H5)4VOF4 and [Cu(NC5H5)4VOF4][Cu(NC5H5)4(H2O)VOF4],H2O Margaret E. Welk, Charlotte L. Stern, Kenneth R. Poeppelmeier, and Alexander JVed December 11, 2006 ABSTRACT: The acentric anion, [VOF4]2-, has been incorporated into two new compounds, [Cu

Poeppelmeier, Kenneth R.

16

A DFT based equilibrium study on the hydrolysis and the dehydration reactions of MgCl2 hydrates  

NASA Astrophysics Data System (ADS)

Magnesium chloride hydrates are characterized as promising energy storage materials in the built-environment. During the dehydration of these materials, there are chances for the release of harmful HCl gas, which can potentially damage the material as well as the equipment. Hydrolysis reactions in magnesium chloride hydrates are subject of study for industrial applications. However, the information about the possibility of hydrolysis reaction, and its preference over dehydration in energy storage systems is still ambiguous at the operating conditions in a seasonal heat storage system. A density functional theory level study is performed to determine molecular structures, charges, and harmonic frequencies in order to identify the formation of HCl at the operating temperatures in an energy storage system. The preference of hydrolysis over dehydration is quantified by applying thermodynamic equilibrium principles by calculating Gibbs free energies of the hydrated magnesium chloride molecules. The molecular structures of the hydrates (n = 0, 1, 2, 4, and 6) of MgCl2 are investigated to understand the stability and symmetry of these molecules. The structures are found to be noncomplex with almost no meta-stable isomers, which may be related to the faster kinetics observed in the hydration of chlorides compared to sulfates. Also, the frequency spectra of these molecules are calculated, which in turn are used to calculate the changes in Gibbs free energy of dehydration and hydrolysis reactions. From these calculations, it is found that the probability for hydrolysis to occur is larger for lower hydrates. Hydrolysis occurring from the hexa-, tetra-, and di-hydrate is only possible when the temperature is increased too fast to a very high value. In the case of the mono-hydrate, hydrolysis may become favorable at high water vapor pressure and at low HCl pressure.

Smeets, B.; Iype, E.; Nedea, S. V.; Zondag, H. A.; Rindt, C. C. M.

2013-09-01

17

A new BPO 4 catalyst in organic reactions. Dehydration of cycloalkanols  

Microsoft Academic Search

The synthesis of some new and economical BPO4 catalysts is described. The chemical and textural properties and the thermogravimetric analysis (TGA) of these catalysts is given. The dehydration of cyclohexanol, cycloheptanol and cyclooctanol catalyzed by these new BPO4 catalysts is studied using the microcatalytic pulse technique.

J. M. Marinas; J. V. Sinisterra

1985-01-01

18

Low-energy electron-induced reactions in condensed matter  

NASA Astrophysics Data System (ADS)

The goal of this review is to discuss post-irradiation analysis of low-energy (?50 eV) electron-induced processes in nanoscale thin films. Because electron-induced surface reactions in monolayer adsorbates have been extensively reviewed, we will instead focus on low-energy electron-induced reactions in multilayer adsorbates. The latter studies, involving nanoscale thin films, serve to elucidate the pivotal role that the low-energy electron-induced reactions play in high-energy radiation-induced chemical reactions in condensed matter. Although electron-stimulated desorption (ESD) experiments conducted during irradiation have yielded vital information relevant to primary or initial electron-induced processes, we wish to demonstrate in this review that analyzing the products following low-energy electron irradiation can provide new insights into radiation chemistry. This review presents studies of electron-induced reactions in nanoscale films of molecular species such as oxygen, nitrogen trifluoride, water, alkanes, alcohols, aldehydes, ketones, carboxylic acids, nitriles, halocarbons, alkane and phenyl thiols, thiophenes, ferrocene, amino acids, nucleotides, and DNA using post-irradiation techniques such as temperature-programmed desorption (TPD), reflection-absorption infrared spectroscopy (RAIRS), X-ray photoelectron spectroscopy (XPS), high-resolution electron energy loss spectroscopy (HREELS), gel electrophoresis, and microarray fluorescence. Post-irradiation temperature-programmed desorption, in particular, has been shown to be useful in identifying labile radiolysis products as demonstrated by the first identification of methoxymethanol as a reaction product of methanol radiolysis. Results of post-irradiation studies have been used not only to identify radiolysis products, but also to determine the dynamics of electron-induced reactions. For example, studies of the radiolysis yield as a function of incident electron energy have shown that dissociative electron attachment plays an important role in the electron-induced single strand breaks in DNA leading to mutagenic damage. Studies such as these not only provide insight into the fundamentals of electron-molecule interactions in the condensed phase but also may provide information valuable to (a) furthering cost-efficient destruction of hazardous chemicals, (b) understanding the electron-induced decomposition of feed gases used in the plasma processing of semiconductor devices, (c) clarifying the role, if any, of low-energy electrons, produced by cosmic rays, contributing to the formation of the ozone hole by interacting with halocarbons and producing Cl atoms, (d) illuminating the dynamics of electron-induced oligomerization and/or polymerization, and (e) explicating the astrochemistry of icy grains.

Arumainayagam, Christopher R.; Lee, Hsiao-Lu; Nelson, Rachel B.; Haines, David R.; Gunawardane, Richard P.

2010-01-01

19

Oriented growth of garnet by topotactic reactions and epitaxy in high-pressure, mafic garnet granulite formed by dehydration  

E-print Network

granulite formed by dehydration melting of metastable hornblende-gabbronorite (Jijal Complex, Kohistan by dehydration melting of hornblende- gabbronorite protoliths in the Jijal complex (Kohistan palaeo-island arc. Key words: amphibole dehydration-melting; EBSD; garnet; HP mafic granulite; Jijal complex; Kohistan

Tommasi, Andrea

20

On the Reaction Mechanism of Tirapazamine Reduction Chemistry: Unimolecular N-OH Homolysis, Stepwise Dehydration, or Triazene  

E-print Network

, Stepwise Dehydration, or Triazene Ring-Opening Jian Yin, Rainer Glaser,*, and Kent S. Gates*,, Departments and 4 6 + ·OH or, alternatively, whether 3 and/or 4 may react by dehydration and form aminyl radicals on the chemistry after the homolysis of 3 and/or 4, that is, dehydration may be the result of a two-step sequence

Glaser, Rainer

21

Effects of novel supports on the physical and catalytic properties of tungstophosphoric acid for alcohol dehydration reactions  

SciTech Connect

The catalytic behavior of tungstophosphoric acid supported on modified mesoporous silica materials for the dehydration of 2-butanol and methanol was studied. Specifically, the supports evaluated here consisted of unmodified MCM-41 and SBA-15 mesoporous silicas, and these materials coated with sub-monolayer quantities of alumina, titania, and zirconia. UV-Vis DRS and 31P-NMR spectroscopy showed that the tungstophosphoric acid species retained their chemical identity in the synthesized supported form, although the spectra were influenced by the specific support material used. In addition, their acidic properties were evaluated using temperature programmed oxidation of isopropyl amine. The differences in reaction rates between the samples reflect both the diversity in the amount of Brønsted acidic sites available for catalysis and dissimilarities in coking resistance. These two characteristics depend, in turn, on the type of support modifier used to prepare the catalyst.

Herrera, Jose E.; Kwak, Ja Hun; Hu, Jian Zhi; Wang, Yong; Peden, Charles HF

2008-08-17

22

Intrinsic and global reaction rate of methanol dehydration over [gamma]-Al[sub 2]O[sub 3] pellets  

SciTech Connect

Dehydration of methanol on [gamma]-Al[sub 2]O[sub 3] was studied in a differential fixed-bed reactor at a pressure of 146 kPa in a temperature range of 290-360 [degrees]C. A kinetic equation which describes a Langmuir-Hinshelwood surface controlled reaction with dissociative adsorption of methanol was found to fit the experimental results quite well. Coefficients in the equation follow the Arrhenius and the van't Hoff relation. The calculated value for the activation energy was found to be 143.7 kJ/mol, while calculated values for the heat of adsorption of methanol and water were 70.5 and 42.1 kJ/mol, respectively. The measured global reaction rates for 3-mm catalyst particles were compared to those calculated by means of intrinsic kinetics and transport processes within the particles. A reasonable agreement was found when the effective diffusion coefficients for reaction components were calculated using a parallel-pore model assuming that only Knudsen diffusion is important.

Bercic, G.; Levec, J. (Dept. of Catalysis, Chemical Reaction Engineering, Boris Kidric Inst. of Chemistry, Dept. of Chemical Engineering, Univ. of Ljubljana, 61000 Ljublijana, Slovenia (Yugoslavia))

1992-04-01

23

Reactions of 3-formylchromone with active methylene and methyl compounds and some subsequent reactions of the resulting condensation products.  

PubMed

This review presents a survey of the condensations of 3-formylchromone with various active methylene and methyl compounds, e.g. malonic or barbituric acid derivatives, five-membered heterocycles, etc. The utilisation of the condensation products for the synthesis of different heterocyclic systems, which is based on the ability of the gamma-pyrone ring to be opened by the nucleophilic attack is also reviewed. Finally, the applications of microwave irradiation as an unconventional method of reaction activation in the synthesis of condensation products is described and the biological activity of some chromone derivatives is noted. PMID:18007363

Gasparová, Renata; Lácová, Margita

2005-01-01

24

Investigation of the stability of a stationary exothermic reaction front in a condensed phase  

Microsoft Academic Search

A model system of combustion theory describing an exothermic reaction in a condensed phase is investigated. The Arrhenius dependence of reaction rate on temperature is replaced by a piecewise-constant dependence. This makes it possible to find the distribution of the quantities in the stationary wave and to investigate the stability of the solution with respect to one-dimensional perturbations.

P. A. Avdeev

1985-01-01

25

Alternative Interpretation of Low-Energy Nuclear Reaction Processes with Deuterated Metals Based on The Bose-Einstein Condensation Mechanism  

Microsoft Academic Search

Recently, a generalization of the Bose-Einstein condensation (BEC) mechanism has been made to a ground-state mixture of two different species of positively charged bosons in harmonic traps. The theory has been used to describe (D + Li) reactions in the low energy nuclear reaction (LENR) processes in condensed matter and predicts that the (D + Li) reaction rates can be

Yeong E. Kim; Thomas O. Passell

26

Alternative Interpretation of Low-Energy Nuclear Reaction Processes with Deuterated Metals Based on the Bose-Einstein Condensation Mechanism  

Microsoft Academic Search

Recently, a generalization of the Bose-Einstein condensation (BEC) mechanism has been made to a ground-state mixture of two different species of positively charged bosons in harmonic traps. The theory has been used to describe (D + Li) reactions in the low energy nuclear reaction (LENR) processes in condensed matter and predicts that the (D + Li) reaction rates can be

Yeong E. Kim; Thomas O. Passell

2006-01-01

27

Shock-induced inorganic reactions and condensed phase detonations  

Microsoft Academic Search

Existing hugoniot calculations of inorganic chemical reactions in powder mixtures are found to contain errors and ambiguities. Most of the problems were caused by improper identification of the thermodynamic reference state. The derivations have been revised using two different integration paths: i) constant volume, and ii) constant pressure. Sample calculations with a Ni-Al system show that the two schemes yield

L. S. Bennett; Y. Horie

1994-01-01

28

One limiting scheme for the propagation of a pulsating exothermic reaction front in a condensed medium  

Microsoft Academic Search

In connection with studies on the synthesis of various solid substances in a combustion wave (self-propagating high-temperature synthesis) [1 3] a model is proposed for the unsteady combustion of gasless compositions which describes the relaxation mechanism of the propagation of an exothermic chemical reaction front in a condensed system, forming refractory products. The period of the oscillations in the combustion

V. B. Librovich; G. M. Makhviladze

1974-01-01

29

Layer-by-Layer Growth and Condensation Reactions of Niobate and Titanoniobate Thin Films  

E-print Network

and processing techniques. Thin-film capacitors made from high dielectric constant materials are currently under- lems associated with unwanted elements in device fabrication. In the ideal case, thin-film dielectricsLayer-by-Layer Growth and Condensation Reactions of Niobate and Titanoniobate Thin Films Mingming

30

Measurement of Condensed-Phase Reaction Kinetics in the Aerosol Phase Using Single Particle Mass Spectrometry  

E-print Network

-power pulsed laser in the extraction field of the time-of-flight mass spectrometer. The mass spectra thusMeasurement of Condensed-Phase Reaction Kinetics in the Aerosol Phase Using Single Particle Mass mass spectrometer to analyze the elemental composition of individual aerosol particles and applied

Zachariah, Michael R.

31

Method of dehydrating natural gas  

Microsoft Academic Search

A method for dehydration of natural gas is provided wherein well head gas is supplied to a three-phase inlet separator, the vapor mixture of natural gas and water removed from that inlet separator means is supplied to a turboexpander, and the resulting refrigerated mixture of natural gas and condensed water vapor is supplied to a multi-phase outlet separator. The turboexpander

1985-01-01

32

Rapid and Efficient Functionalized Ionic Liquid-Catalyzed Aldol Condensation Reactions Associated with Microwave Irradiation  

PubMed Central

Five quaternary ammonium ionic liquid (IL) and two tetrabutylphosphonium ILs were prepared and characterized. An environmentally benign and convenient functionalized ionic liquid catalytic system was thus explored in the aldol condensation reactions of aromatic aldehydes with acetone. The aldol reactions proceeded more efficiently through microwave-assisted heating than through conventional thermal heating. The yield of products obtained under microwave heating for 30 min was approximately 90%, and the ILs can be recovered and reused at least five times without apparent loss of activity. In addition, this catalytic system can be successfully extended to the Henry reactions. PMID:24445262

Wang, Chang; Liu, Jing; Leng, Wenguang; Gao, Yanan

2014-01-01

33

One-electron oxidation of condensed DNA toroids: injection-site dependent charge (radical cation) mobility.  

PubMed

DNA condensates were formed by treating linear pUC19 plasmids ligated to an AQ-containing oligomer with spermidine. The condensates are toroid-shaped objects having a radius of 70 to 100 nm. Irradiation of the condensates with UV light (absorbed by the anthraquinone) causes the one-electron oxidation of the DNA and concomitant reaction at GG steps of the oligomer. Analysis of the distance dependence of the reaction at guanine in these condensates reveals a dependency on the position of the AQ. This observation is attributed to a reduction in the rate for trapping of the radical cation in the relatively dehydrated interior of the condensate. PMID:18465889

Das, Prolay; Schuster, Gary B

2008-06-01

34

Mixtures of Charged Bosons Confined in Harmonic Traps and Bose-Einstein Condensation Mechanism for Low-Energy Nuclear Reactions and Transmutation Processes in Condensed Matters  

NASA Astrophysics Data System (ADS)

A mixture of two different species of positively charged bosons in harmonic traps is considered in the mean-field approximation. It is shown that depending on the ratio of parameters, the two components may coexist in same regions of space, in spite of the Coulomb repulsion between the two species. Application of this result is discussed for the generalization of the Bose-Einstein condensation mechanism for low-energy nuclear reaction (LENR) and transmutation processes in condensed matters. For the case of deutron-lithium (d + Li) LENR, the result indicates that (d + 6Li) reactions may dominate over (d + d) reactions in LENR experiments.

Kim, Yeong E.; Zubarev, Alexander L.

2006-02-01

35

One limiting scheme for the propagation of a pulsating exothermic reaction front in a condensed medium  

Microsoft Academic Search

In connection with studies on the synthesis of various solid substances in a combustion wave (self-propagating high-temperature synthesis) [1–3] a model is proposed for the unsteady combustion of gasless compositions which describes the relaxation mechanism of the propagation of an exothermic chemical reaction front in a condensed system, forming refractory products. The period of the oscillations in the combustion rate,

V. B. Librovich; G. M. Makhviladze

1974-01-01

36

Negative Resist for i-Line Lithography Utilizing Acid Catalyzed Silanol-Condensation Reaction  

NASA Astrophysics Data System (ADS)

Negative resist systems composed of a novolak resin, diphenylsilanediol (Ph2Si(OH)2) and an acid generator are investigated for i-line lithography. The reaction in this resist system is based on an acid-catalyzed condensation reaction; the acid produced in the exposed area induces a condensation reaction of Ph2Si(OH)2 during post-exposure baking. The condensation product, siloxane, acts as an aqueous-base dissolution inhibitor, while silanol compounds in unexposed areas work as dissolution accelerators. The resist composed of a novolak resin, Ph2Si(OH)2 and 2-naphthoylmethyl-tetramethylenesulfonium hexafluoroantimonate (NMTMS-SbF6) shows a sensitivity of about 200 mJ/cm2 at 365 nm. This sensitivity is lower than that at 248 nm when triphenylsulfonium triflate (Ph3S+OTf-) is used as an acid generator, which can be ascribed to the low quantum yield of acid generation from NMTMS-SbF6. Using this resist, 0.3 ?m space patterns with 1 ?m film thickness were obtained by combining an i-line stepper with a phase-shifting mask.

Hayashi, Nobuaki; Tadano, Keiko; Tanaka, Toshihiko; Shiraishi, Hiroshi; Ueno, Takumi; Iwayanagi, Takao

1990-11-01

37

Molecular aspects of glucose dehydration by chromium chlorides in ionic liquids.  

PubMed

A combined experimental and computational study of the ionic-liquid-mediated dehydration of glucose and fructose by Cr(II) and Cr(III) chlorides has been performed. The ability of chromium to selectively dehydrate glucose to 5-hydroxymethylfurfural (HMF) in the ionic liquid 1-ethyl-3-methyl imidazolium chloride does not depend on the oxidation state of chromium. Nevertheless, Cr(III) exhibits higher activity and selectivity to HMF than Cr(II) . Anhydrous CrCl(2) and CrCl(3)?6?H(2)O readily catalyze glucose dehydration with HMF yields of 60 and 72%, respectively, after 3 h. Anhydrous CrCl(3) has a lower activity, because it only slowly dissolves in the reaction mixture. The transformation of glucose to HMF involves the formation of fructose as an intermediate. The exceptional catalytic performance of the chromium catalysts is explained by their unique ability to catalyze glucose to fructose isomerization and fructose to HMF dehydration with high selectivity. Side reactions leading to humins by means of condensation reactions take predominantly place during fructose dehydration. The higher HMF selectivity for Cr(III) is tentatively explained by the higher activity in fructose dehydration compared to Cr(II) . This limits the concentration of intermediates that are involved in bimolecular condensation reactions. Model DFT calculations indicate a substantially lower activation barrier for glucose isomerization by Cr(III) compared to Cr(II) . Qualitatively, glucose isomerization follows a similar mechanism for Cr(II) and Cr(III) . The mechanism involves ring opening of D-glucopyranose coordinated to a single Cr ion, followed by a transient self-organization of catalytic chromium complexes that promotes the rate-determining hydrogen-shift step. PMID:21488106

Zhang, Yanmei; Pidko, Evgeny A; Hensen, Emiel J M

2011-05-01

38

Hydrolysis and condensation kinetics for liquid-phase tetraethylorthosilicate reactions in alkaline-alcohol solvents  

SciTech Connect

The hydrolysis and condensation kinetics for the Stober-Fink method of producing monodisperse silica particles have been studied by chemical analyses (i.e., gas chromatography and molybdate for determining monomeric silicic acid concentrations) and laser-light-scattering techniques. Studies have been conducted to determine the effects of temperature, reactant and catalyst concentrations, and solvent type (i.e., 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butyl alcohol, and tert-amyl alcohol) on the rate of hydrolysis, rate of condensation, and particle growth kinetics. The effects of hydrogen bonding and steric hinderance of the solvent on the reaction kinetics are discussed. An important aspect of this research is the chemical evidence that monodisperse silica particles are produced by controlled homogeneous precipitation. This study is of fundamental importance for understanding the chemistry and physics of producing small particles that will be used as precursor materials for ceramics and support material for chromatographic packing.

Harris, M.T.; Byers, C.H.; Brunson, R.R.

1987-01-01

39

Onion dehydration  

SciTech Connect

Onion dehydration consists of a continuous operation, belt conveyor using fairly low-temperature hot air from 38-104{degrees}C (100 to 200{degrees}F). Typical processing plants will handle 4500 kg (10,000 pounds) of raw product per hour (single line), reducing the moisture from around 83 % to 4 % (680 to 820 kg - 1,500 to 1,800 pounds finished product). An example of a geothermal processing plant is Integrate Ingredients at Empire, Nevada, in the San Emidio Desert. A total of 6.3 million kg (14 million pounds) of dry product are produced annually: 60% onion and 40% garlic. A 130{degrees}C (266{degrees}F) well provide the necessary heat for the plant.

Lund, J.W. [Geo-Heat Center Oregon Institute of Technology, Kalamath Falls, OR (United States)

1995-12-31

40

Photochemical reactions in dehydrated photosynthetic organisms, leaves, chloroplasts and photosystem II particles: reversible reduction of pheophytin and chlorophyll and oxidation of ?-carotene  

NASA Astrophysics Data System (ADS)

Photoreactions of dehydrated leaves, isolated broken chloroplasts and PSII membrane fragments of spinach ( Spinacia oleracea) were studied at different air humidities and compared with photoreactions of dry fronds of a fern, Polypodium vulgare, and a dry lichen, Parmelia sulcata, which in contrast to spinach are insensitive to photoinactivation in the dry state. Even in very dry air, P700 in the reaction center of photosystem I of dry leaves was oxidized, and the primary quinone acceptor Q A in the reaction center of photosystem II was photoreduced by low light. These reactions were only very slowly reversed in the dark and saturated under low light intensity. Light-minus-dark difference absorption spectra of the dry leaves, isolated chloroplasts and PSII membrane fragments measured at higher light intensities revealed absorbance changes of ?-carotene at 500 nm (light-dependent bleaching) and 980 nm (light-dependent band formation) and bleaching of chlorophyll at 436 and 680 nm with appearance of bands at 450 and 800 nm. Decrease of chlorophyll fluorescence upon strong illumination indicated photoaccumulation of a quencher. All these changes were kinetically related and readily reversible. They are interpreted to show light-induced oxidation of ?-carotene (Car) and reduction of chlorophyll-680 (Chl-680) in the reaction center of photosystem II of the dried leaves, chloroplasts and photosystem II particles. The fluorescence quencher was suggested to be Chl-680 - or Car + in close proximity to P680, the primary electron donor. Appreciable photoaccumulation of reduced pheophytin was only observed in dry leaves after Q A reduction had been lost during heat treatment of hydrated leaves prior to dehydration. The observations are interpreted to show light-dependent cyclic electron flow within the reaction center of photosystem II in which Chl-680 (or Pheo) is reduced by P680 * and Car is oxidized by P680 + with consequent recombination of Car + and Chl-680 - (or Pheo -). Cyclic electron flow is thought to be moderately photoprotective by reducing the concentration of the strong oxidant P680 +. Nevertheless, prolonged strong illumination caused considerable photodamage in the dry spinach leaves, much less damage in dry fern fronds and no damage in the dry lichen in which distinct photoreactions were not expressed at light intensities which were effective in dry leaves and fern fronds.

Shuvalov, Vladimir A.; Heber, Ulrich

2003-11-01

41

Formation of activated biomolecules by condensation on mineral surfaces--a comparison of peptide bond formation and phosphate condensation.  

PubMed

Many studies have reported condensation reactions of prebiotic molecules, such as the formation of peptide bonds between amino acids, to occur to some degree on mineral surfaces. We have studied several such reactions on the same divided silica. When drying steps are applied, the equilibria of peptide formation from glycine, and polyphosphate formation from monophosphate, are displaced to the right because these reactions are dehydrating condensations, accompanied by the emission of water. In contrast, the equilibrium of AMP dismutation is not significantly favored by drying. The silica surface plays little role (if any) in the thermochemistry of the condensation reactions, but is does play a significant kinetic role by acting as a catalyst, lowering the condensation temperatures with respect to bulk solids. Of course, the surface also catalyzes the inverse hydrolysis reactions. PMID:24277128

Georgelin, Thomas; Jaber, Maguy; Bazzi, Houssein; Lambert, Jean-François

2013-10-01

42

Formation of Activated Biomolecules by Condensation on Mineral Surfaces - A Comparison of Peptide Bond Formation and Phosphate Condensation  

NASA Astrophysics Data System (ADS)

Many studies have reported condensation reactions of prebiotic molecules, such as the formation of peptide bonds between amino acids, to occur to some degree on mineral surfaces. We have studied several such reactions on the same divided silica. When drying steps are applied, the equilibria of peptide formation from glycine, and polyphosphate formation from monophosphate, are displaced to the right because these reactions are dehydrating condensations, accompanied by the emission of water. In contrast, the equilibrium of AMP dismutation is not significantly favored by drying. The silica surface plays little role (if any) in the thermochemistry of the condensation reactions, but is does play a significant kinetic role by acting as a catalyst, lowering the condensation temperatures with respect to bulk solids. Of course, the surface also catalyzes the inverse hydrolysis reactions.

Georgelin, Thomas; Jaber, Maguy; Bazzi, Houssein; Lambert, Jean-François

2013-10-01

43

In-place condensation of reaction mixture using hollow fiber membrane reactors improved productivity of cell-free protein synthesis  

Microsoft Academic Search

The authors intended to raise the protein production rate of continuous flow cell-free (CFCF) translation by applying in-place condensation of the reaction mixture containing wheat germ extract (WGE), mRNA, tRNA, amino acids, and high energy biochemicals. A hollow fiber membrane reactor (HFMR) composed of a shell and 80 hollow fibers made of ultrafiltration (UF) membrane was developed for condensing the

Yuichi Yamamoto; Shunjiro Sugimoto; Xin-chun Shen; Teruyuki Nagamune; Shui-liang Yao; Eiji Suzuki

1999-01-01

44

Alternative Interpretation of Low-Energy Nuclear Reaction Processes with Deuterated Metals Based on the Bose-Einstein Condensation Mechanism  

NASA Astrophysics Data System (ADS)

Recently, a generalization of the Bose-Einstein condensation (BEC) mechanism has been made to a ground-state mixture of two different species of positively charged bosons in harmonic traps. The theory has been used to describe (D + Li) reactions in the low energy nuclear reaction (LENR) processes in condensed matter and predicts that the (D + Li) reaction rates can be larger than (D + D) reaction rates by as much as a factor of ~50, implying that (D + Li) reactions may be occuring in addition to the (D + D) reactions. A survey of the existing data from LENR experiments is carried out to check the validity of the theoretical prediction. We conclude that there is compelling experimental evidence which support the theoretical prediction. New experimental tests of the theoretical prediction are suggested.

Kim, Yeong E.; Passell, Thomas O.

2006-02-01

45

Green condensation reaction of aromatic aldehydes with active methylene compounds catalyzed by anion-exchange resin under ultrasound irradiation.  

PubMed

To realize a practical and green chemistry, two important challenges need to be addressed, namely the effective process for the activation of reaction and efficient, eco-friendly and robust chemical methods for the reaction conversion to target products via highly selective catalytic and reactions. Ultrasonic energy promotes the conversion process through its special cavitational effects. Combined with anion-exchange resin as a heterogeneous, reusable and efficient catalyst, Ultrasonic energy enhances the Knoevenagel condensation and leads to reduced reaction time at lower reaction temperature with less amounts of solvent and catalyst. PMID:25112685

Ammar, Hafedh Belhadj; Chtourou, Manef; Frikha, Mohamed Hédi; Trabelsi, Mahmoud

2015-01-01

46

Progress toward chemical accuracy in the computer simulation of condensed phase reactions.  

PubMed Central

We describe a procedure for the generation of chemically accurate computer-simulation models to study chemical reactions in the condensed phase. The process involves (i) the use of a coupled semiempirical quantum and classical molecular mechanics method to represent solutes and solvent, respectively; (ii) the optimization of semiempirical quantum mechanics (QM) parameters to produce a computationally efficient and chemically accurate QM model; (iii) the calibration of a quantum/classical microsolvation model using ab initio quantum theory; and (iv) the use of statistical mechanical principles and methods to simulate, on massively parallel computers, the thermodynamic properties of chemical reactions in aqueous solution. The utility of this process is demonstrated by the calculation of the enthalpy of reaction in vacuum and free energy change in aqueous solution for a proton transfer involving methanol, methoxide, imidazole, and imidazolium, which are functional groups involved with proton transfers in many biochemical systems. An optimized semiempirical QM model is produced, which results in the calculation of heats of formation of the above chemical species to within 1.0 kcal/mol (1 kcal = 4.18 kJ) of experimental values. The use of the calibrated QM and microsolvation QM/MM (molecular mechanics) models for the simulation of a proton transfer in aqueous solution gives a calculated free energy that is within 1.0 kcal/mol (12.2 calculated vs. 12.8 experimental) of a value estimated from experimental pKa values of the reacting species. PMID:11607654

Bash, P A; Ho, L L; MacKerell, A D; Levine, D; Hallstrom, P

1996-01-01

47

Progress toward chemcial accuracy in the computer simulation of condensed phase reactions  

SciTech Connect

A procedure is described for the generation of chemically accurate computer-simulation models to study chemical reactions in the condensed phase. The process involves (1) the use of a coupled semiempirical quantum and classical molecular mechanics method to represent solutes and solvent, respectively; (2) the optimization of semiempirical quantum mechanics (QM) parameters to produce a computationally efficient and chemically accurate QM model; (3) the calibration of a quantum/classical microsolvation model using ab initio quantum theory; and (4) the use of statistical mechanical principles and methods to simulate, on massively parallel computers, the thermodynamic properties of chemical reactions in aqueous solution. The utility of this process is demonstrated by the calculation of the enthalpy of reaction in vacuum and free energy change in aqueous solution for a proton transfer involving methanol, methoxide, imidazole, and imidazolium, which are functional groups involved with proton transfers in many biochemical systems. An optimized semiempirical QM model is produced, which results in the calculation of heats of formation of the above chemical species to within 1.0 kcal/mol of experimental values. The use of the calibrated QM and microsolvation QM/MM models for the simulation of a proton transfer in aqueous solution gives a calculated free energy that is within 1.0 kcal/mol (12.2 calculated vs. 12.8 experimental) of a value estimated from experimental pKa`s of the reacting species.

Bash, P.A.; Levine, D.; Hallstrom, P. [Argonne National Lab., IL (United States); Ho, L.L. [Yale Univ., New Haven, CT (United States). Dept. of Physics; Mackerell, A.D. Jr. [Univ. of Maryland, Baltimore, MD (United States). Dept. of Pharmaceutical Sciences

1996-03-01

48

Dehydration kinetics of shocked serpentine  

NASA Technical Reports Server (NTRS)

Experimental rates of dehydration of shocked and unshocked serpentine were determined using a differential scanning calorimetric technique. Dehydration rates in shocked serpentine are enhanced by orders of magnitude over corresponding rates in unshocked material, even though the impact experiments were carried out under conditions that inhibited direct impact-induced devolatilization. Extrapolation to temperatures of the Martian surface indicates that dehydration of shocked material would occur 20 to 30 orders of magnitude more rapidly than for unshocked serpentine. The results indicate that impacted planetary surfaces and associated atmospheres would reach chemical equilibrium much more quickly than calculations based on unshocked material would indicate, even during the earliest, coldest stages of accretion. Furthermore, it is suggested that chemical weathering of shocked planetary surfaces by solid-gas reactions would be sufficiently rapid that true equilibrium mineral assemblages should form.

Tyburczy, James A.; Ahrens, Thomas J.

1988-01-01

49

Dehydration reactions, mass transfer and rock deformation relationships during subduction of Alpine metabauxites: insights from LIBS compositional profiles between metamorphic veins  

NASA Astrophysics Data System (ADS)

In subduction zones, the significant amounts of aqueous fluid released in the course of the successive dehydration reactions occurring during prograde metamorphism are expected to strongly influence the rock rheology, as well as kinetics of metamorphic reactions and mass transfer efficiency. Mineralized veins, ubiquitous in metamorphic rocks, can be seen as preserved witnesses of fluid and mass redistribution that partly accommodate the rock deformation (lateral segregation). However, the driving forces and mechanisms of mass transfer towards fluid-filled open spaces remain somewhat unclear. The aim of this study is to investigate the modalities of mass transfer during local fluid-rock interactions, and their links with fluid production and rock deformation. This study focuses on karstic pockets (metre scale) of Triassic metabauxites embedded in thick carbonate units, that have been isolated from large-scale fluid flow during HP-LT Alpine metamorphism (W. Vanoise, French Alps). These rocks display several generations of metamorphic veins containing various Al-bearing minerals, which give particular insights into mass transfer processes. It is proposed that the internally-derived fluid (~13 vol% produced by successive dehydration reactions) has promoted the opening of fluid-filled open spaces (euhedral habits of vein minerals) and served as medium for diffusive mass transfer from rock to vein. Based on mineralogical and textural features, two vein types can be distinguished: (1) some veins are filled with newly formed products of either prograde (chloritoid) or retrograde (chlorite) metamorphic reactions; in this case, fluid-filled open spaces seem to offer energetically favourable nucleation/growth sites; (2) the second vein type is filled with cookeite (Li-Al-rich chlorite) or pyrophyllite, that were present in the host rock prior to the vein formation. In this closed chemical system, mass transfer from rock to vein was achieved through the fluid, in a dissolution-transport-precipitation process, possibly stress-assisted. Cookeite is highly concentrated (40-70 vol%) in regularly spaced veins. Laser Induced Breakdown Spectroscopy profiles show that cookeite is evenly distributed in the rock matrix comprised between two veins. The absence of diffusion profiles suggests that the characteristic diffusion length for Li, Al and Si is greater than or equal to the distance separating two cookeite veins (3-6 cm). This is in agreement with characteristic diffusion lengths calculated from both grain boundary and pore fluid diffusion coefficients, for the estimated duration of the peak of metamorphism. Phyllosilicates have very different morphologies in the rock matrix (fibers) compared to veins (euhedral crystals): fluid-mineral interfacial energy may be maximal in the small matrix pores, which can maintain higher cookeite solubility than in fluid-filled open spaces. Therefore, as soon as veins open, chemical potential gradients may develop and drive cookeite transfer from rock matrix to veins.

Verlaguet, A.; Brunet, F.; Goffe, B.; Menut, D.; Findling, N.; Poinssot, C.

2011-12-01

50

Dehydration reactions, mass transfer and rock deformation relationships during subduction of Alpine metabauxites: insights from LIBS compositional profiles between metamorphic veins  

NASA Astrophysics Data System (ADS)

In subduction zones, the significant amounts of aqueous fluid released in the course of the successive dehydration reactions occurring during prograde metamorphism are expected to strongly influence the rock rheology, as well as kinetics of metamorphic reactions and mass transfer efficiency. Mineralized veins, ubiquitous in metamorphic rocks, can be seen as preserved witnesses of fluid and mass redistribution that partly accommodate the rock deformation (lateral segregation). However, the driving forces and mechanisms of mass transfer towards fluid-filled open spaces remain somewhat unclear. The aim of this study is to investigate the vein-forming processes and the modalities of mass transfer during local fluid-rock interactions, and their links with fluid production and rock deformation, with new insights from Laser Induced Breakdown Spectroscopy (LIBS) profiles. This study focuses on karstic pockets (metre scale) of Triassic metabauxites embedded in thick carbonate units, that have been isolated from large-scale fluid flow during HP-LT Alpine metamorphism (W. Vanoise, French Alps). These rocks display several generations of metamorphic veins containing various Al-bearing minerals, which give particular insights into mass transfer processes. It is proposed that the internally-derived fluid (~13 vol% produced by successive dehydration reactions) has promoted the opening of fluid-filled open spaces (euhedral habits of vein minerals) and served as medium for diffusive mass transfer from rock to vein. Based on mineralogical and textural features, two vein types can be distinguished: (1) some veins are filled with newly formed products of either prograde (chloritoid) or retrograde (chlorite) metamorphic reactions; in this case, fluid-filled open spaces seem to offer energetically favourable nucleation/growth sites; (2) the second vein type is filled with cookeite (Li-Al-rich chlorite) or pyrophyllite, that were present in the host rock prior to the vein formation. In this closed chemical system, mass transfer from rock to vein was achieved through the fluid, in a dissolution-transport-precipitation process, possibly stress-assisted. To investigate the modalities of mass transfer towards this second vein type, LIBS profiles were performed in the rock matrix, taking Li concentration as a proxy for cookeite distribution. Cookeite is highly concentrated (40-70 vol%) in regularly spaced veins, and the LIBS profiles show that cookeite is evenly distributed in the rock matrix comprised between two veins. The absence of diffusion profiles suggests that the characteristic diffusion length for Li, Al and Si is greater than or equal to the distance separating two cookeite veins (3-6 cm). This is in agreement with characteristic diffusion lengths calculated from both grain boundary and pore fluid diffusion coefficients, for the estimated duration of the peak of metamorphism. Concerning mass transfer driving forces, phyllosilicates have very different morphologies in the rock matrix (fibers) compared to veins (euhedral crystals): fluid-mineral interfacial energy may be maximal in the small matrix pores, which can maintain higher cookeite solubility than in fluid-filled open spaces. Therefore, as soon as veins open, chemical potential gradients may develop and drive cookeite transfer from rock matrix to veins.

Verlaguet, Anne; Brunet, Fabrice; Goffé, Bruno; Menut, Denis; Findling, Nathaniel; Poinssot, Christophe

2013-04-01

51

Dehydration, dehydrogenation, and condensation of alcohols on supported oxide catalysts based on cyclic (WO3)3 and (MoO3)3 clusters.  

PubMed

Supported early transition metal oxides have important applications in numerous catalytic reactions. In this article, we review the synthesis and activity of well-defined model WO3 and MoO3 catalysts that are prepared via deposition of cyclic gas-phase (WO3)3 and (MoO3)3 clusters generated by sublimation of WO3 and MoO3 powders. Conversion of small aliphatic alcohols to alkenes, aldehydes/ketones, and ethers is employed to probe the structure-activity relationships on model catalysts ranging from unsupported (WO3)3 and (MoO3)3 clusters embedded in alcohol matrices, to (WO3)3 clusters supported on surfaces of other oxides, and epitaxial and nanoporous WO3 films. Detailed theoretical calculations reveal the underlying reaction mechanisms and provide insight into the origin of the differences in the WO3 and MoO3 reactivity. The catalytic activity for a range of interrogated (WO3)3 motifs (from unsupported clusters to nanoporous films) further sheds light onto the role structure and binding of (WO3)3 clusters with the support play in determining their catalytic activity. PMID:24553750

Rousseau, Roger; Dixon, David A; Kay, Bruce D; Dohnálek, Zdenek

2014-10-20

52

Highly Selective Claisen–Schmidt Condensation Catalyzed by Silica Chloride Under Solvent-Free Reaction Conditions  

Microsoft Academic Search

Silica chloride serves as a useful catalyst in the cross-aldol condensation, leading to the synthesis of a wide variety of bisarylidene cycloalkanones and chalcones. The catalyst showed high selectivity; self-condensation of ketones was not observed.

Hassan Hazarkhani; Pradeep Kumar; Kadam Sachin Kondiram; Ikhlas M. Shafi Gadwal

2010-01-01

53

Direct dehydrative N-Pyridinylation of amides, the interrupted Bischler-Napieralski reaction, and the enantioselective total synthesis and arylative dimerization of aspidosperma alkaloids  

E-print Network

I. Direct Dehydrative N-Pyridinylation of Amides A method for the single-step N-pyridinylation of secondary amides is described. The process involves electrophilic activation of secondary amides with trifluoromethanesulfonic ...

Medley, Jonathan William

2013-01-01

54

Dehydration kinetics of neotame monohydrate.  

PubMed

The dehydration of neotame monohydrate was monitored at various temperatures by differential scanning calorimetry (DSC), thermogravimetry (TGA), hot-stage microscopy (HSM), powder X-ray diffractometry (PXRD), and (13)C solid-state nuclear magnetic resonance (SSNMR) spectroscopy. This work emphasizes kinetic analysis of isothermal TGA data by fitting to various solid-state reaction models and by model-free kinetic treatment. The dehydration of neotame monohydrate follows the kinetics of a two-dimensional phase boundary reaction (R2) at 40-50 degrees C with an activation energy of 75 +/- 9 kJ/mol, agreeing well with 60-80 kJ/mol from model-free kinetics. At a low heating rate in DSC and TGA, neotame monohydrate undergoes dehydration to produce anhydrate Form E, which then converts to anhydrate Form A, followed by the melting of A. Neotame monohydrate under dry nitrogen purge at 50 mL/min undergoes partial isothermal dehydration at 50 degrees C to produce neotame anhydrate Form A. When neotame monohydrate is heated very slowly from 50 to 65-70 degrees C over 24 h, pure Form A is obtained. PMID:12115842

Dong, Zedong; Salsbury, Jonathon S; Zhou, Deliang; Munson, Eric J; Schroeder, Steve A; Prakash, Indra; Vyazovkin, Sergey; Wight, Charles A; Grant, David J W

2002-06-01

55

The Partial Substrate Dethiaacetyl-Coenzyme A Mimics All Critical Carbon Acid Reactions in the Condensation Half-Reaction Catalyzed by Thermoplasma acidophilum Citrate Synthase?  

PubMed Central

Citrate synthase (CS) performs two half-reactions: the mechanistically intriguing condensation of acetyl-CoA with oxaloacetate (OAA) to form citryl-CoA, and the subsequent, slower hydrolysis of citryl-CoA that generally dominates steady-state kinetics. The condensation reaction requires the abstraction of a proton from the methyl carbon of acetyl-CoA to generate a reactive enolate intermediate. The carbanion of that intermediate then attacks the OAA carbonyl to furnish citryl-CoA, the initial product. Using stopped-flow and steady-state fluorescence methods, kinetic substrate isotope effects, and mutagenesis of active site residues, we show that all of the processes that occur in the condensation half-reaction performed by Thermoplasma acidophilum citrate synthase (TpCS) with the natural thioester substrate, acetyl-CoA, also occur with the ketone inhibitor dethiaacetyl-CoA. Free energy profiles demonstrate that the non-hydrolysable product of the condensation reaction, dethiacitryl-CoA, forms a particularly stable complex with TpCS but not pig heart CS. PMID:19645419

Kurz, Linda C.; Constantine, Charles Z.; Jiang, Hong; Kappock, T. Joseph

2009-01-01

56

Fe3O4@MOF core-shell magnetic microspheres as excellent catalysts for the Claisen-Schmidt condensation reaction  

NASA Astrophysics Data System (ADS)

Separation and recycling of catalysts after catalytic reactions are critically required to reduce the cost of catalysts as well as to avoid the generation of waste in industrial applications. In this work, we present a facile fabrication and characterization of a novel type of MOF-based porous catalyst, namely, Fe3O4@MIL-100(Fe) core-shell magnetic microspheres. It has been shown that these catalysts not only exhibit high catalytic activities for the Claisen-Schmidt condensation reactions under environmentally friendly conditions, but remarkably, they can be easily separated and recycled without significant loss of catalytic efficiency after being used for many times. Therefore, compared to other reported catalysts used in the Claisen-Schmidt condensation reactions, these catalysts are green, cheap and more suitable for large scale industrial applications.Separation and recycling of catalysts after catalytic reactions are critically required to reduce the cost of catalysts as well as to avoid the generation of waste in industrial applications. In this work, we present a facile fabrication and characterization of a novel type of MOF-based porous catalyst, namely, Fe3O4@MIL-100(Fe) core-shell magnetic microspheres. It has been shown that these catalysts not only exhibit high catalytic activities for the Claisen-Schmidt condensation reactions under environmentally friendly conditions, but remarkably, they can be easily separated and recycled without significant loss of catalytic efficiency after being used for many times. Therefore, compared to other reported catalysts used in the Claisen-Schmidt condensation reactions, these catalysts are green, cheap and more suitable for large scale industrial applications. Electronic supplementary information (ESI) available: SEM and TEM images, and GC-MS spectra for chalcones. See DOI: 10.1039/c3nr05051c

Ke, Fei; Qiu, Ling-Guang; Zhu, Junfa

2014-01-01

57

Direct Observation of Ultrafast Excited State Dynamics in Condensed Phase Photochemical Reactions  

NASA Astrophysics Data System (ADS)

Tunable ultrashort pulses of 23-70 fs at peak wavelengths ranging from 268 nm to 690 nm are being used to investigate excited electronic state dynamics in a variety of different systems. The use of such short pulses permits, for the first time, direct observation of the initial photochemical and photophysical dynamics in complicated molecules in condensed phase environments. Several different systems are being investigated for which results will be presented here. The femtosecond excited state internal conversion dynamics of simple polyenes are being investigated by using ultrashort (40-70 fs) pulses in the deep ultraviolet. Measurements were performed in alcohol and alkane solvents on cis- and trans-1,3,5-hexatriene, 1,3-cyclohexadiene, and the related molecule 7-dehydrocholesterol (Provitamin D3). These measurements permit direct observation of the internal conversion from the initially excited state (S2) to the lower energy S1 state and the subsequent internal conversion from the S1 state to the ground state. In a related study, tunable ultrashort visible pulses, 23-40 fs at 520 nm, are being used to investigate the excited state dynamics of B12 cofactors, including ultrafast internal conversion processes, and picosecond bond-cleavage. Wavelength dependent photochemistry (400 nm to 520 nm) has been observed for several cobalamins including the biologically active coenzyme methylcobalamin. Ultrashort pulses are being used to investigate the partitioning between reaction pathways, and the time scales for the initial bond cleavage process. Finally, ultrashort pulses of 23-40 fs with peak wavelengths between 650 nm and 690 nm are being used to study the ultrafast energy transfer and electron transfer processes in the photosystem II reaction center of green plants. These pulses permit coherent excitation of the entire Qy absorption band. The subsequent dynamics reflect ultrafast charge separation, excited state localization, and protein relaxation. A substantial percentage of the total charge separation occurs on a truly ultrafast, sub 100 fs, time scale.

Sension, Roseanne

2000-03-01

58

Golden rule kinetics of transfer reactions in condensed phase: The microscopic model of electron transfer reactions in disordered solid matrices  

NASA Astrophysics Data System (ADS)

The algorithm for a theoretical calculation of transfer reaction rates for light quantum particles (i.e., the electron and H-atom transfers) in non-polar solid matrices is formulated and justified. The mechanism postulated involves a local mode (an either intra- or inter-molecular one) serving as a mediator which accomplishes the energy exchange between the reacting high-frequency quantum mode and the phonon modes belonging to the environment. This approach uses as a background the Fermi golden rule beyond the usually applied spin-boson approximation. The dynamical treatment rests on the one-dimensional version of the standard quantum relaxation equation for the reduced density matrix, which describes the frequency fluctuation spectrum for the local mode under consideration. The temperature dependence of a reaction rate is controlled by the dimensionless parameter ?0 = ??0/kBT where ?0 is the frequency of the local mode and T is the temperature. The realization of the computational scheme is different for the high/intermediate (?0 < 1 - 3) and for low (?0 ? 1) temperature ranges. For the first (quasi-classical) kinetic regime, the Redfield approximation to the solution of the relaxation equation proved to be sufficient and efficient in practical applications. The study of the essentially quantum-mechanical low-temperature kinetic regime in its asymptotic limit requires the implementation of the exact relaxation equation. The coherent mechanism providing a non-vanishing reaction rate has been revealed when T ? 0. An accurate computational methodology for the cross-over kinetic regime needs a further elaboration. The original model of the hopping mechanism for electronic conduction in photosensitive organic materials is considered, based on the above techniques. The electron transfer (ET) in active centers of such systems proceeds via local intra- and intermolecular modes. The active modes, as a rule, operate beyond the kinetic regimes, which are usually postulated in the existing theories of the ET. Our alternative dynamic ET model for local modes immersed in the continuum harmonic medium is formulated for both classical and quantum regimes, and accounts explicitly for the mode/medium interaction. The kinetics of the energy exchange between the local ET subsystem and the surrounding environment essentially determine the total ET rate. The efficient computer code for rate computations is elaborated on. The computations are available for a wide range of system parameters, such as the temperature, external field, local mode frequency, and characteristics of mode/medium interaction. The relation of the present approach to the Marcus ET theory and to the quantum-statistical reaction rate theory [V. G. Levich and R. R. Dogonadze, Dokl. Akad. Nauk SSSR, Ser. Fiz. Khim. 124, 213 (1959); J. Ulstrup, Charge Transfer in Condensed Media (Springer, Berlin, 1979); M. Bixon and J. Jortner, Adv. Chem. Phys. 106, 35 (1999)] underlying it is discussed and illustrated by the results of computations for practically important target systems.

Basilevsky, M. V.; Odinokov, A. V.; Titov, S. V.; Mitina, E. A.

2013-12-01

59

Catalytic performance of Metal-Organic-Frameworks vs. extra-large pore zeolite UTL in condensation reactions  

PubMed Central

Catalytic behavior of isomorphously substituted B-, Al-, Ga-, and Fe-containing extra-large pore UTL zeolites was investigated in Knoevenagel condensation involving aldehydes, Pechmann condensation of 1-naphthol with ethylacetoacetate, and Prins reaction of ?-pinene with formaldehyde and compared with large-pore aluminosilicate zeolite beta and representative Metal-Organic-Frameworks Cu3(BTC)2 and Fe(BTC). The yield of the target product over the investigated catalysts in Knoevenagel condensation increases in the following sequence: (Al)beta < (Al)UTL < (Ga)UTL < (Fe)UTL < Fe(BTC) < (B)UTL < Cu3(BTC)2 being mainly related to the improving selectivity with decreasing strength of active sites of the individual catalysts. The catalytic performance of Fe(BTC), containing the highest concentration of Lewis acid sites of the appropriate strength is superior over large-pore zeolite (Al)beta and B-, Al-, Ga-, Fe-substituted extra-large pore zeolites UTL in Prins reaction of ?-pinene with formaldehyde and Pechmann condensation of 1-naphthol with ethylacetoacetate. PMID:24790940

Shamzhy, Mariya; Opanasenko, Maksym; Shvets, Oleksiy; Cejka, Jiri

2013-01-01

60

Photochemical reactions in dehydrated photosynthetic organisms, leaves, chloroplasts and photosystem II particles: reversible reduction of pheophytin and chlorophyll and oxidation of ?-carotene  

Microsoft Academic Search

Photoreactions of dehydrated leaves, isolated broken chloroplasts and PSII membrane fragments of spinach (Spinacia oleracea) were studied at different air humidities and compared with photoreactions of dry fronds of a fern, Polypodium vulgare, and a dry lichen, Parmelia sulcata, which in contrast to spinach are insensitive to photoinactivation in the dry state. Even in very dry air, P700 in the

Vladimir A. Shuvalov; Ulrich Heber

2003-01-01

61

Synthesis of 1,5-Benzodiazepine and Its Derivatives by Condensation Reaction Using H-MCM-22 as Catalyst  

PubMed Central

A simple and versatile method for the synthesis of 1,5-benzodiazepines is via condensation of o-phenylenediamines (OPDA) and ketones in the presence of catalytic amount of H-MCM-22 using acetonitrile as solvent at room temperature. In all the cases, the reactions are highly selective and are completed within 1–3?h. The method is applicable to both cyclic and acyclic ketones without significant differences. The reaction proceeds efficiently under ambient conditions with good-to-excellent yields. PMID:22570531

Majid, Sheikh Abdul; Khanday, Waheed Ahmad; Tomar, Radha

2012-01-01

62

Thirst, Drinking Behavior, And Dehydration  

NASA Technical Reports Server (NTRS)

Report describes review of physiological mechanisms of involuntary dehydration. Researchers considered cellular dehydration and effects of sodium on thirst, as well as extracellular dehydration and restoration of vascular volume, effects of renin on thirst, and effects of heat.

Greenleaf, John

1996-01-01

63

Proposal for New Experimental Tests of the Bose-Einstein Condensation Mechanism for Low Energy Nuclear Reaction and Transmutation Processes in Deuterium Loaded Micro and Nano Scale Cavities  

Microsoft Academic Search

Most of experimental results of low energy nuclear reaction (LENR) reported so far cannot be reproduced on demand. There have been persistent experimental results indicating that the LENR and transmutation processes in condensed matters (LENRTPCM) are surface phenomena rather than bulk phenomena. Recently proposed Bose-Einstein condensation (BEC) mechanism may provide a suitable theoretical description of the surface phenomena. New experiments

Yeong E. Kim; David S. Koltick; Ronald G. Reifenberger; Alexander L. Zubarev

64

Mechanism of the intramolecular Claisen condensation reaction catalyzed by MenB, a crotonase superfamily member.  

PubMed

MenB, the 1,4-dihydroxy-2-naphthoyl-CoA synthase from the bacterial menaquinone biosynthesis pathway, catalyzes an intramolecular Claisen condensation (Dieckmann reaction) in which the electrophile is an unactivated carboxylic acid. Mechanistic studies on this crotonase family member have been hindered by partial active site disorder in existing MenB X-ray structures. In the current work the 2.0 Å structure of O-succinylbenzoyl-aminoCoA (OSB-NCoA) bound to the MenB from Escherichia coli provides important insight into the catalytic mechanism by revealing the position of all active site residues. This has been accomplished by the use of a stable analogue of the O-succinylbenzoyl-CoA (OSB-CoA) substrate in which the CoA thiol has been replaced by an amine. The resulting OSB-NCoA is stable, and the X-ray structure of this molecule bound to MenB reveals the structure of the enzyme-substrate complex poised for carbon-carbon bond formation. The structural data support a mechanism in which two conserved active site Tyr residues, Y97 and Y258, participate directly in the intramolecular transfer of the substrate ?-proton to the benzylic carboxylate of the substrate, leading to protonation of the electrophile and formation of the required carbanion. Y97 and Y258 are also ideally positioned to function as the second oxyanion hole required for stabilization of the tetrahedral intermediate formed during carbon-carbon bond formation. In contrast, D163, which is structurally homologous to the acid-base catalyst E144 in crotonase (enoyl-CoA hydratase), is not directly involved in carbanion formation and may instead play a structural role by stabilizing the loop that carries Y97. When similar studies were performed on the MenB from Mycobacterium tuberculosis, a twisted hexamer was unexpectedly observed, demonstrating the flexibility of the interfacial loops that are involved in the generation of the novel tertiary and quaternary structures found in the crotonase superfamily. This work reinforces the utility of using a stable substrate analogue as a mechanistic probe in which only one atom has been altered leading to a decrease in ?-proton acidity. PMID:21830810

Li, Huei-Jiun; Li, Xiaokai; Liu, Nina; Zhang, Huaning; Truglio, James J; Mishra, Shambhavi; Kisker, Caroline; Garcia-Diaz, Miguel; Tonge, Peter J

2011-11-01

65

Low-energy electron-induced chemistry of condensed-phase hexamethyldisiloxane: Initiating dissociative process and subsequent reactions  

NASA Astrophysics Data System (ADS)

Thin films of condensed hexamethyldisiloxane (HMDSO) have been exposed to electron irradiation at incident energies between 5 and 15 eV and analysed afterwards by thermal desorption spectrometry (TDS). Formation of products is observed at energies at and above 11 eV and quantified at 15 eV by comparison with reference samples of known composition. Gas-phase measurements aiming at detection of dissociative electron attachment (DEA) were, in addition, performed to obtain more insight into the dominant electron-induced dissociation channel expected to initiate further reactions in the condensed phase. Apart from CH4 which is the most obvious product present in exposed films of HMDSO, tetramethylsilane (TMS) and smaller amounts of C2H6 have been detected. The quantity of the products is by one to two orders of magnitude smaller than the amount of decomposed HMDSO. In addition, signals ascribed to unquantified amounts of larger siloxanes have been observed. The present results together with previous gas-phase results from literature suggest that dissociative ionisation leading to Si-C bond rupture and release of a methyl radical is the most important electron-driven initial reaction step. Possible mechanisms of the subsequent reactions induced by the fragments of the initial dissociation reaction are reviewed and discussed in relation to the observed product quantities.

Ipolyi, I.; Burean, E.; Hamann, T.; Cingel, M.; Matejcik, S.; Swiderek, P.

2009-05-01

66

"Solvent Usage in Biorefineries Biphasic Dehydration of Xylose to Furfural" Maheen Khan  

E-print Network

"Solvent Usage in Biorefineries ­ Biphasic Dehydration of Xylose to Furfural" Maheen Khan Faculty) to furfural in a biphasic dehydration reaction, the two phases being an organic phase and an aqueous phase

Mountziaris, T. J.

67

An investigation of the role of water on retrograde/condensation reactions and enhanced liquefaction yields. Final report  

SciTech Connect

While great strides have been made in developing the technology of coal liquefaction processes in recent years, many unsolved problems still remain before a viable and economical process can be achieved. The technological problems that still exist can be solved through a more fundamental understanding of the chemistry associated with each stage of the coal liquefaction process, starting with any pretreatment steps that may be carried out on the coal itself. Western Research Institute, under the a contract from the US Department of Energy, has conducted a study of different methods of coal drying as pretreatment steps before liquefaction. The results of that study are the subject of this report. Coals that were dried or partially dried thermally and with microwaves had lower liquefaction conversions than coals containing equilibrium moisture contents. However, chemically dried coals had conversions equal to or greater than the premoisturized coals. The conversion behavior is consistent with changes in the physical structure and cross linking reactions because of drying. Thermal and microwave drying appear to cause a collapse in the pore structure, thus preventing donor solvents such as tetralin from contacting reactive sites inside the coals. Chemical dehydration does not appear to collapse the pore structure. From the study of the kinetics of the chemical dehydration of coals, it was possible to quantify the amount of water on the surface, the amount readily accessible in pores, and the amount more strongly bonded in the internal structure of the coals. The results indicate that high-rank coals have proportionally less surface and easily accessible water than the lower rank coals.

Miknis, F.P.; Netzel, D.A.; Wallace, J.C. Jr.; Butcher, C.H.; Mitzel, J.M.; Turner, T.F.

1995-02-01

68

Rational design of a GH1 beta-glycosidase to prevent self-condensation during the transglycosylation reaction.  

PubMed

Mutant N282T of a thermostable beta-glycosidase from GH1 family (TtbetaGly) presenting a high transglycosidase activity was previously obtained by directed evolution. However, it displays a self-condensation activity with the donor 2-nitrophenyl-beta-d-galactopyranoside (oNPGal) which competes with the condensation reaction and entails undesirable effects. In order to prevent this reaction, we rationally modified this enzyme at the [+1]/[+2] subsites so that oNPGal would bind less tightly. Molecular modeling (MM) suggested the mutation A221W, which decreased the affinity of the donor at these sites and moved it away from the bound galactose at the -1 subsite. A single (A221W) and a double mutant (A221W/N282T) were constructed, and they gave rise to a drastic decrease in self-condensation. The A221W mutant had no transglycosylation activity whereas the A221W/N282T mutant still displayed a condensation activity, comparable to that of the N282T mutant for the transfer on pNPGlcNAc. MM revealed that the double mutant A221W/N282T could induce the synthesis of a glycosidic bond between a donor and an acceptor displaying an equatorial 4-position. Moreover, it is suggested that mutation N282T could change the orientation of residue N219, leading to a stabilization of the acceptor with a new hydrogen bond. This finding opens the way to further improvements of evolved transglycosidases. PMID:19926593

Tran, Vinh; Hoffmann, Lionel; Rabiller, Claude; Tellier, Charles; Dion, Michel

2010-01-01

69

Dynamic Effects Dictate the Mechanism and Selectivity of Dehydration-Rearrangement Reactions of Protonated Alcohols [Me2 (R)CCH(OH2 )Me](+) (R=Me, Et, iPr) in the Gas Phase.  

PubMed

The gas-phase dehydration-rearrangement (DR) reactions of protonated alcohols [Me2 (R)CCH(OH2 )Me](+) [R=Me (ME), Et (ET), and iPr (I-PR)] were studied by using static approaches (intrinsic reaction coordinate (IRC), Rice-Ramsperger-Kassel-Marcus theory) and dynamics (quasiclassical trajectory) simulations at the B3LYP/6-31G(d) level of theory. The concerted mechanism involves simultaneous water dissociation and alkyl migration, whereas in the stepwise reaction pathway the dehydration step leads to a secondary carbocation intermediate followed by alkyl migration. Internal rotation (IR) can change the relative position of the migrating alkyl group and the leaving group (water), so distinct products may be obtained: [Me(R)CCH(Me)Me???OH2 ](+) and [Me(Me)CCH(R)Me???OH2 ](+) . The static approach predicts that these reactions are concerted, with the selectivity towards these different products determined by the proportion of the conformers of the initial protonated alcohols. These selectivities are explained by the DR processes being much faster than IR. These results are in direct contradiction with the dynamics simulations, which indicate a predominantly stepwise mechanism and selectivities that depend on the alkyl groups and dynamics effects. Indeed, despite the lifetimes of the secondary carbocations being short (<0.5?ps), IR can take place and thus provide a rich selectivity. These different selectivities, particularly for ET and I-PR, are amenable to experimental observation and provide evidence for the minor role played by potential-energy surface and the relevance of the dynamics effects (non-IRC pathways, IR) in determining the reaction mechanisms and product distribution (selectivity). PMID:25179304

de Souza, Miguel A F; Ventura, Elizete; Monte, Silmar A do; Riveros, José M; Longo, Ricardo L

2014-10-13

70

The relationship of intermediate-and deep-focus seismicity to the hydration and dehydration of subducting slabs  

E-print Network

The relationship of intermediate- and deep-focus seismicity to the hydration and dehydration Accepted 26 June 2012 Available online 9 August 2012 Keywords: deep earthquakes dehydration embrittlement in subducting slabs may result from dehydration reactions. We investigate the importance of dehydration

Hacker, Bradley R.

71

The relationship of intermediate-and deep-focus seismicity to the hydration and dehydration of subducting slabs  

E-print Network

The relationship of intermediate- and deep-focus seismicity to the hydration and dehydration Accepted 26 June 2012 Keywords: deep earthquakes dehydration embrittlement subduction zone water a b s t r result from dehydration reactions. We investigate the importance of dehydration in facilitating

van Keken, Peter

72

Electrolyte Concentrates Treat Dehydration  

NASA Technical Reports Server (NTRS)

Wellness Brands Inc. of Boulder, Colorado, exclusively licensed a unique electrolyte concentrate formula developed by Ames Research Center to treat and prevent dehydration in astronauts returning to Earth. Marketed as The Right Stuff, the company's NASA-derived formula is an ideal measure for athletes looking to combat dehydration and boost performance. Wellness Brands also plans to expand with products that make use of the formula's effective hydration properties to help treat conditions including heat stroke, altitude sickness, jet lag, and disease.

2009-01-01

73

THE DEHYDRATION OF TOBERMORITE  

Microsoft Academic Search

Tobermorite (Ca 4 (Si6018H2)Ca.4I-IaO ) is a hydrated calcimn silicate mineral with a layer structure which in some respects resembles that of vermiculite. Its dehydration has been studied using single crystals from Ballyeraigy, N. Ireland. The three most frequently encountered hych'ation states are characterized by basal spacings (d002) of 14.0, 11.3 and 9.35~. Dehydration to the 9.35~ state is complete

F. W. TAYLOR

74

Cognitive performance and dehydration.  

PubMed

No matter how mild, dehydration is not a desirable condition because there is an imbalance in the homeostatic function of the internal environment. This can adversely affect cognitive performance, not only in groups more vulnerable to dehydration, such as children and the elderly, but also in young adults. However, few studies have examined the impact of mild or moderate dehydration on cognitive performance. This paper reviews the principal findings from studies published to date examining cognitive skills. Being dehydrated by just 2% impairs performance in tasks that require attention, psychomotor, and immediate memory skills, as well as assessment of the subjective state. In contrast, the performance of long-term and working memory tasks and executive functions is more preserved, especially if the cause of dehydration is moderate physical exercise. The lack of consistency in the evidence published to date is largely due to the different methodology applied, and an attempt should be made to standardize methods for future studies. These differences relate to the assessment of cognitive performance, the method used to cause dehydration, and the characteristics of the participants. PMID:22855911

Adan, Ana

2012-04-01

75

Experimental and phenomenological comparison between Piezonuclear reactions and Condensed Matter Nuclear Science phenomenology  

Microsoft Academic Search

The purpose of this paper is to place side by side the experimental results of Piezonu- clear reactions, which have been recently unveiled, and those collected during the last twenty years of experiments on low energy nuclear reactions (LENR). We will briefy re- port the results of our campaign of piezonuclear reactions experiments where ultrasounds and cavitation were applied to

F. Cardone; R. Mignani; A. Petrucci

2011-01-01

76

Hydrolysis and condensation kinetics for liquid-phase tetraethylorthosilicate reactions in alkaline-alcohol solvents  

Microsoft Academic Search

The hydrolysis and condensation kinetics for the Stober-Fink method of producing monodisperse silica particles have been studied by chemical analyses (i.e., gas chromatography and molybdate for determining monomeric silicic acid concentrations) and laser-light-scattering techniques. Studies have been conducted to determine the effects of temperature, reactant and catalyst concentrations, and solvent type (i.e., 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butyl alcohol, and tert-amyl

M. T. Harris; C. H. Byers; R. R. Brunson

1987-01-01

77

Carbon dioxide hydrationand dehydration kinetics in seawater  

Microsoft Academic Search

Rate constants for the hydration and dehydration reactions of carbon dioxide with water and with hydroxyl ion were measured in seawater by a pH-stat method at salinities (X lO:l) from 3.4 to 37.06 at 25°C and from 5\\

Kenneth S. Johnson

1982-01-01

78

Various regimes of externally maintained propagation of an exothermal reaction front in a condensed medium  

Microsoft Academic Search

The approximation of an infinitesimally thin reaction zone is used in a study of a onedimensional model of the propagation of an exothermal reaction front in the case of additional external heating of a substance by laser radiation. Steady-state solutions are obtained and the ranges of their stability are found in a plane formed by the velocity of the laser

O P Ivanov; A L Chernyakov

1986-01-01

79

ARTICLES: Various regimes of externally maintained propagation of an exothermal reaction front in a condensed medium  

Microsoft Academic Search

The approximation of an infinitesimally thin reaction zone is used in a study of a onedimensional model of the propagation of an exothermal reaction front in the case of additional external heating of a substance by laser radiation. Steady-state solutions are obtained and the ranges of their stability are found in a plane formed by the velocity of the laser

O. P. Ivanov; A. L. Chernyakov

1986-01-01

80

Modeling the dehydration of t-butanol and avoidance of the formation of oligomers  

E-print Network

Modeling the dehydration of t-butanol and avoidance of the formation of oligomers Dieter Bothe A new mechanistic reaction scheme of the dehydration of t-butanol in sulfuric acid is proposed which of isobutene is t-butanol. Besides other heterogeneous catalytic pro- cesses, the dehydration of t-butanol (TBA

Bothe, Dieter

81

Successive hydration and dehydration of high-P mafic granofels involving clinopyroxenekyanite symplectites, Mt Daniel,  

E-print Network

Successive hydration and dehydration of high-P mafic granofels involving clinopyroxene reaction zones and symplectites was promoted by dehydration most probably following cooling of the contact: dehydration; garnet granulite; hornblende­clinozoisite and clinopyroxene­kyanite symplectites; lower crust

Daczko, Nathan

82

Plastic and dehydration instabilities of antigorite serpentinite  

NASA Astrophysics Data System (ADS)

We conducted a constant displacement rate test of antigorite serpentinite by a triaxial solid medium deformation apparatus installed at Hiroshima University. Experimental conditions were P = ca. 1.0 GPa, T = 450 C to 800 C, which cover from stability to dehydration conditions of antigorite, and strain rate of digit of 10-5 /sec. Samples were cylindrical shape cored from serpentinite and their sizes were 7 mm x 7 mm and 5 mm x 5 mm in diameter by length. Faults were observed in recovered samples from all temperature conditions. Mechanical data of faulted samples showed stress drop of several 10 MPa during experiments. The followings summarize microstructural observations of the recovered samples, and propose generation processes of fault at stability and dehydration conditions. 1) Stability field (plastic instability): Antigorite grains develop a lattice preferred orientation (LPO) along a fault, which characterized by (001) cleavage face parallel to fault plane. This fact suggests the fault is generated by the following process. i) Antigorite grains on the plane applied by maximum shear stress are preferentially deformed by plastic manner, and then develop the LPO. ii) The arrangement of cleavage face gradually reduces the strength of this plane. iii) Eventually, embrittlement occurs at the critical point when the rock strength along this weak plane becomes smaller than shear stress. 2) Dehydration condition (dehydration instability): Fine grained dehydration phases less than 1 micrometer in size such as olivine and talc are detected as a thin vein along the fault. Moreover, talc and olivine, or antigorite ca. 1 - 5 micrometers in size with angular shape are observed within the fault as a fault gauge. These facts suggest the following generation process of fault. i) Dehydration reaction of antigorite begins on the plane applied by maximum shear stress and expands along this plane. ii) The dehydration gradually reduces the strength of this plane. iii) Eventually, embrittlement occurs at the critical point when the rock strength along this weak plane becomes smaller than shear stress.

Ando, J.; Katayama, I.; Ohfuji, H.; Terada, Y.

2008-12-01

83

Rehydration of Dehydrated Foods  

Microsoft Academic Search

Dehydrated products readily take up moisture when immersed in a liquid medium, leading to significant changes in their thermophysical properties. The rehydration kinetics, the structural properties (apparent density, true density, specific volume and internal porosity), the viscoelastic behavior (compression tests), and the flavor losses were investigated during rehydration of various fruits and vegetables. The effect of temperature on the above

M. K. Krokida; C. Philippopoulos

2005-01-01

84

Models of glycolysis: Glyceraldehyde as a source of energy and monomers for prebiotic condensation reactions  

NASA Technical Reports Server (NTRS)

All organisms require energy in a chemical form for maintenance and growth. In contemporary life this chemical energy is obtained by the synthesis of the phosphoanhydride bonds of ATP. Among the biological processes that yield ATP, fermentation is generally considered primitive, because it operates under anaerobic conditions by substrate-level phosphorylation which does not require compartmentation by membranes. Fermentation by the glycolytic pathway, which is found in almost every living cell, is an especially attractive energy source for primitive life. Glycolysis not only produces useful chemical energy (ATP), but intermediates of this pathway are also involved in amino acid synthesis and photosynthetic carbon-fixation. It is believed that energy and substrates needed for the origin of life were provided by nonenzymatic chemical reactions that resemble the enzyme-mediated reactions of glycolysis. These nonenzymatic reactions would have provided a starting point for the evolutionary development of glycolysis.

Weber, A. L.

1986-01-01

85

6, 69036931, 2006 Dehydration in  

E-print Network

ACPD 6, 6903­6931, 2006 Dehydration in tropical tropopause layer F. Hasebe et al. Title Page Chemistry and Physics Discussions In situ observations of "cold trap" dehydration in the western tropical Correspondence to: F. Hasebe (f-hasebe@ees.hokudai.ac.jp) 6903 #12;ACPD 6, 6903­6931, 2006 Dehydration

Paris-Sud XI, Université de

86

Original article Effect of dehydration  

E-print Network

Original article Effect of dehydration on ruminal degradability of lucerne José Luis REPETTO 28 October 1999; accepted 17 February 2000) Abstract -- The effects of industrial dehydration obtained at harvest or after the process of dehydration and compression of this forage. Rumen degradability

Paris-Sud XI, Université de

87

5, 97699799, 2005 Cirrus dehydration  

E-print Network

ACPD 5, 9769­9799, 2005 Cirrus dehydration potential S. Fueglistaler and M. B. Baker Title Page. 9769 #12;ACPD 5, 9769­9799, 2005 Cirrus dehydration potential S. Fueglistaler and M. B. Baker Title.g., gravity waves) are not found to efficiently dehydrate over most of the upper troposphere. A conse- quence

Paris-Sud XI, Université de

88

Condensation reactions of guanidines with bis-electrophiles: Formation of highly nitrogenous heterocyclesa  

PubMed Central

2-Amino-1,4-dihydropyrimidines were reacted with bis-electrophiles to produce novel fused bi-pyrimidine, pyrimido-aminotriazine, and pyrimido-sulfonamide scaffolds. In addition, a quinazoline library was constructed using a guanidine Atwal-Biginelli reaction with 1-(quinazolin-2-yl)guanidines. The product heterocycles have novel constitutions with high nitrogen atom counts and represent valuable additions to screening libraries for the discovery of new modulators of biological targets. PMID:23976798

Arnold, David M.; LaPorte, Matthew G.; Anderson, Shelby M.; Wipf, Peter

2013-01-01

89

Experimental and phenomenological comparison between Piezonuclear reactions and Condensed Matter Nuclear Science phenomenology  

E-print Network

The purpose of this paper is to place side by side the experimental results of Piezonu- clear reactions, which have been recently unveiled, and those collected during the last twenty years of experiments on low energy nuclear reactions (LENR). We will briefy re- port the results of our campaign of piezonuclear reactions experiments where ultrasounds and cavitation were applied to solutions of stable elements. These outcomes will be shown to be compatible with the results and evidences obtained from low energy nuclear reac- tion experiments. Some theoretical concepts and ideas, on which our experiments are grounded, will be sketched and it will be shown that, in order to trigger our measured effects, it exists an energy threshold, that has to be overcome, and a maximum inter- val of time for this energy to be released to the nuclear system. Eventually, a research hypothesis will be put forward about the chance to raise the level of analogy from the mere comparison of results up to the phenomenological level. H...

Cardone, F; Petrucci, A

2011-01-01

90

Experimental and phenomenological comparison between Piezonuclear reactions and Condensed Matter Nuclear Science phenomenology  

E-print Network

The purpose of this paper is to place side by side the experimental results of Piezonu- clear reactions, which have been recently unveiled, and those collected during the last twenty years of experiments on low energy nuclear reactions (LENR). We will briefy re- port the results of our campaign of piezonuclear reactions experiments where ultrasounds and cavitation were applied to solutions of stable elements. These outcomes will be shown to be compatible with the results and evidences obtained from low energy nuclear reac- tion experiments. Some theoretical concepts and ideas, on which our experiments are grounded, will be sketched and it will be shown that, in order to trigger our measured effects, it exists an energy threshold, that has to be overcome, and a maximum inter- val of time for this energy to be released to the nuclear system. Eventually, a research hypothesis will be put forward about the chance to raise the level of analogy from the mere comparison of results up to the phenomenological level. Here, among the various evidences collected in LENR experiments, we will search for hints about the overcome of the energy threshold and about the mechanism that releases the loaded energy in a suitable interval of time.

F. Cardone; R. Mignani; A. Petrucci

2011-03-06

91

Experimental evidence for condensation reactions between sugars and proteins in carbonate skeletons  

NASA Astrophysics Data System (ADS)

Melanoidins, condensation products formed from protein and polysaccharide precursors, were once thought to be an important geological sink for organic carbon. The active microbial recycling of the precursors, coupled with an inability to demonstrate the formation of covalent linkages between amino acids and sugars in melanoidins, has shaped a powerful argument against this view. Yet, melanoidins may still be an abundant source of macromolecules in fossil biominerals such as shells, in which the proteins and polysaccharides are well protected from microbial degradation. We have modelled diagenetic changes in a biomineral by heating at 90°C mixtures of protein, polysaccharides and finely ground calcite crystals in sealed glass vials. Changes to the protein bovine serum albumin (BSA, fraction V) were monitored by means of gel electrophoresis and immunology. In the presence of water, BSA was rapidly hydrolyzed and remained immunologically reactive for less than 9 h. Under anhydrous conditions the protein was immunologically reactive for the whole period of the experiment (1281 h), unless mono- or disaccharide sugars were also present. In the presence of these reactive sugars, browning, a discrete increase in molecular weight of the protein and a concomitant loss of antigenicity confirmed that the sugars were attaching covalently to the protein, forming melanoidins. The de novo formation of products cross-reactive with antibodies raised against organic matter isolated from the shells of a fossil mollusc ( Mercenaria mercenaria) indicated that at least in part the model simulated natural diagenesis. We roughly estimate that, at the global scale, 2.4 × 10 6 tonnes of calcified tissue matrix glycoproteins is processed annually through the melanoidin pathway. This amount would be equivalent to 7 per mil of the total flux of organic carbon into marine sediments.

Collins, M. J.; Westbroek, P.; Muyzer, G.; de Leeuw, J. W.

1992-04-01

92

Development of Encapsulation Dehydration  

Microsoft Academic Search

The application of cryopreservation to plants is relatively recent as the first report of successful cryopreservation was\\u000a published by Sakai in 1960 with silver birch twigs, and in-vitro cultured flax cells were frozen by Quatrano in 1968. The first protocols developed in the 1980s included pre-treatment with\\u000a cryoprotectants followed by controlled rate cooling. These protocols were based on freeze-induced dehydration

Florent Engelmann; Maria-Teresa Gonzalez Arnao; Yongjie Wu; Roosevelt Escobar

93

Method of dehydrating natural gas  

SciTech Connect

A method for dehydration of natural gas is provided wherein well head gas is supplied to a three-phase inlet separator, the vapor mixture of natural gas and water removed from that inlet separator means is supplied to a turboexpander, and the resulting refrigerated mixture of natural gas and condensed water vapor is supplied to a multi-phase outlet separator. The turboexpander may have integral means for subsequent compression of the refrigerated mixture and may be coupled through reduction gears to a means for generating electricity. A portion of the refrigerated mixture may be connected to a heat exchanger for cooling the well head natural gas prior to entry into the inlet separator. The flow of refrigerated mixture to this heat exchanger may be controlled by a temperature sensitive valve downstream of the heat exchanger. Methanol may be injected into the vapor mixture prior to entry into the turboexpander. The flow of methanol into the vapor mixture may be controlled by a valve sensitive to the flow rate of the vapor mixture and the water vapor content of the refrigerated mixture. Natural gas vapor from the outlet separator may be recirculated through the turboexpander if the output water vapor content of the natural gas vapor stream is too high.

Wells, R. E.

1985-01-01

94

A recyclable bifunctional acid-base organocatalyst with ionic liquid character. The role of site separation and spatial configuration on different condensation reactions.  

PubMed

A series of bifunctional organic catalysts containing acid and basic sites with ionic liquid characteristics have been prepared and their catalytic activity and reaction coordinate for aldol and Knoevenagel condensations have been compared. While the only factor controlling catalyst activity for the Knoevenagel condensation was the distance between the acid and base sites, the spatial orientation of the organocatalyst is also key to achieve high activity and selectivity in the Claisen-Schmidt condensation. Mechanistic studies based on theoretical DFT calculations show that the acid-base bifunctional organocatalyst follows a mechanism inspired in natural aldolases for the synthesis of trans-chalcones, being able to produce a large variety of these compounds of industrial interest. The combination of the acid-base pairs within the proper geometry and the ionic liquid nature makes this catalyst active, selective and recyclable. PMID:21879067

Corma, Avelino; Boronat, Mercedes; Climent, María José; Iborra, Sara; Montón, Raquel; Sabater, María J

2011-10-14

95

Dehydration-induced luminescence in clay minerals  

NASA Technical Reports Server (NTRS)

Reports of triboluminescent phenomena in organic crystalline materials prompted a search for related processes in clay minerals. The reported extensive mechanical distortion produced on freezing and drying of montmorillonite was particularly interesting because of studies of condensation reactions in a wet/dry cycled reaction sequence. The discovery of an unusual luminescent process in several clay minerals is reported and its characteristics are described.

Coyne, L. M.; Lahav, N.; Lawless, J. G.

1981-01-01

96

7 CFR 993.15 - Dehydrator.  

...PRUNES PRODUCED IN CALIFORNIA Order Regulating Handling Definitions § 993.15 Dehydrator. Dehydrator means any person who produces prunes by drying or dehydrating plums by means of sun-drying or artificial...

2014-01-01

97

Survey of quality indicators in commercial dehydrated fruits.  

PubMed

Physical and chemical quality parameters (dry matter, aw, protein, carbohydrates, vitamin C, 2-furoylmethyl amino acids, rehydration ratio and leaching loss) have been determined in 30 commercial dehydrated fruits (strawberry, blueberry, raspberry, cranberry, cherry, apple, grapefruit, mango, kiwifruit, pineapple, melon, coconut, banana and papaya). For comparison purposes, strawberry samples processed in the laboratory by freeze-drying and by convective drying were used as control samples. Overall quality of dehydrated fruits seemed to be greatly dependent on processing conditions and, in a cluster analysis, samples which were presumably subjected to osmotic dehydration were separated from the rest of fruits. These samples presented the lowest concentration of vitamin C and the highest evolution of Maillard reaction, as evidenced by its high concentration of 2-furoylmethyl amino acids. This is the first study on the usefulness of this combination of chemical and physical indicators to assess the overall quality of commercial dehydrated fruits. PMID:24360417

Megías-Pérez, Roberto; Gamboa-Santos, Juliana; Soria, Ana Cristina; Villamiel, Mar; Montilla, Antonia

2014-05-01

98

7 CFR 989.12 - Dehydrator.  

Code of Federal Regulations, 2011 CFR

...Nuts), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN IN CALIFORNIA Order Regulating Handling Definitions...Dehydrator means any person who produces raisins by dehydrating grapes by artificial...

2011-01-01

99

7 CFR 989.12 - Dehydrator.  

Code of Federal Regulations, 2010 CFR

...Nuts), DEPARTMENT OF AGRICULTURE RAISINS PRODUCED FROM GRAPES GROWN IN CALIFORNIA Order Regulating Handling Definitions...Dehydrator means any person who produces raisins by dehydrating grapes by artificial...

2010-01-01

100

NUMERICAL TECHNIQUES TO SOLVE CONDENSATIONAL AND DISSOLUTIONAL GROWTH EQUATIONS WHEN GROWTH IS COUPLED TO REVERSIBLE REACTIONS (R823186)  

EPA Science Inventory

Noniterative, unconditionally stable numerical techniques for solving condensational and dissolutional growth equations are given. Growth solutions are compared to Gear-code solutions for three cases when growth is coupled to reversible equilibrium chemistry. In all cases, ...

101

Proposal for New Experimental Tests of the Bose-Einstein Condensation Mechanism for Low-Energy Nuclear Reaction and Transmutation Processes in Deuterium Loaded - and Nano-Scale Cavities  

Microsoft Academic Search

Most of experimental results of low-energy nuclear reaction (LENR) reported so far cannot be reproduced on demand. There have been persistent experimental results indicating that the LENR and transmutation processes in condensed matters (LENRTPCM) are surface phenomena rather than bulk phenomena. Recently proposed Bose-Einstein condensation (BEC) mechanism may provide a suitable theoretical description of the surface phenomena. New experiments are

Yeong E. Kim; David S. Koltick; Ronald G. Reifenberger; Alexander L. Zubarev

2006-01-01

102

An investigation of the role of water on retrograde/condensation reactions and enhanced liquefaction yields. Quarterly progress report, January 1, 1994--March 31, 1994  

SciTech Connect

The results of coal swelling measurements using 1,4-dioxane as the swelling reagent for premoisturized coals (raw) and coal dried thermally, chemically, and with microwave radiation are presented. An increase in the swelling ratio relative to raw coal indicates a decrease in the amount of cross-linking in the coal. Conversely, a decrease in the ratio indicates an increase in cross-linking. The extent of cross-linking (as measured by 1,4-dioxane) for Texas, Black Thunder, and Eagle Butte Coals are about the same. Illinois {number_sign}6 coal appears to have less cross-linking relative to the other three coals. These results are expected on the basis of coal rank. The increase in cross linking is most pronounced for coals dried thermally and with microwave radiation. A decrease in the swelling ratios for all four coals suggests that cross-linking had occurred possibly due to partial devolatilization process. However, low temperature, chemical dehydration of the coals causes only a small or no change in the internal structure for Texas and Illinois {number_sign}6 coals whereas a significant decrease in the cross-linking structure for the Black Thunder and Eagle Butte coals is observed. It is possible that the solvent (CH{sub 3}OH) and products resulting from the chemical dehydrating (acetone and methanol) occupy the surface sites that water had before the reaction and thus preventing cross-linking to occur. These reagents can also promote swelling of coals and may account for some of the decrease in the cross-linking of the coal structure observed for the chemically dried coals.

Miknis, F.P.; Netzel, D.A.

1994-04-01

103

HClO 4–SiO 2 and PPA–SiO 2 catalyzed efficient one-pot Knoevenagel condensation, Michael addition and cyclo-dehydration of dimedone and aldehydes in acetonitrile, aqueous and solvent free conditions: Scope and limitations  

Microsoft Academic Search

Efficient one-pot Knoevenagel condensation, Michael addition and cyclodehydration of dimedone with various aldehydes in acetonitrile and solvent free conditions using PPA–SiO2 catalyst gave 1,8-dioxo-octahydroxanthenes 3 in excellent yields; whereas in the presence of HClO4–SiO2 catalyst the reaction is limited to give only 2,2?-arylmethylene bis(3-hydroxy-5,5-dimethyl-2-cyclohexene-1-one) 4 in very good yields. In aqueous medium both HClO4–SiO2 and PPA–SiO2 catalysts yielded only 4

Srinivas Kantevari; Rajashaker Bantu; Lingaiah Nagarapu

2007-01-01

104

Carbohydrate Dehydration Demonstrations.  

ERIC Educational Resources Information Center

Discusses the impact of various factors on the "charring reaction" of a carbohydrate with concentrated sulfuric acid including the type of sugar, the degree of fineness of the sugar crystals, and the amount of water added. (JRH)

Dolson, David A.; And Others

1995-01-01

105

Textbook Forum: Equilibrium Constants of Chemical Reactions Involving Condensed Phases: Pressure Dependence and Choice of Standard State.  

ERIC Educational Resources Information Center

Problems of equilibria in condensed phases (particularly those involving solutes in dilute solutions) are encountered by students in their laboratory work; the thermodynamics of these equilibria is neglected in many textbooks. Therefore, several aspects of this topic are explored, focusing on pressure dependence and choice of standard state. (JN)

Perlmutter-Hayman, Berta

1984-01-01

106

DNA condensation  

Microsoft Academic Search

Recent progress in our understanding of DNA condensation includes the observation of the collapse of single DNA molecules, greater insights into the intermolecular forces driving condensation, the recognition of helix-structure perturbation in condensed DNA, and the increasing recognition of the likely biological consequences of condensation. DNA condensed with cationic liposomes is an efficient agent for the transfection of eukaryotic cells,

Victor A Bloomfield

1996-01-01

107

Alcohol dehydration: Mechanism of ether formation using an alumina catalyst  

SciTech Connect

Ether formation during the dehydration of secondary alcohols, namely, 2-butanol, 3-pentanol, and 1-cyclopentylethanol, was investigated. Using the proper reaction conditions, the yield of di-2-butyl ether during the dehydration of 2-butanol on alumina can be as high as 40%. That ether is formed by adding an alcohol to the alkene is ruled out by the results from deuterium tracer studies. Results from experiments using S(+)- 2-butanol suggest that the formation of di-2-butyl ether occurs by a S{sub N}2-type mechanism. 33 refs., 5 figs., 3 tabs.

Shi, B.; Davis, B.H. [Univ. of Kentucky, Lexington, KY (United States)] [Univ. of Kentucky, Lexington, KY (United States)

1995-12-01

108

Dehydration of glycerol over niobia-supported silicotungstic acid catalysts.  

PubMed

Liquid-phase dehydration of glycerol to acrolein over nanosized niobia-supported silicotungstic acid catalysts was performed to investigate the effect of the silicotungstic acid loading on the catalytic performance of the catalysts. The catalysts were prepared by following an impregnation method with different HSiW loadings in the range of 10-50 wt%. The prepared catalysts were characterized by N2 physisorption, XRD, FT-IR, TPD of ammonia, and TGA. Dehydration of glycerol was conducted in an autoclave reactor under the conditions of controlled reaction temperatures under corresponding pressure. Increasing HSiW loading rapidly increased the acidity of HSiW/Nb205 catalyst and rate of glycerol conversion, but acrolein selectivity decreased due to enhanced deactivation of the catalyst by carbon deposit. Consequently, it was confirmed that catalytic activity for the dehydration of glycerol to acrolein was dependant on the acidity of catalyst and can be controlled by HSiW loading. PMID:23646735

Lee, Young Yi; Ok, Hye Jeong; Moon, Dong Ju; Kim, Jong Ho; Park, Nam Cook; Kim, Young Chul

2013-01-01

109

Dehydration Kinetics of Volterra Gypsum: Experiments and Overview  

NASA Astrophysics Data System (ADS)

Dehydration reactions are often envisaged as a triggering mechanism for seismicity in rocks under tectonic loads due to the reduction in effective pressure during the release of fluids that may eventually produce mechanical embrittlement. Understanding of metamorphic transformation in deforming rocks is even more important in fault zones where periods of seismic slip are reported. Dehydration of gypsum under controlled conditions, in laboratory experiments and in numerical models, provides information on deformation processes operating in seismically active regions and may be of help in understanding their cyclicity and their evolution. Two series of simple heating experiments of Volterra gypsum samples at room pressure, using intact and powdered specimens, provide reference data for further experiments under confining and differential stress during dehydration. Heating experiments were run at constant temperature between 80 degC and 140 °C in intact specimens and at 86 °C and 97 °C using powders with five different grain size fractions: <0.063, 0.063-0.125, 0.125-0.25, 0.25-0.5 and >0.5 mm. The complete dehydration of 1 mol of gypsum produces 1 mol of anhydrite and two moles of water generating a porosity of about 38% and implying a weight loss of 21% upon removal of water. The progressive loss of weight during dehydration was used as the method to estimate the progress of the reaction. The reaction is characterized by an initial stage under 10% reaction were reaction rate accelerates, which is followed by a linear stage for about 50 to 70% of the reaction and a final third stage with decelerating reaction rates. All tests run above 85 °C reached about 90% reaction. Those below 85 °C seem to converge to a lower final fraction (75%) suggesting partial dehydration, very likely to bassanite. The temperature dependence of the linear rates indicates in an Arrhenius plot that the full dehydration of gypsum has an activation enthalpy of 96 kJ/mol. The two temperatures tested with powdered specimens are consistent with this activation enthalpy, although the higher intercepts with the y-axis indicate that reaction rates are about one order of magnitude faster. This is interpreted in relation to the very large initial porosity of the un-compacted specimens (>45% porosity). There is an additional increase in rates in powdered specimens as the grain size decreases, however, the difference is marginal despite the eight-times difference in grain size. At laboratory deformation rates, gypsum behaves in a brittle-ductile mode by a mixture of plasticity (twinning) and cataclasis in discrete and short-lived bands. A first series of deformation tests on dry gypsum have also been run to set a reference for mechanical behaviour to be compared in the future with behaviour during syn-tectonic dehydration. The deformation tests were run at room temperature, at strain rates of 2x10-5s-1 and confining pressures of 13, 50, 100, 146, 190 MPa. Tests were run in a triaxial rig using 20 mm diameter by 45 mm length specimens. Stress-strain curves show well-defined yield points and an almost straight plastic behaviour with a slight strain hardening component, similar to previous work. Stress-strain curves have minor, episodic and short-lived stress drops that have been related with the development of cataclastic bands (Milsch and Scholz, 2005). The grain fracturing associated with the generation of these cataclastic bands during experimental deformation of gypsum will have an effect in the dehydration kinetics by providing fined-grained gypsum and thus high surface area to speed up the reaction.

Llana-Funez, S.; Wheeler, J.; Faulkner, D.

2007-12-01

110

Artificially dehydrated lucerne for horses  

Microsoft Academic Search

Artificially dehydrated lucerne produced in the United Kingdom has been shown to be a better source of nutrients for horses than grass hay. Horses eat more lucerne when it is pelleted, and the processing has little effect on its nutritive value. Lucerne does not appear to contain any antinutritional factors of significance to horses. Lucerne contains readily available calcium and

D Cuddeford

1994-01-01

111

Dehydration and the dying patient  

Microsoft Academic Search

This study investigated the relationship between symptoms and dehydration in 82 subjects with malignant disease. Assessment of respiratory tract secretions, thirst, and dry mouth were made during the dying phase, and serum biochemistry was analyzed. Follow-up data were also collected when the patient died. The median time from entry into the study until death was 2 days. All subjects died

John E. Ellershaw; Jane M. Sutcliffe; Cicely M. Saunders

1995-01-01

112

Bifunctional building blocks in the Ugi-azide condensation reaction: A general strategy toward exploration of new molecular diversity†  

PubMed Central

1,5-disubstituted tetrazoles are an important drug-like scaffold known for their ability to mimic the cis-amide bond conformation. The scaffold is readily accessible via substitution of the carboxylic acid component of the Ugi multi-component reaction (MCR) with TMSN3 in what is herein denoted the Ugi-azide reaction. This full paper presents a concise, novel, general strategy to access a plethora of new heterocylic scaffolds utilizing tethered aldo/keto-acids/esters in the Ugi-azide reaction followed by a ring closing event that generates novel highly complex bis-heterocyclic lactam-tetrazoles. PMID:23912086

Gunawan, Steven; Hulme, Christopher

2013-01-01

113

Enhancement of the promiscuous aldolase and dehydration activities of 4-oxalocrotonate tautomerase by protein engineering.  

PubMed

Double play: The enzyme 4-oxalocrotonate tautomerase (4-OT) catalyzes not only the initial cross-coupling of acetaldehyde and benzaldehyde to yield 3-hydroxy-3-phenylpropanal, but also the subsequent dehydration of this aldol compound to yield cinnamaldehyde as the final product. Mechanism-inspired engineering provided an active site mutant (F50A) with strongly enhanced aldol condensation activity. PMID:22615135

Zandvoort, Ellen; Geertsema, Edzard M; Quax, Wim J; Poelarends, Gerrit J

2012-06-18

114

Distortions in the photocycle of bacteriorhodopsin at moderate dehydration.  

PubMed Central

The photoreaction of bacteriorhodopsin was studied in moderately dehydrated films (relative humidities between 100 and 65%). Time-resolved difference spectra from a gated optical multichannel analyzer, between 100 ns and 100 ms after photoexcitation, were decomposed into sums of difference spectra of the intermediates K, L, M, N, and O, and the kinetics obtained were fitted to various alternative schemes. The data confirm the model of a single reaction sequence with reversible reactions we proposed recently for purple membrane suspensions (Váró, G., and J. K. Lanyi. Biochemistry. 1990. 29:2241-2250) but including reversibility also for the reaction K in equilibrium with L in addition to L in equilibrium with M, M in equilibrium with N, and N in equilibrium with O. With increasing dehydration the kinetics were increasingly dominated by the reverse reactions. As before, fitting the data required the existence of two M species in series: L in equilibrium with M1 in equilibrium with M2 in equilibrium with N. The M1 in equilibrium with M2 reaction was greatly slowed at lower humidities. This step might be the switch for the unidirectional transfer of protons. With increasing dehydration recovery of BR occurred less and less via the N intermediate and increasingly via direct shunts from the two M species. As indicated earlier by electrical measurements with similarly dried bacteriorhodopsin films (Váró, G., and L. Keszthelyi, 1983. Biophys. J. 43:47-51). The latter are pathways not necessarily associated with net proton translocation. PMID:2009355

Váró, G; Lanyi, J K

1991-01-01

115

Dehydration History of Subducted Lithologies, Sifnos, Greece  

NASA Astrophysics Data System (ADS)

Garnet-forming reactions in subduction zones may be linked directly to dehydration. When coupled with precise zoned garnet geochronology, this permits quantification of H2O release rates and evaluation of models for progressive metamorphism (and thus dehydration) in subduction zones. Here, an integrated geochronologic and thermodynamic analysis seeks to determine the devolatization history of subducted lithologies from Sifnos, Greece, in the Attic Cycladic Blueschist Belt. Based on major element zoning, microsampling and Sm-Nd dating of chemically zoned garnets (greater than 1cm in diameter) from various lithologies, we constrain the rates and duration of garnet growth. Combined with bulk garnet analyses on several other samples where crystals were not sufficiently large for age zoning work, a chronology of garnet growth across all lithologies was constructed. After the slow initiation of garnet growth recorded by one 5cm crystal from a quartzofeldspathic gneiss (the innermost 1cm, radially, grew from 52.7 ± 3.3Ma to 47.19 ± 0.21 Ma), relatively rapid growth prevailed from 45.92 ± 0.18 Ma to 45.63 ± 0.22 Ma for the outermost 0.9 cm of the crystal. This equates to acceleration in volumetric growth rate of two orders of magnitude. In addition, garnet ages from six intermediate to mafic garnet-bearing lithologies span 46.48 ± 0.82 Ma to 43.90 ± 1.92 Ma, at least one of which (a mafic blueschist) indicates growth spanning just hundreds of thousands of years. Analysis of the garnet-forming reaction(s) provides information on the stoichiometric ratio between garnet produced and water released. For a range of bulk rock compositions, we find that garnet:water molar production ratios vary from approximately 0.4:1 to 1.2:1, depending mostly on the portion of the P-T path over which reaction occurs, the bulk composition, and the hydrous phases from which garnet forms. Hydrous phases contributing to garnet growth and water release typically include chloritoid, lawsonite, epidote/clinozoisite, chlorite and Na-amphibole. Published studies arrive at maximum pressures and temperatures for these Sifnos rocks ranging from 1.8 to 2.3 GPa and 500-580 C. New phase equilibria (pseudosection) modeling of the varied lithologies in this study further constrain their P-T paths, linking garnet growth (and related dehydration) to geodynamic conditions during subduction. Early slow growth in the large garnet from the quartzofeldspathic rock initiates during burial (as P and T continue to increase) at ca. 53 Ma. Later, between ca. 46 and 44 Ma, rapid growth of garnet in both the quartzfeldspathic rock and more mafic lithologies occurs during near isobaric heating and/or decompression of the system, during which the subducted unit may already have detached from the slab, incurring rapid mineral growth, and concomitant dehydration.

Dragovic, B.; Baxter, E. F.; Caddick, M. J.

2011-12-01

116

CONDENSED MATTER: STRUCTURE, THERMAL AND MECHANICAL PROPERTIES: Nanoporous AlN particle production from a solid-state metathesis reaction  

NASA Astrophysics Data System (ADS)

This paper reports that nanoporous AlN particles are synthesized from solid-state metathesis reactions using AlCl3 and Mg3N2 as reactants. The samples are characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction, high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible (UV-vis) absorption spectroscopy and Raman spectroscopy. The results show that samples with walls 10 nm in thickness and pores between 10 nm and 100 nm in diameter were produced successfully from these reactions, and their band gap and vibration modes agree with those of AlN bulk crystal.

Yan, Guo-Jun; Chen, Guang-De; Wu, Ye-Long

2009-07-01

117

Condensed Matter Cluster Reactions in LENR Power Cells for a Radical New Type of Space Power Source  

Microsoft Academic Search

This paper reviews previous theoretical and experimental study on the possibility of nuclear events in multilayer thin film electrodes (Lipson &etal;, 2004 and 2005; Miley &etal;, 2007), including the correlation between excess heat and transmutations (Miley and Shrestha, 2003) and the cluster theory that predicts it. As a result of this added understanding of cluster reactions, a new class of

Xiaoling Yang; George H. Miley; Heinz Hora

2009-01-01

118

Steam generators, turbines, and condensers. Volume six  

SciTech Connect

Volume six covers steam generators (How steam is generated, steam generation in a PWR, vertical U-tube steam generators, once-through steam generators, how much steam do steam generators make.), turbines (basic turbine principles, impulse turbines, reaction turbines, turbine stages, turbine arrangements, turbine steam flow, steam admission to turbines, turbine seals and supports, turbine oil system, generators), and condensers (need for condensers, basic condenser principles, condenser arrangements, heat transfer in condensers, air removal from condensers, circulating water system, heat loss to the circulating water system, factors affecting condenser performance, condenser auxiliaries).

Not Available

1986-01-01

119

Washing Machine Dehydration Dynamics Analysis  

Microsoft Academic Search

This paper presents how an FEA model using MSC.NASTRAN was developed to simulate dehydration dynamics of a washing machine with spinning basket rotating about vertical axis. Gyroscopic effect centrifugal forces and self?balancing mechanism (liquid balancer associated with rotating structures were considered in the simulation. Using the model frequency response analysis was performed to simulate response of non?rotating structures in operating

Morio MITSUISHI Morio MITSUISHI; Changmin SONG Changmin SONG; Changmin SAMSUNG; Changsub KIM; Changsub SAMSUNG

120

Acid-catalyzed condensed-phase reactions of limonene and terpineol and their impacts on gas-to-particle partitioning in the formation of organic aerosols.  

PubMed

We investigated the condensed-phase reactions of biogenic VOCs with C double bond C bonds (limonene, C(10)H(16), and terpineol, C(10)H(18)O) catalyzed by sulfuric acid by both bulk solution (BS) experiments and gas-particle (GP) experiments using a flow cell reactor. Product analysis by gas chromatography-mass spectrometry (GC-MS) showed that cationic polymerization led to dimeric and trimeric product formation under conditions of relative humidity (RH) <20% (in the GP experiments) and a sulfuric acid concentration of 57.8 wt % (in the BS experiments), while hydration occurred under conditions of RH > 20% (in the GP experiments) and sulfuric acid concentrations of 46.3 wt % or lower (in the BS experiments). Apparent partitioning coefficients (K(p,rxn)) were estimated from the GP experiments by including the reaction products. Only under extremely low RH conditions (RH < 5%) did the values of K(p,rxn) ( approximately 5 x 10(-6) m(3)/microg for limonene and approximately 2 x 10(-5) m(3)/microg for terpineol) substantially exceed the physical partitioning coefficients (K(p) = 6.5 x 10(-8) m(3)/microg for limonene and =2.3 x 10(-6) m(3)/microg for terpineol) derived from the absorptive partitioning theory. At RH higher than 5%, the apparent partitioning coefficients (K(p,rxn)) of both limonene and terpineol were in the same order of magnitude as the K(p) values derived from the absorptive partitioning theory. Compared with other conditions including VOC concentration and degree of neutralization (by ammonium) of acidic particles, RH is a critical parameter that influences both the reaction mechanisms and the uptake ability (K(p,rxn) values) of these processes. The finding suggests that RH needs to be considered when taking the effects of acid-catalyzed reactions into account in estimating organic aerosol formation from C double bond C containing VOCs. PMID:20550185

Li, Yong Jie; Cheong, Gema Y L; Lau, Arthur P S; Chan, Chak K

2010-07-15

121

Towards the sustainable production of acrolein by glycerol dehydration.  

PubMed

The massive increase in biodiesel production by transesterification of vegatable oils goes hand-in-hand with the availability of a large volume of glycerol, which must be valorized. Glycerol dehydration to acrolein over acid catalysts is one of the most promising ways of valorization, because this compound is an important chemical intermediate used in, for example, the DL-methionine synthesis. In this Minireview, we give a detailed critical view of the state-of-the-art of this dehydration reaction. The processes developed in both the liquid and the gas phases are detailed and the best catalytic results obtained so far are reported as a benchmark for future developments. The advances on the understanding of the reaction mechanism are also discussed and we further focus particularly on the main obstacles for an immediate industrial application of this technology, namely catalyst coking and crude glycerol direct-use issues. PMID:19693786

Katryniok, Benjamin; Paul, Sébastien; Capron, Mickaël; Dumeignil, Franck

2009-01-01

122

Kinetic study of the thermal dehydration of borogypsum.  

PubMed

In Turkey, a large amount of borogypsum waste is discharged by the economically important boric acid industry. Calcination of this waste provides a promising technique not only for recovering an economic value but also for reducing its environmental impact. The aim of this work is to study the thermal behavior of borogypsum, which contains gypsum crystals, boron oxide and some impurities under nonisothermal conditions in air atmosphere by using thermogravimetry and differential thermal analysis techniques (TG-DTA). Experiments were carried out at temperatures ranging from ambient to 773 K at different heating rates. The temperatures of conversion from gypsum to hemihydrate and anhydrite states were determined. Various methods were used to analyze the TG and DTA data for determination of reaction kinetics. The activation energy and frequency factor were calculated for dehydration of borogypsum. Activation energy values of the main dehydration reaction of borogypsum were calculated to be approximately 95-114 kJ mol(-1). PMID:15561369

Elbeyli, Iffet Yakar; Pi?kin, Sabriye

2004-12-10

123

Functional Identification of the General Acid and Base in the Dehydration Step of Indole-3-glycerol Phosphate Synthase Catalysis*  

PubMed Central

The tryptophan biosynthetic enzyme indole-3-glycerol phosphate synthase is a proposed target for new antimicrobials and is a favored starting framework in enzyme engineering studies. Forty years ago, Parry proposed that the enzyme mechanism proceeds through two intermediates in a series of condensation, decarboxylation, and dehydration steps. X-ray crystal structures have suggested that Lys-110 (numbering according to the Sulfolobus solfataricus enzyme) behaves as a general acid both in the condensation and dehydration steps, but did not reveal an efficient pathway for the reprotonation of this critical residue. Our mutagenesis and kinetic experiments suggest an alternative mechanism whereby Lys-110 acts as a general acid in the condensation step, but another invariant residue, Lys-53, acts as the general acid in the dehydration step. These studies also indicate that the conserved residue Glu-51 acts as the general base in the dehydration step. The revised mechanism effectively divides the active site into discrete regions where the catalytic surfaces containing Lys-110 and Lys-53/Glu-51 catalyze the ring closure (i.e. condensation and decarboxylation) and dehydration steps, respectively. These results can be leveraged toward the development of novel inhibitors against this validated antimicrobial target and toward the rational engineering of the enzyme to produce indole derivatives that are highly prized by the pharmaceutical and agricultural industries. PMID:23900843

Zaccardi, Margot J.; Yezdimer, Eric M.; Boehr, David D.

2013-01-01

124

The physiological effects of dehydration caused by sweat loss. [athletes  

NASA Technical Reports Server (NTRS)

The mechanisms of fluid loss in the human body while sweating due to physical exercise are discussed. Trained and untrained persons were examined and compared. Since sweat is hypotonous, a disruption in the hydrosalinic balance occurs; the consequences of this finding, also pertaining to the fluid and electrolytic substitution, are presented. Further explanations on the problem of dehydration refer to reactions of individual organ systems, to alterations in bodily capabilities as well as to questions relating to sex and age.

Israel, S.

1981-01-01

125

Condensed Matter Cluster Reactions in LENR Power Cells for a Radical New Type of Space Power Source  

NASA Astrophysics Data System (ADS)

This paper reviews previous theoretical and experimental study on the possibility of nuclear events in multilayer thin film electrodes (Lipson et al., 2004 and 2005; Miley et al., 2007), including the correlation between excess heat and transmutations (Miley and Shrestha, 2003) and the cluster theory that predicts it. As a result of this added understanding of cluster reactions, a new class of electrodes is under development at the University of Illinois. These electrodes are designed to enhance cluster formation and subsequent reactions. Two approaches are under development. The first employs improved loading-unloading techniques, intending to obtain a higher volumetric density of sites favoring cluster formation. The second is designed to create nanostructures on the electrode where the cluster state is formed by electroless deposition of palladium on nickel micro structures. Power units employing these electrodes should offer unique advantages for space applications. This is a fundamental new nuclear energy source that is environmentally compatible with a minimum of radiation involvement, high specific power, very long lifetime, and scalable from micro power to kilowatts.

Yang, Xiaoling; Miley, George H.; Hora, Heinz

2009-03-01

126

Condensed Matter Cluster Reactions in LENR Power Cells for a Radical New Type of Space Power Source  

SciTech Connect

This paper reviews previous theoretical and experimental study on the possibility of nuclear events in multilayer thin film electrodes (Lipson et al., 2004 and 2005; Miley et al., 2007), including the correlation between excess heat and transmutations (Miley and Shrestha, 2003) and the cluster theory that predicts it. As a result of this added understanding of cluster reactions, a new class of electrodes is under development at the University of Illinois. These electrodes are designed to enhance cluster formation and subsequent reactions. Two approaches are under development. The first employs improved loading-unloading techniques, intending to obtain a higher volumetric density of sites favoring cluster formation. The second is designed to create nanostructures on the electrode where the cluster state is formed by electroless deposition of palladium on nickel micro structures. Power units employing these electrodes should offer unique advantages for space applications. This is a fundamental new nuclear energy source that is environmentally compatible with a minimum of radiation involvement, high specific power, very long lifetime, and scalable from micro power to kilowatts.

Yang Xiaoling; Miley, George H.; Hora, Heinz [University of Illinois Urbana-Champaign, NPL Associates, Urbana, IL 217-333-3772 (United States); Department of Theoretical Physics Univ. of New South Wales Sydney (Australia)

2009-03-16

127

A dehydration mechanism for the stratosphere  

NASA Technical Reports Server (NTRS)

Although mean circulations are generally credited with dehydration of the earth's stratosphere, convective instability in the tropics converts mean circulations to small residuals of local convective circulations. The effects of large cumulonimbus which penetrate the stratosphere and form huge anvils in the lower stratosphere are discussed with respect to hydration and dehydration of the stratosphere. Radiative heating at anvil base combined with cooling at anvil top drives a dehydration engine considered essential to explain the dry stratosphere. Seasonal and longitudinal variations in dehydration potentials are examined with maximum potential attributed to Micronesian area during winter and early spring.

Danielsen, E. F.

1982-01-01

128

Image analysis of osmotically dehydrated fruits: melons dehydration in a ternary system  

Microsoft Academic Search

Osmotic dehydration represents a technological alternative to reduce post-harvest losses of fruits. In this work, the osmotic\\u000a dehydration of a ternary system (water\\/sugar\\/salt) was investigated for melon (Curcumis melo L.) dehydration using image analysis. Three kinds of sugars were used to formulate the osmotic solutions: sucrose, glucose\\u000a and manitol. The process of osmotic dehydration was studied and the effects of

Sueli Rodrigues; Fabiano A. N. Fernandes

2007-01-01

129

Dehydration of different ketoses and aldoses to 5-hydroxymethylfurfural.  

PubMed

5-Hydroxymethylfurfural (HMF) is considered an important building block for future bio-based chemicals. Here, we present an experimental study using different ketoses (fructose, sorbose, tagatose) and aldoses (glucose, mannose, galactose) under aqueous acidic conditions (65 g L(-1) substrate, 100-160?°C, 33-300 mM H2 SO4 ) to gain insights into reaction pathways for hexose dehydration to HMF. Both reaction rates and HMF selectivities were significantly higher for ketoses than for aldoses, which is in line with literature. Screening and kinetic experiments showed that the reactivity of the different ketoses is a function of the hydroxyl group orientation at the C3 and C4 positions. These results, in combination with DFT calculations, point to a dehydration mechanism involving cyclic intermediates. For aldoses, no influence of the hydroxyl group orientation was observed, indicating a different rate-determining step. The combination of the knowledge from the literature and the findings in this work indicates that aldoses require an isomerization to ketose prior to dehydration to obtain high HMF yields. PMID:24039165

van Putten, Robert-Jan; Soetedjo, Jenny N M; Pidko, Evgeny A; van der Waal, Jan C; Hensen, Emiel J M; de Jong, Ed; Heeres, Hero J

2013-09-01

130

Bismuth(III)-catalyzed dehydrative etherification and thioetherification of phenolic hydroxy groups.  

PubMed

Use of a bismuth catalyst allowed efficient dehydrative substitution of phenolic hydroxy groups with alcohols and thiols to form C-O and C-S bonds. The reaction required equimolar amounts of two readily available substrates that generated H(2)O as the only byproduct. The relatively mild reaction conditions were compatible with the functional groups selected, and provided excellent chemoselectivity. PMID:25007290

Murai, Masahito; Origuchi, Kazuki; Takai, Kazuhiko

2014-07-18

131

Amine catalyzed condensation of tetraethylorthosilicate  

NASA Technical Reports Server (NTRS)

The catalysis of the condensation of hydrolyzed metal alkoxides by amines has been mentioned in the literature, but there has been no systematic study of their influence on the rate of the condensation reaction of the alkoxide and the microstructure of the resultant gel.

Jones, S.

2001-01-01

132

Spectral effects of dehydration on phyllosilicates  

NASA Technical Reports Server (NTRS)

Six phyllosilicates were progressively dehydrated under controlled conditions in an effort to study the spectral effects of their dehydration. The spectra obtained at each level of hydration provide information that may be used in future spectroscopic observations of the planets, as well as a data set which compliments the existing body of terrestrial soil knowledge.

Bruckenthal, E. A.; Singer, R. B.

1987-01-01

133

Nonconventional Hydrolytic Dehalogenation of 1-Chlorobutane by Dehydrated Bacteria  

E-print Network

Nonconventional Hydrolytic Dehalogenation of 1-Chlorobutane by Dehydrated Bacteria in a Continuous for Xanthobacter autotrophicus). After dehydration, these bacteria can catalyze the hy- drolytic dehalogenation of dehydrated Xantho- bacter autotrophicus cells is different from that observed with Rhododcoccus erythropolis

Paris-Sud XI, Université de

134

Artificially dehydrated lucerne for horses.  

PubMed

Artificially dehydrated lucerne produced in the United Kingdom has been shown to be a better source of nutrients for horses than grass hay. Horses eat more lucerne when it is pelleted, and the processing has little effect on its nutritive value. Lucerne does not appear to contain any antinutritional factors of significance to horses. Lucerne contains readily available calcium and protein and can thus be used as a cereal-balancer or to upgrade poor quality roughages. Because lucerne is a good source of digestible nutrients it has therapeutic applications, including the correction of electrolyte imbalances and hoof horn problems, and it can be used for intragastric nutrition and for feeding old horses. PMID:7846834

Cuddeford, D

1994-10-29

135

Bronsted Acid Catalyzed Dehydration of Neat Supercritical tert-Butanol in a Capillary Micro-Reactor  

SciTech Connect

Dehydration of supercritical t-butanol to yield 2-methyl-propene was observed to occur rapidly and in high yield at elevated pressures without addition of a catalyst. A capillary micro-reactor was used to carry out the reaction at pressures up to 3.1 kbar. The products were characterized in-situ using FTIR, GC-MS and NMR. The dehydration reaction is proposed to occur by a self-catalyzed Bronsted acid mechanism. An addition driving force for the reaction was the phase separation of the 2-methyl-propene product. Self-catalyzed dehydration of t-butanol is a limiting factor for operations in supercritical t-butanol, but it implies the t-butanol may be employed as a self-neutralizing catalyst under these conditions.

Henry, Matthew C.; Yonker, Clement R.

2006-02-01

136

Dehydration Processes of Sugar Glasses and Crystals  

NASA Astrophysics Data System (ADS)

The dehydration processes of sugar glasses and sugar crystals were studied by using Thermogravimetry — Differential Thermal Analysis method. We used three monosaccharide sugars (fructose, galactose, and glucose) and three disaccharide sugars (sucrose, maltose and trehalose). It was found that a trehalose showed different dehydration process compared to the other sugars. The amount of mass reductions in sugar glasses is larger than that in sugar crystals. However, in the case of trehalose, the amount of mass reduction in trehalose glasses is smaller than that in trehalose crystals. It seems to be possible that this unique dehydration property of trehalose glasses maybe relate to the cell protection ability during an anhydrobiosis process.

Seo, Jeong-Ah; Kwon, Hyun-Joung; Kim, Hyung Kook; Hwang, Yoon-Hwae

2006-05-01

137

Charged Condensation  

E-print Network

We consider Bose-Einstein condensation of massive electrically charged scalars in a uniform background of charged fermions. We focus on the case when the scalar condensate screens the background charge, while the net charge of the system resides on its boundary surface. A distinctive signature of this substance is that the photon acquires a Lorentz-violating mass in the bulk of the condensate. Due to this mass, the transverse and longitudinal gauge modes propagate with different group velocities. We give qualitative arguments that at high enough densities and low temperatures a charged system of electrons and helium-4 nuclei, if held together by laboratory devices or by force of gravity, can form such a substance. We briefly discuss possible manifestations of the charged condensate in compact astrophysical objects.

Gregory Gabadadze; Rachel A. Rosen

2007-06-15

138

Zinc oxide as an economical and efficient catalyst for the one-pot preparation of ?-acetamido ketones via a four-component condensation reaction  

Microsoft Academic Search

A new, efficient, one-pot, four-component condensation of benzaldehyde derivatives, acetophenone derivatives, acetyl chloride and acetonitrile in the presence of zinc oxide as catalyst is described for the synthesis of ?-acetamido ketones.

Malek Taher Maghsoodlou; Asadollah Hassankhani; Hamid Reza Shaterian; Sayyed Mostafa Habibi-Khorasani; Elaheh Mosaddegh

2007-01-01

139

Dehydrated Lanthanum-exchanged Type Y Zeolite  

Microsoft Academic Search

Lanthanum atoms occupy different sites in the crystal structure of dehydrated type Y zeolite as the temperature changes, probably because of the absence of residual molecules for bonding at 725° C compared with their presence at lower temperatures.

J. V. Smith; J. M. Bennett; E. M. FLANIGEN

1967-01-01

140

Observations of denitrification and dehydration in the winter polar stratospheres  

NASA Technical Reports Server (NTRS)

It is argued that denitrification of the Arctic stratosphere can be explained by the selective growth and sedimentation of aerosol particles rich in nitric acid. Because reactive nitrogen species moderate the destruction of ozone by chlorine-catalyzed reactions by sequestering chlorine in reservoir species such as ClONO2, the possibility of the removal of reactive nitrogen without dehydration should be allowed for in attempts to model ozone depletion in the Arctic. Indeed, denitrification along with elevated concentrations of reactive chlorine observed in 1989 indicate that the Arctic was chemically primed for ozone destruction without an extended period of temperatures below the frost point, as is characteristic of the Antarctic.

Fahey, D. W.; Kelly, K. K.; Kawa, S. R.; Tuck, A. F.; Loewenstein, M.

1990-01-01

141

Linked strategy for the production of fuels via formose reaction.  

PubMed

Formose reaction converts formaldehyde to carbohydrates. We found that formose reaction can be used linking the biomass gasification with the aqueous-phase processing (APP) to produce liquid transportation fuel in three steps. First, formaldehyde from syn-gas was converted to triose. This was followed by aldol condensation and dehydration to 4-hydroxymethylfurfural (4-HMF). Finally, 4-HMF was hydrogenated to produce 2,4-dimethylfuran (2,4-DMF) or C(9)-C(15) branched-chain alkanes as liquid transportation fuels. In the linked strategy, high energy-consuming pretreatment as well as expensive and polluting hydrolysis of biomass were omitted, but the high energy recovery of APP was inherited. In addition, the hexoketoses via formose reaction could be converted to HMFs directly without isomerization. A potential platform molecule 4-HMF was formed simultaneously in APP. PMID:23393625

Deng, Jin; Pan, Tao; Xu, Qing; Chen, Meng-Yuan; Zhang, Ying; Guo, Qing-Xiang; Fu, Yao

2013-01-01

142

Neuropsychological Performance, Postural Stability, and Symptoms After Dehydration  

Microsoft Academic Search

Context: Dehydration and concussion are common in athletic performance. Some experts have speculated that dehydration may negatively influence performance on tests commonly used for concussion assessment. Objective: To determine how the signs and symptoms, neu- ropsychological performance, and postural stability are affected by dehydration. Design: Repeated-measures design assessing subjects in the euhydrated and dehydrated conditions. Setting: Sports Medicine Research Laboratory.

Akshay V. Patel; Jason P. Mihalik; Andrew J. Notebaert; Kevin M. Guskiewicz; William E. Prentice

143

Instrument for Determining Depth of Dehydration of Frozen Fish  

E-print Network

Instrument for Determining Depth of Dehydration of Frozen Fish JOHN G. CALLAN and JOHN J. RYAN defect the presence of dehydration. It is considered a quality defect both because product weight is lost of the dehydration and the area affected. To date, the depth of dehydration has been determined by scraping the dehy

144

Efficient and selective dehydration of fructose to 5-hydroxymethylfurfural catalyzed by Brønsted-acidic ionic liquids.  

PubMed

The dehydration of D-fructose and glucose has been studied with acidic ionic liquids as catalysts. A series of Brønsted-acidic ionic liquids has been synthesized and tested in the dehydration of D-fructose. The results showed that N-methyl-2-pyrrolidonium methyl sulfonate [NMP](+)[CH(3)SO(3)](-) and N-methyl-2-pyrrolidonium hydrogen sulfate [NMP](+)[HSO(4)](-) have high catalytic activity. Highly efficient and selective dehydration of D-fructose to 5-hydroxymethylfurfural (HMF) was achieved in dimethyl sulfoxide (DMSO) under mild conditions. For example, a 72.3 % yield of HMF with 87.2 % selectivity were obtained for 2 h at 90 degrees C in the presence of 7.5 mol % [NMP](+)[CH(3)SO(3)](-). The effects of the reaction temperature, time, and solvent were investigated in detail. The catalyst and solvent can be recycled for the dehydration of D-fructose. The Hammett method was used to determine the acidities of these ionic liquids, which indicated that the acidity and molecular structure have strong effects on the catalytic activity of ionic liquids. Based on the experimental results, a possible reaction mechanism for the dehydration of D-fructose is proposed. PMID:20082406

Tong, Xinli; Li, Yongdan

2010-03-22

145

Dehydration of 2-Methylbutanal and Methyl Isopropyl Ketone to Isoprene Using Boron and Aluminium Phosphate Catalysts  

Microsoft Academic Search

The synthesis of isoprene from the dehydration of 2-methylbutanal is described using boron phosphate, aluminium phosphate, and mixed boron\\/aluminium phosphates as catalysts. Both boron phosphate and aluminium phosphate deactivate steadily with reaction time due to loss of catalyst activity but the selectivity to isoprene is not significantly affected by catalyst deactivation. Catalyst deactivation is shown to be due to two

Graham J. Hutchings; Ian D. Hudson; Donald Bethell; Don G. Timms

1999-01-01

146

Dropwise condensation  

PubMed Central

Dropwise condensation of water vapor from a naturally cooling, hot water reservoir onto a hydrophobic polymer film and a silanized glass slide was studied by direct observation and simulations. The observed drop growth kinetics suggest that smallest drops grow principally by the diffusion of water adsorbed on the substrate to the drop perimeter, while drops larger than 50 ?m in diameter grow principally by direct deposition from the vapor onto the drop surface. Drop coalescence plays a critical role in determining the drop size distribution, and stimulates the nucleation of new, small drops on the substrates. Simulations of drop growth incorporating these growth mechanisms provide a good description of the observed drop size distribution. Because of the large role played by coalescence, details of individual drop growth make little difference to the final drop size distribution. The rate of condensation per unit substrate area is especially high for the smallest drops, and may help account for the high heat transfer rates associated with dropwise condensation relative to filmwise condensation in heat exchange applications. PMID:17014129

Leach, R. N.; Stevens, F.; Langford, S. C.; Dickinson, J. T.

2008-01-01

147

Dehydration kinetics of talc at 1 bar  

NASA Technical Reports Server (NTRS)

Experimental results on the dehydration kinetics of talc, which is likely to be a major potential resource for water and hydrogen in carbonaceous chondrites, is presented. The rate of dehydration of an essentially pure Mg-end member natural talc, (Mg(.99)Fe(.01))3Si4O10(OH)2, was studied by measuring in situ weight change under isothermal condition at 1 bar as a function of time in the temperature range 775 to 985 C. The grain size of the starting material was 0.7 to 1 micron. It was found that the data up to 50 to 60 percent dehydration can be fitted by an equation of the form alpha = exp(-Kt(exp n)), where alpha is the weight fraction of talc remaining, K is a rate constant and n is a numerical constant for a given temperature. For any set of isothermal data, there is a major change in the value of n for larger dehydration. For up to approximately 50 percent dehydration, all rate constants can be described by an Arrheniun relation with an activation energy of 432 (+/- 30) kJ/mol; n has a nearly constant value of 0.54 between 775 and 875 C, but increases almost linearly according to n = -10.77 + 0.012T C at T greater than or equal to 875 C.

Ganguly, J.; Bose, K.

1991-01-01

148

Structural characterization and dehydration kinetics of Kirka inderite mineral: Application of non-isothermal models  

SciTech Connect

Coats-Redfern, Arrhenius, Ozawa, Kissinger, and Doyle non-isothermal kinetic models were used to calculate the dynamic kinetic parameters for dehydration reaction of Mg-borate mineral, inderite (Kirka - Turkey) based on thermogravimetric analysis, derivative thermogravimetric analysis and differential thermal analysis. Dehydration experiments were carried out at different heating rates of 2, 5, 10, 15, and 20 deg. C/min in a pure nitrogen atmosphere. Structural and morphological properties have been characterized by X-Ray diffraction, Fourier transform-infrared spectroscopy, Scanning electron microscopy-energy dispersive spectroscopy, and Inductively coupled plasma-optical emission spectroscopy techniques.

Figen, Aysel Kantuerk, E-mail: akanturk@yildiz.edu.tr [Yildiz Technical University, Department of Chemical Engineering, Davutpasa Campus., N.127, Esenler, Istanbul (Turkey); Yilmaz, Muege Sari, E-mail: mugesari@yildiz.edu.tr [Yildiz Technical University, Department of Chemical Engineering, Davutpasa Campus., N.127, Esenler, Istanbul (Turkey); Piskin, Sabriye, E-mail: piskin@yildiz.edu.tr [Yildiz Technical University, Department of Chemical Engineering, Davutpasa Campus., N.127, Esenler, Istanbul (Turkey)

2010-06-15

149

Sequential organocatalytic Stetter and Michael-Aldol condensation reaction: asymmetric synthesis of fully substituted cyclopentenes via a [1 + 2 + 2] annulation strategy.  

PubMed

A stereoselective synthesis of fully substituted cyclopentenes has been achieved by a sequential organocatalyzed Stetter and Michael-aldol condensation of aromatic aldehydes, nitroalkenes, and ?,?-unsaturated aldehydes via the [1 + 2 + 2] annulation strategy with excellent diastereoselectivities and enantioselectivities (up to >99% ee). PMID:20936853

Hong, Bor-Cherng; Dange, Nitin S; Hsu, Che-Sheng; Liao, Ju-Hsiou

2010-11-01

150

Dehydration kinetics of talc and 10 Å phase: Consequences for subduction zone seismicity  

NASA Astrophysics Data System (ADS)

The process of dehydration embrittlement is usually proposed as an explanation for the presence of intermediate-depth earthquakes in subduction zones. It assumes that the release of water by hydrous mineral breakdown is fast enough to provoke brittle failure. We performed high-pressure, high-temperature, dehydration experiments of talc and 10 Å phase coupled with in situ measurement of reaction kinetics using synchrotron X-ray diffraction. Newly developed, X-ray transparent, pressure-sealed, titanium capsule ensured a closed thermochemical environment. From isothermal kinetics data fitted to the Avrami's equation and from the texture of reaction products, we conclude that dehydration rates of these minerals are limited by diffusion. Predicted minimum rates of fluid release range from 10 - 4 to 9 × 10 - 6 m 3fluid m - 3 rock s - 1 , and are fast enough to provoke hydraulic rupture since Maxwell relaxation rate of rocks relevant of subduction zones are slower than the rate of fluid release. These rates are comparable between talc, 10 Å phase and antigorite also [Perrillat, J.-P., Daniel, I., Koga, K.T., Reynard, B., Cardon, H., Crichton, W.A., 2005. Kinetics of antigorite dehydration: a real-time X-ray diffraction study. Earth Planet. Sci. Lett. 236, 899-913]. Consequently, we suggest that the dehydration of hydrous minerals may eventually be fast enough to trigger the intermediate-depth earthquakes, and that the deepest among intermediate-depth earthquakes may actually locate the limits for dehydration of hydrous minerals in the downgoing lithosphere.

Chollet, Mélanie; Daniel, Isabelle; Koga, Kenneth T.; Petitgirard, Sylvain; Morard, Guillaume

2009-06-01

151

Enantioselective organocatalytic one-pot amination/aza-Michael/aldol condensation reaction sequence: synthesis of 3-pyrrolines with a quaternary stereocenter.  

PubMed

Primary amine-catalyzed direct conversion of ?,?-disubstituted aldehydes into 3-pyrrolines with a quaternary stereocenter is reported. The one-pot enantioselective sequence is based on a ?-amination, an aza-Michael addition of hydrazine, an aldol condensation dehydratation and proceeds with good yields and excellent levels of enantioselectivity. Synthetically attractive applications including the formation of aziridinopyrrolidine or epoxypyrrolidine derivatives with good yields and selectivities are also described. PMID:22927036

Desmarchelier, Alaric; Coeffard, Vincent; Moreau, Xavier; Greck, Christine

2012-10-01

152

21 CFR 73.40 - Dehydrated beets (beet powder).  

Code of Federal Regulations, 2013 CFR

...Identity. (1) The color additive dehydrated beets is a dark red powder prepared by dehydrating sound, mature, good quality...additive shall conform to the following specifications: Volatile matter, not more than 4 percent. Acid insoluble ash, not...

2013-04-01

153

21 CFR 73.40 - Dehydrated beets (beet powder).  

Code of Federal Regulations, 2012 CFR

...Identity. (1) The color additive dehydrated beets is a dark red powder prepared by dehydrating sound, mature, good quality...additive shall conform to the following specifications: Volatile matter, not more than 4 percent. Acid insoluble ash, not...

2012-04-01

154

21 CFR 73.40 - Dehydrated beets (beet powder).  

Code of Federal Regulations, 2010 CFR

...Identity. (1) The color additive dehydrated beets is a dark red powder prepared by dehydrating sound, mature, good quality...additive shall conform to the following specifications: Volatile matter, not more than 4 percent. Acid insoluble ash, not...

2010-04-01

155

21 CFR 73.40 - Dehydrated beets (beet powder).  

Code of Federal Regulations, 2011 CFR

...Identity. (1) The color additive dehydrated beets is a dark red powder prepared by dehydrating sound, mature, good quality...additive shall conform to the following specifications: Volatile matter, not more than 4 percent. Acid insoluble ash, not...

2011-04-01

156

ADVANCED DEHYDRATOR DESIGN SAVES GAS AND REDUCES HAP EMISSIONS  

EPA Science Inventory

Glycol dehydrators remove water from gas pipe lines. An advanced dehydrator by Engineered Concepts, Farmington, NM, saves a significant amount of gas, while reducing hazardous air pollutants, volatile organic compounds and CO2 air pollutants...

157

Water, water everywhere: dehydration in the elderly.  

PubMed

Dehydration is a common disorder in the frail elderly patient. Understanding the mechanisms by which fluid and electrolyte abnormalities occur, as well as the implications of specific laboratory values, is key to providing optimal diagnosis and treatment. Management of fluid abnormalities relies on gradual rehydration with the proper fluids to restore both fluid and electrolytes. PMID:16548671

Sacks, Gordon S; Martin, Caren McHenry

2005-11-01

158

Geothermal demonstration: Zunil food dehydration facility  

Microsoft Academic Search

A food dehydration facility was constructed near the town of Zunil, Guatemala, to demonstrate the use of geothermal energy for industrial applications. The facility, with some modifications to the design, was found to work quite satisfactorily. Tests using five different products were completed during the time geothermal energy was used in the plant. During the time the plant was not

O. Maldonado; J. Altseimer; G. R. Thayer; L. Cooper; A. Caicedo

1991-01-01

159

Pelagic sea snakes dehydrate at sea.  

PubMed

Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis (Pelamis) platurus, which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall. These animals do not drink seawater and must rehydrate by drinking from a freshwater lens that forms on the ocean surface during heavy precipitation. The new data based on field studies indicate unequivocally that this marine vertebrate dehydrates at sea where individuals may live in a dehydrated state for possibly six to seven months at a time. This information provides new insights for understanding water requirements of sea snakes, reasons for recent declines and extinctions of sea snakes and more accurate prediction for how changing patterns of precipitation might affect these and other secondarily marine vertebrates living in tropical oceans. PMID:24648228

Lillywhite, Harvey B; Sheehy, Coleman M; Brischoux, François; Grech, Alana

2014-05-01

160

Delirium and dehydration: some fluid for thought?  

Microsoft Academic Search

Delirium is a frequent complication of advanced cancer. It is characterized by cognitive deficits and behavioral disturbance, and therefore can potentially result in severe symptom distress and impeded communication between patient and family and between patient and medical staff. The reversibility of delirium depends on its underlying causes. Delirium is multifactorial in origin, and precipitating or contributory factors include dehydration

Peter G. Lawlor

2002-01-01

161

Dehydration in the Winter Arctic Tropopause Region  

NASA Technical Reports Server (NTRS)

Recent work has shown that limited amounts of tropospheric air can penetrate as much as 1 km into the middleworld stratosphere during the arctic winter. This, coupled with temperatures that are cold enough to produce saturation mixing ratios of less than 5 ppmv at the tropopause, results in stratospheric cloud formation and upper tropospheric dehydration. Even though these "cold outbreaks" occupy only a small portion of the area in the arctic (1-2%), their importance is magnified by an order of magnitude because of the air flow through them. This is reinforced by evidence of progressive drying through the winter measured during SOLVE-1. The significance of this process lies in its effect on the upper tropospheric water content of the middle and high latitude tropopause region, which plays an important role in regulating the earth's radiative balance. There appears to be significant year-to-year variability in the incidence of the cold outbreaks. This work has two parts. First, we describe case studies of dehydration taken from the SOLVE and SOLVE2 aircraft sampling missions during the Arctic winters of 2000 and 2003 respectively. Trajectory based microphysical modeling is employed to examine the sensitivity of the dehydration to microphysical parameters and the nature of sub-grid scale temperature fluctuations. We then examine the year-to-year variations in potential dehydration using a trajectory climatology.

Pfister, Leonhard; Jensen, Eric; Podolske, James; Selkirk, Henry; Anderson, Bruce; Avery, Melody; Diskin. Glenn

2004-01-01

162

Problem: thirst, drinking behavior, and involuntary dehydration.  

PubMed

The phenomenon of involuntary dehydration, the delay in full restoration of a body water deficit by drinking, has been described extensively but relatively little is known about its physiological mechanism. It occurs primarily in humans when they are exposed to various stresses including exercise, environmental heat and cold, altitude, water immersion, dehydration, and perhaps microgravity, singly and in various combinations. The level of involuntary dehydration is approximately proportional to the degree of total stress imposed on the body. Involuntary dehydration appears to be controlled by more than one factor including social customs that influence what is consumed, the capacity and rate of fluid absorption from the gastrointestinal system, the level of cellular hydration involving the osmotic-vasopressin interaction with sensitive cells or structures in the central nervous system, and, to a lesser extent, hypovolemic-angiotensin II stimuli. Since humans drink when there is no apparent physiological stimulus, the psychological component should always be considered when investigating the total mechanisms for drinking. PMID:1602937

Greenleaf, J E

1992-06-01

163

Human Brain Has Coping Mechanism for Dehydration  

MedlinePLUS

... understand a lot more about how the human brain responds to extreme exercise in extreme conditions," study first author Steven Trangmar, ... became dehydrated, the cyclists developed reduced body mass, brain blood flow and ability to exercise, as well as an increase in their internal ...

164

Dehydration of incoming sediments at the Japan Trench  

NASA Astrophysics Data System (ADS)

In the 2011 Tohoku-oki earthquake, the seismic fault slip propagated close to the axis of the Japan Trench and caused an extremely large tsunami (Ide et al., 2011). It is generally considered that ductile deformation of unconsolidated sediments is commonly prominent in the aseismic shallow parts of the subduction zone. Therefore, it is unknown how the seismic rupture reached the nearby trench axis. The plate-boundary megathrust of the Japan Trench is characterized by a prominent seismic reflector, suggesting that the megathrust may host highly pressurized fluids (Kimura et al., 2012). Based on the result of Deep Sea Drilling Project (DSDP) Leg 56 at site 436 (reference, 1977), it is expected that the subducting sediments at the Japan Trench mainly consist of vitric diatomaceous and radiolarian ooze with pelagic clay intervals. Opal-A in the pelagic sediments transforms into quartz, and smectite transforms into illite. Kinetic modeling demonstrated that these reactions will progress with active dehydration at 50-60 km horizontally away from the deformation front and with a temperature of 100-120°C. This region coincides with the plate-boundary marked by a prominent seismic reflector, and suggests that the main source of highly pressured fluids is the dehydration of pelagic sediments (Kimura et al., 2012). However, detailed dehydration processes are still unclear mainly due to lack of quantitative sediment composition data. Therefore, in this study, we examined whole rock composition including amorphous silica of the core samples recovered at site 436 as well as those from the Japan Trench by the IODP 343 Japan Trench Fast Drilling Project (JFAST). Analysis of amorphous silica at site 436 documents that dehydration of the sediments is able to contribute to excess pressure at the shallow part of the megathrust if they underthrust as the same composition. At the drilling site of JFAST, a plate-boundary shear zone was identified around 820 mbsf, which was supposed to cause the 2011 Tohoku-oki earthquake (Chester., et al., 2012). Our analysis showed that the shear zone is characterized by extremely high concentration of smectite (~70 wt.%). These results suggest that the abundant smectite may have possibly fostered localized rupture and slip during the earthquake, because smectite has low frictional coefficient.

Shimizu, M.; Kameda, J.; Hamada, Y.; Kimura, G.

2013-12-01

165

Dehydration and rehydration of a tuff vitrophyre  

SciTech Connect

The basal vitrophyre of the Topopah Spring Member of the Paintbrush Tuff at Yucca Mountain, Nevada, is a perlitic glass with 2.8 to 4.6% water. The dehydration of this vitrophyre was studied by thermogravimetric analysis (TGA) and by isothermal heating at 50{degrees}, 100{degrees}, 200{degrees}, and 400{degrees}C for 3.4 years followed by 1.1 years of rehydration at high controlled humidity ({approximately}79% relative humidity). No crystallization of the glass was observed in long-term dehydration or rehydration; the only observed chemical alteration was loss of up to 60% of original fluorine. TGA studies show a characteristic two-stage dehydration of the vitrophyre, with two-thirds to three-fourths weight loss occurring most rapidly at temperatures ranging from 278{degrees} to 346{degrees}C in 10{degrees}C/min heating experiments. The remaining water, about 1% in all of the vitrophyre samples studied regardless of total water content, is lost only on second-stage heating to temperatures above 650{degrees}C. Long-term isothermal heating at {le}400{degrees}C releases only the first-stage water. Loss of essentially all first-stage water occurred in less than 1 hour at 400{degrees}C; proportionately lower losses were obtained at 200{degrees} and 100{degrees}C. Small (0.2%) water loss occurred in the 50{degrees}C experiment. A time-temperature-dehydration diagram generated from the isothermal heating data shows a clustering of dehydration contours that are the equilibrium equivalent of the rapid first-stage water loss in dynamic TGA experiments. These dry-heating experiments provide an end-member characterization of glass transformations for comparison with water-saturated heating experiments in which glass alteration is prominent. 29 figs., 7 figs., 7 tabs.

Vaniman, D.; Bish, D., Chipera, S. [Los Alamos National Lab., NM (United States)

1993-12-10

166

Double seismic zone and dehydration embrittlement of the subducting slab  

E-print Network

Double seismic zone and dehydration embrittlement of the subducting slab Tadashi Yamasaki1; revised 5 November 2002; accepted 7 January 2003; published 23 April 2003. [1] Dehydration embrittlement on geologically estimated subduction histories of these regions. We then determine dehydration loci

Seno, Tetsuzo

167

Leaf Shrinkage with Dehydration: Coordination with Hydraulic Vulnerability and Drought  

E-print Network

Leaf Shrinkage with Dehydration: Coordination with Hydraulic Vulnerability and Drought Tolerance1[C shrinkage with dehydration has attracted attention for over 100 years, especially as it becomes visibly diverse species, we tested the hypothesis that shrinkage during dehydration (i.e. in whole leaf, cell

Sack, Lawren

168

Satellite observation of dehydration in the Arctic Polar stratosphere  

E-print Network

Satellite observation of dehydration in the Arctic Polar stratosphere L. L. Pan,1 W. J. Randel,1 H 2002. [1] We report the first space-borne observation of dehydration in the Arctic polar stratosphere between 23 and 26 km. In some cases, the dehydrated air was downwind from mountain wave induced Polar

Pan, Laura

169

Can overshooting convection dehydrate the tropical tropopause layer?  

E-print Network

Can overshooting convection dehydrate the tropical tropopause layer? E. J. Jensen,1 A. S. Ackerman dehydration near the tropical tropopause caused by overshooting deep convection. We show that convective temperature, these small crystals sublimate and rehydrate the air, resulting in no irreversible dehydration

170

3D Magnetic Resonance Microscopy of Dehydrated Biological Specimens  

E-print Network

3D Magnetic Resonance Microscopy of Dehydrated Biological Specimens Dissertation zur Erlangung des and Mechatronics ­ 3D Magnetic Resonance Microscopy of Dehydrated Biological Specimens Daniel Mietchen Thesis Dehydration beyond a critical threshold poses a serious threat to most or- ganisms in their active state

Hammerton, James

171

Rate of Nucleation in Condensed Systems  

Microsoft Academic Search

On the basis of the nucleation theory developed by Volmer, Becker, and co-workers, and the theory of absolute reaction rates, an expression is derived for the absolute rate of nucleation in condensed systems.

D. Turnbull; J. C. Fisher

1949-01-01

172

Evolution of microstructure and elastic wave velocities in dehydrated gypsum samples  

NASA Astrophysics Data System (ADS)

We report on changes in P and S-wave velocities and rock microstructure induced by devolatilization reactions using gypsum as a reference analog material. Cylindrical samples of natural alabaster were dehydrated in air, at ambient pressure, and temperatures between 378 and 423 K. Dehydration did not proceed homogeneously but via a reaction front moving sample inwards separating an outer highly porous rim from the remaining gypsum which, above approximately 393 (±5) K, concurrently decomposed into hemihydrate. Overall porosity was observed to continuously increase with reaction progress from approximately 2% for fully hydrated samples to 30% for completely dehydrated ones. Concurrently, P and S-wave velocities linearly decreased with porosity from 5.2 and 2.7 km/s to 1.0 and 0.7 km/s, respectively. It is concluded that a linearized empirical Raymer-type model extended by a critical porosity term and based on the respective time dependent mineral and pore volumes reasonably replicates the P and S-wave data in relation to reaction progress and porosity.

Milsch, Harald; Priegnitz, Mike

2012-12-01

173

Preparation of osmotic dehydrated ripe banana slices  

Microsoft Academic Search

Process for preparation of ripe banana slices using osmotic dehydration was standardized. Fully ripe banana fruits were peeled\\u000a and slices of 8 mm thickness were prepared. The slices were divided into 5 lots and pretreated with sulphur fumigation @ 2\\u000a g\\/kg of slices for 2 h then each lot was soaked in 60 0Brix sugar syrup containing 0.1% KMS +

U. D. Chavan; A. E. Prabhukhanolkar; V. D. Pawar

2010-01-01

174

Could Neonatal Hypernatremia Dehydration Influence Hearing Status?  

PubMed Central

Introduction: Neonatal hypernatremia dehydration (NHD) is a dangerous condition in neonates, which is accompanied by acute complications (renal failure, cerebral edema, and cerebral hemorrhage) and chronic complications (developmental delay). Children begin learning language from birth, and hearing impairment interferes with this process. We assessed the hearing status of infants with hypernatremia dehydration. Materials and Methods: In a case-control study in 110 infants presenting at the Ghaem Hospital (Mashhad, Iran) between 2007 and 2011, we examined the incidence of hearing impairment in infants suffering from hypernatremia dehydration (serum sodium >150 mEq/L) in comparison with infants with normal sodium level (serum sodium ?150 mEq/L). Results: Three of 110 cases examined in the study group showed a transient hearing impairment. A mean serum sodium level of 173mg/dl was reported among hearing-impaired infants. Conclusion: Transient hearing impairment was higher in infants with hypernatremia; although this difference was not significant (P>0.05). Hearing impairment was observed in cases of severe hypernatremia. PMID:24505569

Boskabadi, Hassan; Anvarifar, Farnaz; Nourizadeh, Navid

2014-01-01

175

Proposal for New Experimental Tests of the Bose-Einstein Condensation Mechanism for Low-Energy Nuclear Reaction and Transmutation Processes in Deuterium Loaded - and Nano-Scale Cavities  

NASA Astrophysics Data System (ADS)

Most of experimental results of low-energy nuclear reaction (LENR) reported so far cannot be reproduced on demand. There have been persistent experimental results indicating that the LENR and transmutation processes in condensed matters (LENRTPCM) are surface phenomena rather than bulk phenomena. Recently proposed Bose-Einstein condensation (BEC) mechanism may provide a suitable theoretical description of the surface phenomena. New experiments are proposed and described for testing the BEC mechanism for LENR and transmutation processes in micro- and nano-scale traps. (1) We propose the use of micro- or nano-porous conducting materials as a cathode in electrolysis experiments with heavy water with or without Li in order to stabilize the active surface spots and to enhance the effect for the purpose of improving the reproducibility of excess heat generation and nuclear emission. (2) We propose new experimental tests of the BEC mechanism by measuring the pressure and temperature dependence of LENR events using deuterium gas and these deuterated metals with or without Li. If the LENRTPCM are surface phenomena, the proposed use of micro-/nano-scale porous materials is expected to enhance and scale up the LENRTPCM effects by many order of magnitude, and thus may lead to better reproductivity and theoretical understanding of the phenomena.

Kim, Yeong E.; Koltick, David S.; Reifenberger, Ronald G.; Zubarev, Alexander L.

2006-02-01

176

Nonisothermal Kinetics Analysis of the Dehydration of Ziprasidone Hydrochloride Monohydrate by Thermogravimetry  

PubMed Central

In the current work the kinetics of dehydration of ziprasidone hydrochloride monohydrate was studied by nonisothermal thermogravimetry. Ziprasidone hydrochloride monohydrate was heated from 30 to 150° with a heating rate of 5° per min under nitrogen gas atmosphere and weight loss data were collected. Powder X-ray difraction was used to characterize the solid before and after dehydration. The well accepted Coats-Redfern model fitting approach was applied to the thermogravimetry data for the kinetic analysis. Thirteen solid state reaction models were studied; among them one-dimensional diffusion model was found to be the best fit model for this reaction with an excellent correlation 0.9994. The Arrhenius parameters, activation energy, and pre-exponential factor were determined, the values were found to be 28 k.cal/mol and 9.53×1013 sec?1, respectively. PMID:24082354

Ravikiran, A.; Arthanareeswari, M.; Kamaraj, P.; Praveen, C.

2013-01-01

177

Photochemical, thermal, and base-induced access to hydroazulene derivatives via two-carbon ring-enlargement reactions of condensed electrophilic cyclobutenes.  

PubMed

Enamines, silyl enol ethers, and beta-keto ester anions derived from bicyclo[3.3.0]octan-2-one efficiently underwent a formal [2 + 2] cycloaddition reaction with DMAD and ethyl propynoate leading to a large variety of electrophilic cyclobutenes. The latter were transformed into polyfunctionalized bicyclo[5.3.0]decane (or hydroazulene) ring systems in high yields by fragmentation of the cyclobutene moiety. These two-carbon ring-enlargement reactions were utilized as a synthetic tool for the construction of a polyfunctionalized hydroazulene derivative that represents a potential precursor of the tricyclic framework of ingenol. PMID:12530869

Mislin, Gaëtan L; Miesch, Michel

2003-01-24

178

Dehydration of 1-pentanol to di- n-pentyl ether over ion-exchange resin catalysts  

Microsoft Academic Search

The dehydration reaction of 1-pentanol to di-n-pentyl ether (DNPE) and water in the liquid phase was studied at 110–180°C and 1MPa on sulfonic styrene–divinylbenzene (S\\/DVB) copolymers and the perfluoroalkanesulfonic resin NR50. S\\/DVB-based catalysts were macroreticular and gel-type resins both sulfonated conventionally and oversulfonated. Macroreticular resins tested include resins whose working phase in catalysis is gel phase (i.e. Amberlyst-15 and Amberlyst-35)

J. Tejero; F. Cunill; M. Iborra; J. F. Izquierdo; C. Fité

2002-01-01

179

Condensation model for the ESBWR passive condensers  

SciTech Connect

In the General Electric's Economic simplified boiling water reactor (GE-ESBWR) the passive containment cooling system (PCCS) plays a major role in containment pressure control in case of an loss of coolant accident. The PCCS condenser must be able to remove sufficient energy from the reactor containment to prevent containment from exceeding its design pressure following a design basis accident. There are three PCCS condensation modes depending on the containment pressurization due to coolant discharge; complete condensation, cyclic venting and flow through mode. The present work reviews the models and presents model predictive capability along with comparison with existing data from separate effects test. The condensation models in thermal hydraulics code RELAP5 are also assessed to examine its application to various flow modes of condensation. The default model in the code predicts complete condensation well, and basically is Nusselt solution. The UCB model predicts through flow well. None of condensation model in RELAP5 predict complete condensation, cyclic venting, and through flow condensation consistently. New condensation correlations are given that accurately predict all three modes of PCCS condensation. (authors)

Revankar, S. T. [Pohang Univ. of Science and Technology, 400 Central Drive, West Lafayette, IN 47906 (United States); Zhou, W.; Wolf, B.; Oh, S. [Purdue Univ., West Lafayette, IN 47906 (United States)

2012-07-01

180

Dehydration of football referees during a match  

PubMed Central

Objectives: To study hydration status in referees (main) and assistant referees (linesmen) during official football matches. Methods: Twelve male football referees were evaluated; all were volunteers. Before and after each match, the referee and one of the assistants were weighed without clothes and a blood sample was taken. Total water loss was determined for each subject from the change in body weight. The main haematological variables were analysed in the blood samples. Total plasma protein concentration and osmolarity were also determined. Variation in plasma volume was determined from changes in packed cell volume and a combination of changes in packed cell volume and haemoglobin concentrations. Results: During a match, total body water loss was 1.60 (0.13) litres, equivalent to 2.05 (0.18)% of body weight. Body weight was reduced by 1.55 (0.12)%, showing that water ingestion during the interval replaces only 24.4% of the body fluids lost during the match. The assistants lost 0.79 (0.19) litre of water, equivalent to 1.05 (0.25)% of body weight. The referees showed a significant decrease in plasma volume of 4.99 (1.33)%. The assistants showed a non-significant increase in plasma volume. The reduction in plasma volume observed in the referees correlated significantly with total body water loss (r = 0.9623). From these data, it is possible to predict that a dehydration of 1% reflects a reduction in plasma volume of nearly 2.5%. Conclusions: Referees are moderately dehydrated after a football match (2%), whereas assistants show a non-significant dehydration of 1% of their body weight. PMID:14665588

Da Silva, A I; Fernandez, R

2003-01-01

181

Complications Due to Breastfeeding Associated Hypernatremic Dehydration  

PubMed Central

Objective: The aim was to assess the incidence, presenting features, and complications of breastfeeding associated hypernatremic dehydration among hospitalized neonates. Materials and Methods: A retrospective study over a period of 18 months to identify term and near term (?35 weeks of gestation) breastfed neonates, who were admitted with serum sodium concentration of ?150 mEq/l and no apparent explanation for their hypernatremia other than inadequate breastmilk intake. Results: The incidence of breastfeeding associated hypernatremic dehydration among 2100 term and near term neonates was 1.38%. The median serum sodium at presentation was 164 mEq/l (range: 151-191 mEq/l). The mean weight loss in these patients was 10.16% ±6.6%. The reasons for seeking medical attention were refusal of feeds (72.41%), lethargy (68.96%), decreased urine output (44.82%), jaundice (27.58%) and fever (24.13%). Five patients (17.24%) had seizures and three (10.34%) had coagulopathy. Other complications included hypoglycemia, hypocalcemia, acute kidney injury (AKI) (37.93%) and intraventricular hemorrhage. The mean serum creatinine was 1.82 ± 2.5 mg/dl (range: 0.19-9.6). A statistically significant association was seen between serum sodium concentration at presentation and AKI. It was also found that those patients who had AKI had a higher weight loss and had presented later to the hospital than those without AKI. One patient died within 12 h of admission. This child had disseminated intravascular coagulopathy, AKI, and hypoglycemia. Conclusions: Breastfeeding associated hypernatremic dehydration is a serious condition with many serious complications and even results in death if detected late. Health care providers have increasing responsibilities of promoting proper breastfeeding techniques and taking measures for early diagnosis and treatment of this problem.

Ahmed, Asif; Iqbal, Javeed; Ahmad, Ikhlas; Charoo, Bashir A; Ahmad, Qazi Iqbal; Ahmad, Sheikh Mushtaq

2014-01-01

182

Intrastab Earthquakes: Dehydration of the Cascadia Slab  

USGS Publications Warehouse

We simultaneously invert travel times of refracted and wide-angle reflected waves for three-dimensional compressional-wave velocity structure, earthquake locations, and reflector geometry in northwest Washington state. The reflector, interpreted to be the crust-mantle boundary (Moho) of the subducting Juan de Fuca plate, separates intrastab earthquakes into two groups, permitting a new understanding of the origins of intrastab earthquakes in Cascadia. Earthquakes up-dip of the Moho's 45-kilometer depth contour occur below the reflector, in the subducted oceanic mantle, consistent with serpentinite dehydration; earthquakes located down-dip occur primarily within the subducted crust, consistent with the basalt-to-eclogite transformation.

Preston, L.A.; Creager, K.C.; Crosson, R.S.; Brocher, T.M.; Trehu, A.M.

2003-01-01

183

Geothermal steam condensate reinjection  

Microsoft Academic Search

Geothermal electric generating plants which use condensing turbines and generate and excess of condensed steam which must be disposed of are discussed. At the Geysers, California, the largest geothermal development in the world, this steam condensate has been reinjected into the steam reservoir since 1968. A total of 3,150,000,000 gallons of steam condensate has been reinjected since that time with

A. J. Chasteen

1974-01-01

184

Effects of Dehydration on Fish Muscles at Chilled Temperature  

NASA Astrophysics Data System (ADS)

Recently,new method of removing water from fish fillet at low temperature using dehydration sheet have been reported. The present study is concerned with the factors to affect the quality during dehydration of horse mackerel muscle at low temperature. The rate of dehydration at -3 °C was about two times faster than that at 0 °C. The rate of denaturation of fish muscle protein was kept less than about 10 % (ATPase activity) of the undenaturated initial values after removing free water content. Present results suggest the practical possibility of the dehydration at -3 °C for keeping quality of fish flesh.

Miki, Hidemasa; Seto, Fuminori; Nishimoto, Motomi; Nishimoto, Junichi

185

Modulation of Dehydration Tolerance in Soybean Seedlings (Dehydrin Mat1 Is Induced by Dehydration but Not by Abscisic Acid).  

PubMed Central

Germinated soybean (Glycine max L. cv Williams 82) seedlings subjected to rapid dehydration begin to lose the ability to recover when the relative water content of the plant decreases below 60%. The expanded cells of the hypocotyl appear more susceptible to dehydration-induced damage than do cells in the hypocotyl zone of cell growth. Pretreatment of seedlings prior to rapid dehydration with nonlethal water deficit or exogenous abscisic acid (ABA) shifts this viability threshold to progressively lower relative water contents, indicating the acquisition of increased dehydration tolerance. Increased tolerance is associated with osmotic adjustment in the hypocotyl zone of cell growth and with increases in soybean dehydrin Mat1 mRNA levels. The accumulation of Mat1 mRNA is dehydration dependent but insensitive to ABA. Induction of Mat1 mRNA accumulation by dehydration but not by ABA makes it an unusual member of the dehydrin family. PMID:12223753

Whitsitt, M. S.; Collins, R. G.; Mullet, J. E.

1997-01-01

186

The effects of dehydration, moderate alcohol consumption, and rehydration on cognitive functions.  

PubMed

This study investigated the impact of mild-moderate dehydration on alcohol-induced deteriorations in cognitive functions. Sixteen healthy males participated in a single-blind, placebo-controlled cross-over design study involving 4 experimental trials (separated by ?7 d). In each trial, participants were dehydrated by 2.5% body mass through exercise. After 1 h recovery in a thermo-neutral environment (22 ± 2 °C, 60-70% relative humidity) 4 tasks from the Cambridge Neuropsychological Test Automated Battery (CANTAB) were administered to the participants (test 1). In two of the trials, participants were provided with water equivalent to either 50% or 150% body mass loss and given salt (NaCl) capsules (50 mmol/L). A set volume of alcohol or placebo was then consumed in each trial, incorporating the conditions: dehydration-placebo (DP), dehydration-alcohol (DA), partial rehydration-alcohol (PA), and full rehydration-alcohol (FA). The same 4 CANTAB tasks were then re-administered (test 2). Subjective ratings of mood and estimates of alcohol intoxication and driving impairment were also recorded in each trial. Alcohol consumption caused deterioration on 3 of the 4 CANTAB measures (viz., choice reaction time, executive function and response inhibition). This reduction in performance was exacerbated when participants were dehydrated compared to trials where full rehydration occurred. Subjective ratings of impairment and intoxication were not significantly different between any of the trials where alcohol was consumed; however ratings for alcohol trials were significantly higher than in the placebo trial. These findings suggest that rehydration after exercise that causes fluid loss can attenuate alcohol-related deterioration of cognitive functions. This may pose implications for post match fluid replacement if a moderate amount of alcohol is also consumed. PMID:23352231

Irwin, Christopher; Leveritt, Michael; Shum, David; Desbrow, Ben

2013-05-01

187

Selective preparation of monobenzyl glyceryl ethers by the condensation reaction of glycerol with benzyl alcohols in the presence of zeolite catalysts.  

PubMed

The selective preparation of monobenzyl glyceryl ethers, which are potential commodity chemicals with special functions, was explored to find new applications for glycerol. Among the acid catalysts investigated (sulfuric acid, heteropoly acid, Nafion(R), and zeolite), Zeolite Socony Mobil-5 (ZSM-5) afforded better results. The reaction of equimolar amounts of glycerol and benzyl alcohol at 150ºC for 7 h in the presence of 2 wt% ZSM-5 selectively afforded 3-(benzyloxy)propane-1,2-diol with a very small amount of the corresponding 2-benzyloxy isomer in 86% gas chromatography yield. PMID:25213442

Kubota, Mari; Sakamoto, Aki; Komatsu, Masanori; Maeno, Katsuhiro; Masuyama, Araki

2014-10-01

188

Treatment of dredged sludge by mechanical dehydration  

SciTech Connect

Sludge deposits in the water area damage the ecosystems and environments; their elimination has always been an urgent task for human communities. Generally, sludge deposits are dredged out of the bottom of the water area, transported to, and discharged at a large disposal area on land. Recently, however, it has become increasingly difficult to secure disposal areas and routes of speedy transportation for disposal of dredged sludge. Accordingly, there is an urgent need to reduce both the volume of dredged sludge and the size of the disposal area. This mechanical method is different from the conventional engineering dehydration by loading, consolidation, and drainage in that the dredged sludge is separated into sludge cakes and clean water that can be returned to the water area through mechanical centrifugal dehydration. Sludge deposits are distributed thin and wide on the bottom of the water area, and a pump dredge has been proved effective in many cases for dredging the upper layers of sludge deposits accurately and without creating turbidity in water. This mechanical sludge treatment technique can be most efficient when used in combination with a pump dredge. This method offers the following advantages: (a) It requires smaller space for treatment and disposal of dredged sludge than the conventional method. (b) Facilities and costs for transportation can be reduced. (c) Various systems can be adopted for transportation of sludge cakes. (d) This system is transportable and compact and can be constructed anywhere either on land or on water.

Maekawa, T.

1992-03-01

189

Dehydration-melting of amphibolite at 10 kbar: the effects of temperature and time  

Microsoft Academic Search

We have simulated the dehydration-melting of a natural, low-K, calcic amphibolite (67.4% hornblende, 32.5% anorthite) in piston-cylinder experiments at 10 kbar and 750–1000°C, for 1–9 days. The solidus temperature is lower than 750°C; garnet appears at 850°C. The overall reaction is: Hb+P?L+Cpx+Al-Hb+Ca-Hb+Ga+Opx. Three stages of reaction are: (1) melting dominated by the growth of clinopyroxene and garnet, with little change

Michael B. Wolf; Peter J. Wyllie

1994-01-01

190

Brønsted instead of Lewis acidity in functionalized MIL-101Cr MOFs for efficient heterogeneous (nano-MOF) catalysis in the condensation reaction of aldehydes with alcohols.  

PubMed

Porous chromium(III) 2-nitro-, 2-amino-, and nonfunctionalized terephthalate (MIL-101Cr) metal organic frameworks are heterogeneous catalysts for diacetal formation from benzaldehyde and methanol (B-M reaction) as well as other aldehydes and alcohols. MIL-101Cr-NO2 obtained by direct reaction between CrO3 and 2-nitro-terephthalate showed the highest activity with 99% conversion in the B-M reaction in 90 min and turnover numbers of 114. The activity decreased in the order MIL-101Cr-NO2 > MIL-101Cr > MIL-101Cr-NH2. Within different samples of nonfunctionalized MIL-101Cr the activity increased with surface area. Methanol gas sorption of the different MIL materials correlates with the BET surface area and pore volume but not with the diacetalization activity. Benzaldehyde adsorption from heptane showed no significant difference for the different MILs. Gas sorption studies of CD3CN to probe for a higher Lewis acidity in MIL-101Cr-NO2 remained inconclusive. A high B-M catalytic activity of wet MIL-101Cr-NO2 excluded significant contributions from coordinatively unsaturated Lewis-acid sites. pH measurements of methanol dispersions of the MIL materials gave the most acidic pH (as low as 1.9) for MIL-101Cr-NO2, which significantly increased over MIL-101Cr (3.0) to MIL-101Cr-NH2 (3.3). The increase in acidity is of short range or a surface effect to the heterogeneous MIL particles as protons dissociating from the polarized aqua ligands (Cr-OH2) have to stay near the insoluble counteranionic framework. The variation in Brønsted acidity of MIL-101Cr-NO2 > MIL-101Cr ? MIL-101Cr-NH2 correlates with the withdrawing effect of NO2 and the diacetalization activity. The catalytic B-M activity of soluble, substitution-inert, and acidic Cr(NO3)3·9H2O supports the Brønsted-acid effect of the MIL materials. Filtration and centrifugation experiments with MIL-101Cr-NO2 revealed that about 2/3 of the catalytic activity comes from nano-MOF particles with a diameter below 200 nm. The MIL-101Cr-NO2 catalysts can be recycled five times with very little loss in activity. The diacetalization activity of MIL-101Cr-NO2 decreases with the alcohol chain length from methanol over ethanol, n-propanol, n-butanol, to almost inactive n-pentanol, while conversions for benzaldehyde, paratolylaldehyde, 4-chlorobenzaldehyde, and cyclohexanone all reach 90% or more after 90 min. PMID:25006999

Herbst, Annika; Khutia, Anupam; Janiak, Christoph

2014-07-21

191

Dehydration and Dehydrogenation of Ethylene Glycol on Rutile TiO2(110)  

SciTech Connect

The interactions of ethylene glycol (EG) with partially reduced rutile TiO2(110) surface have been studied using temperature programmed desorption (TPD). The saturation coverage on the surface Ti rows is determined to be 0.43 monolayer (ML), slightly less than one EG per two Ti sites. Most of the adsorbed ethanol (~80%) undergoes further reactions to other products. Two major channels are observed, dehydration yielding ethylene and water and dehydrogenation yielding acetaldehyde and hydrogen. Hydrogen formation is rather surprising as it has not been observed previously on TiO2(110) from simple organic molecules. The coverage dependent yields of ethylene and acetaldehyde correlate well with that of water and hydrogen, respectively. Dehydration dominates at lower EG coverages (< 0.2 ML) and plateaus as the coverage is increased to saturation. Dehydrogenation is observed primarily at higher EG coverages (>0.2 ML). Our results suggest that the observed dehydration and dehydrogenation reactions proceed via different surface intermediates.

Li, Zhenjun; Kay, Bruce D.; Dohnalek, Zdenek

2013-08-07

192

Air-dry primer coatings from dehydrated lesquerella oil  

Microsoft Academic Search

Lesquerella oil (LO), a domestic vegetable oil of hydroxy fatty acid content, was dehydrated (DLO) and the product used to synthesize oil modified polyesters. The polyesters were comparatively evaluated with analogous dehydrated castor oil (DCO) polyesters. Accordingly, polyesters were synthesized from DLO and DCO, and subsequently formulated into air-drying, anti-corrosive primers for evaluation. The DLO and DCO coatings gave comparable

Shelby F. Thames; Haibin Yu; Min D. Wang

1997-01-01

193

Dehydration and drinking responses in a pelagic sea snake.  

PubMed

Recent investigations of water balance in sea snakes demonstrated that amphibious sea kraits (Laticauda spp.) dehydrate in seawater and require fresh water to restore deficits in body water. Here, we report similar findings for Pelamis platurus, a viviparous, pelagic, entirely marine species of hydrophiine ("true") sea snake. We sampled snakes at Golfo de Papagayo, Guanacaste, Costa Rica and demonstrated they do not drink seawater but fresh water at variable deficits of body water incurred by dehydration. The threshold dehydration at which snakes first drink fresh water is -18.3 ± 1.1 % (mean ± SE) loss of body mass, which is roughly twice the magnitude of mass deficit at which sea kraits drink fresh water. Compared to sea kraits, Pelamis drink relatively larger volumes of water and make up a larger percentage of the dehydration deficit. Some dehydrated Pelamis also were shown to drink brackish water up to 50% seawater, but most drank at lower brackish values and 20% of the snakes tested did not drink at all. Like sea kraits, Pelamis dehydrate when kept in seawater in the laboratory. Moreover, some individuals drank fresh water immediately following capture, providing preliminary evidence that Pelamis dehydrate at sea. Thus, this widely distributed pelagic species remains subject to dehydration in marine environments where it retains a capacity to sense and to drink fresh water. In comparison with sea kraits, however, Pelamis represents a more advanced stage in the evolutionary transition to a fully marine life and appears to be less dependent on fresh water. PMID:22510231

Lillywhite, Harvey B; Brischoux, François; Sheehy, Coleman M; Pfaller, Joseph B

2012-08-01

194

Geothermal vegetable dehydration at Brady`s Hot Springs, Nevada  

Microsoft Academic Search

This article describes the utilization of the Brady`s Springs geothermal resource for heat generation used in the food dehydration process. This geothermal system is located in the Forty-Mile Desert area of Nevada. Geothermal Food Processors, Inc. of Reno, Nevada started construction of the geothermal vegetable dehydration plant in 1978, and the plant started operations in 1979. The industrial process of

1994-01-01

195

Vacuum impregnation for development of new dehydrated products  

Microsoft Academic Search

Vacuum impregnation (VI) of structured foods implies the partial release of gas from pores and its substitution by an external liquid. Therefore, important changes in physicochemical and structural properties take place in the food and these affect its behavior in drying operations (air-drying (AD) and\\/or osmotic dehydration (OD)). The adequate control of VI prior to dehydration may be used as

Pedro Fito; Amparo Chiralt; José M Barat; Ana Andrés; Javier Mart??nez-Monzó; Nuria Mart??nez-Navarrete

2001-01-01

196

Recent developments in osmotic dehydration: methods to enhance mass transfer  

Microsoft Academic Search

Osmotic dehydration, due to its energy and quality related advantages, is gaining popularity as a complimentary processing step in the chain of integrated food processing. Generally, osmotic dehydration being a slow process, there has been a need for additional ways to increase the mass transfer without adversely affecting the quality. This gave the required motivation for many recent advances in

N. K. Rastogi; K. S. M. S. Raghavarao; K. Niranjan; D. Knorr

2002-01-01

197

OSMOTIC DEHYDRATION OF FOODS: MASS TRANSFER AND MODELING ASPECTS  

Microsoft Academic Search

Biological materials contain a variety of individual soluble components. When cellular biological materials are immersed in osmotic solution, multicomponent mass transfer occurs, which ultimately leads to the loss of water from the food, or osmotic dehydration. Mass transfer of food constituents during osmotic dehydration may cause changes in food quality in terms of nutritional value, texture, color, and taste. The

John Shi; Marc Le Maguer

2002-01-01

198

40 CFR 63.765 - Glycol dehydration unit process vent standards.  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Glycol dehydration unit process vent standards...Facilities § 63.765 Glycol dehydration unit process vent standards...section applies to each glycol dehydration unit subject to this...

2012-07-01

199

40 CFR 63.1275 - Glycol dehydration unit process vent standards.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Glycol dehydration unit process vent standards...Facilities § 63.1275 Glycol dehydration unit process vent standards...section applies to each glycol dehydration unit subject to this...

2011-07-01

200

40 CFR 63.1275 - Glycol dehydration unit process vent standards.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Glycol dehydration unit process vent standards...Facilities § 63.1275 Glycol dehydration unit process vent standards...section applies to each glycol dehydration unit subject to this...

2010-07-01

201

40 CFR 63.1275 - Glycol dehydration unit process vent standards.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Glycol dehydration unit process vent standards...Facilities § 63.1275 Glycol dehydration unit process vent standards...section applies to each glycol dehydration unit subject to this...

2013-07-01

202

40 CFR 63.765 - Glycol dehydration unit process vent standards.  

Code of Federal Regulations, 2011 CFR

...2011-07-01 false Glycol dehydration unit process vent standards...Facilities § 63.765 Glycol dehydration unit process vent standards...section applies to each glycol dehydration unit subject to this...

2011-07-01

203

40 CFR 63.1275 - Glycol dehydration unit process vent standards.  

...2014-07-01 false Glycol dehydration unit process vent standards...Facilities § 63.1275 Glycol dehydration unit process vent standards...section applies to each glycol dehydration unit subject to this...

2014-07-01

204

40 CFR 63.765 - Glycol dehydration unit process vent standards.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Glycol dehydration unit process vent standards...Facilities § 63.765 Glycol dehydration unit process vent standards...section applies to each glycol dehydration unit subject to this...

2013-07-01

205

40 CFR 63.1275 - Glycol dehydration unit process vent standards.  

Code of Federal Regulations, 2012 CFR

...2011-07-01 true Glycol dehydration unit process vent standards...Facilities § 63.1275 Glycol dehydration unit process vent standards...section applies to each glycol dehydration unit subject to this...

2012-07-01

206

40 CFR 63.765 - Glycol dehydration unit process vent standards.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Glycol dehydration unit process vent standards...Facilities § 63.765 Glycol dehydration unit process vent standards...section applies to each glycol dehydration unit subject to this...

2010-07-01

207

Preparation of serial sections of arthropods using 2, 2-dimethoxypropane dehydration and epoxy  

E-print Network

Preparation of serial sections of arthropods using 2, 2-dimethoxypropane dehydration and epoxy arthropods using serial semithin sections. The specimens were dehydrated with acidified 2, 2 diamond knives are used. Key words: arthropods, dehydration, 2, 2-dimethoxypropane, DMP, resin embedding

Krenn, Harald W.

208

40 CFR 63.765 - Glycol dehydration unit process vent standards.  

...2014-07-01 false Glycol dehydration unit process vent standards...Facilities § 63.765 Glycol dehydration unit process vent standards...section applies to each glycol dehydration unit subject to this...

2014-07-01

209

Condensation system for power plant  

Microsoft Academic Search

A condensation system for use in a power plant including a steam generator and steam turbine comprises at least one side stream condenser. The side stream condenser defines therein first and second hot wells with the first hot well receiving therein condensate produced by condensing steam exhausted from the steam turbine. A condensate pump device forcibly delivers the condensate through

H. Ishimaru; T. Masuda; Y. Nagai

1984-01-01

210

Dehydration and ionic conductance quantization in nanopores  

E-print Network

There has been tremendous experimental progress in the last decade in identifying the structure and function of biological pores (ion channels) and fabricating synthetic pores. Despite this progress, many questions still remain about the mechanisms and universal features of ionic transport in these systems. In this paper, we examine the use of nanopores to probe ion transport and to construct functional nanoscale devices. Specifically, we focus on the newly predicted phenomenon of quantized ionic conductance in nanopores as a function of the effective pore radius - a prediction that yields a particularly transparent way to probe the contribution of dehydration to ionic transport. We study the role of ionic species in the formation of hydration layers inside and outside of pores. We find that the ion type plays only a minor role in the radial positions of the predicted steps in the ion conductance. However, ions with higher valency form stronger hydration shells, and thus, provide even more pronounced, and the...

Zwolak, Michael; Di Ventra, Massimiliano

2010-01-01

211

Two-stage dehydration of sugars  

DOEpatents

The invention includes methods for producing dianhydrosugar alcohol by providing an acid catalyst within a reactor and passing a starting material through the reactor at a first temperature. At least a portion of the staring material is converted to a monoanhydrosugar isomer during the passing through the column. The monoanhydrosugar is subjected to a second temperature which is greater than the first to produce a dianhydrosugar. The invention includes a method of producing isosorbide. An initial feed stream containing sorbitol is fed into a continuous reactor containing an acid catalyst at a temperature of less than 120.degree. C. The residence time for the reactor is less than or equal to about 30 minutes. Sorbitol converted to 1,4-sorbitan in the continuous reactor is subsequently provided to a second reactor and is dehydrated at a temperature of at least 120.degree. C. to produce isosorbide.

Holladay, Johnathan E. (Kennewick, WA); Hu, Jianli (Kennewick, WA); Wang, Yong (Richland, WA); Werpy, Todd A. (West Richland, WA)

2009-11-10

212

Afm Study on Condensation of DNA by Spermidine  

NASA Astrophysics Data System (ADS)

We studied on condensates of a circular and a linear plasmid pUC19 DNA with spermidine in view of reaction time. DNA-spermidine condensates were produced by mixture of 2?l of 5?g/ml DNA solution with 2?l of 0.5mM spermidine aqueous solution. Reaction time is the time elapsed until the mixture is dropped on mica substrate to be imaged with a tapping mode AFM. The reaction times are 30, 15 and 1min. The intermediate progress of DNA-spermidine condensation was found from AFM images dependent on the reaction time.

Katsumata, Shunji; Kigasawa, Harunori; Utsuno, Kuniharu

2001-04-01

213

Condensed Matter Physics  

Microsoft Academic Search

A modern, unified treatment of condensed matter physics This new work presents for the first time in decades a sweeping review of the whole field of condensed matter physics. It consolidates new and classic topics from disparate sources, teaching \\

Michael P. Marder

2000-01-01

214

Ethanol dehydration to ethylene in a stratified autothermal millisecond reactor.  

PubMed

The concurrent decomposition and deoxygenation of ethanol was accomplished in a stratified reactor with 50-80 ms contact times. The stratified reactor comprised an upstream oxidation zone that contained Pt-coated Al(2)O(3) beads and a downstream dehydration zone consisting of H-ZSM-5 zeolite films deposited on Al(2)O(3) monoliths. Ethanol conversion, product selectivity, and reactor temperature profiles were measured for a range of fuel:oxygen ratios for two autothermal reactor configurations using two different sacrificial fuel mixtures: a parallel hydrogen-ethanol feed system and a series methane-ethanol feed system. Increasing the amount of oxygen relative to the fuel resulted in a monotonic increase in ethanol conversion in both reaction zones. The majority of the converted carbon was in the form of ethylene, where the ethanol carbon-carbon bonds stayed intact while the oxygen was removed. Over 90% yield of ethylene was achieved by using methane as a sacrificial fuel. These results demonstrate that noble metals can be successfully paired with zeolites to create a stratified autothermal reactor capable of removing oxygen from biomass model compounds in a compact, continuous flow system that can be configured to have multiple feed inputs, depending on process restrictions. PMID:21834091

Skinner, Michael J; Michor, Edward L; Fan, Wei; Tsapatsis, Michael; Bhan, Aditya; Schmidt, Lanny D

2011-08-22

215

Condensation in Microchannels  

Microsoft Academic Search

Condensation in microchannels has applications in a wide variety of advanced microthermal devices. Presented here is a review of both experimental and theoretical analyses of condensation in these microchannels, with special attention given to the effects of channel diameter and surface conditions on the flow regimes of condensing flows occurring in these channels. This review suggests that surface tension, rather

Yongping Chen; Mingheng Shi; Ping Cheng; G. P. Peterson

2008-01-01

216

Beware of condenser fouling  

Microsoft Academic Search

Many chemical process plants generate steam for power production and process use. Recovering this steam as condensate, and returning it to the boiler, is an economical way to recycle heat. This is usually done in a watercooled, steam-surface condenser located at the exhaust of a turbine. Poor performance of such a condenser -- which is really a large heat exchanger

Buecker

1995-01-01

217

Low Energy Nuclear Reactions: 2007 Update  

Microsoft Academic Search

This paper presents an overview of low energy nuclear reactions, a subset of the field of condensed matter nuclear science. Condensed matter nuclear science studies nuclear effects in and\\/or on condensed matter, including low energy nuclear reactions, an entirely new branch of science that gained widespread attention and notoriety beginning in 1989 with the announcement of a previously unrecognized source

Steven B. Krivit

2007-01-01

218

Elastic wave velocity and acoustic emission monitoring during Gypsum dehydration under triaxial stress conditions  

NASA Astrophysics Data System (ADS)

Dehydration experiments were performed on natural Gypsum polycrystal samples coming from Volterra, Italy in order to study contemporaneously the evolution of P and S elastic wave velocities and acoustic emission (AE) triggering. During these experiments, temperature was slowly raised at 0.15 degrees C per minute under constant stress conditions. Two experiments were realized under quasi-hydrostatic stress (15 and 55 MPa respectively). The third experiment was realized under constant triaxial stress (?3=45MPa, ?1=75MPa). All three were drained (10MPa constant pore pressure). In each experiments, both P and S wave velocities reduced drastically (as much as approx. 50% in the low confining pressure case) at the onset of dehydration. Importantly, the Vp/Vs ratio also decreased. Shortly after the onset of decrease in P and S wave velocities, the dehydration reaction was also accompanied by bursts of AEs. Time serie locations of the AEs show that they initiated from the pore pressure port, ie from where the pore fluid could easily be drained, and then slowly migrated within the sample. In each experiments, the AE rate could be positively correlated to the reaction rate, inferred from pore volumetry. In such a way, the AE rate reached a peak when the reaction was the fastest. Focal mechanism analysis of the largest AEs showed they had a large volumetric component in compaction, confirming that AEs were indeed related to pore closure and/or collapse. In addition, the AE rate also increased with confinement, ie when a larger amount of compaction was observed. Interestingly, when under differential stress conditions, AE focal mechanisms were mainly in shear. Additional dehydration experiments performed within an environmental scanning electron microscope under low vacuum highlight that, in drained conditions at least, the reaction seems to take place in two phases. First, cracks are being opened along cleavage planes within a single gypsum crystal, which allows for the fluid to escape. Second, the solid volume shrinks and pore collapse can occur. Such a scenario is also consistent with our in-situ analysis under pressure. Finally, a differential effective medium theory approach is used to invert crack density and crack average aspect ratio from elastic wave velocity measurements. Coupling this to Biot-Gassman equation, we can correct for some of the dispersion effects (mainly squirt flow) between the ultrasonic (MHz) and the seismic frequency (Hz) ranges. When doing so, we observe, that, under low confining pressures and in drained conditions at least, the evolution of elastic wave velocities is dominated by the effect due to nucleation of low aspect ratio crack during dehydration. Our results thus seem to point out that, because dehydration reaction are accompanied with crack nucleation, the signature of these reactions in nature, should, in fact, possibly be that of a low Vp/Vs ratio, contrarily to what has been instinctively assumed until now.

Brantut, N.; David, E. C.; Héripré, E.; Schubnel, A. J.; Zimmerman, R. W.; Gueguen, Y.

2010-12-01

219

Condensed Matter Nuclear Science  

NASA Astrophysics Data System (ADS)

1. General. A tribute to gene Mallove - the "Genie" reactor / K. Wallace and R. Stringham. An update of LENR for ICCF-11 (short course, 10/31/04) / E. Storms. New physical effects in metal deuterides / P. L. Hagelstein ... [et al.]. Reproducibility, controllability, and optimization of LENR experiments / D. J. Nagel -- 2. Experiments. Electrochemistry. Evidence of electromagnetic radiation from Ni-H systems / S. Focardi ... [et al.]. Superwave reality / I. Dardik. Excess heat in electrolysis experiments at energetics technologies / I. Dardik ... [et al.]. "Excess heat" during electrolysis in platinum/K[symbol]CO[symbol]/nickel light water system / J. Tian ... [et al.]. Innovative procedure for the, in situ, measurement of the resistive thermal coefficient of H(D)/Pd during electrolysis; cross-comparison of new elements detected in the Th-Hg-Pd-D(H) electrolytic cells / F. Celani ... [et al.]. Emergence of a high-temperature superconductivity in hydrogen cycled Pd compounds as an evidence for superstoihiometric H/D sites / A. Lipson ... [et al.]. Plasma electrolysis. Calorimetry of energy-efficient glow discharge - apparatus design and calibration / T. B. Benson and T. O. Passell. Generation of heat and products during plasma electrolysis / T. Mizuno ... [et al.]. Glow discharge. Excess heat production in Pd/D during periodic pulse discharge current in various conditions / A. B. Karabut. Beam experiments. Accelerator experiments and theoretical models for the electron screening effect in metallic environments / A. Huke, K. Czerski, and P. Heide. Evidence for a target-material dependence of the neutron-proton branching ratio in d+d reactions for deuteron energies below 20keV / A. Huke ... [et al.]. Experiments on condensed matter nuclear events in Kobe University / T. Minari ... [et al.]. Electron screening constraints for the cold fusion / K. Czerski, P. Heide, and A. Huke. Cavitation. Low mass 1.6 MHz sonofusion reactor / R. Stringham. Particle detection. Research into characteristics of X-ray emission laser beams from solidstate cathode medium of high-current glow discharge / A. B. Karabut. Charged particles from Ti and Pd foils / L. Kowalski ... [et al.]. Cr-39 track detectors in cold fusion experiments: review and perspectives / A. S. Roussetski. Energetic particle shower in the vapor from electrolysis / R. A. Oriani and J. C. Fisher. Nuclear reactions produced in an operating electrolysis cell / R. A. Oriani and J. C. Fisher. Evidence of microscopic ball lightning in cold fusion experiments / E. H. Lewis. Neutron emission from D[symbol] gas in magnetic fields under low temperature / T. Mizuno ... [et al.]. Energetic charged particle emission from hydrogen-loaded Pd and Ti cathodes and its enhancement by He-4 implantation / A. G. Lipson ... [et al.]. H-D permeation. Observation of nuclear transmutation reactions induced by D[symbol] gas permeation through Pd complexes / Y. Iwamura ... [et al.]. Deuterium (hydrogen) flux permeating through palladium and condensed matter nuclear science / Q. M. Wei ... [et al.]. Triggering. Precursors and the fusion reactions in polarized Pd/D-D[symbol]O system: effect of an external electric field / S. Szpak, P. A. Mosier-Boss, and F. E. Gordon. Calorimetric and neutron diagnostics of liquids during laser irradiation / Yu. N. Bazhutov ... [et al.]. Anomalous neutron capture and plastic deformation of Cu and Pd cathodes during electrolysis in a weak thermalized neutron field: evidence of nuclei-lattice exchange / A. G. Lipson and G. H. Miley. H-D loading. An overview of experimental studies on H/Pd over-loading with thin Pd wires and different electrolytic solutions / A. Spallone ... [et al.] -- 3. Transmutations. Photon and particle emission, heat production, and surface transformation in Ni-H system / E. Campari ... [et al.]. Surface analysis of hydrogen-loaded nickel alloys / E. Campari ... [et al.]. Low-energy nuclear reactions and the leptonic monopole / G. Lochak and L. Urutskoev. Results of analysis of Ti foil after glow discharge with deuterium / I. B. Savvat

Biberian, Jean-Paul

2006-02-01

220

Mild dehydration: a risk factor of constipation?  

PubMed

Constipation defined as changes in the frequency, volume, weight, consistency and ease of passage of the stool occurs in any age group. The most important factors known to promote constipation are reduced physical activity and inadequate dietary intake of fibres, carbohydrates and fluids. Fluid losses induced by diarrhoea and febrile illness alter water balance and promote constipation. When children increase their water consumption above their usual intake, no change in stool frequency and consistency was observed. The improvement of constipation by increasing water intake, therefore, may be effective in children only when voluntary fluid consumption is lower-than-normal for the child's age and activity level. In the elderly, low fluid intake, which may be indicative of hypohydration, was a cause of constipation and a significant relationship between liquid deprivation from 2500 to 500 ml per day and constipation was reported. Dehydration is also observed when saline laxatives are used for the treatment of constipation if fluid replacement is not maintained and may affect the efficacy of the treatment. While sulphate in drinking water does not appear to have a significant laxative effect, fluid intake and magnesium sulphate-rich mineral waters were shown to improve constipation in healthy infants. In conclusion, fluid loss and fluid restriction and thus de-or hypohydration increase constipation. It is thus important to maintain euhydration as a prevention of constipation. PMID:14681719

Arnaud, M J

2003-12-01

221

Dehydration and ionic conductance quantization in nanopores  

E-print Network

There has been tremendous experimental progress in the last decade in identifying the structure and function of biological pores (ion channels) and fabricating synthetic pores. Despite this progress, many questions still remain about the mechanisms and universal features of ionic transport in these systems. In this paper, we examine the use of nanopores to probe ion transport and to construct functional nanoscale devices. Specifically, we focus on the newly predicted phenomenon of quantized ionic conductance in nanopores as a function of the effective pore radius - a prediction that yields a particularly transparent way to probe the contribution of dehydration to ionic transport. We study the role of ionic species in the formation of hydration layers inside and outside of pores. We find that the ion type plays only a minor role in the radial positions of the predicted steps in the ion conductance. However, ions with higher valency form stronger hydration shells, and thus, provide even more pronounced, and therefore, more easily detected, drops in the ionic current. Measuring this phenomenon directly, or from the resulting noise, with synthetic nanopores would provide evidence of the deviation from macroscopic (continuum) dielectric behavior due to microscopic features at the nanoscale and may shed light on the behavior of ions in more complex biological channels.

Michael Zwolak; James Wilson; Massimiliano Di Ventra

2010-05-14

222

25. BUILDING NO. 527, DEHYDRATING HOUSE, DETAIL OF SOLVENT RECOVERY ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

25. BUILDING NO. 527, DEHYDRATING HOUSE, DETAIL OF SOLVENT RECOVERY DUCTS. SOUTH SIDE OF BUILDING. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

223

Dehydration and crystallization kinetics of zirconia-yttria gels  

SciTech Connect

Zirconia and zirconia-yttria gels containing 4 and 8 mol% yttria were obtained by coprecipitation and drying at 373 K. The dehydration and crystallization behavior of the dried gels was studied by DSC, TG, and XRD. The gels undergo elimination of water over a wide temperature range of 373--673 K. The peak temperature of the endotherm corresponding to dehydration and the kinetic constants for the process were not influenced by the yttria content of the gel. The enthalpy of dehydration observed was in good agreement with the heat of vaporization data. The dehydration was followed by a sharp exothermic crystallization process. The peak temperature of the exotherm and the activation energy of the process increased with an increase in yttria content, while the enthalpy of crystallization showed a decrease. The ``glow effect`` reduced with increasing yttria content. Pure zirconia crystallizes in the tetragonal form while the zirconia containing 4 and 8 mol% yttria appears to crystallize in the cubic form.

Ramanathan, S.; Muraleedharan, R.V.; Roy, S.K.; Nayar, P.K.K. [Bhabha Atomic Research Centre, Bombay (India). Metallurgy Division

1995-02-01

224

Volcanic fronts as a consequence of serpentinite dehydration in the fore-arc mantle wedge  

E-print Network

page -1- Volcanic fronts as a consequence of serpentinite dehydration in the fore-arc mantle wedge to deeper, hotter levels in the mantle. Eventual dehydration of these serpentinites discharges the fluid and subsequent dehydration of peridotites in mantle wedges, instead of direct dehydration of subducting slabs

Boyer, Edmond

225

Slab dehydration in the Earth's mantle transition zone Guillaume Richard , David Bercovici, Shun-Ichiro Karato  

E-print Network

Slab dehydration in the Earth's mantle transition zone Guillaume Richard , David Bercovici, Shun. One such mechanism could be linked to the dehydration of the slab. Studies of slab dehydration mainly this article as: Guillaume Richard et al., Slab dehydration in the Earth's mantle transition zone, Earth

226

Intra- and Extracellular Dehydration-Induced Thirst-Related Behavior in an Amphibian  

Microsoft Academic Search

The behavioral response to dehydration is critical to an animal’s survival. Because of their permeable skin, amphibians are particularly sensitive to dehydrating conditions. We tested the hypothesis that different forms of dehydration induce water absorption response (WR) behavior in the desert spadefoot toad, Scaphiopus couchii. First, we determined the behavioral response to intracellular dehydration by treating fully hydrated toads with

Kris Taylor; Loretta P. Mayer; Catherine R. Propper

1998-01-01

227

Quality evaluation of onion (Allium cepa) cultivars for dehydration  

E-print Network

QUALITY EVALUATION OF ONION (Allium ~ce a) CULTIVARS FOR DEHYDRATION A Thesis by LINDA JEAN TALLEY Submitted to the Graduate College of Texas A8M Uni vers i ty in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE... December 1979 Major Subject: Food Science and Technology EQUALITY EVALUATION OF ONION (Allium ~ce a) CULTIVARS FOR DEHYDRATION A Thesis by LINDA JEAN TALLEY Approved as to style and content by: (Chairman of Committee) (Head of Department) ~4'EZ...

Talley, Linda Jean

2012-06-07

228

Fatal cerebral edema and intracranial hemorrhage associated with hypernatremic dehydration  

Microsoft Academic Search

We report neuroimaging findings of intracranial hemorrhage and cerebral edema in an infant with obtundation and seizures,\\u000a initially suspected to be secondary to non-accidental trauma but finally attributed to hypernatremic dehydration. Neuroimaging\\u000a findings due to hypernatremic dehydration have not been previously described in the radiologic literature. Hypernatremia should\\u000a be included in the differential diagnosis of intracranial hemorrhage in the infant

Raman Mocharla; Steven M. Schexnayder; Charles M. Glasier

1997-01-01

229

Fatal cerebral edema and intracranial hemorrhage associated with hypernatremic dehydration.  

PubMed

We report neuroimaging findings of intracranial hemorrhage and cerebral edema in an infant with obtundation and seizures, initially suspected to be secondary to non-accidental trauma but finally attributed to hypernatremic dehydration. Neuroimaging findings due to hypernatremic dehydration have not been previously described in the radiologic literature. Hypernatremia should be included in the differential diagnosis of intracranial hemorrhage in the infant without evidence of nonaccidental trauma. PMID:9323240

Mocharla, R; Schexnayder, S M; Glasier, C M

1997-10-01

230

Energy Reduction in the Production of Ethanol by Membrane Dehydration  

Microsoft Academic Search

Distillation\\/dehydration represents the largest fraction of the energy used in the production of ethanol. The Siftek technology introduced in this paper carries the potential of reducing energy consumption of distillation\\/dehydration by up to 50% through the single pass removal of water from the water\\/ethanol stream at the beer column outlet, using a novel membrane process. For a modern corn-based ethanol

Pierre Côté; Christian Roy; Normand Bernier

2009-01-01

231

External Validation and Comparison of Three Pediatric Clinical Dehydration Scales  

PubMed Central

Objective To prospectively validate three popular clinical dehydration scales and overall physician gestalt in children with vomiting or diarrhea relative to the criterion standard of percent weight change with rehydration. Methods We prospectively enrolled a non-consecutive cohort of children ? 18 years of age with an acute episode of diarrhea or vomiting. Patient weight, clinical scale variables and physician clinical impression, or gestalt, were recorded before and after fluid resuscitation in the emergency department and upon hospital discharge. The percent weight change from presentation to discharge was used to calculate the degree of dehydration, with a weight change of ? 5% considered significant dehydration. Receiver operating characteristics (ROC) curves were constructed for each of the three clinical scales and physician gestalt. Sensitivity and specificity were calculated based on the best cut-points of the ROC curve. Results We approached 209 patients, and of those, 148 were enrolled and 113 patients had complete data for analysis. Of these, 10.6% had significant dehydration based on our criterion standard. The Clinical Dehydration Scale (CDS) and Gorelick scales both had an area under the ROC curve (AUC) statistically different from the reference line with AUCs of 0.72 (95% CI 0.60, 0.84) and 0.71 (95% CI 0.57, 0.85) respectively. The World Health Organization (WHO) scale and physician gestalt had AUCs of 0.61 (95% CI 0.45, 0.77) and 0.61 (0.44, 0.78) respectively, which were not statistically significant. Conclusion The Gorelick scale and Clinical Dehydration Scale were fair predictors of dehydration in children with diarrhea or vomiting. The World Health Organization scale and physician gestalt were not helpful predictors of dehydration in our cohort. PMID:24788134

Jauregui, Joshua; Nelson, Daniel; Choo, Esther; Stearns, Branden; Levine, Adam C.; Liebmann, Otto; Shah, Sachita P.

2014-01-01

232

The dehydration process of gypsum under high pressure  

NASA Astrophysics Data System (ADS)

The effects of pressure on the dehydration of gypsum materials were investigated up to 633 K and 25 GPa by using Raman spectroscopy and synchrotron X-ray diffraction with an externally heated diamond anvil cell. At 2.5 GPa, gypsum starts to dehydrate around 428 K, by forming bassanite, CaSO4 hemihydrate, which completely dehydrates to ?-anhydrite at 488 K. All the sulphate modes decrease linearly between 293 and 427 K with temperature coefficients ranging from -0.119 to -0.021 cm-1 K-1, where an abrupt change in the ?3 mode and in the OH-stretching region indicates the beginning of dehydration. Increasing the temperature to 488 K, the OH-stretching modes completely disappear, marking the complete dehydration and formation of ?-anhydrite. Moreover, the sample changes from transparent to opaque to transparent again during the dehydration sequence gypsum-bassanite-?-anhydrite, which irreversibly transforms to ?-anhydrite form at 593 K. These data compared with the dehydration temperature at room pressure indicate that the dehydration temperature increases with pressure with a ? P/? T slope equal to 230 bar/K. Synchrotron X-ray diffraction experiments show similar values of temperature and pressure for the first appearance of bassanite. Evidence of phase transition from ?-anhydrite structure to the monazite type was observed at about 2 GPa under cold compression. On the other hand at the same pressure (2 GPa and 633 K), ?-anhydrite was found, indicating a positive Clausis-Clayperon slope of the transition. This transformation is completely reversible as showed by the Raman spectra on the sample recovered after phase transition.

Comodi, P.; Kurnosov, A.; Nazzareni, S.; Dubrovinsky, L.

2012-01-01

233

Fructokinase activity mediates dehydration-induced renal injury  

PubMed Central

The epidemic of chronic kidney disease in Nicaragua (Mesoamerican nephropathy) has been linked with recurrent dehydration. Here we tested whether recurrent dehydration may cause renal injury by activation of the polyol pathway, resulting in the generation of endogenous fructose in the kidney that might subsequently induce renal injury via metabolism by fructokinase. Wild-type and fructokinase-deficient mice were subjected to recurrent heat-induced dehydration. One group of each genotype was provided water throughout the day and the other group was hydrated at night, after the dehydration. Both groups received the same total hydration in 24?h. Wild-type mice that received delayed hydration developed renal injury, with elevated serum creatinine, increased urinary NGAL, proximal tubular injury, and renal inflammation and fibrosis. This was associated with activation of the polyol pathway, with increased renal cortical sorbitol and fructose levels. Fructokinase-knockout mice with delayed hydration were protected from renal injury. Thus, recurrent dehydration can induce renal injury via a fructokinase-dependent mechanism, likely from the generation of endogenous fructose via the polyol pathway. Access to sufficient water during the dehydration period can protect mice from developing renal injury. These studies provide a potential mechanism for Mesoamerican nephropathy. PMID:24336030

Roncal Jimenez, Carlos A; Ishimoto, Takuji; Lanaspa, Miguel A; Rivard, Christopher J; Nakagawa, Takahiko; Ejaz, A. Ahsan; Cicerchi, Christina; Inaba, Shinichiro; Le, MyPhuong; Miyazaki, Makoto; Glaser, Jason; Correa-Rotter, Ricardo; González, Marvin A; Aragón, Aurora; Wesseling, Catharina; Sánchez-Lozada, Laura G; Johnson, Richard J

2014-01-01

234

Dehydration of alcohols over alumina: effect of sodium impregnation on the mode of elimination  

SciTech Connect

Dehydration of secondary alcohols has always been the key to studying reaction mechanisms of reactions catalyzed by oxides. The ..gamma..-alumina-promoted reactions always afforded a low S/sub 12/ (1-olefin/2-olefin) and high S/sub Ct/ (Cis/trans). These were shown to proceed by the anti mode of the elimination of elements of water. The effect of sodium impregnation has been studied, in detail, to understand the mode of elimination operative over these doped catalysts. Studies were conducted with 2-butanol and threo-3-methyl-2-pentanol over these catalysts. It appears that although sodium poisoning affected selectivity S/sub 12/, it did not show any variation in S/sub ct/, suggesting no variation in the mode of elimination. The studies conducted with threo-3-methyl-2-pentanol confirm that only the anti mode of elimination is operative on these catalysts.

Siddhan, S.; Narayanan, K.

1981-04-01

235

Quark Condensates: Flavour Dependence  

E-print Network

We determine the q-bar q condensate for quark masses from zero up to that of the strange quark within a phenomenologically successful modelling of continuum QCD by solving the quark Schwinger-Dyson equation. The existence of multiple solutions to this equation is the key to an accurate and reliable extraction of this condensate using the operator product expansion. We explain why alternative definitions fail to give the physical condensate.

R. Williams; C. S. Fischer; M. R. Pennington

2007-03-23

236

Economical Condensing Turbines?  

E-print Network

Economical Condensing Turbines? by J.E.Dean, P.E. Steam turbines have long been used at utilities and in industry to generate power. There are three basic types of steam turbines: condensing, letdown 1 and extraction/condensing. ? Letdown... turbines reduce the pressure of the incoming steam to one or more pressures and generate power very efficiently, assuming that all the letdown steam has a use. Two caveats: ? Letdown turbines produce power based upon steam requirements and not based upon...

Dean, J. E.

237

Development of substituted dihydrofurans and 1,2,3-NH-triazoles through Lewis base catalyzed cascade condensation and their application in synthesis of chiral triazole derivatives through Mitsunobu reaction.  

E-print Network

??Part 1: A one-pot synthesis of substituted dihydrofurans was developed from a Lewis base catalyzed three-component cascade condensation with nitroalkenes, aldehydes and 1,3-dicarbonyl compounds. A… (more)

Liao, Tao, 1986-

2011-01-01

238

Muscovite dehydration melting in Si-rich metapelites: microstructural evidence from trondhjemitic migmatites, Roded, Southern Israel  

NASA Astrophysics Data System (ADS)

Making a distinction between partial melting and subsolidus segregation in amphibolite facies migmatites is difficult. The only significant melting reactions at lowpressures, either vapour saturated or muscovite dehydration melting, do not produce melanocratic peritectic phases. If protoliths are Si-rich and K-poor, then peritectic sillimanite and K-feldspar will form in scarce amounts, and may be lost by retrograde rehydration. The Roded migmatites of southern Israel (northernmost Arabian Nubian Shield) formed at P = 4.5 ± 1 kbar and T ? 700 °C and include Si-rich, K-poor paragneissic paleosome and trondhjemitic leucosomes. The lack of K-feldspar in leucosomes was taken as evidence for the non-anatectic origin of the Roded migmatites (Gutkin and Eyal, Isr J Earth Sci 47:117, 1998). It is shown here that although the Roded migmatites experienced significant post-peak deformation and recrystallization, microstructural evidence for partial melting is retained. Based on these microstructures, coupled with pseudosection modelling, indicators of anatexis in retrograded migmatites are established. Phase diagram modelling of neosomes shows the onset of muscovite dehydration melting at 4.5 kbar and 660 °C, forming peritectic sillimanite and K-feldspar. Adjacent non-melted paleosomes lack muscovite and would thus not melt by this reaction. Vapour saturation was not attained, as it would have formed cordierite that does not exist. Furthermore, vapour saturation would not allow peritectic K-feldspar to form, however K-feldspar is ubiquitous in melanosomes. Direct petrographic evidence for anatexis is rare and includes euhedral plagioclase phenocrysts in leucosomes and quartz-filled embayments in corroded plagioclase at leucosome-melanosome interfaces. In deformed and recrystallized rocks muscovite dehydration melting is inferred by: (1) lenticular K-feldspar enclosed by biotite in melanosomes, (2) abundant myrmekite in leucosomes, (3) muscovite-quartz symplectites after sillimanite in melanosomes and associated with myrmekite in leucosomes. While peritectic K-feldspar formed in melanosomes by muscovite dehydration melting reaction, K-feldspar crystallizing from granitic melt in adjacent leucosome was myrmekitized. Excess potassium was used in rehydration of sillimanite to muscovite.

Anenburg, Michael; Katzir, Yaron

2014-02-01

239

Enantioselective dehydration of butan-2-ol using zeolite Y modified with dithiane oxides  

SciTech Connect

Modification of zeolite H-Y by dithiane oxides (2-R-1,3-dithiane 1-oxide; R = H, CH{sub 3}, C{sub 6}H{sub 5}) is shown to enhance significantly its activity for the acid catalyzed gas phase dehydration of butan-2-ol. The rate enhancement is observed for catalysts that are prepared by adding the dithiane oxide to the zeolite synthesis gel or by adsorption of the dithiane oxide onto commercial samples of zeolite H-Y. The origin of the rate enhancement is considered to result from a specific interaction between the dithiane oxide modifier with both the extra-framework and framework aluminum in the zeolite. Modification of zeolite H-Y with (R)-1,3-dithiane 1-oxide enhances the conversion of (S)-butan-2-ol compared to (R)-butan-2-ol in the temperature range 110-150{degrees}C when the two enantiomers are reacted separately. Modification with (S)-2-phenyl-1,3-dithiane 1-oxide gives a catalyst for which (R)-butan-2-ol is the most reactive of the two enantiomers. Reaction of racemic butan-2-ol over these chirally modified H-Y zeolites demonstrates that this modification procedure makes the zeolite enantiomerically discriminating and one enantiomer preferentially reacts, although both are present in the micropores under the reaction conditions. This effect is considered to be due to enantioselective rate enhancement, since, although the rate of dehydration of both enantiomers is enhanced in the chiral environment, the dehydration rate of one enantiomer is accelerated relative to the other. It is suggested that the effect is due to preferential adsorption at the chiral active site. 34 refs., 7 figs., 6 tabs.

Feast, S.; Siddiqui, H.; Bethell, D. [Univ. of Liverpool (United Kingdom)] [and others] [Univ. of Liverpool (United Kingdom); and others

1997-04-15

240

Condensation Energy of a Spacetime Condensate  

E-print Network

Starting from an analogy between the Planck-Einstein scale and the dual length scales in Ginzburg-Landau theory of superconductivity, and assuming that space-time is a condensate of neutral fermionic particles with Planck mass, we derive the baryonic mass of the universe. In that theoretical framework baryonic matter appears to be associated with the condensation energy gained by spacetime in the transition from its normal (symetric) to its (less symetric) superconducting-like phase. It is shown however that the critical transition temperature cannot be the Planck temperature. Thus leaving open the enigma of the microscopic description of spacetime at quantum level.

Clovis Jacinto de Matos; Pavol Valko

2010-12-17

241

Dehydration of Methylcyclohexanol Isomers in the Undergraduate Organic Laboratory and Product Analysis by Gas Chromatography-Mass Spectroscopy (GC-MS)  

ERIC Educational Resources Information Center

Dehydrations of "cis"- and "trans"-2-methylcyclohexanol mixtures were carried out with 60% sulfuric acid at 78-80 [degrees]C as a function of time and the products were identified by gas chromatography-mass spectroscopy (GC-MS) analysis. The compounds identified in the reaction mixtures include alkenes, 1-, 3-, and 4-methylcyclohexenes and…

Clennan, Malgorzata M.; Clennan, Edward L.

2011-01-01

242

The use of the Ugi four-component condensation  

Microsoft Academic Search

This protocol describes a procedure for the Ugi four-component condensation. It describes the general mechanism as well as the effects of the nature of the components on the Ugi reaction. It also describes the effects of the reaction conditions on the reaction, along with special procedures and workup. The experimental procedure is exemplified by a description of the preparation of

Stefano Marcaccini; Tomás Torroba

2007-01-01

243

Proceedings: Condenser Technology Conference  

Microsoft Academic Search

Steam surface condenser and associated systems performance strongly affects availability and. heat rate in nuclear and fossil power plants. Thirty-one papers presented at the 1993 conference discuss research results, industry experience, and case histories of condenser problems and solutions. These papers have been cataloged separately elsewhere.

Mussalli

1994-01-01

244

Catalytic conversion of alcohols: the impact of inductive effect for secondary alcohol dehydration  

SciTech Connect

The use of linear free energy relationships (LFER) has become widespread in chemistry and correlations of product selectivity data for elimination reactions have resulted from application of LFER. A number of these correlations have involved heterogeneous catalysis. Dautzenberg and Knoezinger reported that the 1-alkene selectivity from the dehydration of 2-ols, with the general formula RCH/sub 2/CHOHCH/sub 3/, where R varied from methyl to tert-butyl, fit a LFER when correlated with Taft's inductive constant. Davis found that isomerization of the primary alkene products from 2-butanol and 2-pentanol could make a significant contribution in determining the slope of the LFER plot for an alumina catalyst. Davis contended that the inductive effect had little, if any, impact in determining the selectivity for terminal alkene. In view of the results with the alumina catalysts, it appeared desirable to extend the alcohol dehydration study to include other catalysts. Davis found that 2-octanol, because of its higher boiling point, provided a higher relative pressure and, as a consequence, a higher surface coverage than 2-butanol; thus, at low (less than ca. 20%) conversion 2-octanol effectively retarded secondary reactions of the primary butene and pentene products. Consequently, 2-butanol and 2-pentanol were converted in the presence of 2-octanol in these studies. Data are given for the following catalysts: aluminum oxide, thorium oxide, tungsten oxide, gallium oxide, indium oxide, and titanium oxide. 14 references.

Dabbagh, H.A.; Davis, B.H.

1988-04-01

245

Mechanisms of liquefaction and pyrolysis reactions of biomass  

Microsoft Academic Search

In the liquefaction process, the micellar-like broken down fragments produced by hydrolysis are degraded to smaller compounds by dehydration, dehydrogenation, deoxygenation and decarboxylation. These compounds once produced, rearrange through condensation, cyclization and polymerization, leading to new compounds. Thermal depolymerization and decomposition of biomass, cellulose, hemicelluloses and products were formed as well as a solid residue of charcoal. The mechanism of

A. Demirba?

2000-01-01

246

Serum markers of chronic dehydration are associated with saliva spinability.  

PubMed

Findings of a relationship between saliva and dehydration have been observed, but the precise nature of these relationships is unclear and no evidence of a direct link has been found. In particular, no study reports a relationship between chronic dehydration and saliva conditions in community-dwelling older adults. This study aimed to identify whether salivary conditions are sensitive to body hydration markers in an elderly population. A total of 403 subjects aged 76 years participated in the study. Stimulated saliva flow rate and spinability of saliva were measured. In addition, determinations of serum levels of uric acid, blood urea nitrogen (BUN), creatinine, sodium and potassium were made. Dehydration was defined as uric acid >/= 7 mg dL(-1) according to the standard value. The salivary spinability were significantly associated with the concentration of uric acid (OR=2.06, P=0.044) according to multiple logistic regression analysis. In addition, after adjusting for gender, the uric acid concentration and the salivary spinability was significantly associated with BUN, potassium and creatinine levels. The subjects with high uric acid levels (>/= 7 mg dL(-1)) had the most elastic saliva. Both BUN and serum creatinine are the most commonly used indicators of renal function. Therefore, our findings might demonstrate that older adults who are dehydrated showed highly elastic saliva, which was associated with renal function. In conclusion, this study suggests that there is a significant relationship between chronic dehydration status and salivary spinability level. PMID:17824885

Yoshihara, A; Hirotomi, T; Takano, N; Kondo, T; Hanada, N; Miyazaki, H

2007-10-01

247

Evolution of microstructure and elastic wave velocities in dehydrated gypsum samples  

NASA Astrophysics Data System (ADS)

This study aims at contributing to the experimental database of changes in rock physical properties, particularly elastic wave velocities, induced by devolatilization reactions. Cylindrical samples of natural gypsum were dehydrated in air for up to 800 h at ambient pressure and temperatures between 378 and 423 K. Subsequently, the transformation kinetics, reaction induced changes in microstructure and porosity and the concurrent evolution of the sample P and S-wave velocities were constrained. Weighing the heated samples in predefined time intervals yielded the reaction progress where the stoichiometric mass balance indicated an ultimate dehydration to anhydrite regardless of temperature. Porosity was observed to continuously increase with reaction progress from approximately 2 % for fully hydrated samples to 30 % for completely dehydrated ones, whilst the initial bulk volume was preserved. In a first set, P-wave velocity was measured at ambient conditions with ultrasonic transducers indicating a linear decrease with porosity from 5.2 km/s at 2 % to 1.0 km/s at 30 %. Results of a second set of ultrasonic measurements for both P and S-waves will be presented as well aiming at a spatially resolved wave velocity dependence on microstructure. For P-waves three different effective medium models - Voigt, Wyllie (Reuss), and Nur - were compared to the data. The linear dependence of P-wave velocity on porosity observed is best represented by the Voigt bound. The Voigt bound, however, overestimates the measured values significantly. The Wyllie-Equation (the Reuss bound) does not replicate the linear decrease in P-wave velocity with porosity and generally underestimates the data. However, at porosities above approximately 25 % the agreement with measured values is excellent. The Nur-Model yields a nonlinear dependence but replicates the data best for model-inherent critical porosities between 0.25 and 0.3. Thin section micrographs taken on selected samples reveal a sharp reaction front progressively migrating sample inwards. SEM imaging confirmed this observation, additionally showing (1) that the cylindrical outer rim consists of a highly porous network within an anhydrite matrix and (2) that the remaining inner cylinder appears unaltered at 388 K whereas bassanite needles progressively turning into anhydrite can be found at 398 K.

Milsch, H.; Priegnitz, M.

2012-04-01

248

Isothermal dehydration of thin films of water and sugar solutions  

NASA Astrophysics Data System (ADS)

The process of quasi-isothermal dehydration of thin films of pure water and aqueous sugar solutions is investigated with a dual experimental and theoretical approach. A nanoporous paper disk with a homogeneous internal structure was used as a substrate. This experimental set-up makes it possible to gather thermodynamic data under well-defined conditions, develop a numerical model, and extract needed information about the dehydration process, in particular the water activity. It is found that the temperature evolution of the pure water film is not strictly isothermal during the drying process, possibly due to the influence of water diffusion through the cellulose web of the substrate. The role of sugar is clearly detectable and its influence on the dehydration process can be identified. At the end of the drying process, trehalose molecules slow down the diffusion of water molecules through the substrate in a more pronounced way than do the glucose molecules.

Heyd, R.; Rampino, A.; Bellich, B.; Elisei, E.; Cesàro, A.; Saboungi, M.-L.

2014-03-01

249

Isothermal dehydration of thin films of water and sugar solutions.  

PubMed

The process of quasi-isothermal dehydration of thin films of pure water and aqueous sugar solutions is investigated with a dual experimental and theoretical approach. A nanoporous paper disk with a homogeneous internal structure was used as a substrate. This experimental set-up makes it possible to gather thermodynamic data under well-defined conditions, develop a numerical model, and extract needed information about the dehydration process, in particular the water activity. It is found that the temperature evolution of the pure water film is not strictly isothermal during the drying process, possibly due to the influence of water diffusion through the cellulose web of the substrate. The role of sugar is clearly detectable and its influence on the dehydration process can be identified. At the end of the drying process, trehalose molecules slow down the diffusion of water molecules through the substrate in a more pronounced way than do the glucose molecules. PMID:24697464

Heyd, R; Rampino, A; Bellich, B; Elisei, E; Cesàro, A; Saboungi, M-L

2014-03-28

250

Functional and technological potential of dehydrated Phaseolus vulgaris L. flours.  

PubMed

The effect of cooking followed by dehydration was evaluated on the bioactive composition, antioxidant activity and technological properties of two varieties (Negro 8025 and Bayo Madero) of common beans. Quercetin, rutin, and phenolic acids were the most abundant phenolics found. Cooking processes resulted in decreased values of some phenolic compounds and antioxidant capacity. A subsequent dehydration increased TEAC values, resistant starch content and decreased starch digestibility. Oligosaccharides and dietary fibre were preserved in both treatments. Variety had a strong impact on phytochemical profile, being Negro 8025 that exhibited the highest content of most of the compounds assessed. Water absorption index (WAI) and oil absorption capacity (OAC) were determined in order to measure technological suitability. Dehydration produced flours with stable WAI and low oil pick up. The results suggest that the flours of Negro 8025 beans have a good potential to be considered as functional ingredient for healthy food products. PMID:24837948

Ramírez-Jiménez, A K; Reynoso-Camacho, R; Mendoza-Díaz, S; Loarca-Piña, G

2014-10-15

251

Effect of experimental and sample factors on dehydration kinetics of mildronate dihydrate: mechanism of dehydration and determination of kinetic parameters.  

PubMed

The dehydration kinetics of mildronate dihydrate [3-(1,1,1-trimethylhydrazin-1-ium-2-yl)propionate dihydrate] was analyzed in isothermal and nonisothermal modes. The particle size, sample preparation and storage, sample weight, nitrogen flow rate, relative humidity, and sample history were varied in order to evaluate the effect of these factors and to more accurately interpret the data obtained from such analysis. It was determined that comparable kinetic parameters can be obtained in both isothermal and nonisothermal mode. However, dehydration activation energy values obtained in nonisothermal mode showed variation with conversion degree because of different rate-limiting step energy at higher temperature. Moreover, carrying out experiments in this mode required consideration of additional experimental complications. Our study of the different sample and experimental factor effect revealed information about changes of the dehydration rate-limiting step energy, variable contribution from different rate limiting steps, as well as clarified the dehydration mechanism. Procedures for convenient and fast determination of dehydration kinetic parameters were offered. PMID:24729295

B?rzi?š, Agris; Acti?š, Andris

2014-06-01

252

The BUDDY (Bedside Ultrasound to Detect Dehydration in Youth) study  

PubMed Central

Background Prior research suggests that the ratio of the ultrasound-measured diameter of the inferior vena cava to the aorta correlates with the level of dehydration in children. This study was designed to externally validate this and to access the accuracy of the ultrasound measured inspiratory IVC collapse and physician gestalt to predict significant dehydration in children in the emergency department. Methods We prospectively enrolled a non-consecutive cohort of children ?18 years old. Patient weight, ultrasound measurements of the IVC and Ao, and physician gestalt were recorded. The percent weight change from presentation to discharge was used to calculate the degree of dehydration. A weight change of ?5% was considered clinically significant dehydration. Receiver operating characteristic (ROC) curves were constructed for each of the ultrasound measurements and physician gestalt. Sensitivity (SN) and specificity (SP) were calculated based on previously established cutoff points of the IVC/Ao ratio (0.8), the IVC collapsibility index of 50%, and a new cut off point of IVC collapsibility index of 80% or greater. Intra-class correlation coefficients were calculated to assess the degree of inter-rater reliability between ultrasound observers. Results Of 113 patients, 10.6% had significant dehydration. The IVC/Ao ratio had an area under the ROC curve (AUC) of 0.72 (95% CI 0.53 to 0.91) and, with a cutoff of 0.8, produced a SN of 67% and a SP of 71% for the diagnosis of significant dehydration. The IVC collapsibility index of 50% had an AUC of 0.58 (95% CI 0.44 to 0.72) and, with a cutoff of 80% collapsibility, produced a SN of 83% and a SP of 42%. The intra-class correlation coefficient was 0.83 for the IVC/Ao ratio and 0.70 for the IVC collapsibility. Physician gestalt had an AUC of 0.61 (95% CI 0.44 to 0.78) and, with a cutoff point of 5, produced a SN of 42% and a SP of 65%. Conclusions The ultrasound-measured IVC/Ao ratio is a modest predictor of significant dehydration in children. The inspiratory IVC collapse and physician gestalt were poor predictors of the actual level of dehydration in this study. PMID:25411590

2014-01-01

253

Electrolyte vapor condenser  

DOEpatents

A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well. 3 figs.

Sederquist, R.A.; Szydlowski, D.F.; Sawyer, R.D.

1983-02-08

254

Electrolyte vapor condenser  

DOEpatents

A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well.

Sederquist, Richard A. (Newington, CT); Szydlowski, Donald F. (East Hartford, CT); Sawyer, Richard D. (Canton, CT)

1983-01-01

255

Steam condenser performance  

SciTech Connect

To understand condenser performance, it is necessary to perceive it as a whole machine and not just a single tube or tube bundle. A new heat-transfer rate is defined based on overall tube-bundle performance. This condenser performance standard has achieved its intended mission. Overall tube-bundle heat-transfer rates ensure that users can rely on the results in their plant design. It also assures users that they can purchase the performance from competent manufacturers. The paper discusses condenser operation and design, tube bundle operation and design, and heat transfer rate.

NONE

1995-05-01

256

Polariton Condensate Transistor Switch  

E-print Network

A polariton condensate transistor switch is realized through optical excitation of a microcavity ridge with two beams. The ballistically ejected polaritons from a condensate formed at the source are gated using the 20 times weaker second beam to switch on and off the flux of polaritons. In the absence of the gate beam the small built-in detuning creates potential landscape in which ejected polaritons are channelled toward the end of the ridge where they condense. The low loss photon-like propagation combined with strong nonlinearities associated with their excitonic component makes polariton based transistors particularly attractive for the implementation of all-optical integrated circuits.

Gao, T; Liew, T C H; Tsintzos, S I; Stavrinidis, G; Deligeorgis, G; Hatzopoulos, Z; Savvidis, P G

2012-01-01

257

Condensed Matter Nuclear Science  

NASA Astrophysics Data System (ADS)

Preface -- 1. General. Progress in condensed matter nuclear science / A. Takahashi. Summary of ICCF-12 / X. Z. Li. Overview of light water/hydrogen-based low-energy nuclear reactions / G. H. Miley and P. J. Shrestha -- 2. Excess heat and He detection. Development of "DS-reactor" as the practical reactor of "cold fusion" based on the "DS-cell" with "DS-cathode" / Y. Arata and Y.-C. Zhang. Progress in excess of power experiments with electrochemical loading of deuterium in palladium / V. Violante ... [et al.]. Anomalous energy generation during conventional electrolysis / T. Mizuno and Y. Toriyabe. "Excess heat" induced by deuterium flux in palladium film / B. Liu ... [et al.]. Abnormal excess heat observed during Mizuno-type experiments / J.-F. Fauvarque, P. P. Clauzon and G. J.-M. Lallevé. Seebeck envelope calorimetry with a Pd|D[symbol]O + H[symbol]SO[symbol] electrolytic cell / W.-S. Zhang, J. Dash and Q. Wang. Observation and investigation of nuclear fusion and self-induced electric discharges in liquids / A. I. Koldamasov ... [et al.]. Description of a sensitive seebeck calorimeter used for cold fusion studies / E. Storms. Some recent results at ENEA / M. Apicella ... [et al.]. Heat measurement during plasma electrolysis / K. Iizumi ... [et al.]. Effect of an additive on thermal output during electrolysis of heavy water with a palladium cathode / Q. Wang and J. Dash. Thermal analysis of calorimetric systems / L. D'Aulerio ... [et al.]. Surface plasmons and low-energy nuclear reactions triggering / E. Castagna ... [et al.]. Production method for violent TCB jet plasma from cavity / F. Amini. New results and an ongoing excess heat controversy / L. Kowalski ... [et al.] -- 3. Transmutation. Observation of surface distribution of products by X-ray fluorescence spectrometry during D[symbol] gas permeation through Pd Complexes / Y. Iwamura ... [et al.]. Discharge experiment using Pd/CaO/Pd multi-layered cathode / S. Narita ... [et al.]. Producing transmutation element on multi-layered Pd sample by deuterium permeation / H. Yamada ... [et al.]. Experimental observation and combined investigation of high-performance fusion of iron-region isotopes in optimal growing microbiological associations / V. I. Vysotskii ... [et al.]. Research into low-energy nuclear reactions in cathode sample solid with production of excess heat, stable and radioactive impurity nuclides / A. B. Karabut. Influence of parameters of the glow discharge on change of structure and the isotope composition of the cathode materials / I. B. Savvatimova and D. V. Gavritenkov. Elemental analysis of palladium electrodes after Pd/Pd light water critical electrolysis / Y. Toriyabe ... [et al.]. Progress on the study of isotopic composition in metallic thin films undergone to electrochemical loading of hydrogen / M. Apicella ... [et al.]. In situ accelerator analyses of palladium complex under deuterium permeation / A. Kitamura ... [et al.]. High-resolution mass spectrum for deuterium (hydrogen) gas permeating palladium film / Q. M. Wei ... [et al.]. ICP-MS analysis of electrodes and electrolytes after HNO[symbol]/H[symbol]O electrolysis / S. Taniguchi ... [et al.]. The Italy-Japan project - fundamental research on cold transmutation process for treatment of nuclear wastes / A. Takahashi, F. Celani and Y. Iwamura -- 4. Nuclear physics approach. Reproducible nuclear emissions from Pd/PdO:Dx heterostructure during controlled exothermic deuterium desorption / A. G. Lipson ... [et al.]. Correct identification of energetic alpha and proton tracks in experiments on CR-39 charged particle detection during hydrogen desorption from Pd/PdO:H[symbol] heterostructure / A. S. Roussetski ... [et al.]. Intense non-linear soft X-ray emission from a hydride target during pulsed D bombardment / G. H. Miley ... [et al.]. Enhancement of first wall damage in ITER type TOKAMAK due to LENR effects / A. G. Lipson, G. H. Miley and H. Momota. Generation of DD-reactions in a ferroelectric KD[symbol]PO[symbol] single crystal during transition

Takahashi, Akito; Ota, Ken-Ichiro; Iwamura, Yashuhiro

258

Catalytic dehydration of carbohydrates on in situ exfoliatable layered niobic acid in an aqueous system under microwave irradiation.  

PubMed

A simple and efficient microwave-assisted HNb(3)O(8) catalytic process is proposed for the dehydration of carbohydrates in the aqueous phase. A 5-hydroxymethylfurfural (HMF) yield of 55.9 % was achieved at a high substrate/catalyst weight ratio of 50 from a 10 wt % fructose solution, which is close to the yield achieved by homogeneous aqueous systems. The critical factor for this performance is the fast in situ exfoliation of layered HNb(3)O(8) with the aid of microwave irradiation, which leads to quasi-homogeneous catalytic behavior. Importantly, the catalytic system is also applicable for the one-pot production of HMF from di- and polysaccharides, such as inulin, through a consecutive hydrolysis-dehydration reaction. Additionally, the unique restacking feature of the exfoliated HNb(3)O(8) ensures the good reusability of the catalyst. PMID:23606474

Wu, Qingbin; Yan, Yani; Zhang, Qian; Lu, Jinhua; Yang, Zhijian; Zhang, Yahong; Tang, Yi

2013-05-01

259

Ghost condensate busting  

SciTech Connect

Applying the Thomas-Fermi approximation to renormalizable field theories, we construct ghost condensation models that are free of the instabilities associated with violations of the null-energy condition.

Bilic, Neven [Rudjer Boskovic Institute, 10002 Zagreb (Croatia)] [Rudjer Boskovic Institute, 10002 Zagreb (Croatia); Tupper, Gary B; Viollier, Raoul D, E-mail: bilic@thphys.irb.hr, E-mail: gary.tupper@uct.ac.za, E-mail: raoul.viollier@uct.ac.za [Centre of Theoretical Physics and Astrophysics, University of Cape Town, Rondebosch 7701 (South Africa)

2008-09-15

260

THE COLOR GLASS CONDENSATE.  

SciTech Connect

The Color Glass Condensate is a state of high density gluonic matter which controls the high energy limit of hadronic interactions. Its properties are important for the initial conditions for matter produced at RHIC.

MCLERRAN,L.

2001-08-26

261

Key condenser failure mechanisms  

SciTech Connect

Eight practical lessons highlight many of the factors that can influence condenser tube corrosion at coal-fired utilities and the effects contaminant in-leakage can have on steam generating units. 1 ref., 4 figs.

Buecker, B.

2009-04-15

262

Ghost Condensate Busting  

E-print Network

Applying the Thomas-Fermi approximation to renormalizable field theories, we construct ghost condensation models that are free of the instabilities associated with violations of the null-energy condition.

Neven Bili?; Gary B. Tupper; Raoul D. Viollier

2008-01-25

263

Measure Guideline: Evaporative Condensers  

SciTech Connect

The purpose of this measure guideline on evaporative condensers is to provide information on a cost-effective solution for energy and demand savings in homes with cooling loads. This is a prescriptive approach that outlines selection criteria, design and installation procedures, and operation and maintenance best practices. This document has been prepared to provide a process for properly designing, installing, and maintaining evaporative condenser systems as well as understanding the benefits, costs, and tradeoffs.

German, A.; Dakin, B.; Hoeschele, M.

2012-03-01

264

Condensate dark matter stars  

E-print Network

We investigate the structure and stability properties of compact astrophysical objects that may be formed from the Bose-Einstein condensation of dark matter. Once the critical temperature of a boson gas is less than the critical temperature, a Bose-Einstein Condensation process can always take place during the cosmic history of the universe. Therefore we model the dark matter inside the star as a Bose-Einstein condensate. In the condensate dark matter star model, the dark matter equation of state can be described by a polytropic equation of state, with polytropic index equal to one. We derive the basic general relativistic equations describing the equilibrium structure of the condensate dark matter star with spherically symmetric static geometry. The structure equations of the condensate dark matter stars are studied numerically. The critical mass and radius of the dark matter star are given by $M_{crit}\\approx 2(l_a/1fm)^{1/2}(m_{\\chi}/1\\;{\\rm GeV})^{-3/2}M_{\\odot}$ and $R_{crit}\\approx 1.1 \\times 10^6(l_a/1\\;{\\rm fm})^{1/2}(m_{\\chi}/1\\;{\\rm GeV})^{-3/2}$ cm respectively, where $l_a$ and $m_{\\chi}$ are the scattering length and the mass of dark matter particle, respectively.

X. Y. Li; T. Harko; K. S. Cheng

2012-05-14

265

A Preliminary Study on Pattern Analysis of Dehydrated Droplets Matjaz Bevk, Igor Kononenko, Marko Robnik Sikonja  

E-print Network

A Preliminary Study on Pattern Analysis of Dehydrated Droplets Matjaz Bevk, Igor Kononenko, Marko the conclusions of this research. 2 The observation method The method of observing the dehydrated droplets

Kononenko, Igor

266

EARLY RESPONSIVE TO DEHYDRATION 15, a Negative Regulator of Abscisic Acid Responses in Arabidopsis1  

E-print Network

EARLY RESPONSIVE TO DEHYDRATION 15, a Negative Regulator of Abscisic Acid Responses in Arabidopsis1, FIN­00014, Helsinki, Finland EARLY RESPONSIVE TO DEHYDRATION 15 (ERD15) is rapidly induced in response

Palva, Tapio

267

Compositional Constraints on Dehydration Embrittlement in Serpentinized Peridotite  

NASA Astrophysics Data System (ADS)

Double seismic zones (DSZ) which have two parallel planes of seismicity separated by 15-40 km are a global feature of subduction zones in the 70-250 km depth range (Brudzinski et al., 2007). While the physical mechanism of lower plane seismicity is still controversial, the leading hypotheses currently are associated with dehydration of antigorite serpentine within the subducting mantle plate (Peacock, 2001; Jung et al., 2004). In this study, we are conducting high-pressure (1-3GPa), high-temperature (720-750 Celsius), deformation experiments on specimens of varying compositions of serpentine plus peridotite in our 4GPa Modified Griggs apparatus. Using samples composed of interlayered thin discs of antigorite and harzburgite, we find that dehydration embrittlement occurs down to less than ~30 vol % antigorite. Interlayered mineralogy was impractical at lower antigorite fractions so we prepared homogeneous mixtures of powders of the two rock types (35-75 ?m grain-size) and "warm" pressed them to a coherent solid with little porosity. Subsequent deformation of these specimens extended the faulting regime to as little as ~8 vol % antigorite. In summary, we find that faulting occurs during dehydration in a wide range of serpentinized peridotite compositions but not during dehydration of nearly pure serpentinite nor nearly pure peridotite. We suggest that the lack of faulting in nearly pure peridotite is a consequence of too little H2O production and the lack of faulting in nearly pure serpentine is due to extensive crystal plasticity.

Xia, G.; Zhang, J.; Green, H. W.

2012-12-01

268

CDT retroelement: The stratagem to survive extreme vegetative dehydration.  

PubMed

The resurrection plant Craterostigma plantagineum can tolerate up to 96% loss of its water content and recover from such extreme dehydration within several hours. This property is not shared by callus which has a strict requirement for exogenous abscissic acid (ABA) to survive severe water loss. ABA treatment and dehydration result in the induction of similar drought-responsive genes. Activation tagging led to the isolation of CDT-1 gene which renders callus desiccation tolerant bypassing the ABA requirement. This gene belongs to a retroelement family, members of which are induced by ABA and dehydration in callus, supporting its role in desiccation tolerance. Indeed, CDT genes have been detected in other desiccation tolerant Craterostigma species. CDT-1 RNA of both strands was identified by in situ hybridization and a CDT-1-derived short interfering RNA was detected in desiccation tolerant tissues and was able to induce dehydration genes in transfected protoplasts to the same extent as an ABA treatment. Thus, under environmental stress the induced transposition, over generations, directs the amplification of CDT-copy number in the genome and increases the desiccation tolerance phenomenon. PMID:19704456

Furini, Antonella

2008-12-01

269

Study of wound dressing structure and hydration/dehydration properties  

NASA Astrophysics Data System (ADS)

Hydrogels manufactured by radio-induced crosslinking and simultaneous sterilisation of hydrogels of PVP, PEG and agar, according to the Rosiak method, have many desirable properties for using as wound dressings. However, some properties need to be improved or better controlled. The membranes need to be strong enough to be freely used. Another important property to be controlled is the capacity of absorption of exudate and the kinetics of drying. Therefore, it was necessary to understand the role of main parameters (agar, PVP, PEG concentration and dose) in the structure of the net and in the hydration and dehydration properties. The structure of the membranes was studied by sol analysis and the hydrating/dehydrating properties were studied by isothermal thermogravimetric analysis. The gel content for all samples were always in agreement with expected values considering that only PVP undergoes crosslinking. The hydrating and dehydration results did not show variation with the tested parameters. It was concluded that the network was solely composed of crosslinked PVP plasticezed by the other compounds. The properties of hydration/dehydration is related rather to diffusion than to capillarity or osmose and to the chemical retention of water in the polymeric matrix.

Lugão, A. B.; Machado, L. D. B.; Miranda, L. F.; Alvarez, M. R.; Rosiak, J. M.

1998-06-01

270

Microglassification(TM): a novel technique for protein dehydration.  

PubMed

The dehydration of biologics is commonly employed to achieve solid-dose formulation and enhanced stability during long-term preservation. We have developed a novel process, Microglassification(TM) , which can rapidly and controllably dehydrate protein solutions into solid amorphous microspheres at room temperature. Single bovine serum albumin (BSA) microdroplets were suspended in pentanol or decanol using a micropipette, and the dynamic changes in droplet dissolution were observed in real-time and correlated to protein's water of hydration, medium's water activity, and microsphere protein concentration. Microglassification(TM) was also carried out at bulk scale, and changes in BSA secondary structure were analyzed by Fourier transform infrared spectroscopy and fluorescence spectroscopy; multimer formation was detected by native gel electrophoresis. BSA concentration in the microsphere increased with solvent exposure time and decreasing water activity. Image analysis at single particle and bulk scale showed the formation of solid BSA microspheres with a maximum protein concentration of 1147 ± 32 mg/mL. The native BSA samples were dehydrated to approximately 450 waters per BSA, which is well below monolayer coverage of 1282 waters per BSA. The secondary structure of Microglassified(TM) BSA reverted to native-like conformation upon rehydration with only minor irreversible aggregation (2.7%). Results of the study establish the efficacy of the Microglassification(TM) for the successful dehydration of biologics. PMID:24415208

Aniket; Gaul, David A; Rickard, Deborah L; Needham, David

2014-03-01

271

Chemical Clearing and Dehydration of GFP Expressing Mouse Brains  

PubMed Central

Generally, chemical tissue clearing is performed by a solution consisting of two parts benzyl benzoate and one part benzyl alcohol. However, prolonged exposure to this mixture markedly reduces the fluorescence of GFP expressing specimens, so that one has to compromise between clearing quality and fluorescence preservation. This can be a severe drawback when working with specimens exhibiting low GFP expression rates. Thus, we screened for a substitute and found that dibenzyl ether (phenylmethoxymethylbenzene, CAS 103-50-4) can be applied as a more GFP-friendly clearing medium. Clearing with dibenzyl ether provides improved tissue transparency and strikingly improved fluorescence intensity in GFP expressing mouse brains and other samples as mouse spinal cords, or embryos. Chemical clearing, staining, and embedding of biological samples mostly requires careful foregoing tissue dehydration. The commonly applied tissue dehydration medium is ethanol, which also can markedly impair GFP fluorescence. Screening for a substitute also for ethanol we found that tetrahydrofuran (CAS 109-99-9) is a more GFP-friendly dehydration medium than ethanol, providing better tissue transparency obtained by successive clearing. Combined, tetrahydrofuran and dibenzyl ether allow dehydration and chemical clearing of even delicate samples for UM, confocal microscopy, and other microscopy techniques. PMID:22479475

Saghafi, Saiedeh; Weiler, Reto; Dodt, Hans-Ulrich

2012-01-01

272

21 CFR 73.40 - Dehydrated beets (beet powder).  

...percent. Lead (as Pb), not more than 10 parts per million. Arsenic (as As), not more than 1 part per million. Mercury (as Hg), not more than 1 part per million. (c) Uses and restrictions. Dehydrated beets may be safely used...

2014-04-01

273

Physicochemical analyses on dehydrated bovine serum decontaminated by gamma irradiation  

Microsoft Academic Search

The purpose of this work was to evaluate the effect of various radiation doses on some physicochemical parameters of dehydrated bovine serum which were considered indicative of its functional properties in the uses it is destinated (incorporation to sausages and flour products, mainly). Samples were packed in polyethylene, irradiated with dose of 0, 5, 7.5 and 10 kGy and stored

P. Narvaiz

1996-01-01

274

Horizontal transport and the dehydration of the stratosphere  

Microsoft Academic Search

The coldest tropopause temperatures occur over the equatorial West Pacific during Northern Hemisphere winter. Horizontal transport through this ``cold trap'' region causes air parcels that reach the tropopause at other longitudes to be dehydrated to the very low saturation mixing ratios characteristic of the cold trap, and hence can explain why observed tropical stratospheric water vapor mixing ratios are often

James R. Holton; Andrew Gettelman

2001-01-01

275

Dehydration and melting experiments constrain the fate of subducted sediments  

Microsoft Academic Search

Geochemical tracers demonstrate that elements are cycled from subducted sediments into the arc melting regime at subduction zones, although the transfer mechanism is poorly understood. Are key elements (Th, Be, Rb) lost during sediment dehydration or is sediment melting required? To investigate this question, we conducted phase equilibria and trace element partitioning experiments on a pelagic red clay for conditions

Marie C. Johnson; Terry Plank

1999-01-01

276

Locating QTL for osmotic adjustment and dehydration tolerance in rice  

Microsoft Academic Search

Research was conducted to identify and map quantit- ative trait loci (QTL) associated with dehydration tolerance and osmotic adjustment of rice. Osmotic adjustment capacity and lethal osmotic potential were determined for 52 recombinant inbred lines grown in a controlled environment under conditions of a slowly developed stress. The lines were from a cross between an Indica cultivar, Co39, of lowland

J. M. Lilley; M. M. Ludlow; S. R. McCouch; J. C. O'Toole

1996-01-01

277

POULTRY EXCRETA DEHYDRATION AND UTILIZATION: SYSTEM DEVELOPMENT AND DEMONSTRATION  

EPA Science Inventory

A manure handling and drying system involving caged layers with daily manure collection, air drying, and dehydration in a flash-type dryer has been studied. Objectives of the study were to: (1) Develop a complete manure handling system to maximize pollution control; (2) determine...

278

Progressive cellular dehydration and proteolysis in critically ill patients  

Microsoft Academic Search

SummaryBackground According to a recent hypothesis, the profound loss of body protein that occurs in critically ill patients is triggered and maintained by cell shrinkage secondary to cellular dehydration. We tested this hypothesis by studying sequential changes in intracellular water, total body protein, total body potassium, and intracellular potassium in patients receiving intensive care for blunt trauma or sepsis.Methods Nine

P. J Finn; L. D Plank; M. A Clark; A. B Connolly; G. L Hill

1996-01-01

279

Recycled dehydrated lithosphere observed in plume-influenced  

E-print Network

Recycled dehydrated lithosphere observed in plume-influenced mid-ocean-ridge basalt Jacqueline Eaby mantle components as sampled by ocean island basalts and mid-ocean- ridge basalts. Although all mantle plume (ocean island) basalts seem to contain more water than mid-ocean-ridge basalts, we demonstrate

Langmuir, Charles H.

280

Experimental apparatus for simultaneous dehydration and sweetening of natural gas  

E-print Network

Page Typical glycol dehydrator flow diagram. . 8 Typical amine-based gas treating process flow diagram. . . . Simplified schematic of packed column absorber. . . , . 19 Overall schematic of apparatus. 21 Schematic of absorption column... solvents. . 10 Characteristics of some popular gas sweetening processes. . Typical industrial gas analyzers . 37 Summary of pertinent design and operating data. . . . . . . . 40 Calibration gas calculation data. . . 44 Times of events for calibration...

Pace, Christopher Lee

2012-06-07

281

Phenol–urea–formaldehyde (PUF) co-condensed wood adhesives  

Microsoft Academic Search

The reaction of urea with methylolphenol under acidic conditions was investigated. The alternating copolymer of urea and phenol could be synthesized by the reaction of urea and 2,4,6-trimethylolphenol. The reactions of urea with polymethylolphenol mixtures also were investigated by changing the reaction conditions, such as the molar ratio and acidity. The co-condensates were analysed by carbon-13 nuclear magnetic resonance spectroscopy

Bunichiro Tomita; Chung-Yun Hse

1998-01-01

282

Reactivity of condensed thiophenes in the Diels-Alder reaction: The reactivity of 3-aminothieno [3,4:3`,4`] benzo [ b] pyranone; 3-aminothieno [3,4- c] quinoline and of 5-amino-7-substituted thieno [3,4- d] pyridazinone toward electron-poor olefins and acetylenes  

Microsoft Academic Search

The thieno [3,4:3`,4`] benzo [b] pyranone (3b) and the thieno [3,4-c] quinoline (3c) are prepared via reacting 4-methylcoumarin-3-carbonitrile (9a) and 4-methyl-2-oxo-1,2-dihydroquinolin-3-carbonitrile (9b) with elemental sulphur. Similarly the thieno [3,4:3`,4`] naphtho [1,2-b] pyran (11) is prepared from reaction of (10) and elemental sulphur. The condensed thiophenes (3b,c) and (11) react with a variety of electron-poor olefins to yield products of addition

Fatima Al-Omran; Mervat Mohammed Abdel Khalik; Hanan Al-Awadhi; Mohammed Hilmy Elnagdi

1996-01-01

283

Open Problems in $?$ Particle Condensation  

E-print Network

$\\alpha$ particle condensation is a novel state in nuclear systems. We briefly review the present status on the study of $\\alpha$ particle condensation and address the open problems in this research field: $\\alpha$ particle condensation in heavier systems other than the Hoyle state, linear chain and $\\alpha$ particle rings, Hoyle-analogue states with extra neutrons, $\\alpha$ particle condensation related to astrophysics, etc.

Y. Funaki; M. Girod; H. Horiuchi; G. Roepke; P. Schuck; A. Tohsaki; T. Yamada

2010-03-05

284

Osmoregulatory responses of glaucous-winged gulls ( Larus glaucescens ) to dehydration and hemorrhage  

Microsoft Academic Search

The effects of dehydration and hemorrhage on plasma ionic, osmotic, and antidiuretic hormone (arginine vasotocin) concentrations and of hemorrhage on salt gland secretion and glomerular filtration rate were evaluated in glaucous-winged gulls, Larus glaucescens. Dehydration for 24 h did not affect plasma ionic, osmotic or arginine vasotocin concentrations; 72 h dehydration significantly elevated plasma osmolality, plasma sodium and chloride concentrations,

M. R. Hughes; D. L. Goldstein; L. Raveendran

1993-01-01

285

Lateral Reorganization of Plasma Membrane is involved in the Yeast Resistance to Severe Dehydration  

E-print Network

Lateral Reorganization of Plasma Membrane is involved in the Yeast Resistance to Severe Dehydration: Laurent Beney, laurent.beney@u-bourgogne.fr Keywords: Dehydration kinetic ­ Cell survival ­ Microdomains.01.015 #12;Summary In this study, we investigated the kinetics of severe dehydrations on yeast plasma

Paris-Sud XI, Université de

286

Coseismic dehydration of serpentinite: Evidence from high-velocity friction experiments  

E-print Network

Coseismic dehydration of serpentinite: Evidence from high-velocity friction experiments Aiming Lin. Hilton Keywords: Dehydration Serpentinite High-velocity slip Fault strength Dynamic weakening in the slip zone and its bounding zones was released due to dehydration during the HVF experiments. Our

Kanagawa, Kyuichi

287

ORIGINAL PAPER Osmotic and metabolic responses to dehydration and urea-loading  

E-print Network

ORIGINAL PAPER Osmotic and metabolic responses to dehydration and urea-loading in a dormant Abstract Physiological responses to dehydration in amphibians are reasonably well documented, although urea did not differ initially; however, upon dehydration, metabolic rates decreased sooner in the urea

Lee Jr., Richard E.

288

Instability of myelin tubes under dehydration: Deswelling of layered cylindrical structures C.-M. Chen,1  

E-print Network

Instability of myelin tubes under dehydration: Deswelling of layered cylindrical structures C stress swelling or dehydration , we find a stable, deformed state in which the layer deformation is given, and h is the repeat distance of layers. Also, above a finite threshold of dehydration or osmotic stress

Chen, Chi-Ming

289

Effects of Dehydration on the Viscoelastic Properties of Vocal Folds in Large Deformations  

E-print Network

Effects of Dehydration on the Viscoelastic Properties of Vocal Folds in Large Deformations Amir K. Miri, Franc¸ois Barthelat, and Luc Mongeau, Montreal, Canada Summary: Dehydration may alter vocal fold dehydrated by immersion in a hypertonic solution, and quasi-static and low-frequency dynamic traction tests

Barthelat, Francois

290

Research on the use of dehydrated whole maize plant in the feed of growing rabbits  

E-print Network

Research on the use of dehydrated whole maize plant in the feed of growing rabbits Maria during the trial, but significantly until 60 days of age. Utilization of dehydrated whole maize plant Cunicole, 95450 Vigny (France). Four trials were made to study dehydrated whole maize plant as crude fibre

Paris-Sud XI, Université de

291

Water vapor transport and dehydration above convective outflow during Asian monsoon  

E-print Network

Water vapor transport and dehydration above convective outflow during Asian monsoon R. James,1 M dehydrated, avoiding the coldest temperatures of the TTL. Convective moistening accounts for about 0.3 ppmv and dehydration above convective outflow during Asian monsoon, Geophys. Res. Lett., 35, L20810, doi:10.1029/2008GL

Legras, Bernard

292

Earth Planets Space, 53, 861871, 2001 Dehydration of serpentinized slab mantle: Seismic evidence from southwest Japan  

E-print Network

Earth Planets Space, 53, 861­871, 2001 Dehydration of serpentinized slab mantle: Seismic evidence this variety on the basis of dehydration embrittlement in the subducting oceanic crust and/or mantle. The PHS may reflect dehydration embrittlement in the hydrated subducting oceanic crust only, implying the lack

Seno, Tetsuzo

293

Structural modifications of Callovo-Oxfordian argillite under hydration/dehydration conditions  

E-print Network

Structural modifications of Callovo-Oxfordian argillite under hydration/dehydration conditions H rapid, is the hydration and/or dehydration of swelling clays minerals. These processes could generate) according hydration­dehydration cycles, an Environmental Scanning Electron Microscope (ESEM) was used

Montes-Hernandez, German

294

Intermediate magnetite formation during dehydration of O zden O zdemir *, David J. Dunlop  

E-print Network

Intermediate magnetite formation during dehydration of goethite Oë zden Oë zdemir *, David J The dehydration of goethite has been studied by low-temperature induced magnetization (LTIM) and X-ray diffraction³C, for which only hematite was found. However, partially dehydrated goethites after the 238^402³C

Dunlop, David J.

295

Effect of dehydration by sun or by oven on volatiles and aroma compounds of Trachanas  

E-print Network

Note Effect of dehydration by sun or by oven on volatiles and aroma compounds of Trachanas Stefania. The mixture is then dried and stored in the form of "biscuits". Dehydration is performed either by sun/MS/O in the sun-dried samples, revealing that the use of the oven in the dehydration process generally resulted

Paris-Sud XI, Université de

296

Spectroscopic study of the dehydration and/or dehydroxylation of phyllosilicate and zeolite minerals  

E-print Network

Spectroscopic study of the dehydration and/or dehydroxylation of phyllosilicate and zeolite] Phyllosilicates on Mars mapped by infrared spectroscopic techniques could have been affected by dehydration and with meteor impact. The effects of heatinduced dehydration and/or dehydroxylation on the infrared spectra

Glotch, Timothy D.

297

Hot-spot combustion of heterogeneous condensed mixtures. Thermal percolation  

Microsoft Academic Search

A model of combustion of heterogeneous condensed mixtures composed of reactive particles separated by an inert heat-conducting substance is considered. Propagation of the reaction in a one-dimensional periodic system of point reaction cells connected by inert thermal bridges is examined. The burning rate is determined as a function of the basic parameters of the system, and stability of the steady

S. A. Rashkovskii

2005-01-01

298

Framework for Understanding LENR Processes, Using Conventional Condensed Matter Physics  

Microsoft Academic Search

Conventional Condensed Matter physics provides a unifying framework for understanding Low Energy Nuclear Reactions (LENR's) in solids. In the paper, standard many-body physics techniques are used to illustrate this fact. Specifically, the paper shows that formally the theories by Schwinger, Hagelstein, and Chubb and Chubb (C&C), all can be related to a common set of equations, associated with reaction rate

Scott R. Chubb

299

Mass condensation on networks  

NASA Astrophysics Data System (ADS)

We construct classical stochastic mass transport processes for stationary states which are chosen to factorize over pairs of sites of an undirected, connected, but otherwise arbitrary graph. For the special topology of a ring we derive static properties such as the critical point of the transition between the liquid and the condensed phase, the shape of the condensate and its scaling with the system size. It turns out that the shape is not universal, but determined by the interplay of local and ultralocal interactions. In two dimensions the effect of anisotropic interactions of hopping rates can be treated analytically, since the partition function allows a dimensional reduction to an effective one-dimensional zero-range process. Here we predict the onset, shape and scaling of the condensate on a square lattice. We indicate further extensions in the outlook.

Waclaw, B.; Sopik, J.; Janke, W.; Meyer-Ortmanns, H.

2010-09-01

300

Condensation phenomena in plasmonics  

E-print Network

We study arrays of plasmonic nanoparticles combined with quantum emitters, quantum plasmonic lattices, as a platform for room temperature studies of quantum many-body physics. We outline a theory to describe surface plasmon polariton distributions when they are coupled to externally pumped molecules. The possibility of tailoring the dispersion in plasmonic lattices allows realization of a variety of distributions, including the Bose-Einstein distribution as in photon condensation. We show that the presence of losses can relax some of the standard dimensionality restrictions for condensation.

Martikainen, J -P; Törmä, P

2014-01-01

301

Galaxies as condensates  

E-print Network

A novel interpretation of MOND is presented. For galactic data, in addition to Newtonian acceleration, there is an attractive acceleration peaking at Milgrom's parameter a_0. The peak lies within experimental error where a_0 = cH_0/2\\pi and H_0 is the present-time value of the Hubble constant. This peaking may be understood in terms of quantum mechanical mixing between Newtonian gravitation and the condensation mechanism. There are five pointers towards galaxies being Fermi-Dirac condensates.

D. V. Bugg

2012-10-27

302

Dehydration and crystallization of amorphous calcium carbonate in solution and in air  

PubMed Central

The mechanisms by which amorphous intermediates transform into crystalline materials are poorly understood. Currently, attracting enormous interest is the crystallization of amorphous calcium carbonate, a key intermediary in synthetic, biological and environmental systems. Here we attempt to unify many contrasting and apparently contradictory studies by investigating this process in detail. We show that amorphous calcium carbonate can dehydrate before crystallizing, both in solution and in air, while thermal analyses and solid-state nuclear magnetic resonance measurements reveal that its water is present in distinct environments. Loss of the final water fraction—comprising less than 15% of the total—then triggers crystallization. The high activation energy of this step suggests that it occurs by partial dissolution/recrystallization, mediated by surface water, and the majority of the particle then crystallizes by a solid-state transformation. Such mechanisms are likely to be widespread in solid-state reactions and their characterization will facilitate greater control over these processes. PMID:24469266

Ihli, Johannes; Wong, Wai Ching; Noel, Elizabeth H.; Kim, Yi-Yeoun; Kulak, Alexander N.; Christenson, Hugo K.; Duer, Melinda J.; Meldrum, Fiona C.

2014-01-01

303

Kinetic, spectroscopic, and theoretical assessment of associative and dissociative methanol dehydration routes in zeolites.  

PubMed

Mechanistic interpretations of rates and in?situ IR spectra combined with density functionals that account for van der Waals interactions of intermediates and transition states within confining voids show that associative routes mediate the formation of dimethyl ether from methanol on zeolitic acids at the temperatures and pressures of practical dehydration catalysis. Methoxy-mediated dissociative routes become prevalent at higher temperatures and lower pressures, because they involve smaller transition states with higher enthalpy, but also higher entropy, than those in associative routes. These enthalpy-entropy trade-offs merely reflect the intervening role of temperature in activation free energies and the prevalence of more complex transition states at low temperatures and high pressures. This work provides a foundation for further inquiry into the contributions of H-bonded methanol and methoxy species in homologation and hydrocarbon synthesis reactions from methanol. PMID:25212869

Jones, Andrew J; Iglesia, Enrique

2014-11-01

304

Dehydration and crystallization of amorphous calcium carbonate in solution and in air  

NASA Astrophysics Data System (ADS)

The mechanisms by which amorphous intermediates transform into crystalline materials are poorly understood. Currently, attracting enormous interest is the crystallization of amorphous calcium carbonate, a key intermediary in synthetic, biological and environmental systems. Here we attempt to unify many contrasting and apparently contradictory studies by investigating this process in detail. We show that amorphous calcium carbonate can dehydrate before crystallizing, both in solution and in air, while thermal analyses and solid-state nuclear magnetic resonance measurements reveal that its water is present in distinct environments. Loss of the final water fraction—comprising less than 15% of the total—then triggers crystallization. The high activation energy of this step suggests that it occurs by partial dissolution/recrystallization, mediated by surface water, and the majority of the particle then crystallizes by a solid-state transformation. Such mechanisms are likely to be widespread in solid-state reactions and their characterization will facilitate greater control over these processes.

Ihli, Johannes; Wong, Wai Ching; Noel, Elizabeth H.; Kim, Yi-Yeoun; Kulak, Alexander N.; Christenson, Hugo K.; Duer, Melinda J.; Meldrum, Fiona C.

2014-01-01

305

Experimental study of trace element release during ultrahigh-pressure serpentinite dehydration  

NASA Astrophysics Data System (ADS)

Subduction of serpentinite is envisaged to play a key role in volatile and element recycling at convergent plate margins, but there is currently little known about the composition of the fluid phase(s) released by devolatilisation of deeply subducted serpentinite. We have performed a series of ultrahigh pressure experiments to examine the phase relations and fluid compositions produced by reaction of a natural serpentinite under sub-arc conditions. We employ a novel technique of forming synthetic fluid inclusions in olivine at run conditions to preserve samples of experimental fluids for subsequent analysis. Our experiments confirm that the breakdown of antigorite and chlorite are the most important fluid-producing reactions from serpentinite at sub-arc depths. For our low CaO/Al2O3 peridotitic composition at 3.5 to 4.0 GPa we find that clinopyroxene reacts out below 750 °C and chlorite breaks down progressively between 700 and 800 °C to form garnet harzburgite. Raman analysis of synthetic fluid inclusions indicates that all experiments contained a single aqueous fluid phase, which - together with a lack of textural or mineralogical evidence for hydrous melting - indicates that the water-saturated solidus for our starting composition is above 900 °C at 4.0 GPa. Element concentrations in the fluid for three experiments were determined in situ via laser ablation ICP-MS of individual fluid inclusions. In general, the fluids are enriched in trace elements compared to the bulk starting material, but particularly so for Li, B, LILE, LREE, and U. Chlorite dehydration fluids have high Li/B, LREE/HREE and Ce/Y due to retention of some B in olivine, and retention of Y and HREE in garnet. Our results indicate that fluids produced by serpentinite dehydration at sub-arc depths may carry some of the slab-derived trace elements required for arc magmatism, and may fractionate key trace element ratios in the dehydrated residues, which in turn may ultimately contribute to the geochemical heterogeneity of mantle-derived magmas.

Spandler, Carl; Pettke, Thomas; Hermann, Joerg

2014-04-01

306

LEA proteins: IDPs with versatile functions in cellular dehydration tolerance.  

PubMed

LEA (late embryogenesis abundant) proteins were originally described almost 30 years ago as accumulating late in plant seed development. They were later found to be induced in vegetative plant tissues under environmental stress conditions and also in desiccation-tolerant micro-organisms and invertebrates. Although they are widely assumed to play crucial roles in cellular dehydration tolerance, their physiological and biochemical functions are largely unknown. Most LEA proteins are predicted to be intrinsically disordered and this has been experimentally verified in several cases. In addition, some LEA proteins partially fold, mainly into ?-helices, during drying or in the presence of membranes. Recent studies have concentrated on the potential roles of LEA proteins in stabilizing membranes or sensitive enzymes during freezing or drying, and the present review concentrates on these two possible functions of LEA proteins in cellular dehydration tolerance. PMID:22988854

Hincha, Dirk K; Thalhammer, Anja

2012-10-01

307

Methods for dehydration of sugars and sugar alcohols  

DOEpatents

The invention includes a method of dehydration of a sugar using a dehydration catalyst and a co-catalyst within a reactor. A sugar is introduced and H.sub.2 is flowed through the reactor at a pressure of less than or equal to about 300 psig to convert at least some of the sugar into an anhydrosugar product. The invention includes a process for producing isosorbide. A starting material comprising sorbitol is flowed into a reactor. H.sub.2 is counter flowed through the reactor. The starting material is exposed to a catalyst in the presence of a co-catalyst which comprises at least one metal. The exposing is conducted at a hydrogen pressure of less than or equal to 300 psig within the reactor and the hydrogen removes at least some of any water present during the exposing and inhibits formation of colored byproducts.

Holladay, Johnathan E [Kennewick, WA; Hu, Jianli [Kennewick, WA; Zhang, Xinjie [Burlington, MA; Wang, Yong [Richland, WA

2010-08-10

308

Hydration and dehydration of Zeolitic Tuff from Yucca Mountain, Nevada  

NASA Astrophysics Data System (ADS)

Naturally occurring zeolites expand and contract when hydrated or dehydrated. In tuffaceous rock composed largely of such zeolites, the entire rock may swell or contract significantly as the rock becomes saturated or dries out. If such rock is constrained, significant stresses may develop as a result of hydration or dehydration. We present experimental results that substantiate this. In a zeolitized, non-welded tuff from Yucca Mountain, NV, rock permeability governs the swelling rate since the major constituent, clinoptilolite, hydrates as fast as it can be exposed to water. At Yucca Mountain, where a nuclear waste repository is proposed, strata of welded, devitrified tuff overlie non-welded, zeolitic tuff. Should the hydration state of the units change significantly over the repository lifetime, additional stresses on the same order of magnitude as now exist may develop.

Kranz, R. L.; Bish, D. L.; Blacic, J. D.

1989-10-01

309

Drying Kinetics and Color Retention of Dehydrated Rosehips  

Microsoft Academic Search

Freshly harvested rosehips (Rosa canina L.) were dehydrated in a parallel flow type air dryer at six air temperatures (30, 40, 50, 60, and 70°C) at air velocities of 0.5, 1.0, and 1.5 m\\/s. Drying air temperature and velocity significantly influenced drying time and energy requirement. Minimum and maximum energy requirement for drying of rosehips were determined as 6.69 kWh\\/kg for 70°C

T. Koyuncu; I. Tosun; N. S. Ustun

2003-01-01

310

Dehydration of tetrahydrofuran by pervaporation using a composite membrane  

Microsoft Academic Search

Tetrahydrofuran (THF) is a strong aprotic solvent, commonly used in the pharmaceuticals industry due to its broad solvency for both polar and non-polar compounds. THF and water form a homogeneous azeotrope at 5.3wt.% water thus simple distillation is not feasible to dehydrate THF below this concentration. Pervaporation offers a solution since it is not governed by vapour–liquid equilibria. However many

Peter D. Chapman; Xiaoyao Tan; Andrew G. Livingston; K. Li; Teresa Oliveira

2006-01-01

311

30. BUILDING NO. 527, DEHYDRATING PRESSES, LOOKING SOUTH. ALUMINUM NARROWGUAGE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

30. BUILDING NO. 527, DEHYDRATING PRESSES, LOOKING SOUTH. ALUMINUM NARROW-GUAGE GONDOLA CAR IN LEFT BACKGROUND BROUGHT MOISTENED GUN COTTON FROM REST HOUSE (BUILDING NO. 320-B) IN CANS. (ONE OF THESE CANS IS ON UNLOADING PLATFORM RUNNING BESIDE PRESSES). CONTENTS OF CANS WERE UNLOADED INTO PRESSES BY HAND. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

312

28. BUILDING NO. 527, DEHYDRATING HOUSE, LOOKING SOUTH AT NORTH ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

28. BUILDING NO. 527, DEHYDRATING HOUSE, LOOKING SOUTH AT NORTH (REAR) ELEVATION OF PRELIMINARY SOLVENT RECOVERY WING. RAILS LEADING FROM DOORS CARRIED STANDARD GUAGE R.R. CARTS ONTO SMALL FLATCARS RIDING IN TRACKS IN FOREGROUND. FROM HERE THE CARS WERE TAKEN TO BUILDING NO. 533, SOLVENT RECOVERY. BUILDING NO. 540, LOADING DOCK (STORAGE FOR POWDER BUGGIES) IN BACKGROUND LEFT. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

313

Colour and flavour changes during osmotic dehydration of fruits  

Microsoft Academic Search

Andes berry (Rubus glaucus Benth.) and tamarillo (Solanum betaceum Cav., dark-red strain) fruit were separately submitted to osmotic dehydration with three different osmotic agents: sucrose (70%), sucrose (70%)-glycerol (65%) 1:1, and ethanol. This process decreased the water activity in the fruits and promoted the transfer of main pigments (anthocyanins) and flavour constituents to the osmotic solutions. Tristimulus colorimetry was applied

Coralia Osorio; Martha Sofía Franco; Maria Paola Castaño; Maria Lourdes González-Miret; Francisco J. Heredia; Alicia Lucía Morales

2007-01-01

314

Enhanced condensation heat transfer  

SciTech Connect

For the past four years, work has been in progress at ORNL to develop improved condensers for geothermal binary power cycles. The work has centered on optimizing the design variables associated with fluted surfaces on vertical tubes and comparing the tube performance with available enhanced tubes either for vertical or horizontal operation. Data with seven fluids including a hydrocarbon, fluorocarbons, and ammonia condensing on up to 30 different tubes have been obtained. Data for tubes of different effective lengths (1/2 to 4 ft) and inclination have also been obtained. The primary conclusion from this work is that the best fluted tubes can provide an enhancement in condensation coefficient by a factor of approximately 6 over smooth vertical tube performance and a factor of approximately 2 over the best enhanced commercial tubes either operating vertically or horizontally. These data, together with field test data have formed the basis for designing two prototype condensers, one for the 60 kWe Raft River, Idaho, pilot plant and one for the 500 kWe East Mesa, California, direct-contact demonstration plant.

Michel, J.W.; Murphy, R.W.

1980-01-01

315

Condenser biofouling control  

SciTech Connect

A compilation of most of the papers presented at the March 1979 symposium in Atlanta, GA on condensor biofouling control is presented. The following aspects of power plant condenser biofouling are discussed: effects on power plant equipment and operations; cost impact; biofilm formation; corrosive effects; control practices using chlorine or bromine chlorides, and the dechlorination of discharges of chlorinated coolants. (LCL)

Garey, J.F.; Jorden, R.M.; Aitken, A.H.; Burton, D.T.; Gray, R.H. (eds.)

1980-01-01

316

Condensed Matter Physics  

Microsoft Academic Search

Condensed matter physics constitutes nowadays an enormous field of knowledge. To write a good textbook covering all main topics in that field in a suitable way and in a reasonable volume is very hard indeed. I believe Michael Marder has achieved this goal with great success. The text is arranged in six parts. Part I describes the atomic structure of

I Strzalkowski

2000-01-01

317

Soft condensed matter physics  

Microsoft Academic Search

Soft condensed matter physics is the study of materials, such as fluids, liquid crystals, polymers, colloids and emulsions, that are “soft” to the touch. This article will review some properties, such as the dominance of entropy, that are unique to soft materials and some properties such as the interplay between broken-symmetry, dynamic mode structure and topological defects that are common

T. C. Lubensky

1997-01-01

318

Condensed-Matter Physics.  

ERIC Educational Resources Information Center

Discusses ways computers are being used in condensed-matter physics by experimenters and theorists. Experimenters use them to control experiments and to gather and analyze data. Theorists use them for detailed predictions based on realistic models and for studies on systems not realizable in practice. (JN)

Hirsch, Jorge E.; Scalapino, Douglas J.

1983-01-01

319

Condensed matter physics journals  

Microsoft Academic Search

On the basis of a citation\\/reference criterion, 20 core journals are selected in the field of condensed matter physics. Citation data and indicators from 1980Journal Citation Reports reveal their different characteristic features such as applied orientation, communication function and longevity. The manually obtained data for the core journals are written into a matrix in order to determine an appropriate ranking

R. Todorov

1983-01-01

320

Exciton-polariton condensates  

NASA Astrophysics Data System (ADS)

Recently a new type of system exhibiting spontaneous coherence has emerged--the exciton-polariton condensate. Exciton-polaritons (or polaritons for short) are bosonic quasiparticles that exist inside semiconductor microcavities, consisting of a superposition of an exciton and a cavity photon. Above a threshold density the polaritons macroscopically occupy the same quantum state, forming a condensate. The polaritons have a lifetime that is typically comparable to or shorter than thermalization times, giving them an inherently non-equilibrium nature. Nevertheless, they exhibit many of the features that would be expected of equilibrium Bose-Einstein condensates (BECs). The non-equilibrium nature of the system raises fundamental questions as to what it means for a system to be a BEC, and introduces new physics beyond that seen in other macroscopically coherent systems. In this review we focus on several physical phenomena exhibited by exciton-polariton condensates. In particular, we examine topics such as the difference between a polariton BEC, a polariton laser and a photon laser, as well as physical phenomena such as superfluidity, vortex formation, and Berezinskii-Kosterlitz-Thouless and Bardeen-Cooper-Schrieffer physics. We also discuss the physics and applications of engineered polariton structures.

Byrnes, Tim; Kim, Na Young; Yamamoto, Yoshihisa

2014-11-01

321

Top Quark Condensate Revisited  

Microsoft Academic Search

In the light of recent discovery of a very heavy top quark, we reexamine the top quark condensate model proposed by Miransky, Tanabashi and Yamawaki (MTY) and by Nambu. We first review the original MTY formulation based on the ladder Schwinger-Dyson equation and the Pagels-Stokar formula. It is particularly emphasized that the critical phenomenon gives a simple reason why the

Koichi Yamawaki

1996-01-01

322

The Color Glass Condensate  

E-print Network

We provide a broad overview of the theoretical status and phenomenological applications of the Color Glass Condensate effective field theory describing universal properties of saturated gluons in hadron wavefunctions that are extracted from deeply inelastic scattering and hadron-hadron collision experiments at high energies.

F. Gelis; E. Iancu; J. Jalilian-Marian; R. Venugopalan

2010-02-01

323

Inhibition of plasma vasopressin after drinking in dehydrated humans  

NASA Technical Reports Server (NTRS)

The effects of nonosmotic and nonvolumetric factors on vasopressin secretion in dehydrated humans has been investigated experimentally, before and after drinking. The subjects of the experiment were five adult men and three adult women weighing 69-77 kg. In order to determine the influence of nonosmotic and nonvolumetric factors on vasopressin secretion, measurements were obtained of the following blood hematological indices: serum Na(+) content; serum K(+) content; osmolality; and hemoglobin. Measurements of hematocrit, plasma arginine vasopressin (AVP), aldosterone, and renin activity were also obtained. It is found that dehydration increased mean serum Na(+) content, osmolality,and AVP. No significant changes were observed in renin activity, hemoglobin, hematocrit, or plasma volume, while plasma aldosterone increased from 11.1 ng/dl after dehydration to 15.6 ng/dl between 30 and 60 min after drinking. A rapid fall of AVP content following rehydration occurred in the absence of changes in the primary regulators of AVP osmolality and plasma volume, with no change in blood pressure. On the basis of the experimental results, it is suggested that oropharyngeal factors may be the mechanism, for the observed decrease in AVP following rehydration.

Geelen, G.; Keil, L. C.; Kravik, S. E.; Wade, C. E.; Thrasher, T. N.; Barnes, P. R.; Pyka, G.; Nesvig, C.; Greenleaf, J. E.

1984-01-01

324

Inhibition of chloroplastic respiration by osmotic dehydration. [Spinacia oleracea L  

SciTech Connect

The respiratory capacity of isolated spinach (Spinacia oleracea L.) chloroplasts, measured as the rate of {sup 14}CO{sub 2} evolved from the oxidative pentose phosphate cycle in darkened chloroplasts exogenously supplied with ({sup 14}C)glucose, was progressively diminished by escalating osmotic dehydration with betaine or sorbitol. Comparing the inhibitions of CO{sub 2} evolution generated by osmotic dehydration in chloroplasts given C-1 and C-6 labeled glucose, 54% and 84%, respectively, indicates that osmotic dehydration effects to a greater extent the recycling of the oxidative pentose phosphate intermediates, fructose-6P and glyceraldehyde-3P. Respiratory inhibition in the darkened chloroplast could be alleviated by addition of NH{sub 4}Cl (a stromal alkylating agent), iodoacetamide (an inhibitor of glyceraldehyde-3P dehydrogenase), or glycolate-2P (an inhibitor of phosphofructokinase). It is concluded that the site which primarily mediates respiratory inhibition in the darkened chloroplast occurs at the fructose 1,6-bisphosphatase/phosphofructokinase junction.

Willeford, K.O.; Ahluwalia, K.J.K.; Gibbs, M. (Brandeis Univ., Waltham, MA (USA))

1989-04-01

325

Dehydration Influences Mood and Cognition: A Plausible Hypothesis?  

PubMed Central

The hypothesis was considered that a low fluid intake disrupts cognition and mood. Most research has been carried out on young fit adults, who typically have exercised, often in heat. The results of these studies are inconsistent, preventing any conclusion. Even if the findings had been consistent, confounding variables such as fatigue and increased temperature make it unwise to extrapolate these findings. Thus in young adults there is little evidence that under normal living conditions dehydration disrupts cognition, although this may simply reflect a lack of relevant evidence. There remains the possibility that particular populations are at high risk of dehydration. It is known that renal function declines in many older individuals and thirst mechanisms become less effective. Although there are a few reports that more dehydrated older adults perform cognitive tasks less well, the body of information is limited and there have been little attempt to improve functioning by increasing hydration status. Although children are another potentially vulnerable group that have also been subject to little study, they are the group that has produced the only consistent findings in this area. Four intervention studies have found improved performance in children aged 7 to 9 years. In these studies children, eating and drinking as normal, have been tested on occasions when they have and not have consumed a drink. After a drink both memory and attention have been found to be improved. PMID:22254111

Benton, David

2011-01-01

326

Mechanism and temperature-dependent kinetics of the dehydration of tert-butyl alcohol in hot compressed liquid water  

SciTech Connect

In the presence of acid or base, or under neutral conditions, isobutylene is the only observed product of the reactions of tert-butyl alcohol in compressed liquid water at 225, 250, and 320 C. On the basis of a kinetic analysis of limited results at 250 C, an earlier paper concluded that tert-butyl alcohol dissociates as an Arrhenius acid at 250 C and thereby catalyzes its own dehydration to isobutylene. Kinetic analyses of the data sets contained in this paper do not corroborate the alleged ability of tert-butyl alcohol to protonate water. Instead, the authors find that hydronium ions formed by the ordinary dissociation of water are the primary catalytic agents for the dehydration reaction. In agreement with the earlier work, all three data sets are consistent with a heterolytic reaction mechanism involving protonated alcohol, carbocation, di-tert-butyl ether, and protonated ether as intermediates. The kinetics still suggest that tert-butyl alcohol weakly dissociated as a Bronsted acid at these conditions. Values of K{sub w} determined by the kinetic model enjoy good agreement with electrochemical values available in the literature. Values of the other parameters (rate constants) which compose the kinetic model are evaluated with less precision, and a novel method is proposed to estimate the uncertainty associated with each parameter.

Xu, X.; Antal, M.J. Jr. [Univ. of Hawaii, Honolulu, HI (United States)] [Univ. of Hawaii, Honolulu, HI (United States); Anderson, D.G.M. [Harvard Univ., Cambridge, MA (United States). Aiken Computation Lab.] [Harvard Univ., Cambridge, MA (United States). Aiken Computation Lab.

1997-01-01

327

Modeling of B concentrations and isotopic compositions in subducted slabs and dehydration fluids  

NASA Astrophysics Data System (ADS)

The oceanic lithosphere plays a key role regarding global scale element cycles. Seawater-rock interaction at the ocean floor causes intense chemical modification of the basaltic oceanic crust and possibly also the upper parts of the oceanic mantle. Later subduction of the modified oceanic lithosphere leads to dehydration, which again enables redistribution of major and trace elements in the subducted slab. This dehydration process is responsible for arc volcanism, subduction-related ore formation but also controls the distribution of elements that are recycled into the upper plate and the atmosphere and those that are incorporated into refractory minerals and are recycled into the deeper mantle. Regarding the water budget and thus the element transport in a subduction zone, the potentially hydrated oceanic mantle plays a major role as it can store large amounts of water in hydrous minerals, such as chlorite and serpentine. The pressure and temperature conditions as well as the fluid-rock interaction within the subducted slab controls whether water - and elements solved therein - can escape the slab or are deeply subducted and recycled into the Earth's mantle. Boron concentrations and isotopic compositions are excellent tracers for the contribution of oceanic lithospheric mantle to the water and trace element budget in subduction zones: boron is incorporated at significant amounts in serpentine, it is highly fluid mobile and its two stable isotopes (10B and 11B) undergo equilibrium fractionation between fluid and solid phases. In this contribution, thermal and thermodynamic models of subduction of oceanic lithosphere are combined with trace element and isotope partitioning data in order to quantify boron concentrations and its isotopic composition in coexisting fluid and solid phases during devolatilisation, fluid migration and fluid-rock interaction in a subducted slab. The results show that fluid-mobile elements undergo complex liberation and resorption processes during fluid migration in a dehydrating slab, which leads to re-enrichment of previously leached lithologies. Such internal redistribution of trace elements within the slab enables recycling of fluid mobile elements beyond the dehydration interval into the deep mantle beyond sub-arc depths. Further, this study shows that across arc variations of the isotopic composition of boron in arc volcanics can be used as indicator for the hydration state of the subducted oceanic mantle lithosphere. Increases in boron concentrations and ?11B in rear- and back-arc volcanic rocks, as observed for example in Kamchatka and Northern Japan, can be explained by dehydration of serpentinized upper oceanic mantle.This release occurs over a small pressure and temperature range and, despite intense fluid-rock interaction in the slab crust, the associated trace element signal is transferred to the slab surface and into the mantle wedge. The position of the serpentinite-out reaction and thus the associated trace element signal is dependent on the thermal structure within the slab. Consequently complex across-arc variations in boron concentrations and boron isotopic compositions can be used as constraining parameters in thermomechanical subduction zone models.

Konrad-Schmolke, Matthias

2013-04-01

328

Glucose and fructose decomposition in subcritical and supercritical water: Detailed reaction pathway, mechanisms, and kinetics  

SciTech Connect

The authors are developing a new catalyst-free process of cellulose decomposition in supercritical water. In their initial study on the cellulose decomposition in supercritical water, the main products of cellulose decomposition were found to be oligomers of glucose (cellobiose, cellotriose, etc.) and glucose at short residence times (400 C, 25 MPa, 0.05 s). The kinetics of glucose at these conditions can be useful in understanding the reaction pathways of cellulose. Experiments were performed on the products of glucose decomposition at short residence times to elucidate the reaction pathways and evaluate kinetics of glucose and fructose decomposition in sub- and supercritical water. The conditions were a temperature of 300--400 C and pressure of 25--40 MPa for extremely short residence times between 0.02 and 2 s. The products of glucose decomposition were fructose, a product of isomerization, 1,6-anhydroglucose, a product of dehydration, and erythrose and glyceraldehyde, products of C-C bond cleavage. Fructose underwent reactions similar to glucose except that it did not form 1,6-anhydroglucose and isomerization to glucose is negligible. The mechanism for the products formed from C-C bond cleavage could be explained by reverse aldol condensation and the double-bond rule of the respective enediols formed during the Lobry de Bruyn Alberda van Ekenstein transformation. The differential equations resulting from the proposed pathways were fit to experimental results to obtain the kinetic rate constants.

Kabyemela, B.M.; Adschiri, T.; Malaluan, R.M.; Arai, K. [Tohoku Univ., Sendai (Japan). Dept. of Chemical Engineering] [Tohoku Univ., Sendai (Japan). Dept. of Chemical Engineering

1999-08-01

329

Gunion - Nevada`s most innovative geothermal food dehydration facility  

SciTech Connect

The Gunion (garlic and onion) dehydration plant, owned and operated by Integrated Ingredients, a Division of Burns Philp Food, Incorporated, uses geothermal fluids at a temperature of 306{degrees}F to dehydrate 50 to 70-thousand pounds per day of garlic and onions. The geothermal fluids are provided by Empire Farms, who has the rights for development of the resource and is the lease holder of fee land known as the Kosmos Lease. The San Emidio KGRA is located in northern Washoe County, 90 miles north-northeast of Reno, Nevada and 20 miles south of Gerlach, Nevada. Geothermal fluids exit the plant at 242{degrees}F and are piped to an injection well located 3,000 feet south-southwest of the plant. The plant location was selected not only for the geothermal resource, but also for the area`s low relative humidity. Currently, 1100-1200 gpm of geothermal fluids, at an inlet temperature of 302{degrees}F, are sufficient to provide the dryer line with ample BTU`s. Three geothermal wells drilled to depths ranging from 493 to 1817 feet produce fluids ranging in temperature from 266 to 306{degrees}F. One well can easily provide the heat required by the dryer line and will be capable of providing heat for a planned three-fold expansion of the facility. The remaining two wells are used as backup, or may be used for other applications such as soil sterilization. The fluid exiting the plant at 242{degrees}F may be cascaded and used for greenhouses and soil warming in the future. Geothermal heat is also used to dehumidify onions placed in the cold storage facility. The dehydration process takes 5-6 hours to dry the product to a 4.5% moisture content. The dried product is then milled to various sizes from powder to granules. The dehydration plant operates 24 hours/day 7 days a week. Currently 80 people are employed full-time at the plant. The dehydrated onion and garlic are used in condiments, soups, sauces and salad dressing.

Trexler, D.T.; Taylan, G.; Stewart, M.B.; Baker, S.

1995-12-31

330

Analysis of Dehydration and Strength in Elite Badminton Players  

PubMed Central

Background The negative effects of dehydration on aerobic activities are well established. However, it is unknown how dehydration affects intermittent sports performance. The purpose of this study was to identify the level of dehydration in elite badminton players and its relation to muscle strength and power production. Methodology Seventy matches from the National Spanish badminton championship were analyzed (46 men’s singles and 24 women’s singles). Before and after each match, jump height and power production were determined during a countermovement jump on a force platform. Participants’ body weight and a urine sample were also obtained before and after each match. The amount of liquid that the players drank during the match was also calculated by weighing their individual drinking bottles. Results and Discussion Sweat rate during the game was 1.14±0.46 l/h in men and 1.02±0.64 l/h in women. The players rehydrated at a rate of 1.10±0.55 l/h and 1.01±0.44 l/h in the male and female groups respectively. Thus, the dehydration attained during the game was only 0.37±0.50% in men and 0.32±0.83% in women. No differences were found in any of the parameters analyzed during the vertical jump (men: from 31.82±5.29 to 32.90±4.49 W/kg; p>0.05, women: from 26.36±4.73 to 27.25±4.44 W/kg; p>0.05). Post-exercise urine samples revealed proteinuria (60.9% of cases in men and 66.7% in women), leukocyturia (men?=?43.5% and women?=?50.0%) and erythrocyturia (men?=?50.0% and women?=?21.7%). Conclusions Despite a moderate sweat rate, badminton players adequately hydrated during a game and thus the dehydration attained was low. The badminton match did not cause muscle fatigue but it significantly increased the prevalence of proteinuria, leukocyturia and erythrocyturia. PMID:22666396

Abian-Vicen, Javier; Del Coso, Juan; Gonzalez-Millan, Cristina; Salinero, Juan Jose; Abian, Pablo

2012-01-01

331

Effects of dehydration on organ metabolism in the frog Pseudacris crucifer : hyperglycemic responses to dehydration mimic freezing-induced cryoprotectant production  

Microsoft Academic Search

The metabolic effects of evaporative water loss at 5 °C were assessed for both fall- and spring-collected spring peepersPsuedacris crucifer. Frogs readily endured the loss of 50% of total body water. During dehydration organ water content was defended with no change in water content in skeletal muscle, gut, and kidney of 50% dehydrated frogs and reduced water content in liver,

T. A. Churchill; K. B. Storey

1994-01-01

332

Principles of Condensed Matter Physics  

Microsoft Academic Search

Although there are many books on solid state physics and condensed matter, I suspect very few cover the same content as that found in {\\\\it Principles of Condensed Matter Physics} by Chaikin and Lubensky. The title is rather misleading as it suggests a survey of the important concepts in condensed matter. In spite of this there is much to commend

C C Matthai

2000-01-01

333

Physics 232 Condensed Matter Physics  

E-print Network

1 Physics 232 Condensed Matter Physics Instructor: Peter Young Office: 212 ISB Telephone: 459://apyoung.com/232 TOPICS This course on condensed matter physics will cover three areas: · magnetism, · optical physics such as Condensed Matter Physics by M. Mardar Solid State Physics by N. Ashroft and N. D. Mermin

Young, A. Peter

334

Condenser procurement guidelines. Final report  

Microsoft Academic Search

Steam surface condensers have a major impact on power plant availability and efficiency. Since supplying condensers to the utility industry is a very competitive buisness, it is essential that all of the requirements, all of the operating and design conditions, and any off standard conditions which can affect the condenser design and performance be clearly communicated to potential suppliers. These

Impagliazzo

1985-01-01

335

ENHANCED TUBES FOR STEAM CONDENSERS  

Microsoft Academic Search

This article provides data on enhanced tubes developed especially for application to steam condensers. Data are provided for different types of tube-side (cooling water) and shell-side (steam) enhancements. The first test series involved measuring the condensing coefficient at a 327 K saturation temperature. Average enhancement levels (defined as the ratio of the condensing coefficient of an enhanced tube to that

M. Hassib Jaber; Ralph L. Webb

1993-01-01

336

Steam condensate corrosion; mechanism; prevention  

Microsoft Academic Search

Steam condensate is a potential corrosion problem in most industries, and because of the tremendous cost involved to protect piping and condensate recovery systems, the problem is greatly increased. The various stages of steam condensate are discussed from its beginning as raw water, through its conversion to steam in a boiler, and to its disposal to a steam consumer, such

1966-01-01

337

Classic Organic Reactions  

NSDL National Science Digital Library

Despite the fact that the Classic Organic Reactions Page was designed for commercial purposes, to demonstrate the capabilities of ChemPen chemical structure drawing software for Windows, the page offers a useful resource for chemistry students and professionals. The creator of this page, and author and proprietor of ChemPen, Dr. Hilton Evans, has cited the literature for each reaction. The site contains drawings for over 300 alphabetically listed classic organic reactions. The list begins with the Acetoacetic Ester Condensation and ends with the Zinke-Suhl Reaction.

2007-05-12

338

New technology in condensate polishing  

SciTech Connect

Sulfonic acid ion exchange resins. when carried into a boiler or steam generator, thermally decompose releasing large amounts of corrosive, sulfates. Replacement of the sulfonic acid resin with a carboxylic acid resin would eliminate this source of contamination. The sulfonic acid resin is a strong acid: the carboxylic acid resin is a weak acid. The carboxylic acid resin alone is not capable of splitting salts which limits its use to mixed resin beds or to its use in single or individual beds with feeds of high alkalinity or high pH values. Laboratory, pilot plant and full scale plant tests compared the two resins in precoat filters. When the resins in mixed beds were in the acid form, the weakly acid resin was almost as effective in removing sodium ion as the strongly acid resin. In the ammonium form. the weakly acid resin was generally more effective in removing sodium than the strongly acid resin. Condensate polishing reduced the sodium ion to a few parts per billion (ppB). Complete resin separation before regeneration is more important for the weakly acid resin than for the strongly acid resin. Another development found that the hydrazine reaction with oxygen could be catalyzed by powdered activated carbon combined with microfibers on a Powdex substrate. The carbon should be thoroughly washed to reduce its residual sodium content. In plant tests, the carbon reduced the oxygen concentration in condensate about 50% during startup. In preliminary tests believed to be typical, carbon lowered the oxygen concentration below 10 ppB in about 6 hours compared to 18 hours without the carbon. Oxygen is also reduced during normal operation.

Kunin, R.; Salem, E.; Libutti, B. (Graver Co., Union, NJ (United States). Water Div.)

1992-08-01

339

Non-iterative condensation modeling for steam condensation with non-condensable gas in a vertical tube  

Microsoft Academic Search

Based on a heat and mass transfer analogy, an iterative condensation model for steam condensation in the presence of a non-condensable gas in a vertical tube is proposed including the high mass transfer effect, entrance effect, and interfacial waviness effect on condensation. A non-iterative condensation model is proposed for easy engineering application using the iterative condensation model and the assumption

Hee Cheon No; Hyun Sik Park

2002-01-01

340

Topology and Fermionic Condensate  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to investigate an influence of a space-time topology on the formation of fermionic condensate in the model with four-fermion interaction ()2. The value for the space-time with topology of R1 × R1 × S1 is found. Moreover a relation of the value of fermionic condensate to a periodic length is studied. In this connection the possibility of a relation of the topologic deposits to structure of hadrons is discussed.Translated AbstractTopologie und FermikondensatEs wird der Einfluß einer Raum-Zeittopologie auf die Bildung des Fermikondensats in einem Modell mit Vierfermionenwechselwirkung ()2 untersucht. Für eine Raum-Zeit mit der Topologie R1 × R2 × S1 werden die Parameter gegeben. Weiterhin wird die Relation der Größe des Fermikondensats zu einer periodischen Länge untersucht. In diesem Zusammenhang wird die Verbindung des topologischen Depots zur Struktur der Hadronen diskutiert.

Kulikov, I.; Pronin, P.

341

Condenser performance monitoring and cleaning  

SciTech Connect

The main condenser at Ginna Station was retubed from admiralty brass to 316 stainless steel. A condenser performance monitoring spreadsheet was developed using EPRI guidelines after fouling was discovered. PEPSE computer models were used to determine the power loss and confirm the spreadsheet results. Cleaning of the condenser was performed using plastic scrubbers. Condenser performance improved dramatically following the cleaning. PEPSE, condenser spreadsheet performance, and actual observed plant data correlated well together. The fouling mechanism was determined to be a common lake bacteria and fungus growth which was combined with silt. Chlorination of the circulating water system at the allowable limits is keeping the biofouling under control.

Walden, J.V. [Rochester Gas and Electric, Ontario, NY (United States)

1998-12-31

342

Reactions of trichlorogermane with alkyl, alkenyl, and alkynyl halides  

Microsoft Academic Search

1.The condensation of trichlorogermane with allyl-type halides, which consists in the replacement of halogen in the latter by the trichlorogermyl group, can be extended to tertiary saturated halides. Secondary and primary alkyl halides do not undergo this reaction.2.3-Chloro- and 3-bromo-propynes also condense with trichlorogermane, but the reaction is accompanied by an addition reaction.3.The possibility of condensation occurring is probably determined

V. F. Mironov; T. K. Gar

1965-01-01

343

Improvements in the order, isotropy and electron density of glypican-1 crystals by controlled dehydration  

PubMed Central

The use of controlled dehydration for improvement of protein crystal diffraction quality is increasing in popularity, although there are still relatively few documented examples of success. A study has been carried out to establish whether controlled dehydration could be used to improve the anisotropy of crystals of the core protein of the human proteoglycan glypican-1. Crystals were subjected to controlled dehydration using the HC1 device. The optimal protocol for dehydration was developed by careful investigation of the following parameters: dehydration rate, final relative humidity and total incubation time T inc. Of these, the most important was shown to be T inc. After dehydration using the optimal protocol the crystals showed significantly reduced anisotropy and improved electron density, allowing the building of previously dis­ordered parts of the structure. PMID:24311593

Awad, Wael; Svensson Birkedal, Gabriel; Thunnissen, Marjolein M. G. M.; Mani, Katrin; Logan, Derek T.

2013-01-01

344

Characterization of dehydration-induced luminescence of kaolinite.  

PubMed

Dehydration-induced luminescence (DIL), the emission of light from a clay paste upon dehydration, was characterized experimentally for a colloidal kaolinite. The relationship between total photon count of the emitted light and film thickness is linear up to a thickness of 30 micrometers. The photon emission was obtained over a critical range of water contents (25-60%) of the oven-dry clay, and the kinetics of photon emission was presumed to be closely associated with the kinetics of film dehydration. Whether drying proceeded throughout the bulk or via a moving front was undetermined, but in either mode it was preceded by the formation of a thin dry film at the interface with the atmosphere. Grinding of the kaolinite for several minutes by mortar and pestle before paste preparations resulted in an overall increase of photon emission compared to unground kaolinite and in the formation of more than one emission peak, as well as a prolongation of the light emission. This effect on the kinetics of light emittance was observed for about two months after the application of the mechanical stress and suggests a means of detecting the mechanical stress history of a clay. An estimate was made of the spectral characteristics of the emitted light using optical filters and by incorporating tryptophan and salicylic acid into the kaolinite paste where they acted as fluorescent probes. The latter technique shifted the frequency of the light emitted by the kaolinite from the ultraviolet to the visible range where it was less effectively reabsorbed. The first method showed that the wavelengths of 97% of the emitted light was <460 nm and that 75% of the light had wavelengths < 410 nm. The second method showed that the total intensity of DIL increased in the presence of fluorescence molecules, suggesting that the emittance was in the ultraviolet range. PMID:11542013

Lahav, N; Coyne, L; Lawless, J G

1985-01-01

345

Voluntary dehydration in runners despite favorable conditions for fluid intake.  

PubMed

This study investigated the relationship between runners' perceptions of fluid needs and drinking behavior under conditions of compensable heat stress (ambient temperature = 20.5 +/- 0.7 degrees C, 68.9 degrees F; relative humidity = 76.6%). Eighteen experienced runners (15 men, 40.5 +/- 2.5 y, and 3 women, 42 +/- 2.3 y) were given ad libitum access to a sports drink (6% carbohydrate-electrolyte solution) at Miles 2, 4, 6, and 8. After the run (75.5 +/- 8.0 min), subjects completed questionnaires that required them to estimate their individual fluid intake and sweat loss. Dehydration averaged 1.9% +/- 0.8% of initial body weight (a mean sweat loss of 21.6 +/- 5.1 mL.kg-1.h-1). Subjects replaced only 30.5% +/- 18.1% of sweat loss and underestimated their sweat loss by 42.5% +/- 36.6% (P dehydrate (P dehydration. This conclusion suggests that runners should not depend on self-assessment to maintain adequate hydration, underscores the need for runners to enhance their ability to self-assess sweat losses, and suggests that a predetermined regimen of fluid ingestion might be necessary if they wish to maintain more optimal hydration. PMID:17693689

Passe, Dennis; Horn, Mary; Stofan, John; Horswill, Craig; Murray, Robert

2007-06-01

346

Buffering limits plasma HCO 3 ? dehydration when red blood cell anion exchange is inhibited  

Microsoft Academic Search

Theory suggests that HCO3? dehydration in the plasma of rainbow trout is limited by both the absence of carbonic anhydrase (CA) activity and the low non-bicarbonate buffer capacity of the plasma (?plasma). The potential for ?plasma to limit plasma HCO3? dehydration was assessed in rainbow trout in which HCO3? dehydration via the red blood cell (RBC) was inhibited using the

K. M. Gilmour; P. R. Desforges; S. F. Perry

2004-01-01

347

The Infrared Spectra Study of Dehydrated and Dehydroxylated Clay Samples  

NASA Astrophysics Data System (ADS)

The OMEGA visible and near infrared imaging spectrometer detected phyllosilicates in ancient Noachian terrains of Mars-an observation later confirmed by CRISM imaging spectrometer. Detailed mapping showed that the phyllosilicates, most of which are clay minerals, are found in ancient, heavily cratered terrains. These clay-bearing deposits contain interbedded and buried craters, and it is possible the clay minerals were repeatedly subjected to high temperatures resulting from impact processes. We hypothesize that the dehydration and dehydroxylation of clay minerals subjected to impact was a widespread process on early Mars, and that dehydrated and dehydroxylated clay minerals may be still abundant on the surface of Mars. The objective of this study is to characterize the infrared spectral features of clay minerals when they are heated to increasingly higher temperatures. Using a Nicolet 6700 FTIR spectrometer, we have acquired mid-infrared reflectance (500cm-1-7000cm-1), far-infrared reflectance (60cm-1-500cm-1) and ATR (attenuated total reflectance)(500cm-1-4000cm-1) spectra of 13 clay samples at different temperatures(from 100°C to 900°C). All of the clay samples have been prepared to be very pure (<2?m size fraction) and they were heated for 24 hours at each temperature. The structures of clay minerals are well known because of their typical layer structure and complex relations with water and OH bonds. Our data show that the infrared spectra of clay minerals changed as the temperature increased, which helps us to understand the temperature-related processes including removal of water and OH groups, change of Si-O bond, even the complete destruction of clay layer structures. Differences among dehydration and dehydroxylation conditions for these clay minerals are also discussed in this work. In our future work, we will continue to collect the infrared spectra of more clay minerals and collect additional data for our samples, including VNIR reflectance, XRD, NMR, and emissivity spectra, which can provide insights into the crystal structures and help us to answer the very first question: is it possible that dehydrated and dehydroxylated clay minerals are an explanation for poorly crystalline or amorphous materials on Mars?

Che, C.; Glotch, T.; Cintrón, I.

2008-12-01

348

Observational Evidence for Incomplete Dehydration in the TTL  

NASA Astrophysics Data System (ADS)

The tropical tropopause layer (TTL) is the primary gateway for entry of air into the stratosphere from the troposphere. Because the coldest region of the TTL is found above the western Pacific, dehydration of stratosphere-bound air parcels in this region by deposition of water vapour to form ice crystals is therefore a key process controlling the humidity of the stratospheric overworld. Strong correlations between stratospheric humidity and TTL temperatures on intra-annual and interannual timescales have demonstrated that this mechanism is largely correct, and that the majority of the variability in stratospheric humidity can be attributed to TTL temperature fluctuations. What is less clear is exactly how air is finally dehydrated on its passage through the TTL, setting the mixing ratio of water vapour entering the stratosphere. Cirrus microphysics is complex, and there are multiple reasons to expect that air parcels containing relative humidity with respect to ice (RHi) greater than 100% may frequently pass the through the Lagrangian dry point and enter the stratosphere. For example, in the absence of appropriate particles to act as heterogeneous nuclei for ice crystal formation, RHi exceeding 160% at TTL temperatures is required for clouds to initially form and remove water from the gas phase. Once cirrus clouds form, if ice crystal concentrations are low (~100 / liter or less), the time for thermodynamic gas/particle equilibrium to be achieved can be hours and is potentially slower than passage through the coldest regions. Here we present aircraft measurements from the NASA Global Hawk Airborne Tropical Tropopause Experiment (ATTREX-2) of relative humidity, ice water content, and ice crystal concentrations from the central and eastern Pacific TTL in February - March 2013. This dataset provides unprecedented high-quality observations of the key parameters required to test theoretical descriptions of dehydration in the TTL. During ATTREX-2, the cirrus clouds encountered most frequently had low ice crystal concentrations. While the few clouds encountered with high ice crystal concentrations contained RHi very close to 100%, the more common thin clouds had higher average and more variable RHi. A number of these observations show supersaturated air near 380K potential temperature, the typical cold point tropopause. ATTREX-2 achieved a significant number of flight hours sampling air in this key region of the atmosphere. These observations provide evidence that suggest that the average entry value of water vapour into the stratosphere may be somewhat supersaturated due to the typical low concentrations of ice crystals in the dehydrating cirrus clouds. Additional measurements in the western Pacific during winter 2014 (ATTREX-3) will significantly improve the statistics of these observations.

Rollins, D. W.; Thornberry, T. D.; Gao, R.; Lawson, P.; Bui, T. V.; Fahey, D. W.

2013-12-01

349

Effect of spontaneous condensation on condensation heat transfer in the presence of non-condensable gases  

SciTech Connect

The presence of non condensable gases like nitrogen or air reduces the condensation heat transfer during condensation of binary steam mixtures. The non condensable gas accumulates in the vapor phase boundary layer and causes a high heat transfer resistance. Especially with high pressures and low water temperatures spontaneous condensation reduces heat transfer additionally. Fog forms within the steam-nitrogen boundary layer and the steam condenses on the water droplets of the fog layer. The convective mass transfer to the cooling water interface diminishes. Raman spectroscopy and film theory are used to quantify this effect locally. The calculation of overall condensation rates in large steam nitrogen systems requires to use three dimensional CFD codes. The paper presents equations to predict fog formation in the boundary layer which can be implemented in CFD codes.

Karl, J.; Hein, D.

1999-07-01

350

Effects of dehydration on immune functions after a judo practice session.  

PubMed

We investigated the effects of dehydration after a judo practice session on player muscle and immune functions. Subjects included 25 female university judoists. Investigations were performed before and after 2.5 h of regular judo practice. Body composition, serum enzymes (myogenic enzymes, immunoglobulins and complements), neutrophils counts, reactive oxygen species (ROS) production capability, and phagocytic activity (PA) were measured. Subjects were divided into two groups according to level of dehydration after practice (mild dehydration and severe dehydration groups) and results were compared. Creatine kinase was found to increase significantly after practice. In addition, neutrophil count also increased significantly after practice in both groups. The changing ratios of IgA, IgG and C3 observed in the mild dehydration group were significantly higher than those in the severe dehydration group. In the severe dehydration group, post-practice PA/neutrophil had decreased significantly. Significant positive correlations were found between severity of dehydration and changing ratios of IgA, IgG, IgM, C3, C4 and ROS production capabilities, whereas no significant association was seen with PA and/or serum SOD activity. These results suggest that dehydration resulted in immunosuppression, including decreased neutrophil function. PMID:22362640

Chishaki, Takeharu; Umeda, Takashi; Takahashi, Ippei; Matsuzaka, Masashi; Iwane, Kaori; Matsumoto, Hidehiko; Ishibashi, Goshi; Ueno, Yuichi; Kashiwa, Naohiro; Nakaji, Shigeyuki

2013-01-01

351

Identification of dehydration tolerance genes in triticale (x Triticosecale Wittm.) seedlings.  

E-print Network

??Dehydration stress triggers many changes in plant gene expression. Triticale (x Triticosecale Wittm.) sequencing using next generation sequencing allowed identification of 107,000 transcripts of which… (more)

Badea, Cosmin

2012-01-01

352

OSMOTIC AND METABOLIC RESPONSES TO DEHYDRATION AND UREA-LOADING IN A TERRESTRIALLY-HIBERNATING FROG.  

E-print Network

??Physiological responses to dehydration in amphibians are reasonably well documented, although little work has addressed this problem in hibernating animals. We investigated osmotic and metabolic… (more)

Muir, Timothy J

2007-01-01

353

Dehydration induced loss of photosynthesis in Arabidopsis leaves during senescence is accompanied by the reversible enhancement in the activity of cell wall ?-glucosidase.  

PubMed

The physiology of loss of photosynthetic production of sugar and the consequent cellular sugar reprogramming during senescence of leaves experiencing environmental stress largely remains unclear. We have shown that leaf senescence in Arabidopsis thaliana causes a significant reduction in the rate of oxygen evolution and net photosynthetic rate (Pn). The decline in photosynthesis is further aggravated by dehydration. During dehydration, primary photochemical reaction of thylakoids and net photosynthesis decrease in parallel with the increase in water deficit. Senescence induced loss in photosynthesis is accompanied by a significant increase in the activity of cell wall hydrolyzing enzyme such as ?-glucosidase associated with cell wall catabolism. The activity of this enzyme is further enhanced when the senescing leaves experience dehydration stress. It is possible that both senescence and stress separately or in combination result in the loss in photosynthesis which could be a signal for an enhancement in the activity of ?-glucosidase that breaks down cell wall polysaccharides to sugar to sustain respiration for metabolic activities of plants experiencing stress. Thus dehydration response of cell wall hydrolases of senescing leaves is considered as plants' strategy to have cell wall polysaccharides as an alternative energy source for completion of energy requiring senescence process, stress survival and maintenance of recovery potential of energy deficit cells in the background of loss in photosynthesis. Withdrawal of stress (rehydration) distinctly exhibits recovery of photosynthesis and suppression of enzyme activity. Retention of the signaling for sugar reprogramming through breakdown of cell wall polysaccharides in the senescing leaves exposed to severe drought stress suggests that senescing leaves like mature ones possess potential for stress recovery. The precise mechanism of stress adaptation of senescing leaves is yet to be known. A significant accumulation of anthocyanin and flavonoids may be an indicator of stress adaptation of senescing leaves. In addition, stress induced enhancement of nonphotochemical quenching (NPQ), a stress protection provision in green plants, also suggests the potential of the leaves to develop adaptational mechanism to counter the dehydration stress. PMID:24793323

Patro, Lichita; Mohapatra, Pranab Kishor; Biswal, Udaya Chand; Biswal, Basanti

2014-08-01

354

Gravitational Condensate Stars  

NASA Astrophysics Data System (ADS)

The issue of the final state of the gravitational collapse will be addressed. Ishall present physical arguments to the effect that the remnant of the gravitationalcollapse of super-massive stars is a cold and dark super-dense object which isthermodynamically and dynamically stable: a Gravitational Condensate Star orQuasi Black Hole (QBH). A QBH is characterized by a huge, but not an infinite,surface redshift. This surface redshift depends universally on the total mass of aQBH and the proper thickness of a thin shell of an exotic matter described bythe Zel'dovich equation of state p = c2 . The velocity of sound in a thin shell isequal to the velocity of light. Hence, this thin shell replaces the event horizon of amathematical black hole ( = 0). Inside a thin shell the zero entropy gravitationalcondensate characterized by the cosmological equation of state p = -c2 resides.A QBH is described by a new static and spherically symmetric solution of Ein-stein's equations supplemented with the proper boundary conditions based on mi-crophysics considerations. The new solution has no singularities and no eventhorizons. Its entropy is maximized under small fluctuations and is given by thestandard hydrodynamic entropy of the thin shell which is proportional to the to-tal mass instead of the Bekenstein-Hawking entropy which is proportional to thesquare of the total mass. This resolves the paradox of an excessively high en-tropy of black holes as compared to their progenitors. The formation of such acold gravitational condensate stellar remnant very likely would require a violentcollapse process with an explosive output of energy. Some observational conse-quences of the formation of gravitational condensate stars will be described.

Mazur, P.; Mottola, E.

355

Confinement Contains Condensates  

SciTech Connect

Dynamical chiral symmetry breaking and its connection to the generation of hadron masses has historically been viewed as a vacuum phenomenon. We argue that confinement makes such a position untenable. If quark-hadron duality is a reality in QCD, then condensates, those quantities that have commonly been viewed as constant empirical mass-scales that fill all spacetime, are instead wholly contained within hadrons; i.e., they are a property of hadrons themselves and expressed, e.g., in their Bethe-Salpeter or light-front wave functions. We explain that this paradigm is consistent with empirical evidence, and incidentally expose misconceptions in a recent Comment.

Brodsky, Stanley J.; Roberts, Craig D.; Shrock, Robert; Tandy, Peter C.

2012-03-12

356

Cosmological tachyon condensation  

E-print Network

We consider the prospects for dark matter/energy unification in k-essence type theories. General mappings are established between the k-essence scalar field, the hydrodynamic and braneworld descriptions. We develop an extension of the general relativistic dust model that incorporates the effects of both pressure and the associated acoustic horizon. Applying this to a tachyon model, we show that this inhomogeneous "variable Chaplygin gas" does evolve into a mixed system containing cold dark matter like gravitational condensate in significant quantities. Our methods can be applied to any dark energy model as well as to mixtures of dark energy and traditional dark matter.

Neven Bilic; Gary B. Tupper; Raoul D. Viollier

2008-09-02

357

Calculation of dehydration absorbers based on improved phase equilibrium data  

SciTech Connect

Dehydration using triethylene glycol (TEG) as an absorbent, is a standard process for natural gas treating. New and more accurate TEG/water equilibrium data have been measured between 1980 and 1990. However, this has not influenced much on the design methods of dehydration absorbers. Inaccurate equilibrium data have been extensively used in design calculations. When using data from a common source like Worley, an overall bubble cap tray efficiency between 25--40% has normally been recommended. This has resulted in a quite satisfactory and consistent design method. It is obvious that newer equilibrium data (Herskowitz, Parrish, Bestani) are more accurate. However, to achieve an improved design method, column efficiencies consistent with the new equilibrium data must be recommended. New equilibrium data have been correlated to an activity coefficient model for the liquid phase and combined with an equation of state for the gas phase. Performance data from the North Sea offshore platform Gullfaks C (drying 4--5 MMscmd) have been measured. The bubble cap column has been simulated, and the tray efficiency has been adjusted to fit the performance data. Tray efficiencies calculated with new equilibrium data are higher than 50%. Calculated tray efficiency values are dependent on the equilibrium data used. There are still uncertainties in equilibrium data for the TEC/water/natural gas system. When using accurate equilibrium data, an overall bubble cap tray efficiency of 40--50% and a Murphree efficiency of 55--70% can be expected at normal absorption conditions.

Oi, L.E.

1999-07-01

358

Hydrated Salts: Dehydration, Dissolution, and Incongruent Melting In Terrestrial Evaporites and at Meridiani Planum, Mars  

NASA Astrophysics Data System (ADS)

The Opportunity rover and orbital observations of Meridiani Planum (Mars) have revealed much about the region's stratigraphy, chemistry, sedimentology, and mineralogy of what appears to be a layered lacustrine sedimentary sequence, including chemical sediments deposited by evaporative or freezing processes in a large, saline lake or sea. The roles of evaporation versus freezing are not clearly elucidated in the data, but both freezing and evaporation are likely on Mars for any paleoclimate scenario that minimizes excursions from current climate. The rock sequences reveal many interesting features reported in press accounts, NASA press releases, and in conference presentations by the MER science teams. The topic dealt with here concerns indirect sedimentologic indications of phase changes that seem to have generated negative volume changes due to dehydration, dissolution, and/or annealing. These indicators include microkarstic and polygonal structures in the laminated chemical sediments. These processes have operated on a small scale at Meridiani Planum, and serve as possible analogs for processes operative on mega scales elsewhere on Mars. Comparable processes are common in terrestrial evaporite basins and in sequences of evaporitic rocks. Fluctuations of mineral water content drive large changes in volume and pore fluid pressure, and these exert stresses that can drive extensional fracturing and faulting, folding, thrusting, and diapirism. These processes may be even more important on Mars than on Earth, because on Mars solid salts may be more abundant, more widespread, and subject to larger ranges of hydration states; the effects of these processes may be better preserved for lack of erasure by fluvial erosional processes and other degradational processes on Earth's more active surface. Specific processes and reactions proposed here can account for the sedimentologic structures observed at Meridiani Planum based on aqueous chemical phase equilibria and phase-volume data applied to the mineralogies and chemistries observed or inferred from spacecraft data. Dehydration and/or open-system incongruent dissolution of Mg-Fe-Ca-sulfate hydrates can explain both the microkarstic and decimeter-scale polygonal structures observed by the Opportunity rover. Close analogs of these inferred processes and observed features are common in terrestrial evaporite sequences. Considering scenarios for minimized excursions from current climate, we attribute the structures either to dehydration or dissolution etching by cryogenic acid brines-- or both operating in tandem or in sequence. These processes operating at low rates may remain active even as Opportunity observes the layered/laminated rock sequence. Inclusion on future spacecraft of simple soil pH measurements would do much to resolve questions of possible present-day activity of acidic brine films. Because many salt dehydration steps occur at temperatures far below the melting point of ice, future differential scanning calorimetry/thermal analysis must consider very small increments of heating in the 200-400 K temperature range if we are to understand adequately the composition and hydration states of Martian salts.

Kargel, J. S.; Dougherty, A.; Feldman, W.; Hogenboom, D.; Marion, G.; McCarthy, C.; Prieto-Ballesteros, O.

2004-12-01

359

Subcooled Flow Boiling and Condensation  

Microsoft Academic Search

Fundamental problems in two different flow regimes; subcooled water-steam bubbly condensing flow and subcooled flow boiling, in vertical conduits under low pressure and mass flux conditions, were investigated.\\u000aFor subcooled water-steam condensing bubbly flow, experiments were carried out to obtain a data base for the axial distribution of area-averaged void fraction, interfacial area concentration, interfacial condensation heat transfer and bubble

Obida M. Zeitoun

1994-01-01

360

Subcooled flow boiling and condensation  

Microsoft Academic Search

Fundamental problems in two different flow regimes, subcooled water-steam bubbly condensing flow and subcooled flow boiling, in vertical conduits under low pressure and mass flux conditions, were investigated.^ For subcooled water-steam condensing bubbly flow, experiments were carried out to obtain a database for the axial distribution of area-averaged void fraction, interfacial area concentration, interfacial condensation heat transfer and bubble relative

Obida M Zeitoun

1995-01-01

361

Cosmic curvature and condensation  

NASA Technical Reports Server (NTRS)

It is shown that the universe may consist of a patchwork of domains with different Riemann curvature constants k = 0, +/-1. Features of a phase transition in which flat space breaks up in a transition 2k0 - k(-) + k(+) with initial scale factors R(-) = R(+) are postulated and explored. It is shown that such a transition is energetically permitted, has the equivalent of a Curie temperature, and can lead in a natural way to the formation of voids and galaxies. It is predicted that, if the ambient universe on average is well fitted by a purely k(-) space, with only occasional domains of k(+) containing galaxies, a density parameter of (A(z sub c + 1)) super -1 should be expected, where z sub c represents the redshift of the earliest objects to have condensed, and A takes on values ranging from about 5 to 3. Present observations of quasars would suggest a density of about 0.03 or 0.05, respectively, but it could be lower if earlier condensation took place.

Harwit, Martin

1992-01-01

362

Organic Chemistry 51B -Winter 2013 Organic Chemistry Peer Tutoring Program Chemistry 51B Reactions List  

E-print Network

° alkyl halide 4. Preparation of epoxides (Intramolecular SN2 reaction) #12;Organic Chemistry 51B - Winter attack via SN2 mechanism Reactions of Alcohols 1. Dehydration to form alkenes a. Using strong acid Can may occur) For 1° and methyl alcohols, mechanism is SN2 3. Reaction with other reagents to form RX

Rose, Michael R.

363

Addition polymers from 1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene and Bis-dienes. 2: Evidence for thermal dehydration occurring in the cure process  

NASA Technical Reports Server (NTRS)

Diels-Alder cycloaddition copolymers from 1,4,5,8-tetrahydro-1,4;5,8-diepoxyanthracene and anthracene end-capped polyimide oligomers appear, by thermogravimetric analysis (TGA), to undergo dehydration at elevated temperatures. This would produce thermally stable pentiptycene units along the polymer backbone, and render the polymers incapable of unzipping through a retro-Diels-Alder pathway. High resolution solid 13C nuclear magnetic resonance (NMR) of one formulation of the polymer system before and after heating at elevated temperatures, shows this to indeed be the case. NMR spectra of solid samples of the polymer before and after heating correlated well with those of the parent pentiptycene model compound before and after acid-catalyzed dehydration. Isothermal gravimetric analyses and viscosities of the polymer before and after heat treatment support dehydration as a mechanism for the cure reaction.

Meador, Mary Ann B.; Olshavsky, Michael A.; Meador, Michael A.; Ahn, Myong-Ku

1988-01-01

364

Ferminoic physics in dipolariton condensates.  

PubMed

An exciton polariton is an extremely light bosonic quasiparticle that is composed of an exciton and a photon. We report on a theoretical study of exciton-polariton condensation in a system with tunnel-coupled quantum wells. Because their excitons can carry an electric dipole moment, these systems have been referred to as dipolariton condensates. We use a fermionic mean-field theory that can address quantum well and other internal exciton degrees of freedom to describe the new physics present in dipolariton condensates. We find that the role of underlying fermonic degrees of freedom is enhanced and predict that metallic condensates can occur at high carrier densities. PMID:24702391

Su, Jung-Jung; Kim, Na Young; Yamamoto, Yoshihisa; Macdonald, Allan H

2014-03-21

365

Potentially Prebiotic Syntheses of Condensed Phosphates  

NASA Technical Reports Server (NTRS)

In view of the importance of a prebiotic source of high energy phosphates, we have investigated a number of potentially prebiotic processes to produce condensed phosphates from orthophosphate and cyclic trimetaphosphate from tripolyphosphate. The reagents investigated include polymerizing nitriles, acid anhydrides, lactones, hexamethylene tetramine and carbon suboxide. A number of these processes give substantial yields of pyrophosphate from orthophosphate and trimetaphosphate from tripolyphosphate. Although these reactions may have been applicable in local areas, they are not sufficiently robust to have been of importance in the prebiotic open ocean.

Keefe, Anthony D.; Miller, Stanley L.

1996-01-01

366

Heat Transfer from Condensate Droplets Falling through an Immiscible Layer of Tributyl Phosphate  

Microsoft Academic Search

As part of a safety analysis of reactions in two-layer mixtures of nitric acid and tributyl phosphate (TBP), an experiment was conducted to study how steam condensate mixes with the TBP layer when steam passes over a TBP-nitric acid mixture. The experiments showed that the condensate does not form a separate layer on top of the TBP but instead percolates

Laurinat; James E

2005-01-01

367

Framework for Understanding Lenr Processes, Using Conventional Condensed Matter Physics  

Microsoft Academic Search

Conventional condensed matter physics provides a unifying framework for understanding low-energy nuclear reactions (LENRs) in solids. In the paper, standard many-body physics techniques are used to illustrate this fact. Specifically, the paper shows that formally the theories by Schwinger, Hagelstein, and Chubb and Chubb (C&C), all can be related to a common set of equations, associated with reaction rate and

Scott R. Chubb

2006-01-01

368

Freezing survival and cryoprotective dehydration as cold tolerance mechanisms in the Antarctic nematode Panagrolaimus davidi  

Microsoft Academic Search

The relative importance of freezing tolerance and cryoprotective dehydration in the Antarctic nematode Panagrolaimus davidi has been investigated. If nucleation of the medium is initiated at a high subzero temperature (-1°C), the nematodes do not freeze but dehydrate. This effect occurs in deionised water, indicating that the loss of water is driven by the difference in vapour pressure of ice

David A. Wharton; Gordon Goodall; Craig J. Marshall

2003-01-01

369

Dehydration does not affect the radial pressures produced by the earthworm Aporrectodea caliginosa  

Microsoft Academic Search

As a soil dries, the earthworms in that soil dehydrate and become less active. Moisture stress may weaken an earthworm, lowering the radial pressure that the animal can produce. This possibility was investigated for the earthworm Aporrectodea caliginosa (Savigny). Pressures were compared for saturated earthworms (worms taken from saturated soil) and stressed earthworms (worms that had been partially dehydrated by

Robert J. Stovold; W. Richard Whalley; Peter J. Harris

2003-01-01

370

Waste grape skins thermal dehydration: potential release of colour, phenolic and aroma compounds into wine  

Microsoft Academic Search

Exploitation of grape waste material is scarce. One of the main issues to deal with is its high moisture content, as it causes spoilage and degradation of valuable compounds. In order to assess this limitation, four different Vitis vinifera waste grape skins from the juice industry were dehydrated at 60, 90 and 100°C. Characterisation of dehydrated waste grape skins (DWGS)

Miguel A. Pedroza; Manuel Carmona; Francisco Pardo; M. Rosario Salinas; Amaya Zalacain

2012-01-01

371

Oral hydration in older adults: greater awareness is needed in preventing, recognizing, and treating dehydration.  

PubMed

Maintaining adequate fluid balance is an essential component of health at every stage of life. Age-related changes make older adults more vulnerable to shifts in water balance that can result in overhydration or, more frequently, dehydration. This article reviews age-related changes, risk factors, assessment measures, and nursing interventions for dehydration. PMID:16728843

Mentes, Janet

2006-06-01

372

Effect of blanching\\/osmotic dehydration combined methods on quality and stability of minimally processed strawberries  

Microsoft Academic Search

The combined effect of blanching [steam (S) or microwave (MW)] and osmotic dehydration at atmospheric pressure (OD) or pulsed vacuum treatments (PVOD), on some physiochemical and quality parameters of strawberry (aw, pH, color, firmness, polyphenoloxidase enzyme activity and microstructure), as well as on microbial stability of processed samples, was analyzed. Pulsed vacuum osmotic dehydration with 65 Brix sucrose solution of

J Moreno; A Chiralt; I Escriche; J. A Serra

2000-01-01

373

Dehydration of the upper troposhere and lower stratosphere by subdivisible cirrus clouds near the tropical tropopause  

Microsoft Academic Search

The extreme dryness of the lower stratosphere is believed to be caused by freeze-drying air as it enters the stratosphere through the cold tropical troposphere. Previous investigations have been focused on dehydration occurring at the tops of deep convective cloud systems. However, recent observations of a ubiquitous stratiform cirrus cloud layer near the tropical tropopause suggest the possibility of dehydration

Eric J. Jensen; Owen B. Toon; Leonard Pfister; Henry B. Selkirk

1996-01-01

374

DEHYDRATION OF FRUITS AND VEGETABLES - RECENT DEVELOPMENTS IN PRINCIPLES AND TECHNIQUES  

Microsoft Academic Search

Advances in dehydration techniques and development of novel drying methods have in recentyears enabled the preparation of a wide range of dehydrated products and convenience foods from fruits and vegetables meeting the quality, stability and functional requirements coupled with economy. This has been made possible by the sustained experimental studies over the years to understand the theoretical and fundamental aspects

K. S. Jayaraman; D. K. Das Gupta

1992-01-01

375

Gene expression changes governing extreme dehydration tolerance in an Antarctic insect  

E-print Network

Gene expression changes governing extreme dehydration tolerance in an Antarctic insect Nicholas M transcriptional mechanisms of extreme dehydration tolerance in the Antarctic midge, Belgica antarctica, the world's southernmost insect and only insect endemic to Ant- arctica. Larvae of B. antarctica are remarkably tolerant

Lee Jr., Richard E.

376

Natural gas dehydration: Status and trends. Final report, March-October 1993  

Microsoft Academic Search

Environmental agencies at both the state and national level are beginning to focus on glycol gas dehydration units as possible emission sources that require regulation. This has prompted some states to begin the process of tabulating glycol dehydrators for possible permitting. To determine the economic impact of regulation on a national level this study delves into the current status of

J. F. Graham; M. R. Krenek; D. J. Maxson; J. A. Pierson; J. L. Thompson

1994-01-01

377

An asymptotic theory of condensed two-phase flame propagation  

Microsoft Academic Search

A model is presented for flame propagation though a condensed combustible mixture in which the limiting component of the mixture melts during the reaction process. An asymptotic analysis, valid for large activation energies, is employed to derive a two-term expansion for the steady, planar adiabatic flame speed. A linear stability analysis is then used to show that for sufficiently large

Stephen B. Margolis

1983-01-01

378

J. Condensed Matter Nucl. Sci. 5 (2011) 116139 Research Article  

E-print Network

J. Condensed Matter Nucl. Sci. 5 (2011) 116­139 Research Article Coherent Energy Exchange was nuclear; however, known exothermic nuclear reactions that produce energy do so through energetic particles between two deuterons and a 4He nucleus. Hence, experiment suggests that the energy is probably nuclear

Williams, Brian C.

379

TTL Dehydration Characterized by SOWER Observations over the Pacific  

NASA Astrophysics Data System (ADS)

The Soundings of Ozone and Water in the Equatorial Region (SOWER) has been accumulating observational evidences of atmospheric dehydration taking place for the air parcels advected horizontally in the Tropical Tropopause Layer (TTL). This paper discusses the nature of TTL dehydration using the dataset obtained since initiation in 1998. The cold-trap dehydration associated with the quasi-horizontal advection (Holton and Gettelman, 2001) effectively functions between 360 K and 380 K isentropes leading to the mean water mixing ratio of 1.9 × 0.6 ppmv on arrival at 380 K after slow diabatic assent, while some moistening takes place before the air parcel reaches 400 K. An example from individual soundings shows 80 % supersaturation in relative humidity with respect to ice (RHice) in subvisible cirrus clouds located near the cold point tropopause (CPT) at the temperature around 180 K (Hasebe et al., 2013). The water budget for individual air parcels has been estimated by searching for the opportunity of repeated sampling of the same air parcel (water vapor match) in the TTL (Inai et al., this meeting). Simultaneous observations by lidar and Optical Particle Counters near the CPT reveal cirrus clouds within the aerosol layer composed of liquid phase aqueous sulfuric acid particles. The characteristics of the TTL cirrus cloud particles are discussed by Sakurai et al. (this meeting). The differences in the observed water content are brought about by the temperature history of the air parcels described by the dynamical field as well as the climatological location of observation station. Inai et al. (2012) found that the difference of RHice inside TTL cirrus between the two stations strongly depend on the phase of MJO disturbances. Further analysis shows that the water mixing ratios on 355 K and 360 K are lower (higher) to the east (west) relative to the temperature maximum associated with TTL Kelvin waves. Back trajectory analyses suggest that the difference is brought about by the associated dynamical field (so-called Matsuno-Gill pattern) leading to the exposure of lower (higher) temperature for the air parcels advected to the west (east) in the easterly (westerly) phase of Kelvin waves, which is consistent with the notion by Eguchi and Shiotani (2004). The results from extended analyses will be presented together with more discussions.

Hasebe, F.; Shiotani, M.; Fujiwara, M.; Shibata, T.; Inai, Y.

2013-12-01

380

ROLE OF PRESSURE IN SMECTITE DEHYDRATION - EFFECTS ON GEOPRESSURE AND SMECTITE-TO-ILLITE TRANSFORMATION.  

USGS Publications Warehouse

Evaluation of the effects of pressure on the temperature of interlayer water loss (dehydration) by smectites under diagenetic conditions indicates that smectites are stable as hydrated phases in the deep subsurface. Hydraulic and differential pressure conditions affect dehydration differently. The temperature of dehydration increase with pore fluid pressure and interlayer water density. The temperatures of dehydration increase with pore fluid pressure and interlayer water density. The temperatures of dehydration under differential-presssure conditions are inversely related to pressure and interlayer water density. The model presented assumes the effects of pore fluid composition and 2:1 layer reactivity to be negligible. Agreement between theoretical and experimental results validate this assumption. Additional aspects of the subject are discussed.

Colten-Bradley, Virginia, A.

1987-01-01

381

Pyropia yezoensis can utilize CO2 in the air during moderate dehydration  

NASA Astrophysics Data System (ADS)

Pyropia yezoensis, an intertidal seaweed, experiences regular dehydration and rehydration with the tides. In this study, the responses of P. yezoensis to dehydration and rehydration under high and low CO2 concentrations ((600-700)×10-6 and (40-80)×10-6, named Group I and Group II respectively) were investigated. The thalli of Group I had a significantly higher effective photosystem II quantum yield than the thalli of Group II at 71% absolute water content (AWC). There was little difference between thalli morphology, total Rubisco activity and total protein content at 100% and 71% AWC, which might be the basis for the normal performance of photosynthesis during moderate dehydration. A higher effective photosystem I quantum yield was observed in the thalli subjected to a low CO2 concentration during moderate dehydration, which might be caused by the enhancement of cyclic electron flow. These results suggested that P. yezoensis can directly utilize CO2 in ambient air during moderate dehydration.

Zhou, Wei; He, Linwen; Yang, Fang; Lin, Apeng; Zhang, Baoyu; Niu, Jianfeng; Wang, Guangce

2014-03-01

382

Microgravity condensing heat exchanger  

NASA Technical Reports Server (NTRS)

A heat exchanger having a plurality of heat exchanging aluminum fins with hydrophilic condensing surfaces which are stacked and clamped between two cold plates. The cold plates are aligned radially along a plane extending through the axis of a cylindrical duct and hold the stacked and clamped portions of the heat exchanging fins along the axis of the cylindrical duct. The fins extend outwardly from the clamped portions along approximately radial planes. The spacing between fins is symmetric about the cold plates, and are somewhat more closely spaced as the angle they make with the cold plates approaches 90.degree.. Passageways extend through the fins between vertex spaces which provide capillary storage and communicate with passageways formed in the stacked and clamped portions of the fins, which communicate with water drains connected to a pump externally to the duct. Water with no entrained air is drawn from the capillary spaces.

Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor); North, Andrew (Inventor); Weislogel, Mark M. (Inventor)

2011-01-01

383

Principles of Condensed Matter Physics  

Microsoft Academic Search

Now in paperback, this book provides an overview of the physics of condensed matter systems. Assuming a familiarity with the basics of quantum mechanics and statistical mechanics, the book establishes a general framework for describing condensed phases of matter based on symmetries and conservation laws. After surveying the structure and properties of materials with different symmetries, it explores the role

P. M. Chaikin; T. C. Lubensky

2000-01-01

384

Condensed Matter Physics - Biology Resonance  

Microsoft Academic Search

The field of condensed matter physics had its genesis this century and it has had a remarkable evolution. A closer look at its growth reveals a hidden aim in the collective consciousness of the field - a part of the development this century is a kind of warm up exercise to understand the nature of living condensed matter, namely the

G. Baskaran

2000-01-01

385

Steam condenser thermal design theories  

Microsoft Academic Search

Test data and prediction methods for condensation in steam condenser tube banks are reviewed. Standards for thermal rating; effect of vapor velocity; vapor shear and inundation in tube banks; correction factors to the Nusselt equation; and equations for the combined effect of vapor shear and inundation are discussed. Effects of noncondensible gases; tube side heat transfer; and expressions for combined

B. J. Davidson

1983-01-01

386

Staining Protocol for MCF-10A Frozen Sections Nuclear fast red provides better staining when complete dehydration is desired  

E-print Network

when complete dehydration is desired · Toluidine blue can provide better contrast for hydrated sections and visualize. For nuclear fast red, dehydrate: a. 75% ethanol for 30 sec. b. 95% ethanol for 30 sec. c. 100

387

From Solution to the Gas Phase: Stepwise Dehydration and Kinetic Trapping of Substance P Reveals the Origin of Peptide  

E-print Network

From Solution to the Gas Phase: Stepwise Dehydration and Kinetic Trapping of Substance P Reveals+ , the results demonstrate that a compact dehydrated conformer population can be kinetically trapped on the time

Clemmer, David E.

388

Characterization of dehydration-induced luminescence of kaolinite  

NASA Technical Reports Server (NTRS)

The dehydration-induced luminescence of a colloidal kaolinite is investigated experimentally, with particular attention given to the effect of various treatments on the luminescence characteristics. It is found that the total photon count of the emitted light is linearly related to the film thickness up to a thickness of 30 microns; mechanical stress in the form of grinding increases the photon output and produces extensive changes in the emission kinetics. A direct check of the emission wavelength dependence (by using color filters) indicates that roughly 75 percent of the emission occurs in the wavelength range below 410 nm. It is also found that incorporation of fluorescent molecules into the kaolinite paste increases the photon output and may indicate the transfer of ultraviolet photons to the fluorescent probe.

Lahav, N.; Coyne, L.; Lawless, J. G.

1985-01-01

389

[Hypertonic dehydration in "silent" malnutrition of breast-fed infants].  

PubMed

Two firstborn, breast-fed infants (delivery at home) were admitted to the hospital in a critical state of hypernatraemic dehydration. Case 1, a boy aged 13 days, had suffered 1220 g loss of weight since birth (31%), his serum sodium concentration was 180 mmol/l. Case 2, a girl aged 7 days, had lost 610 g since birth (18%); her serum sodium level was 159 mmol/l. In both cases poor professional support of lactation and lack of weight control had resulted in unnoticed severe malnutrition. After slow rehydration recovery was uneventful. Closer monitoring of babies' weight, e.g. twice a week, is advocated especially for breast-fed firstborns in the early weeks of life. PMID:9623196

van der Heide, P A; Toet, M C; van Diemen-Steenvoorde, J A; Renardel de Lavalette, P A; de Jonge, G A

1998-05-01

390

Hypernatraemic dehydration and breast feeding: a population study  

PubMed Central

As part of a population based regional review of all neonatal readmissions, the incidence of dehydration with hypernatraemia in exclusively breast fed infants was estimated. All readmissions to hospital in the first month of life during 1998 from a population of 32 015 live births were reviewed. Eight of 907 readmissions met the case definition, giving an incidence of at least 2.5 per 10 000 live births. Serum sodium at readmission varied from 150to 175 mmol/l. One infant had convulsions. The sole explanation for hypernatraemia was unsuccessful breast feeding in all cases. The eight cases are compared with the 65 cases published in the literature since 1979. Presentation, incidence, risk factors, pathophysiology, treatment, and prevention are discussed.?? PMID:11567942

Oddie, S; Richmond, S; Coulthard, M

2001-01-01

391

Effect of Dehydration Prior to Cryopreservation of Large Equine Embryos  

PubMed Central

Cryopreservation of equine embryos > 300 ?m in diameter results in low survival rates using protocols that work well for smaller equine embryos. These experiments tested the potential benefit of incorporating a dehydration step prior to standard cryopreservation procedures. Forty-six, d 7–8, grade 1, equine embryos ? 400 ?m in diameter were subjected to one of the following treatments: (A) 2-min in 0.6 M galactose, 10 min in 1.5 M glycerol, slow freeze (n=21); (B) 10 min in 1.5 M glycerol, slow freeze (n=15); (C) 2 min in 0.6 M galactose, 10 min in 1.5 M glycerol, followed by exposure to thaw solutions, then culture medium (n=5); (D) transferred directly to culture medium (n=5). Frozen embryos were thawed and subjected to a 3-step cryoprotectant removal. Five embryos from each treatment were evaluated morphologically after 24 and 48 h culture (1=excellent, 5=degenerate/dead). All treatments had at least 4/5 embryos with a quality score ? 3 at these time points except treatment B (2/5 at 24 h, 1/5 at 48 h). Subsequent embryos from treatment A (n=16) or B (n=10) were matched in sets of two for size and treatment, thawed, and immediately transferred in pairs to 13 recipients. Only two recipient mares were pregnant; one received two 400 ?m embryos from treatment A, and the other one 400 ?m and one 415 ?m embryo from treatment B. There was no advantage of incorporating a 2 min dehydration step into the cryopreservation protocol for large equine embryos. PMID:19375416

Barfield, JP; McCue, PM; Squires, EL; Seidel, GE

2009-01-01

392

Advancing microwave technology for dehydration processing of biologics.  

PubMed

Our prior work has shown that microwave processing can be effective as a method for dehydrating cell-based suspensions in preparation for anhydrous storage, yielding homogenous samples with predictable and reproducible drying times. In the current work an optimized microwave-based drying process was developed that expands upon this previous proof-of-concept. Utilization of a commercial microwave (CEM SAM 255, Matthews, NC) enabled continuous drying at variable low power settings. A new turntable was manufactured from Ultra High Molecular Weight Polyethylene (UHMW-PE; Grainger, Lake Forest, IL) to provide for drying of up to 12 samples at a time. The new process enabled rapid and simultaneous drying of multiple samples in containment devices suitable for long-term storage and aseptic rehydration of the sample. To determine sample repeatability and consistency of drying within the microwave cavity, a concentration series of aqueous trehalose solutions were dried for specific intervals and water content assessed using Karl Fischer Titration at the end of each processing period. Samples were dried on Whatman S-14 conjugate release filters (Whatman, Maidestone, UK), a glass fiber membrane used currently in clinical laboratories. The filters were cut to size for use in a 13 mm Swinnex(®) syringe filter holder (Millipore(™), Billerica, MA). Samples of 40 ?L volume could be dehydrated to the equilibrium moisture content by continuous processing at 20% with excellent sample-to-sample repeatability. The microwave-assisted procedure enabled high throughput, repeatable drying of multiple samples, in a manner easily adaptable for drying a wide array of biological samples. Depending on the tolerance for sample heating, the drying time can be altered by changing the power level of the microwave unit. PMID:24835259

Cellemme, Stephanie L; Van Vorst, Matthew; Paramore, Elisha; Elliott, Gloria D

2013-10-01

393

Advancing Microwave Technology for Dehydration Processing of Biologics  

PubMed Central

Our prior work has shown that microwave processing can be effective as a method for dehydrating cell-based suspensions in preparation for anhydrous storage, yielding homogenous samples with predictable and reproducible drying times. In the current work an optimized microwave-based drying process was developed that expands upon this previous proof-of-concept. Utilization of a commercial microwave (CEM SAM 255, Matthews, NC) enabled continuous drying at variable low power settings. A new turntable was manufactured from Ultra High Molecular Weight Polyethylene (UHMW-PE; Grainger, Lake Forest, IL) to provide for drying of up to 12 samples at a time. The new process enabled rapid and simultaneous drying of multiple samples in containment devices suitable for long-term storage and aseptic rehydration of the sample. To determine sample repeatability and consistency of drying within the microwave cavity, a concentration series of aqueous trehalose solutions were dried for specific intervals and water content assessed using Karl Fischer Titration at the end of each processing period. Samples were dried on Whatman S-14 conjugate release filters (Whatman, Maidestone, UK), a glass fiber membrane used currently in clinical laboratories. The filters were cut to size for use in a 13?mm Swinnex® syringe filter holder (Millipore™, Billerica, MA). Samples of 40??L volume could be dehydrated to the equilibrium moisture content by continuous processing at 20% with excellent sample-to-sample repeatability. The microwave-assisted procedure enabled high throughput, repeatable drying of multiple samples, in a manner easily adaptable for drying a wide array of biological samples. Depending on the tolerance for sample heating, the drying time can be altered by changing the power level of the microwave unit. PMID:24835259

Cellemme, Stephanie L.; Van Vorst, Matthew; Paramore, Elisha

2013-01-01

394

Troubleshooting surface condenser venting systems  

SciTech Connect

In an ideal situation, the condensing pressure achievable in a steam surface condenser is determined by the exiting cooling water temperature. However, the failure of the venting system to properly remove noncondensible gases from the steam condenser will result in elevated condenser pressures. Information is presented in this paper relative to the most common venting systems available, as well as providing procedures for troubleshooting each type of system. A description is given of the various operating characteristics, along with narrative discussions of field problems and experiences. Simple visual, audible and physical guides to the analysis of venting system problems are discussed. Power plant operating personnel will be able to utilize this information when investigating steam condenser performance problems. A check list is provided which can be used to isolate these performance problems. 4 figs., 3 tabs.

Lines, J.R.; Athey, R.E.; Frens, L.L. [Graham Manufacturing Company, Batavia, NY (United States)

1996-08-01

395

A sulfated ZrO2 hollow nanostructure as an acid catalyst in the dehydration of fructose to 5-hydroxymethylfurfural.  

PubMed

Mesoporous hollow colloidal particles with well-defined characteristics have potential use in many applications. In liquid-phase catalysis, in particular, they can provide a large active surface area, reduced diffusion resistance, improved accessibility to reactants, and excellent dispersity in reaction media. Herein, we report the tailored synthesis of sulfated ZrO2 hollow nanostructures and their catalytic applications in the dehydration of fructose. ZrO2 hollow nanoshells with controllable thickness were first synthesized through a robust sol-gel process. Acidic functional groups were further introduced to the surface of hollow ZrO2 shells by sulfuric acid treatment followed by calcination. The resulting sulfated ZrO2 hollow particles showed advantageous properties for liquid-phase catalysis, such as well-maintained structural integrity, good dispersity, favorable mesoporosity, and a strongly acidic surface. By controlling the synthesis and calcination conditions and optimizing the properties of sulfated ZrO2 hollow shells, we have been able to design superacid catalysts with superior performance in the dehydration of fructose to 5-hydroxymethyfurfural than the solid sulfated ZrO2 nanocatalyst. PMID:24023048

Joo, Ji Bong; Vu, Austin; Zhang, Qiao; Dahl, Michael; Gu, Minfen; Zaera, Francisco; Yin, Yadong

2013-10-01

396

Mesoporous siliconiobium phosphate as a pure Brønsted acid catalyst with excellent performance for the dehydration of glycerol to acrolein.  

PubMed

The development of solid acid catalysts that contain a high density of Brønsted acid sites with suitable acidity, as well as a long lifetime, is one of great challenges for the efficient dehydration of glycerol to acrolein. Herein, we report on a mesoporous siliconiobium phosphate (NbPSi-0.5) composite, which is a promising solid Brønsted acid that is a potential candidate for such a high-performance catalyst. A variety of characterization results confirm that NbPSi-0.5 contains nearly pure Brønsted acid sites and has well-defined large mesopores. In addition, NbPSi-0.5 contains a similar amount of acid sites and exhibits weaker acidity than that of the highly acidic niobium phosphate and HZSM-5 zeolite. NbPSi-0.5 is quite stable and has a high activity for the dehydration of glycerol. The stability of NbPSi-0.5 is about three times higher than that of the reported catalyst. The significantly enhanced catalytic performance of NbPSi-0.5 can be attributed to 1) nearly pure Brønsted acidity, which suppresses side reactions that lead to coke formation; 2) a significant reduction of pore blocking due to the mesopores; and 3) a decrease in the amount and oxidation temperature of coke. PMID:23132784

Choi, Youngbo; Park, Dae Sung; Yun, Hyeong Jin; Baek, Jayeon; Yun, Danim; Yi, Jongheop

2012-12-01

397

A critical evaluation of crustal dehydration as the cause of an overpressured and weak San Andreas Fault  

USGS Publications Warehouse

Many plate boundary faults, including the San Andreas Fault, appear to slip at unexpectedly low shear stress. One long-standing explanation for a "weak" San Andreas Fault is that fluid release by dehydration reactions during regional metamorphism generates elevated fluid pressures that are localized within the fault, reducing the effective normal stress. We evaluate this hypothesis by calculating realistic fluid production rates for the San Andreas Fault system, and incorporating them into 2-D fluid flow models. Our results show that for a wide range of permeability distributions, fluid sources from crustal dehydration are too small and short-lived to generate, sustain, or localize fluid pressures in the fault sufficient to explain its apparent mechanical weakness. This suggests that alternative mechanisms, possibly acting locally within the fault zone, such as shear compaction or thermal pressurization, may be necessary to explain a weak San Andreas Fault. More generally, our results demonstrate the difficulty of localizing large fluid pressures generated by regional processes within near-vertical fault zones. ?? 2009 Elsevier B.V.

Fulton, P.M.; Saffer, D.M.; Bekins, B.A.

2009-01-01

398

Formation of condensed 1H-pyrrol-2-ylphosphonates and 1,2-dihydropyridin-2-ylphosphonates via Kabachnik-Fields reaction of acetylenic aldehydes and subsequent 5-exo-dig or 6-endo-dig cyclizations.  

PubMed

Kabachnik-Fields reactions of various carbocyclic or heterocyclic acetylenic aldehydes together with subsequent Lewis acid catalyzed cyclizations have been studied. It was found that 5-exo-dig versus 6-endo-dig cyclization mode strongly depends on the structure of starting materials. Thus, nonaromatic acetylenic ?-anilinomethylphosphonates underwent gold(III)-catalyzed or iodine-mediated 5-exo-dig cyclization to 1H-pyrrol-2-ylphosphonates. In contrast, electron-withdrawing heteroaromatic substrates formed 1,2-dihydropyridin-2-ylphosphonate ring containing materials via an exclusive 6-endo-dig ring-closure process. The dual mode of cyclization is possible only for ?-amino (2-alkynylphenyl)methylphosphonates containing a benzene ring. PMID:24956009

Bukšnaitien?, Rita; Urbanait?, Aurelija; ?ikotien?, Inga

2014-07-18

399

Treatment of arsenic-contaminated groundwater by a low cost activated alumina adsorbent prepared by partial thermal dehydration  

Microsoft Academic Search

Experimental investigations were carried out to remove arsenic from contaminated groundwater by low cost activated alumina based adsorbent prepared by partial thermal dehydration. Activated alumina based adsorbent with high surface area was prepared following partial thermal dehydration of gibbsite precursor and an attempt was made to study the effects of dehydration temperature, residence time, rate of increase of temperature and

Mou Sen; Parimal Pal

2009-01-01

400

Drying of cherry tomato by a combination of different dehydration techniques. Comparison of kinetics and other related properties  

Microsoft Academic Search

Dehydration of tomatoes is a process commonly used to preserve the product and extend shelf-life. However, the quality of the dehydrated product is often poor. Collapse of the structure, discoloration and a tough texture are frequent quality problems. No less important, although not visually apparent, is the lack of flavour and nutritional value. The combination of osmotic dehydration and microwave

A. Heredia; C. Barrera; A. Andrés

2007-01-01

401

Enrichment of HFSE in chlorite-harzburgite produced by high-pressure dehydration of antigorite-serpentinite  

E-print Network

Enrichment of HFSE in chlorite-harzburgite produced by high-pressure dehydration of antigorite oceanic plate. Here we provide field-based and geochemical evidence showing that high-pressure dehydration. Godard (2005), Enrichment of HFSE in chlorite-harzburgite produced by high-pressure dehydration

Demouchy, Sylvie

402

Journal of Biomechanics 40 (2007) 32233229 Dehydration rates of meniscus and articular cartilage in vitro using a  

E-print Network

Journal of Biomechanics 40 (2007) 3223­3229 Dehydration rates of meniscus and articular cartilage are susceptible to dehydration and its effects, such as changes in size and shape as well as changes in structural and material properties. To quantify the effect of dehydration on the meniscus and articular cartilage

Hull, Maury

403

The crystal structure of Fe4S4quinolinate synthase unravels an enzymatic dehydration mechanism that uses tyrosine and  

E-print Network

The crystal structure of Fe4S4quinolinate synthase unravels an enzymatic dehydration mechanism ABSTRACT:Quinolinate synthase (NadA) is a Fe4S4 cluster- containing dehydrating enzyme involved docked the last precursor to be dehydrated to form QA. We find that the only suitably placed residue

Paris-Sud XI, Université de

404

Effect of Dehydration on Sulfate Coordination and Speciation at the Fe-(Hydr)oxide-Water Interface: A  

E-print Network

Effect of Dehydration on Sulfate Coordination and Speciation at the Fe-(Hydr)oxide-Water Interface, Pennsylvania 16802 Received March 9, 2005. In Final Form: September 7, 2005 The effect of dehydration. This investigation proposes that sulfate undergoes a speciation change as a function of surface dehydration

Sparks, Donald L.

405

Characterization of spacecraft humidity condensate  

NASA Technical Reports Server (NTRS)

When construction of Space Station Freedom reaches the Permanent Manned Capability (PMC) stage, the Water Recovery and Management Subsystem will be fully operational such that (distilled) urine, spent hygiene water, and humidity condensate will be reclaimed to provide water of potable quality. The reclamation technologies currently baselined to process these waste waters include adsorption, ion exchange, catalytic oxidation, and disinfection. To ensure that the baseline technologies will be able to effectively remove those compounds presenting a health risk to the crew, the National Research Council has recommended that additional information be gathered on specific contaminants in waste waters representative of those to be encountered on the Space Station. With the application of new analytical methods and the analysis of waste water samples more representative of the Space Station environment, advances in the identification of the specific contaminants continue to be made. Efforts by the Water and Food Analytical Laboratory at JSC were successful in enlarging the database of contaminants in humidity condensate. These efforts have not only included the chemical characterization of condensate generated during ground-based studies, but most significantly the characterization of cabin and Spacelab condensate generated during Shuttle missions. The analytical results presented in this paper will be used to show how the composition of condensate varies amongst enclosed environments and thus the importance of collecting condensate from an environment close to that of the proposed Space Station. Although advances were made in the characterization of space condensate, complete characterization, particularly of the organics, requires further development of analytical methods.

Muckle, Susan; Schultz, John R.; Sauer, Richard L.

1994-01-01

406

Faculty Position Experimental Condensed Matter Physics  

E-print Network

Faculty Position Experimental Condensed Matter Physics Columbia University The Columbia University Department of Physics seeks to appoint an assistant professor in experimental condensed matter physics

Hone, James

407

Condensation on superhydrophobic copper oxide nanostructures  

E-print Network

Condensation is an important process in many power generation and water desalination technologies. Superhydrophobic nanostructured surfaces have unique condensation properties that may enhance heat transfer through a ...

Dou, Nicholas (Nicholas Gang)

2012-01-01

408

Condensation on Superhydrophobic Copper Oxide Nanostructures  

E-print Network

Condensation is an important process in both emerging and traditional power generation and water desalination technologies. Superhydrophobic nanostructures promise enhanced condensation heat transfer by reducing the ...

Enright, Ryan

409

Insights into the dehydration behavior of thiamine hydrochloride (vitamin B1) hydrates: part I.  

PubMed

Thiamine hydrochloride (Vitamin B(1), THCl) can exist as a nonstoichiometric hydrate (NSH) and as a hemihydrate (HH). NSH can contain up to approximately 1 molar equivalent of water and be dehydrated to an isomorphic desolvate (ID) with minimal change in lattice structure. Crystallographic and spectroscopic techniques were used to characterize the influence of structure and mobility on NSH dehydration. Dehydration was accompanied by lattice contraction, as noted by a decrease in the d-spacings. Dehydration also led to the development of surface cracks parallel to the (101*) and (102*) planes in the NSH single crystal, as observed by hot stage microscopy. Step-wise dehydration of NSH produced gradual shifts in XRPD and SSNMR peaks, indicating that NSH (with approximately 1 mole water) and ID represent the two extremes of a continuum in the hydration state. Variable temperature (13)C SSNMR studies showed that water molecules move rapidly at room temperature within the NSH crystal lattice, and the thiamine molecules transiently exist in distinct hydrated and dehydrated states. It is hypothesized that, despite the lack of continuous hydration channels in the NSH crystal lattice, cooperative deformation of the thiamine molecules allows a nondisruptive departure of water molecules from the lattice during dehydration. PMID:19623540

Chakravarty, Paroma; Berendt, Robert T; Munson, Eric J; Young, Victor G; Govindarajan, Ramprakash; Suryanarayanan, Raj

2010-02-01

410

Fluxes, Gaugings and Gaugino Condensates  

E-print Network

Based on the correspondence between the N = 1 superstring compactifications with fluxes and the N = 4 gauged supergravities, we study effective N = 1 four-dimensional supergravity potentials arising from fluxes and gaugino condensates in the framework of orbifold limits of (generalized) Calabi-Yau compactifications. We give examples in heterotic and type II orientifolds in which combined fluxes and condensates lead to vacua with small supersymmetry breaking scale. We clarify the respective roles of fluxes and condensates in supersymmetry breaking, and analyze the scaling properties of the gravitino mass.

J. -P. Derendinger; C. Kounnas; P. M. Petropoulos

2006-02-10

411

Different gene-specific mechanisms determine the 'revised-response' memory transcription patterns of a subset of A. thaliana dehydration stress responding genes  

PubMed Central

Plants that have experienced several exposures to dehydration stress show increased resistance to future exposures by producing faster and/or stronger reactions, while many dehydration stress responding genes in Arabidopsis thaliana super-induce their transcription as a ‘memory’ from the previous encounter. A previously unknown, rather unusual, memory response pattern is displayed by a subset of the dehydration stress response genes. Despite robustly responding to a first stress, these genes return to their initial, pre-stressed, transcript levels during the watered recovery; surprisingly, they do not respond further to subsequent stresses of similar magnitude and duration. This transcriptional behavior defines the ‘revised-response’ memory genes. Here, we investigate the molecular mechanisms regulating this transcription memory behavior. Potential roles of abscisic acid (ABA), of transcription factors (TFs) from the ABA signaling pathways (ABF2/3/4 and MYC2), and of histone modifications (H3K4me3 and H3K27me3) as factors in the revised-response transcription memory patterns are elucidated. We identify the TF MYC2 as the critical component for the memory behavior of a specific subset of MYC2-dependent genes. PMID:24744238

Liu, Ning; Ding, Yong; Fromm, Michael; Avramova, Zoya

2014-01-01

412

On the dehydration mechanism of Mg(OH){sub 2} by a high-energy electron beam  

SciTech Connect

The dehydration process in Mg(OH){sub 2} induced by high-energy electron irradiation is studied by in situ electron energy loss spectroscopy. During dehydration, both the low energy-loss spectra and the Mg L{sub 23} edge show the existence of partially oxidized Mg- or O-deficient MgO in the dehydrated products, which is not seen in the thermally dehydrated MgO. This indicates that the dehydration mechanism under the electron beam may be different from the mechanism involved in a thermal process.

Su Dong; Jiang, Nan; Spence, John C. H. [Department of Physics, Arizona State University, Tempe, Arizona 85287-1504 (United States); He Feng; Petuskey, William T. [Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287 (United States)

2008-09-15

413

Condensation heat transfer under a microgravity environment  

NASA Technical Reports Server (NTRS)

A description of the condensation heat transfer process in microgravity is given. A review of the literature is also reported. The most essential element of condensation heat transfer in microgravity is the condensate removal mechanism. Two mechanisms for condensate removal are analyzed by looking into two problems. The first problem is concerned with film condensation on a flat porous plate with the condensate being removed by suction at the wall. The second problem is an analytical prediction of the heat transfer coefficient for condensing annular flows with the condensate film driven by the vapor shear. It is concluded that both suction and vapor shear can effectively drain the condensate to ensure continuous operation of the condensers operated under a microgravity environment. It is recommended that zero-g flight experiments be carried out to verify the prediction made in the present report. The results contained in this report should also aid in the design of future space condensers.

Chow, L. C.

1986-01-01

414

PVC waterproofing membranes and alkali-aggregated reaction in dams  

SciTech Connect

A waterproofing polyvinylchloride (PVC) based geocomposite was installed on two dams subject to alkali-aggregate reaction, to eliminate water intrusion and to protect the facing from further deterioration. The installation system allows drainage of the infiltrated water, thus accomplishing dehydration of the dam body. On one dam, the membrane also provided protection for future slot cutting.

Scuero, A.M. [C.A.R.P.I. Technologies SA, Lugano (Czech Republic)

1995-12-31

415

A refractory Ca-SiO-H 2-O 2 vapor condensation experiment with implications for calciosilica dust transforming to silicate and carbonate minerals  

NASA Astrophysics Data System (ADS)

Condensates produced in a laboratory condensation experiment of a refractory Ca-SiO-H 2-O 2 vapor define four specific and predictable deep metastable eutectic calciosilica compositions. The condensed nanograins are amorphous solids, including those with the stoichiometric CaSiO 3 pyroxene composition. In evolving dust-condensing astronomical environments they will be highly suitable precursors for thermally supported, dust-aging reactions whereby the condensates form more complex refractory silicates, e.g., diopside and wollastonite, and calcite and dolomite carbonates. This kinetically controlled condensation experiment shows how the aging of amorphous refractory condensates could produce the same minerals that are thought to require high-temperature equilibrium condensation. We submit that evidence for this thermal annealing of dust will be the astronomical detection of silica (amorphous or crystalline) that is the common, predicted, by-product of most of these reactions.

Rietmeijer, Frans J. M.; Pun, Aurora; Kimura, Yuki; Nuth, Joseph A.

2008-05-01

416

Flow Boiling and Condensation Experiment  

NASA Video Gallery

The Flow Boiling and Condensation Experiment is another investigation that examines the flow of a mixture of liquids and the vapors they produce when in contact with hot space system equipment. Coo...

417

Counterion Correlations on Condensed Biopolymers  

NASA Astrophysics Data System (ADS)

Like-charged polyelectrolytes condense into ordered phases in the presence of multivalent ions. The physical origin of the attractive interaction required for this condensation has been intensely debated, but no clear consensus has emerged, although counterion correlations appear to play a key role. In order to elucidate the nature of these interactions, we have performed structural measurements of condensed phases formed between multivalent ions and a range of rod-like polyelectrolytes, including cytoskeletal F-actin, and Fd and M13 filamentary virus particles.šDirect measurements of the counterion density and correlations in different condensed phases will be presented, along with the temperature dependence of these phases. This work was supported by NSF DMR-0071761, DOE DEFG02-91ER45439, the Beckman Young Investigator Program, and the Cystic Fibrosis Foundation.

Angelini, Tommy; Butler, John; Ho, James; Liang, Hongjun; Wong, Gerard

2002-03-01

418

Bose-Einstein Condensate strings  

E-print Network

We consider the possible existence of gravitationally bound general relativistic strings consisting of Bose-Einstein Condensate (BEC) matter which is described, in the Newtonian limit, by the zero temperature time-dependent nonlinear Schr{\\"}odinger equation (the Gross-Pitaevskii equation), with repulsive inter-particle interactions. In the Madelung representation of the wave function, the quantum dynamics of the condensate can be formulated in terms of the classical continuity equation and the hydrodynamic Euler equations. In the case of a condensate with quartic nonlinearity, the condensates can be described as a gas with two pressure terms, the interaction pressure, which is proportional to the square of the matter density, and the quantum pressure, which is without any classical analogue though, when the number of particles in the system is high enough, the latter may be neglected. By assuming cylindrical symmetry, we analyze the physical properties of the BEC strings in both the interaction pressure and ...

Harko, Tiberiu

2014-01-01

419

Inhomogeneous condensates in planar QED  

SciTech Connect

We study the formation of vacuum condensates in (2+1)-dimensional QED in the presence of inhomogeneous background magnetic fields. For a large class of magnetic fields, the condensate is shown to be proportional to the inhomogeneous magnetic field, in the large flux limit. This may be viewed as a {ital local} form of the {ital integrated} degeneracy-flux relation of Aharonov and Casher. {copyright} {ital 1996 The American Physical Society.}

Dunne, G.; Hall, T. [Physics Department, University of Connecticut, Storrs, Connecticut 06269 (United States)] [Physics Department, University of Connecticut, Storrs, Connecticut 06269 (United States)

1996-02-01

420

Cosmological k-ESSENCE Condensation  

NASA Astrophysics Data System (ADS)

We consider a model of dark energy/matter unification based on a k-essence type of theory similar to tachyon condensate models. Using an extension of the general relativistic spherical model which incorporates the effects of both pressure and the acoustic horizon we show that an initially perturbative k-essence fluid evolves into a mixed system containing cold dark matter like gravitational condensate in significant quantities.

Bili?, Neven; Tupper, Gary B.; Viollier, Raoul D.

2011-03-01

421

Stability of Mg-sulfates at-10C and the rates of dehydration/rehydration processes under conditions relevant to Mars  

USGS Publications Warehouse

We report the results of low temperature (-10??C) experiments on the stability fields and phase transition pathways of five hydrous Mg-sulfates. A low temperature form of MgSO 47H 2O (LT-7w) was found to have a wide stability field that extends to low relative humidity (???13% RH at-10??C). Using information on the timing of phase transitions, we extracted information on the reaction rates of five important dehydration and rehydration processes. We found that the temperature dependencies of rate constants for dehydration processes differ from those of rehydration, which reflect differences in reaction mechanisms. By extrapolating these rate constants versus T correlations into the T range relevant to Mars, we can evaluate the possibility of occurrence of specific processes and the presence of common Mg-sulfate species present on Mars in different periods and locations. We anticipate in a moderate obliquity period, starkeyite and LH-MgSO 4H 2O should be two common Mg-sulfates at the surface, another polymorph MH-MgSO 4H 2O can exist at the locations where hydrothermal processes may have occurred. In polar regions or within the subsurface of other regions, meridianiite (coexisting with water ice, near 100% RH) and LT-7w (over a large RH range) are the stable phases. During a high obliquity period, meridianiite and LT-7w should exhibit widespread occurrence. The correlations of reaction rates versus temperature found in this study imply that dehydration and rehydration of hydrous Mg-sulfates would always be slower than the sublimation and crystallization of water ice, which would be supported by mission observations from Odyssey and by Mars Exploration Rovers. Copyright 2011 by the American Geophysical Union.

Wang, A.; Freeman, J.J.; Chou, I.-M.; Jolliff, B.L.

2011-01-01

422

Onion and garlic dehydration in the San Emidio Desert, Nevada  

SciTech Connect

Integrated Ingredients dedicated their new onion and garlic processing plant on May 25th. {open_quotes}Grunion{close_quotes} as the new community of 72 employees has been labeled, is located just south of Empire and Gerlach and about 100 miles north of Reno, Nevada. The plant, run by Integrated Ingredients (based in Alameda, CA), is a division of Burns Philp Food, Inc., which owns brands such as Spice Islands, Durkee-French and Fleischmann`s. This plant gives the company the ability to produce its own products for industrial and consumer markets instead of purchasing them. The plant was located in the San Emidio Desert at the edge of the vast Black Rock Desert and the Great Basin to take advantage of the high temperature geothermal resource (approximately 270{degrees}F). The resource is also used by the OESI/AMOR II 3.6 MW binary plant about a mile south of the dehydration plant and a gold heap leaching operation just to the north of the plant (Wind Mt. mine operated by AMAX). In addition to the geothermal energy, the high desert is an ideal location for onion and garlic processing because the cold winters kill damaging microbes. Dry winters and summers also help.

Lund, J.W.; Lienau, P.J.

1994-07-01

423

Hydrated/Dehydrated lipid phase transitions measured using nanocalorimetry.  

PubMed

The phase transition evolution with hydration of a model system, 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), was investigated with a fast nanocalorimetry system. Using nanocalorimetry, it is possible to measure the gel to liquid phase transitions that occur on millisecond to second time scales and quantify the time to recover the hydrated state. The results show the phase transition occurring in a few milliseconds and the relaxation or recovery time from the dehydrated state back to original hydrated state occurring with times dependent on the local humidity. With relative humidity (RH) of 43% or higher, the recovery time can be less than a few seconds. With RH of 11% or lower, the recovery time is extended to greater than a minute. The recovery process is controlled by mechanisms that depend on the lipid molecular repacking and water transport from the environment. Nanocalorimetry provides a powerful method to investigate the kinetics of such transformations in lipids and other biological and pharmaceutical moieties. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 103:3442-3447, 2014. PMID:25256917

Yi, Feng; Kim, Il Kyoon; Li, Song; Lavan, David A

2014-11-01

424

Freeze avoidance: a dehydrating moss gathers no ice.  

PubMed

Using cryo-SEM with EDX fundamental structural and mechanical properties of the moss Ceratodon purpureus (Hedw.) Brid. were studied in relation to tolerance of freezing temperatures. In contrast to more complex plants, no ice accumulated within the moss during the freezing event. External ice induced desiccation with the response being a function of cell type; water-filled hydroid cells cavitated and were embolized at -4 °C while parenchyma cells of the inner cortex exhibited cytorrhysis, decreasing to ? 20% of their original volume at a nadir temperature of -20 °C. Chlorophyll fluorescence showed that these winter acclimated mosses displayed no evidence of damage after thawing from -20 °C while GCMS showed that sugar concentrations were not sufficient to confer this level of freezing tolerance. In addition, differential scanning calorimetry showed internal ice nucleation occurred in hydrated moss at ?-12 °C while desiccated moss showed no evidence of freezing with lowering of nadir temperature to -20 °C. Therefore the rapid dehydration of the moss provides an elegantly simple solution to the problem of freezing; remove that which freezes. PMID:20525002

Lenné, Thomas; Bryant, Gary; Hocart, Charles H; Huang, Cheng X; Ball, Marilyn C

2010-10-01

425

Simulation of Clay Mineral Dehydration Along the NanTroSEIZE Transect, SW Japan: Implications for Fault Properties and Fluid Flow  

NASA Astrophysics Data System (ADS)

At subduction zones, fluids are expelled as porous sediments on the incoming oceanic plate are either subducted or offscraped and accreted. In the upper ~8-10 km, the dominant sources of fluid are tectonically-driven compaction and burial, and the dehydration of hydrous (smectite family) clays. Potentially elevated pore fluid pressure associated with fluid release has been invoked to explain: (1) zones of anomalously low seismic velocity in the outer forearc (LVZ's) located ~13-30 km and ~31-55 km from the trench; (2) high amplitude negative polarity seismic reflectors along major fault zones; and (3) a transition to unstable fault slip. Here, we incorporate the results of existing thermal modeling and Integrated Ocean Drilling Program (IODP) drilling along the NanTroSEIZE transect, offshore SW Japan, to simulate the magnitude and distribution of fluid release from clay dehydration in 2-D. The thermal models define the temperature structure of the margin, and the drilling results provide constraints on the abundance of hydrous clays in the sediment inputs. The regionally averaged wedge geometry and incoming sediment thickness used in our model are defined from seismic reflection data. We simulate smectite transformation by tracking sediments as they are progressively buried and heated in the subduction complex. The reaction progress is then computed from temperatures and exposure time. We evaluate two thermal models: a "hot" scenario, which is consistent with surface heat flow data, and a "cold" scenario that provides a probable lower bound on subsurface temperatures. For our initial suite of simulations, we consider an average bulk smectite abundance of 45 wt%. We then explore the spatial relationships between the locus of clay dehydration and geophysical signatures interpreted to reflect pore fluid and dehydration processes. Finally, we track the evolution of residual pore fluid chemistry due to consolidation and introduction of fresh water from the dehydration reaction. Simulated peak clay dehydration occurs 8-10 km landward of the trench in the hot scenario, and ~17-20 km landward in the cold scenario, well updip of the high reflectivity fault zones and LVZ's. Within the underthrusting sediments, the simulated reaction is 80% complete by ~15 km and ~25 km landward of the trench for the hot and cold scenarios, respectively. Our results indicate that that the geophysical observations do not map the locus of dehydration. We suggest that compaction disequilibrium is a more plausible explanation for both the high reflectivity and LVZ's. Simulated pore water freshening in the upper wedge is negligible in the outer 26 km of the forearc, and reaches a maximum of ~17% by 75 km landward of the trench. In contrast, simulated pore water freshening in the lower wedge and underthrust sediment begins within ~5-8 km of the trench, and reaches ~65% by 30 km landward. Near the trench, deeply sourced fluids will be diluted by mixing with fluids from the hanging wall. Progressive freshening of the deeply sourced fluids, in combination with decreasing compactive sources in the wedge, should lead to less mixing and thus larger signals of deeply sourced fluid flow farther landward.

Saffer, D. M.; Harris, R. N.; Underwood, M.

2012-12-01

426

Energy efficient recovery and dehydration of ethanol from fermentation broths by Membrane Assisted Vapor Stripping technology  

EPA Science Inventory

Distillation combined with molecular sieve dehydration is the current state of the art for fuel grade ethanol production from fermentation broths. To improve the sustainability of bioethanol production, energy efficient separation alternatives are needed, particularly for lower ...

427

Energy Efficient Hybrid Vapor Stripping-Vapor Permeation Process for Ethanol Recovery ad Dehydration  

EPA Science Inventory

Distillation combined with molecular sieve dehydration is the current state of the art for fuel grade ethanol production from fermentation broths. To improve the sustainability of bioethanol production, energy efficient separation alternatives are needed, particularly for lower f...

428

Comparison of bioavailability and pharmacokinetics of diclofenac sodium and diclofenac potassium in normal and dehydrated rabbits.  

PubMed

Two different salts of diclofenac, diclofenac sodium and diclofenac potassium, in tablet dosage form were tested for their bioavailability and disposition kinetics in a group of eighteen rabbits in normal and experimentally induced dehydrated conditions with a wash out period of 7 days between both stages of study. Biochemical and physiological parameters were also measured in both normal and dehydrated states. Diclofenac levels in plasma were determined using a validated reversed phase HPLC method. Primary kinetic parameters i.e. AUC(0-infinity), Cmax, Tmax and other disposition kinetics were obtained with non-compartmental procedure. Biochemical parameters i.e. packed cell volume, plasma glucose and total lipid concentration in dehydrated rabbits increased significantly. Plasma concentration of diclofenac sodium and diclofenac potassium decreased significantly in water deprived rabbits. In comparison, diclofenac potassium in normal and dehydrated state of the same group of rabbits showed a significantly increased plasma concentration when compared with diclofenac sodium. PMID:19350827

Ahmad, Mahmood; Iqbal, Muhammad; Murtaza, Ghulam

2009-01-01

429

Dehydration-induced conformational transitions in proteins and their inhibition by stabilizers.  

PubMed Central

Dehydration of proteins results in significant, measurable conformational changes as observed using Fourier-transform infrared spectroscopy and resolution-enhancement techniques. For several proteins these conformational changes are at least partially irreversible, since, upon rehydration, denaturation and aggregation are observed. The presence of certain stabilizers inhibited these dehydration-induced transitions; the native structure was preserved in the dried state and upon reconstitution. Conformational transitions were also observed in a model polypeptide, poly-L-lysine, after lyophilization and were inhibited with the addition of stabilizing cosolutes. The ability of a particular additive to preserve the aqueous structure of dehydrated proteins and poly-L-lysine upon dehydration correlates directly with its ability to preserve the activity of lactate dehydrogenase, a labile enzyme, during drying. PMID:7693001

Prestrelski, S J; Tedeschi, N; Arakawa, T; Carpenter, J F

1993-01-01

430

Changes in the nucleolar organizer regions in the tuberomammillar region after dehydration.  

PubMed

The existence of efferent connections between tuberomammillary (TM) and the supraoptic (SON) nuclei led us to study the morphological changes at these levels during dehydration induced in rats by repeated administration of hypertonic saline. The dehydration effects are evaluated by three parameters: nucleus area, argyrophilic nucleolar organizer regions (Ag-NOR) area, and mean number of Ag-NORs. These parameters reflect the level of transcriptional activity of the rRNA genes, which in turn is closely related to the protein synthesis activity of the cell. The technique used is argyrophilic staining which labels the nucleolar organizer regions (NORs) of the nucleoli in the neurons and their area, permitting their quantification with an image analysis system. The statistical analysis reflects the sensitivity to dehydration of these structures at TM level. Our results support the regulatory role of vasopressin secretion by SON through the histaminergic pathways arising from TM in rat dehydration processes. PMID:9587646

Rubio, S; Begega, A; Santín, L J; Arias, J L

1997-10-01

431

76 FR 4284 - Grant of Authority for Subzone Status; Tulkoff Food Products, Inc. (Dehydrated Garlic), Baltimore...  

Federal Register 2010, 2011, 2012, 2013

...Tulkoff Food Products, Inc. (Dehydrated Garlic), Baltimore, MD Pursuant to its authority...establish a special-purpose subzone at the garlic products manufacturing facility of Tulkoff...activity related to the manufacture of garlic products at the Tulkoff Food...

2011-01-25

432

Dehydration and Denitrification in the Arctic Polar Vortex During the 1995-1996 Winter  

NASA Technical Reports Server (NTRS)

Dehydration of more than 0.5 ppmv water was observed between 18 and 19 km (0-450-465 K) at the edge of the Arctic polar vortex on February 1, 1996. More than half the reactive nitrogen (NO(y)) had also been removed, with layers of enhanced NO(y) at lower altitudes. Back trajectory calculations show that air parcels sampled inside the vortex had experienced temperatures as low as 188 K within the previous 12 days, consistent with a small amount of dehydration. The depth of the dehydrated layer (approximately 1 km) and the fact that trajectories passed through the region of ice saturation in one day imply selective growth of a small fraction of particles to sizes large enough (>10 microns) to be irreversibly removed on this timescale. Over 25% of the Arctic vortex in a 20-30 K range of 0 is estimated to have been dehydrated in this event.

Hintsa, E. J.; Newman, P. A.; Jonsson, H. H.; Webster, C. R.; May, R. D.; Herman, R. L.; Lait, L. R.; Schoeberl, M. R.; Elkins, J. W.; Wamsley, P. R.; Dutton, G. S.; Bui, T. P.; Kohn, D. W.; Anderson, J. G.

1998-01-01

433

Dehydration and Denitrification in the Arctic Polar Vortex During the 1995-1996 Winter  

NASA Technical Reports Server (NTRS)

Dehydration of more than 0.5 ppmv water was observed between 18 and 19 km (theta approximately 450-465 K) at the edge of the Arctic polar vortex on February 1, 1996. More than half the reactive nitrogen (NO(y)) had also been removed, with layers of enhanced NO(y) at lower altitudes. Back trajectory calculations show that air parcels sampled inside the vortex had experienced temperatures as low as 188 K within the previous 12 days, consistent with a small amount of dehydration. The depth of the dehydrated layer (approximately 1 km) and the fact that trajectories passed through the region of ice saturation in one day imply selective growth of a small fraction of particles to sizes large enough (>10 micrometers) to be irreversibly removed on this timescale. Over 25% of the Arctic vortex in a 20-30 K range Transport of theta is estimated to have been dehydrated in this event.

Hintsa, E. J.; Newman, P. A.; Jonsson, H. H.; Webster, C. R.; May, R. D.; Herman, R. L.; Lait, L. R.; Schoeberl, M. R.; Elkins, J. W.; Wamsley, P. R.; Dutton, G. S.; Bui, T. P.; Kohn, D. W.; Anderson, J. G.

1998-01-01

434

Dehydration and Denitrification in the Arctic Polar Vortex During the 1995-1996 Winter  

NASA Technical Reports Server (NTRS)

Dehydration of more than 0.5 ppmv water was observed between 18 and 19 km (theta = 450-465 K) at the edge of the Arctic polar vortex on February 1, 1996. More than half the reactive nitrogen (NOy) had also been removed, with layers of enhanced NOy at lower altitudes. Back trajectory calculations show that air parcels sampled inside the vortex had experienced temperatures as low as 188 K within the previous 12 days, consistent with a small amount of dehydration. The depth of the dehydrated layer (approx. 1 km) and the fact that trajectories passed through the region of ice saturation in one day imply selective growth of a small fraction of particles to sizes large enough (>10 micrometers) to be irreversibly removed on this timescale. Over 25% of the Arctic vortex in a 20-30 K range of theta is estimated to have been dehydrated in this event.

Hintsa, E. J.; Newman, P. A.; Jonsson, H. H.; Webster, C. R.; May, R. D.; Herman, R. L.; Lait, L. R.; Schoerberl, M. R.; Elkins, J. W.; Wamsley, P. R.

1998-01-01

435

Dehydration and Denitrification in the Arctic Polar Vortex During the 1995-1996 Winter  

NASA Technical Reports Server (NTRS)

Dehydration of more than 0.5 ppmv water was observed between 18 and 19 km (theta about 450-465 K) at the edge of the Arctic polar vortex on February 1, 1996. More than half the reactive nitrogen (NO(sub y)) had also been removed, with layers of enhanced (sub y) at lower altitudes. Back trajectory calculations show that air parcels sampled inside the vortex had experienced temperatures as low as 188 K within the previous 12 days, consistent with a small amount of dehydration. The depth of the dehydrated layer (about 1 km) and the fact that trajectories passed through the region of ice saturation in one day imply selective growth of a small fraction of particles to sizes large enough (>10 micron) to be irreversibly removed on this timescale. Over 25% of the Arctic vortex in a 20-30 K range of theta is estimated to have been dehydrated in this event.

Hintsa, E. J.; Newman, P. A.; Jonsson, H. H.; Webster, C. R.; May, R. D.; Herman, R. L.; Lait, L. R.; Schoeberl, M. R.; Elkins, J. W.; Wamsley, P. R.; Dutton, G. S.; Bui, T. P.; Kohn, D. W.; Anderson, J. G.

1998-01-01

436

Condenser optimization in steam power plant  

NASA Astrophysics Data System (ADS)

In this paper the effects of the condenser design parameters (such as turbine inlet condition, turbine power and condenser pressure) on heat transfer area, cooling water flow-rate, condenser cost and specific energy generation cost are studied for surface type condenser. The results are given in the text and also shown as diagrams.

Bekdemir, ?ükrü; Öztürk, Recep; Yumurtac, Zehra

2003-05-01

437

Cloud Condensation Nuclei Sizes  

NASA Astrophysics Data System (ADS)

The sizes of cloud condensation nuclei (CCN) can be determined by first passing an aerosol sample through a differential mobility analyzer (DMA) and then to a CCN counter or spectrometer (i.e., Hudson 1989), which provides a mean value of the critical supersaturation (Sc) of the particles. By sequentially dialing in several different DMA sizes a relationship between dry particle size and Sc can be obtained (Hudson and Da 1996). Recent airborne measurements in three different projects in three different environments have confirmed Hudson and Da (1996) that CCN are significantly smaller in clean maritime air masses than they are in more polluted air masses. In clean maritime air CCN sizes are generally consistent with that of pure soluble salts such as NaCl or ammonium sulfate whereas they are two to four times larger in more polluted air masses presumably because they are composed of less soluble material. Associated volatility measurements suggest that they are actually probably also composed of sulfate that is internally mixed with insoluble or less soluble material, which is the cause of the larger measured CCN sizes. Dusek et al. (2006) found only very large CCN; i.e., more than a factor of two larger than we found in maritime air masses. Moreover, the small range of CCN sizes that they measured led them to conclude that CCN can be determined solely based on particle size. If this were true it would better facilitate remote sensing of CCN. The much larger range of CCN sizes that we measured indicates that this conclusion would only be valid in rather polluted air masses. Ironically remote sensing works only over the ocean where CCN sizes are generally much smaller and where a range of CCN sizes up to that which has been found in polluted air may also be found. The actual large range of CCN sizes in the atmosphere invalidates the assumption by Dusek et al. (2006) that CCN concentrations can be ascertained based only on particle size measurements.

Hudson, J. G.; Mishra, S.

2006-12-01

438

Nanoimprint of dehydrated PEDOT:PSS for organic photovoltaics This article has been downloaded from IOPscience. Please scroll down to see the full text article.  

E-print Network

Nanoimprint of dehydrated PEDOT:PSS for organic photovoltaics This article has been downloaded from.1088/0957-4484/22/48/485301 Nanoimprint of dehydrated PEDOT:PSS for organic photovoltaics Y Yang1 , K Lee2 , K Mielczarek2 , W Hu1:PSS) nanogratings by a dehydration-assisted nanoimprint lithographic technique. Dehydration of PEDOT:PSS increases

Hu, Wenchuang "Walter"

439

Mass transport limitations in zeolite catalysts: the dehydration of 1-phenyl-ethanol to styrene  

Microsoft Academic Search

The dehydration of 1-phenyl-ethanol to styrene is a critical step in the styrene\\/propene oxide manufacturing process. An important challenge is to achieve deep dehydration while minimising the oligomerisation of styrene to heavy products that deactivate the catalyst. The present study shows that zeolite-based catalysts can meet the challenge when designed and operated such as to avoid diffusion limitations in the

Jean-Paul Lange; Carl M. A. M Mesters

2001-01-01

440

The roles of oxygen delivery and electrolyte levels in the dehydrational death of Xenopus laevis  

Microsoft Academic Search

Summary  \\u000a1. \\u000aIn order to determine mechanisms which extend desiccation tolerance in terrestrial anurans, a study of the physiological processes failing in dehydrational death was undertaken withXenopus laevis. At various degrees of dehydration, measurements of resting and active metabolic rates, resting and active heart rates, resting arterio-venous blood oxygen contents (a-v differences), and resting whole animal lactate levels were made

Stanley S. Hillman

1978-01-01

441

A rapid and inexpensive method for isolation of total DNA from dehydrated plant tissue  

Microsoft Academic Search

We describe an inexpensive method for dehydration of plant tissue and extraction of high molecular weight DNA. Tissue is dried\\u000a for 12 to 24 hours in a food dehydrator and subsequently powdered for DNA extraction. Dicot tissue can be powdered in centrifuge\\u000a tubesen masse using a commercial paint mixer and glass beads. With the use of the paint mixer, tissue

Thomas H. Tai; Steven D. Tanksley

1990-01-01

442

Dehydration, rehydration, and overhydration alter patterns of gene expression in the Antarctic midge, Belgica antarctica.  

PubMed

We investigated molecular responses elicited by three types of dehydration (fast, slow and cryoprotective), rehydration and overhydration in larvae of the Antarctic midge, Belgica antarctica. The larvae spend most the year encased in ice but during the austral summer are vulnerable to summer storms, osmotic stress from ocean spray and drying conditions due to wind and intense sunlight. Using suppressive subtractive hybridization (SSH), we obtained clones that were potentially responsive to dehydration and then used northern blots to evaluate the gene's responsiveness to different dehydration rates and hydration states. Among the genes most responsive to changes in the hydration state were those encoding heat shock proteins (smHsp, Hsp70, Hsp90), antioxidants (superoxide dismutase, catalase), detoxification (metallothionein, cytochrome p450), genes involved in altering cell membranes (fatty acid desaturase, phospholipase A2 activating protein, fatty acyl CoA desaturase) and the cytoskeleton (actin, muscle-specific actin), and several additional genes including a zinc-finger protein, pacifastin and VATPase. Among the three types of dehydration evaluated, fast dehydration elicited the strongest response (more genes, higher expression), followed by cryoprotective dehydration and slow dehydration. During rehydration most, but not all, genes that were expressed during dehydration continued to be expressed; fatty acid desaturase was the only gene to be uniquely upregulated in response to rehydration. All genes examined, except VATPase, were upregulated in response to overhydration. The midge larvae are thus responding quickly to water loss and gain by expressing genes that encode proteins contributing to maintenance of proper protein function, protection and overall cell homeostasis during times of osmotic flux, a challenge that is particularly acute in this Antarctic environment. PMID:19125254

Lopez-Martinez, Giancarlo; Benoit, Joshua B; Rinehart, Joseph P; Elnitsky, Michael A; Lee, Richard E; Denlinger, David L

2009-05-01

443

Freeze-substitution of dehydrated plant tissues: Artefacts of aqueous fixation revisited  

Microsoft Academic Search

Summary This investigation assessed the extent of rehydration of dehydrated plant tissues during aqueous fixation in comparison with the fine structure revealed by freeze-substitution. Radicles from desiccation-tolerant pea (Pisum sativum L.), desiccation-sensitive jackfruit seeds (Artocarpus heterophyllus Lamk.), and leaves of the resurrection plantEragrostis nindensis Ficalho & Hiern. were selected for their developmentally diverse characteristics. Following freeze-substitution, electron microscopy of dehydrated

James Wesley-Smith

2001-01-01

444

Effects of dehydration and exogenous growth regulators on dormancy, quiescence and germination of grape somatic embryos  

Microsoft Academic Search

Summary  Dormant grape somatic embryos from five genetically distinct culture lines were subjected either to dehydration or exogenous\\u000a growth regulators (benzyladenine, gibberellin or abscisic acid). Of growth regulator treatments tested, benzyladenine resulted\\u000a in the highest germination rate but postgermination growth was abnormal. Abscisic acid treatment resulted in the least germination.\\u000a Dehydration for 21 d under 75–95% relative humidity was effective only

D. J. Gray

1989-01-01

445

Phenolic Profile and Antioxidant Capacity of Chickpeas ( Cicer arietinum L.) as Affected by a Dehydration Process  

Microsoft Academic Search

This study presents the effects of soaking, cooking and industrial dehydration on the phenolic profile, and antioxidant capacity\\u000a in two chickpea varieties (Sinaloa and Castellano). Chromatographic analysis identified a total of 24 phenolic components,\\u000a being isoflavones the main phenolics in raw and processed Sinaloa and Castellano flours. The impact of the industrial dehydration\\u000a was different depending on the chickpea variety.

Yolanda Aguilera; Montserrat Dueñas; Isabel Estrella; Teresa Hernández; Vanesa Benitez; Rosa María Esteban; María A. Martín-Cabrejas

446

Influence of reaction conditions on sol-precipitation process producing silicon oxide particles  

Microsoft Academic Search

The influence of TEOS, water, and ammonia concentrations on the sol-precipitation process for producing silicon oxide particles was investigated. When the hydrolysis and condensation were assumed as simple first-order reactions, the hydrolysis and condensation reaction coefficients were enhanced with an increase in the ammonia concentration due to its catalytic role in the reactions. Likewise, the increased hydrolysis coefficient with increased

Kyung-Soo Kim; Jun-Kyung Kim; Woo-Sik Kim

2002-01-01

447

Dynamics of electronically excited species in gaseous and condensed phase  

NASA Astrophysics Data System (ADS)

In order to assess the potential of energetic molecules to be advanced rocket propellants, the Air Force High Energy Density Materials Program requires theoretical methods to predict the lifetimes of energetic molecules in condensed phase. This research met this need by developing dynamical methods which can be used to elucidate the microscopic dynamics controlling lifetimes relevant to energy storage in isolated and matrix-embedded molecules. This has resulted in the capability to identify important quenching pathways in gas and condensed phases using computational methods. Research consisted of: (1) developing semiclassical methods and computer simulation technology, and (2) applications to thedynamics of electronically inelastic chemistry of light metastables, including helium and hydrogen in the gas and condensed phase. The key accomplishments include: (1) development and validation of general and powerful semiclassical methods for energetic polyatomic species, (2) development of reduced heatbath models of condensed phase helium, (3) development of models of condensed phase hydrogen, and (4) development of simulation procedures for solution-phase reaction and cluster formation of high energy density materials (HEDMs) with solvents.

Swaminathan, P. K.; Redmon, M. J.; Murthy, C. S.; Garrett, B. C.; Natanson, G. A.

1989-12-01

448

Nuclear Alpha-Particle Condensates  

E-print Network

The $\\alpha$-particle condensate in nuclei is a novel state described by a product state of $\\alpha$'s, all with their c.o.m. in the lowest 0S orbit. We demonstrate that a typical $\\alpha$-particle condensate is the Hoyle state ($E_{x}=7.65$ MeV, $0^+_2$ state in $^{12}$C), which plays a crucial role for the synthesis of $^{12}$C in the universe. The influence of antisymmentrization in the Hoyle state on the bosonic character of the $\\alpha$ particle is discussed in detail. It is shown to be weak. The bosonic aspects in the Hoyle state, therefore, are predominant. It is conjectured that $\\alpha$-particle condensate states also exist in heavier $n\\alpha$ nuclei, like $^{16}$O, $^{20}$Ne, etc. For instance the $0^+_6$ state of $^{16}$O at $E_{x}=15.1$ MeV is identified from a theoretical analysis as being a strong candidate of a $4\\alpha$ condensate. The calculated small width (34 keV) of $0^+_6$, consistent with data, lends credit to the existence of heavier Hoyle-analogue states. In non-self-conjugated nuclei such as $^{11}$B and $^{13}$C, we discuss candidates for the product states of clusters, composed of $\\alpha$'s, triton's, and neutrons etc. The relationship of $\\alpha$-particle condensation in finite nuclei to quartetting in symmetric nuclear matter is investigated with the help of an in-medium modified four-nucleon equation. A nonlinear order parameter equation for quartet condensation is derived and solved for $\\alpha$ particle condensation in infinite nuclear matter. The strong qualitative difference with the pairing case is pointed out.

T. Yamada; Y. Funaki; H. Horiuchi; G. Roepke; P. Schuck; A. Tohsaki

2011-03-21

449

Analysis of Performance of Steam Condensation Heat Transfer and Pressure Drop in Plate Condensers  

Microsoft Academic Search

This article describes experimental study and calculation on steam condensation heat transfer and pressure drop in a plate condenser. Based on the results, it presents a formula expressing the relation of condensation heat transfer and having obuious physical meaning. Several important points affecting steam condensation heat transfer in plate condensers are analyzed. The Lockhart-Martinelli model is extended to two-phase nonadiabatic

Zhong-Zheng Wang; Zhen-Nan Zhao

1993-01-01

450

Effects of surface dehydration on mucosal wave amplitude and frequency in excised canine larynges  

PubMed Central

Objective Evaluate the effect of vocal fold surface dehydration on mucosal wave amplitude and frequency. Study Design Controlled test-retest. Setting Larynges were mounted on an excised larynx phonation system and attached to a pseudolung in a triple-walled sound-attenuated room that eliminated background noise and maintained a stabilized room temperature and humidity level. Subjects and Methods High-speed video was recorded for eight excised canine larynges during exposure to dehumidified air at 20 cm H2O. Control trials consisted of high-speed videos recorded for two excised canine larynges during exposure to humidified air at the same pressure. Results In the majority of larynges, increased levels of dehydration were correlated with decreased amplitude and frequency. The slope of the linear regression fitted to the change in amplitude (p=0.003) as well as the percent change (p<0.001) between the initial and final trials were significantly decreased in dehydrated larynges. These measurements with respect to the change in frequency were also significantly decreased in dehydrated larynges (p<0.001; p=0.027). Conclusion Vocal fold surface dehydration caused a decrease in mucosal wave amplitude and frequency. This study provides objective, quantitative support for the mechanism of voice deterioration observed after extreme surface dehydration. PMID:21493398

Witt, Rachel E.; Taylor, Lindsay N.; Regner, Michael F.; Jiang, Jack J.

2011-01-01

451

Proteome analysis of Physcomitrella patens exposed to progressive dehydration and rehydration  

PubMed Central

Physcomitrella patens is an extremely dehydration-tolerant moss. However, the molecular basis of its responses to loss of cellular water remains unclear. A comprehensive proteomic analysis of dehydration- and rehydration-responsive proteins has been conducted using quantitative two-dimensional difference in-gel electrophoresis (2D-DIGE), and traditional 2-D gel electrophoresis (2-DE) combined with MALDI TOF/TOF MS. Of the 216 differentially-expressed protein spots, 112 and 104 were dehydration- and rehydration-responsive proteins, respectively. The functional categories of the most differentially-expressed proteins were seed maturation, defence, protein synthesis and quality control, and energy production. Strikingly, most of the late embryogenesis abundant (LEA) proteins were expressed at a basal level under control conditions and their synthesis was strongly enhanced by dehydration, a pattern that was confirmed by RT-PCR. Actinoporins, phosphatidylethanolamine-binding protein, arabinogalactan protein, and phospholipase are the likely dominant players in the defence system. In addition, 24 proteins of unknown function were identified as novel dehydration- or rehydration-responsive proteins. Our data indicate that Physcomitrella adopts a rapid protein response mechanism to cope with dehydration in its leafy-shoot and basal expression levels of desiccation-tolerant proteins are rapidly upgraded at high levels under stress. This mechanism appears similar to that seen in angiosperm seeds. PMID:21994173

Cui, Suxia; Hu, Jia; Guo, Shilei; Wang, Jie; Cheng, Yali; Dang, Xinxing; Wu, Lili; He, Yikun

2012-01-01

452

Early Transcriptional Response of Soybean Contrasting Accessions to Root Dehydration  

PubMed Central

Drought is a significant constraint to yield increase in soybean. The early perception of water deprivation is critical for recruitment of genes that promote plant tolerance. DeepSuperSAGE libraries, including one control and a bulk of six stress times imposed (from 25 to 150 min of root dehydration) for drought-tolerant and sensitive soybean accessions, allowed to identify new molecular targets for drought tolerance. The survey uncovered 120,770 unique transcripts expressed by the contrasting accessions. Of these, 57,610 aligned with known cDNA sequences, allowing the annotation of 32,373 unitags. A total of 1,127 unitags were up-regulated only in the tolerant accession, whereas 1,557 were up-regulated in both as compared to their controls. An expression profile concerning the most representative Gene Ontology (GO) categories for the tolerant accession revealed the expression “protein binding” as the most represented for “Molecular Function”, whereas CDPK and CBL were the most up-regulated protein families in this category. Furthermore, particular genes expressed different isoforms according to the accession, showing the potential to operate in the distinction of physiological behaviors. Besides, heat maps comprising GO categories related to abiotic stress response and the unitags regulation observed in the expression contrasts covering tolerant and sensitive accessions, revealed the unitags potential for plant breeding. Candidate genes related to “hormone response” (LOX, ERF1b, XET), “water response” (PUB, BMY), “salt stress response” (WRKY, MYB) and “oxidative stress response” (PER) figured among the most promising molecular targets. Additionally, nine transcripts (HMGR, XET, WRKY20, RAP2-4, EREBP, NAC3, PER, GPX5 and BMY) validated by RT-qPCR (four different time points) confirmed their differential expression and pointed that already after 25 minutes a transcriptional reorganization started in response to the new condition, with important differences between both accessions. PMID:24349513

Ferreira Neto, Jose Ribamar Costa; Pandolfi, Valesca; Guimaraes, Francismar Correa Marcelino; Benko-Iseppon, Ana Maria; Romero, Cynara; Silva, Roberta Lane de Oliveira; Rodrigues, Fabiana Aparecida; Abdelnoor, Ricardo Vilela; Nepomuceno, Alexandre Lima; Kido, Ederson Akio

2013-01-01

453

Early transcriptional response of soybean contrasting accessions to root dehydration.  

PubMed

Drought is a significant constraint to yield increase in soybean. The early perception of water deprivation is critical for recruitment of genes that promote plant tolerance. DeepSuperSAGE libraries, including one control and a bulk of six stress times imposed (from 25 to 150 min of root dehydration) for drought-tolerant and sensitive soybean accessions, allowed to identify new molecular targets for drought tolerance. The survey uncovered 120,770 unique transcripts expressed by the contrasting accessions. Of these, 57,610 aligned with known cDNA sequences, allowing the annotation of 32,373 unitags. A total of 1,127 unitags were up-regulated only in the tolerant accession, whereas 1,557 were up-regulated in both as compared to their controls. An expression profile concerning the most representative Gene Ontology (GO) categories for the tolerant accession revealed the expression "protein binding" as the most represented for "Molecular Function", whereas CDPK and CBL were the most up-regulated protein families in this category. Furthermore, particular genes expressed different isoforms according to the accession, showing the potential to operate in the distinction of physiological behaviors. Besides, heat maps comprising GO categories related to abiotic stress response and the unitags regulation observed in the expression contrasts covering tolerant and sensitive accessions, revealed the unitags potential for plant breeding. Candidate genes related to "hormone response" (LOX, ERF1b, XET), "water response" (PUB, BMY), "salt stress response" (WRKY, MYB) and "oxidative stress response" (PER) figured among the most promising molecular targets. Additionally, nine transcripts (HMGR, XET, WRKY20, RAP2-4, EREBP, NAC3,