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Sample records for dehydration condensation reaction

  1. An overview of dehydration, aldol-condensation and hydrogenation processes for production of liquid alkanes from biomass-derived carbohydrates

    Energy Technology Data Exchange (ETDEWEB)

    Chheda, Juben N.; Dumesic, James A. [University of Wisconsin-Madison, Department of Chemical and Biological Engineering, Madison, WI 53706 (United States)

    2007-05-30

    We present results for the conversion of carbohydrate feedstocks to liquid alkanes by the combination of dehydration, aldol-condensation/hydrogenation, and dehydration/hydrogenation processing. With respect to the first dehydration step, we demonstrate that HMF can be produced in good selectivity from abundantly available polysaccharides (such as inulin, sucrose) containing fructose monomer units using a biphasic batch reactor system. The reaction system can be optimized to achieve good yields to 5-hydroxymethylfurfural (HMF) from fructose by varying the contents of aqueous-phase modifiers such as dimethylsulfoxide (DMSO) and 1-methyl-2-pyrrolidinone (NMP). Regarding the aldol-condensation/hydrogenation step, we present the development of stable, solid base catalysts in aqueous environments. We address the effects of various reaction parameters such as the molar ratio of reactants and temperature on overall product yield for sequential aldol-condensation and hydrogenation steps. Overall, our results show that it is technically possible to convert carbohydrate feedstocks to produce liquid alkanes by the combination of dehydration, aldol-condensation/hydrogenation, and dehydration/hydrogenation processing; however, further optimization of these processes is required to decrease the overall number of separate steps (and reactors) required in this conversion. (author)

  2. Dehydration

    Science.gov (United States)

    ... chronic illness have a greater risk. Signs of dehydration in adults include Being thirsty Urinating less often ... skin Feeling tired Dizziness and fainting Signs of dehydration in babies and young children include a dry ...

  3. Metal organic framework MIL-101(Cr) for dehydration reactions

    Indian Academy of Sciences (India)

    als for polymers, and plastics.10,11 Dehydration reaction in gas phase has been carried out over solid acid cata- lysts such as silica gel, alumina, alkali alumina, ... usage of chromium catalyst has adverse effect on envi- ronment due to toxic nature of chromium.16 Therefore, in recent years, considerable attention has been ...

  4. Heterogeneous catalysis in complex, condensed reaction media

    Energy Technology Data Exchange (ETDEWEB)

    Cantu, David C.; Wang, Yang-Gang; Yoon, Yeohoon; Glezakou, Vassiliki-Alexandra; Rousseau, Roger; Weber, Robert S.

    2017-07-01

    Many reactions required for the upgrading of biomass into fuels and chemicals—hydrogenation, hydrodeoxygenation, hydrocracking—are ostensibly similar to those practiced in the upgrading of petroleum into fuels. But, repurposing hydroprocessing catalysts from refinery operations to treat bio-oil has proved to be unsatisfactory. New catalysts are needed because the composition of the biogenic reactants differs from that of petroleum-derived feedstocks (e.g. the low concentration of sulfur in cellulose-derived biomass precludes use of metal sulfide catalysts unless sulfur is added to the reaction stream). New processes are needed because bio-oils oligomerize rapidly, forming intractable coke and “gunk”, at temperatures so low that the desired upgrading reactions are impractically slow, and so low that the bio-oil upgrading must be handled as a condensed fluid. Ideally, the new catalysts and processes would exploit the properties of the multiple phases present in condensed bio-oil, notably the polarizability and structure of the fluid near a catalyst’s surface in the cybotactic region. The results of preliminary modeling of the cybotactic region of different catalyst surfaces in the hydrogenation of phenol suggest that Pd catalysts supported on hydrophilic surfaces are more active than catalysts based on lipophilic supports because the former serve to enhance the concentration of the phenol in the vicinity of the Pd. The effect stems from thermodynamics, not the rate of mass transport. This work was supported by the US Department of Energy, Office of Energy Efficiency and Renewable Energy, Bioenergy Technologies Office. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle.

  5. Condensation reactions of glucose and aromatic ring; Glucose to hokokan tono shukugo hanno

    Energy Technology Data Exchange (ETDEWEB)

    Komano, T.; Mashimo, K.; Wainai, T.; Tanaka, C.; Yoshioka, T. [Nihon University, Tokyo (Japan). College of Science and Technology; Sugimoto, Y.; Miki, Y. [National Institute of Materials and Chemical Research, Tsukuba (Japan)

    1996-10-28

    For artificial coalification, condensation reactions of aromatic ring and activated compounds produced by dehydrating reaction of glucose were studied experimentally. In heat treatment experiment in water, three reaction specimens such as glucose, glucose and phenol, and glucose and benzaldehyde were fed into an autoclave together with distilled water, and subjected to reaction at 180{degree}C under spontaneous pressure for 50 hours. In hydrogenation experiment, the specimens were fed into an autoclave together with tetradecane and sulfurization catalyst, and subjected to reaction at 350{degree}C under initial pressure of 9.8MPa for 2 hours for gas chromatography (GC) analysis of products. As the experimental result, the reaction between glucose and aromatic ring in heat treatment in water occurred between aromatic ring and active fragment with a mean carbon number of 4-5 produced by decomposition of glucose. The reactivity was higher in benzaldehyde addition than phenol addition. 3 refs., 4 figs., 1 tab.

  6. Ultrafast Dynamics of Chemical Reactions in Condensed Phase ...

    Indian Academy of Sciences (India)

    Ultrafast Dynamics of Chemical Reactions in Condensed Phase: Intramolecular Energy Transfer, Charge Transfer & Hydrogen Bond. Dipak K. Palit Radaition & Photochemistry Division Bhabha Atomic Research Centre Mumbai 400 085, India.

  7. Thermodynamic Simulation of Equilibrium Composition of Reaction Products at Dehydration of a Technological Channel in a Uranium-Graphite Reactor

    Science.gov (United States)

    Pavliuk, A. O.; Zagumennov, V. S.; Kotlyarevskiy, S. G.; Bespala, E. V.

    2018-01-01

    The problems of accumulation of nuclear fuel spills in the graphite stack in the course of operation of uranium-graphite nuclear reactors are considered. The results of thermodynamic analysis of the processes in the graphite stack at dehydration of a technological channel, fuel element shell unsealing and migration of fission products, and activation of stable nuclides in structural elements of the reactor and actinides inside the graphite moderator are given. The main chemical reactions and compounds that are produced in these modes in the reactor channel during its operation and that may be hazardous after its shutdown and decommissioning are presented. Thermodynamic simulation of the equilibrium composition is performed using the specialized code TERRA. The results of thermodynamic simulation of the equilibrium composition in different cases of technological channel dehydration in the course of the reactor operation show that, if the temperature inside the active core of the nuclear reactor increases to the melting temperature of the fuel element, oxides and carbides of nuclear fuel are produced. The mathematical model of the nonstationary heat transfer in a graphite stack of a uranium-graphite reactor in the case of the technological channel dehydration is presented. The results of calculated temperature evolution at the center of the fuel element, the replaceable graphite element, the air gap, and in the surface layer of the block graphite are given. The numerical results show that, in the case of dehydration of the technological channel in the uranium-graphite reactor with metallic uranium, the main reaction product is uranium dioxide UO2 in the condensed phase. Low probability of production of pyrophoric uranium compounds (UH3) in the graphite stack is proven, which allows one to disassemble the graphite stack without the risk of spontaneous graphite ignition in the course of decommissioning of the uranium-graphite nuclear reactor.

  8. Dehydrative Mannich-Type Reaction for the Synthesis of Azepinobisindole Alkaloid Iheyamine A.

    Science.gov (United States)

    Abe, Takumi; Yamada, Koji

    2018-03-02

    A concise synthesis of the azepinobisindole alkaloid iheyamine A from an indole-2,3-epoxide equivalent has been achieved. This method features a formal C3 electrophilic reaction of an indole-2,3-epoxide equivalent with tryptamine to form a 3-aminoindoline and a novel In-catalyzed dehydrative Mannich-type reaction of the hemiaminal to give the azepinobisindole core.

  9. Reaction mechanism of initial dehydration of zirconium oxide chloride octahydrate in its thermal decomposition

    International Nuclear Information System (INIS)

    Kikuchi, Masae

    1974-01-01

    Mechanism of initial dehydration of ZrOCl 2 .8H 2 O was investigated by isothermal heating and X-ray diffraction studies. In the range of 50 0 C to 66.5 0 C, two molecules of three-coordinated lattice water are lost in the first step of dehydration and subsequently one molecule of four-coordinated lattice water is lost. After the loss of three molecules of lattice water, the rate of thermal decomposition become slow and the crystal structure changes. It seems that above 66.5 0 C, both dehydration and chemical reaction which produces HCl presumably occur competitively. Activation energy of the initial dehydration is estimated to be 12.9 kcal-mol. (author)

  10. Modeling non-adiabatic photoexcited reaction dynamics in condensed phases

    International Nuclear Information System (INIS)

    Coker, D.F.

    2003-01-01

    Reactions of photoexcited molecules, ions, and radicals in condensed phase environments involve non-adiabatic dynamics over coupled electronic surfaces. We focus on how local environmental symmetries can effect non-adiabatic coupling between excited electronic states and thus influence, in a possibly controllable way, the outcome of photo-excited reactions. Semi-classical and mixed quantum-classical non-adiabatic molecular dynamics methods, together with semi-empirical excited state potentials are used to probe the dynamical mixing of electronic states in different environments from molecular clusters, to simple liquids and solids, and photo-excited reactions in complex reaction environments such as zeolites

  11. Ultrafast Dynamics of Chemical Reactions in Condensed Phase ...

    Indian Academy of Sciences (India)

    Ultrafast Dynamics of Chemical Reactions in Condensed Phase: Intramolecular Energy Transfer, Charge Transfer & Hydrogen Bond · PowerPoint Presentation · Slide 3 · Slide 4 · Slide 5 · Slide 6 · Slide 7 · Slide 8 · Slide 9 · Slide 10 · Slide 11 · Slide 12 · Slide 13 · Slide 14 · Slide 15 · Slide 16 · Slide 17 · Slide 18 · Slide 19.

  12. The mechanism of the dehydration reaction of solid HIO 4. 2H 2O and the role of radiation

    International Nuclear Information System (INIS)

    Takriti, S.

    1998-01-01

    A thermal and kinetic study of dehydration reaction of periodic acid dehydrate has been carried out with isothermal and physical measurements. Isothermal dehydration curves have been studied in the temperature ranges between 333 0 K respectively. Both dehydration processes involve the loss two molecules of water in the studied temperature ranges. Thermodynamic and kinetic parameters have been calculated using different physical models proposed. The data analysis illustrated that activation energy is about 1 eV for the first step and 1.2 eV for second

  13. Modeling of a Reaction-Distillation-Recycle System to Produce Dimethyl Ether through Methanol Dehydration

    Science.gov (United States)

    Muharam, Y.; Zulkarnain, L. M.; Wirya, A. S.

    2018-03-01

    The increase in the dimethyl ether yield through methanol dehydration due to a recycle integration to a reaction-distillation system was studied in this research. A one-dimensional phenomenological model of a methanol dehydration reactor and a shortcut model of distillation columns were used to achieve the aim. Simulation results show that 10.7 moles/s of dimethyl ether is produced in a reaction-distillation system with the reactor length being 4 m, the reactor inlet pressure being 18 atm, the reactor inlet temperature being 533 K, the reactor inlet velocity being 0.408 m/s, and the distillation pressure being 8 atm. The methanol conversion is 90% and the dimethyl ether yield is 48%. The integration of the recycle stream to the system increases the dimethyl ether yield by 8%.

  14. Unconventional application of the Mitsunobu reaction: Selective flavonolignan dehydration yielding hydnocarpins

    Directory of Open Access Journals (Sweden)

    Guozheng Huang

    2016-04-01

    Full Text Available Various Mitsunobu conditions were investigated for a series of flavonolignans (silybin A, silybin B, isosilybin A, and silychristin A to achieve either selective esterification in position C-23 or dehydration in a one-pot reaction yielding the biologically important enantiomers of hydnocarpin D, hydnocarpin and isohydnocarpin, respectively. This represents the only one-pot semi-synthetic method to access these flavonolignans in high yields.

  15. Dynamics of Low-Energy Electron Induced Reactions in Condensed

    Science.gov (United States)

    Boyer, Michael; Soe, Chanmyaemyae; Chamberlain, Kristal; Shyur, Yomay; Arumainayagam, Christopher

    2011-03-01

    We present insights into the dynamics of low-energy electron-induced reactions in thin films of methanol (CH3 OH). Low-energy electrons in matter can initiate chemical reactions though electron impact ionization of a molecule, electron impact excitation of a molecule, or through dissociation of a transient negative ion formed by electron attachment to a molecule. Our studies focus on the dynamics by which low-energy electron interaction with condensed methanol initiates chemical reactions which lead to the formation of methoxymethanol (CH3 O CH2 OH) and ethylene glycol (HO CH2 CH2 OH). The results of our post-irradiation temperature programmed desorption experiments indicate that both products can form from irradiating methanol with electrons at subionization energies. In addition, we find evidence that dissociative electron attachment plays a role in the formation of methoxymethanol but not in ethylene glycol.

  16. Low-Energy Electron Induced Reactions in Condensed Methanol

    Science.gov (United States)

    Boyer, Michael; Boamah, Mavis; Chamberlain, Kristal; Myae Soe, Chanmaye; Bass, Andrew; Sanche, Leon; Arumainayagam, Christopher

    2012-02-01

    We investigate the dynamics of low-energy electron-induced reactions in condensed thin films of methanol (CH3OH) through electron stimulated desorption (ESD) and post-irradiation temperature programmed desorption (TPD) experiments. ESD experiments indicate that the anions which desorb from the methanol thin film during electron irradiation are predominantly formed through the dissociation of temporary negative ions formed by electron capture by methanol molecules, a process known as dissociative electron attachment (DEA). However, based on investigation of reaction products remaining in the methanol thin film post-irradiation through TPD experiments, DEA is not the obvious primary mechanism by which methoxymethanol (CH3OCH2OH) and ethylene glycol (HOCH2CH2OH) are formed. Evidence indicates formation of these molecules may be driven by both DEA and electron impact excitation.

  17. Condensers

    International Nuclear Information System (INIS)

    Andrieux, M.B.

    1984-01-01

    Characteristics of the condenser cooling waters of various French 900 MW nuclear power plants. Design and description of various types of condensers: condensers feeded directly with river water, condensers feeded by cooling towers, condensers feeded with sea water of brackish water. Presentation of the main problems encountered with the brass bundles (ammoniacal corrosion, erosion of the peripheral tubes, vibrations of the tubes), with the titanium bundles, with the tubular plates, the tubes-tubular plates assemblies, the coatings of the condenser water chamber (sea water), the vapor by-pass and with the air inlet. Analysis of the in service performances such as condensation pressure, oxygen content and availability [fr

  18. Assessment of tautomer distribution using the condensed reaction graph approach

    Science.gov (United States)

    Gimadiev, T. R.; Madzhidov, T. I.; Nugmanov, R. I.; Baskin, I. I.; Antipin, I. S.; Varnek, A.

    2018-03-01

    We report the first direct QSPR modeling of equilibrium constants of tautomeric transformations (logK T ) in different solvents and at different temperatures, which do not require intermediate assessment of acidity (basicity) constants for all tautomeric forms. The key step of the modeling consisted in the merging of two tautomers in one sole molecular graph ("condensed reaction graph") which enables to compute molecular descriptors characterizing entire equilibrium. The support vector regression method was used to build the models. The training set consisted of 785 transformations belonging to 11 types of tautomeric reactions with equilibrium constants measured in different solvents and at different temperatures. The models obtained perform well both in cross-validation (Q2 = 0.81 RMSE = 0.7 logK T units) and on two external test sets. Benchmarking studies demonstrate that our models outperform results obtained with DFT B3LYP/6-311 ++ G(d,p) and ChemAxon Tautomerizer applicable only in water at room temperature.

  19. Dehydration reactions of gypsum: A neutron and X-ray diffraction study

    Science.gov (United States)

    Abriel, W.; Reisdorf, K.; Pannetier, J.

    1990-03-01

    The kinetics of the dehydration of gypsum was investigated by powder diffraction methods. Using the incoherent scattering effect of H with the neutron beam, the background intensity as a measure of the water content was checked in the temperature range 295-623 K. The superposed Bragg peaks yielded four major phases: Gypsum, subhydratesCaSO 4(H 2O) x (1 > x > 0),AIII-CaSO 4, AII-CaSO 4. For the subhydrates a maximum water content of x > = 0.74was determined. A different kinetic was found using Guinier X-ray technique with the heated sample prepared on a thin foil. Only with high local H 2O steam pressure, produced in the comparable larger sample container of the neutron diffraction experiment, could this high H 2O occupation of the subhydrate tunnel structure be found. A topotactic mechanism can describe the phase transitions for this reaction.

  20. Implementation of Near-Infrared Spectroscopy for In-Line Monitoring of a Dehydration Reaction in a Tubular Laminar Reactor

    DEFF Research Database (Denmark)

    Mitic, Aleksandar; Cervera Padrell, Albert Emili; Mortensen, Asmus R.

    2016-01-01

    are the main benefits. A good approach to achieve this is to perform continuous manufacturing together with satisfying process analytical technology (PAT) requirements. The example studied here is the dehydration reaction of 9-allyl-2-chlorothioxanthen-9-ol (“N714-allylcarbinol”) to give a mixture of cis...

  1. The reaction mechanism for dehydration process catalyzed by type I dehydroquinate dehydratase from Gram-negative Salmonella enterica

    Science.gov (United States)

    Yao, Yuan; Li, Ze-Sheng

    2012-01-01

    The fundamental reaction mechanism for the dehydration process catalyzed by type I dehydroquinate dehydratase from Gram-negative Salmonella enterica has been studied by density functional theory calculations. The results indicate that the dehydration process undergoes a two-step cis-elimination mechanism, which is different from the previously proposed one. The catalytic roles of both the highly conserved residue His143 and the Schiff base formed between the substrate and Lys170 have also been elucidated. The structural and mechanistic insight presented here may direct the design of type I dehydroquinate dehydratase enzyme inhibitors as non-toxic antimicrobials, anti-fungals, and herbicides.

  2. Mining chemical reactions using neighborhood behavior and condensed graphs of reactions approaches.

    Science.gov (United States)

    de Luca, Aurélie; Horvath, Dragos; Marcou, Gilles; Solov'ev, Vitaly; Varnek, Alexandre

    2012-09-24

    This work addresses the problem of similarity search and classification of chemical reactions using Neighborhood Behavior (NB) and Condensed Graphs of Reaction (CGR) approaches. The CGR formalism represents chemical reactions as a classical molecular graph with dynamic bonds, enabling descriptor calculations on this graph. Different types of the ISIDA fragment descriptors generated for CGRs in combination with two metrics--Tanimoto and Euclidean--were considered as chemical spaces, to serve for reaction dissimilarity scoring. The NB method has been used to select an optimal combination of descriptors which distinguish different types of chemical reactions in a database containing 8544 reactions of 9 classes. Relevance of NB analysis has been validated in generic (multiclass) similarity search and in clustering with Self-Organizing Maps (SOM). NB-compliant sets of descriptors were shown to display enhanced mapping propensities, allowing the construction of better Self-Organizing Maps and similarity searches (NB and classical similarity search criteria--AUC ROC--correlate at a level of 0.7). The analysis of the SOM clusters proved chemically meaningful CGR substructures representing specific reaction signatures.

  3. Highly Enantioselective Construction of Fluoroalkylated Quaternary Stereocenters via Organocatalytic Dehydrated Mannich Reaction of Unprotected Hemiaminals with Ketones.

    Science.gov (United States)

    Zhang, Sheng; Li, Lijun; Hu, Yanbin; Li, Yanan; Yang, Yu; Zha, Zhenggen; Wang, Zhiyong

    2015-10-16

    A general organocatalytic asymmetric dehydrated Mannich reaction of fluoroalkyl hemiaminals with ketones is reported. In this Mannich reaction, previously less explored aryl ketones showed great reactivity. By virtue of this efficient method, a wide range of biologically active β-amino ketones were directly obtained. More importantly, two different intermediates involved in the reaction were detected and identified by (19)F NMR and HRMS analysis. Furthermore, the synthetic utility of the products was demonstrated by the synthesis of the biologically active fluoroalkyl β-amino alcohols.

  4. Surface hydrophobicity and acidity effect on alumina catalyst in catalytic methanol dehydration reaction.

    Science.gov (United States)

    Osman, Ahmed I; Abu-Dahrieh, Jehad K; Rooney, David W; Thompson, Jillian; Halawy, Samih A; Mohamed, Mohamed A

    2017-12-01

    Methanol to dimethyl ether (MTD) is considered one of the main routes for the production of clean bio-fuel. The effect of copper loading on the catalytic performance of different phases of alumina that formed by calcination at two different temperatures was examined for the dehydration of methanol to dimethyl ether (DME). A range of Cu loadings of (1, 2, 4, 6, 10 and 15% Cu wt/wt) on Al 2 O 3 calcined at 350 and 550 °C were prepared and characterized by TGA, XRD, BET, NH 3 -TPD, TEM, H 2 -TPR, SEM, EDX, XPS and DRIFT-Pyridine techniques. The prepared catalysts were used in a fixed bed reactor under reaction conditions in which the temperature ranged from 180-300 °C with weight hourly space velocity (WHSV) = 12.1 h -1 . It was observed that all catalysts calcined at 550 °C (γ-Al 2 O 3 support phase) exhibited higher activity than those calcined at 350 °C (γ-AlOOH), and this is due to the phase support change. Furthermore, the optimum Cu loading was found to be 6% Cu/γ-Al 2 O 3 with this catalyst also showing a high degree of stability under steady state conditions and this is attributed to the enhancement in surface acidity and hydrophobicity. The addition of copper to the support improved the catalyst properties and activity. For all the copper modified catalysts, the optimum catalyst with high degree of activity and stability was 6% copper loaded on gamma alumina. © 2017 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  5. Reactions of 3-Formylchromone with Active Methylene and Methyl Compounds and Some Subsequent Reactions of the Resulting Condensation Products

    Directory of Open Access Journals (Sweden)

    M. Lácova

    2005-08-01

    Full Text Available 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 γ-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.

  6. Investigation of Ultrafast Condensed Phase Reactions Between Nanopowders

    National Research Council Canada - National Science Library

    Puszynski, Jan

    2004-01-01

    .... These models predict qualitatively combustion from propagation in such reacting systems. It was also found that surface functionalization of aluminum nanopowders significantly slows down its reaction with moisture...

  7. Simultaneous observations of reaction kinetics, creep behavior, and AE activities during syndeformational antigorite dehydration at high pressures

    Science.gov (United States)

    Kubo, T.; Iwasato, T.; Higo, Y.; Kato, T.; Kaneshima, S.; Uehara, S.; Koizumi, S.; Imamura, M.; Tange, Y.

    2015-12-01

    Intermediate-depth earthquakes are seismic activities in Wadati-Benioff zone at depths from 60 km to 300 km, where subducting plates deform plastically rather than brittle failure. Although it has been reported that unstable faulting occurred during antigorite dehydration even at higher pressures than ~2 GPa (e.g., Jung et al., 2009), the recent study by Chernak and Hirth (2011) revealed that the syndefromational antigorite dehydration does not produces stick-slip instabilities but stable fault slip. In the present study, we newly developed an AE monitoring system for high-pressure reaction-deformation processes combined with D-DIA and synchrotron monochromatic X-ray to observe reaction kinetics, creep behaviors, and AE activities simultaneously. We applied this technique to investigate shear instability during syndeformational antigorite dehydration. High-pressure deformation experiments were conducted up to ~8 GPa, ~1050 K, and strain rates of 3.4-9.2 x 10-5 s-1 in compression using a D-DIA type apparatus installed at BL-04B1, SPring-8. 50 keV mono X-ray were used to measure reaction kinetics and stress-strain data. To monitor shear instabilities by detecting AEs, six piezoelectric devices were positioned between first and second stage anvils of MA 6-6 type system. We used three kinds of starting materials of polycrystalline antigorite, fine-grained forsterite polycrystal, and two-phase mixtures of antigorite and San Carlos olivine (10%, 30%, and 50%atg). Clear contrasts were observed in AE activities between forsterite and antigorite samples. AE activities detected within the forsterite polycrystal suggested (semi) brittle behaviors at low pressures during the cold compression stage.
Almost no AEs were detected within the antigorite samples during any stages of cold compression, ramping, deformation, and syndeformational dehydration although localized deformation textures were observed in recovered samples. Instead, we detected some AEs outside the sample

  8. Unconventional application of the Mitsunobu reaction: Selective flavonolignan dehydration yielding hydnocarpins

    Czech Academy of Sciences Publication Activity Database

    Huang, G.; Schramm, S.; Heilmann, J.; Biedermann, David; Křen, Vladimír; Decker, M.

    2016-01-01

    Roč. 12, APR8 (2016), s. 662-669 ISSN 1860-5397 R&D Projects: GA MŠk(CZ) LD15085 Institutional support: RVO:61388971 Keywords : dehydration * flavonoid * hydnocarpin Subject RIV: CC - Organic Chemistry Impact factor: 2.337, year: 2016

  9. Analytical solution for transient partitioning and reaction of a condensing vapor species in a droplet

    OpenAIRE

    Liu, Albert Tianxiang; Zaveri, Rahul A.; Seinfeld, John H.

    2014-01-01

    We present the exact analytical solution of the transient equation of gas-phase diffusion of a condensing vapor to, and diffusion and reaction in, an aqueous droplet. Droplet-phase reaction is represented by first-order chemistry. The solution facilitates study of the dynamic nature of the vapor uptake process as a function of droplet size, Henry's law coefficient, and first-order reaction rate constant for conversion in the droplet phase.

  10. Kinetic modeling for thermal dehydration of ferrous oxalate dihydrate polymorphs: a combined model for induction period-surface reaction-phase boundary reaction.

    Science.gov (United States)

    Ogasawara, Haruka; Koga, Nobuyoshi

    2014-04-03

    In this study, ferrous oxalate dihydrate polymorph particles, α- and β-phases, with square bipyramidal and quadratic prismatic shapes, respectively, were synthesized. Thermal dehydration of the samples was subjected to kinetic study as a typical reaction that indicates a significant induction period and a sigmoidal mass-loss behavior. On the basis of the formal kinetic analysis of the mass-loss traces recorded under isothermal, nonisothermal, and constant transformation rate conditions and the morphological observations of the surface textures of the partially reacted sample particles, a combined kinetic model for the induction period-surface reaction-phase boundary reaction was developed. The sigmoidal mass-loss behavior after the significant induction period under isothermal conditions was satisfactorily simulated by the combined kinetic model. The kinetic parameters for the component processes of induction period, surface reaction, and phase boundary reaction were separately determined from the kinetic simulation. The differences in the kinetic behaviors of the induction period and the phase boundary reaction between α- and β-phase samples were well described by the kinetic parameters. The applicability of the combined kinetic model to practical systems was demonstrated through characterizing the physicogeometrical kinetics of the thermal dehydration of ferrous oxalate dihydrate polymorphs.

  11. Study towards benzoin condensation and Baylis-Hillman reactions

    Indian Academy of Sciences (India)

    Abstract. New heterocyclic ring systems consisting of (±) methanodibenzodiazocine and imidazolium/ benzimidazolium salts were synthesized in very good yield. Subsequently, these halide salts were subjected to the anion exchange reaction with KPF6 to yield the corresponding azolium salts in excellent yield.

  12. Direct dimethyl ether synthesis from synthesis gas: The influence of methanol dehydration on methanol synthesis reaction

    OpenAIRE

    Dadgar, Farbod; Myrstad, Rune; Pfeifer, Peter; Holmen, Anders; Venvik, Hilde Johnsen

    2016-01-01

    Direct dimethyl ether (DME) synthesis from synthesis gas is studied with regard to potential effects of methanol dehydration on methanol formation and copper-based catalyst performance. For this, the influence of the operating conditions (space velocity, temperature, pressure, time-on-stream and syngas composition) on activity, selectivity and stability of the catalyst was studied and compared for methanol synthesis and direct DME synthesis. The advantage of the direct over the two-step DME s...

  13. Condensed Matter Deuterium Cluster Target for Study of Pycnonuclear Reactions

    Science.gov (United States)

    Yang, Xiaoling; George, Miley

    2009-11-01

    Fusion reactions have two main classes: thermonuclear and the pycnonuclear. Thermonuclear fusion occurs in low density high temperature plasmas, and is very sensitive to the ion temperature due to Columbic repulsion effects. As the density increases, the Columbic potential barrier is depressed by increased electron screening, allowing fusion at lower temperatures. This type of nuclear reaction is termed a pycnonuclear fusion and is the basis for astrophysical fusion. Ichimarua [1] proposed a laboratory study of this process using explosive mechanical compression of H/D to metallic densities, which would be extremely difficult to implement. Instead, our recent research suggests that metallic-like H/D ``clusters'' can be formed in dislocation loops of thin Palladium foils through electrochemical processes. [2] If this technique is used as a laser compression target, the compressed cluster density would allow study of pycnonuclear reactions. This provides a means of studying astrophysical fusion process, and could also lead to an important non-cryogenic ICF target. [2] [4pt] [1] S. Ichimaru, H. Kitamura. Phys. Plasmas, 6, 2649 (1999) [0pt] [2] G. Miley and X. Yang, Deuterium Cluster Target for Ultra-High Density, 18TH TOFE, San Francisco, CA Sep. 28 -- Oct. 2, 2008

  14. Boehmite-An Efficient and Recyclable Acid-Base Bifunctional Catalyst for Aldol Condensation Reaction.

    Science.gov (United States)

    Reshma, P C Rajan; Vikneshvaran, Sekar; Velmathi, Sivan

    2018-06-01

    In this work boehmite was used as an acid-base bifunctional catalyst for aldol condensation reactions of aromatic aldehydes and ketones. The catalyst was prepared by simple sol-gel method using Al(NO3)3·9H2O and NH4OH as precursors. The catalyst has been characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM), UV-visible spectroscopy (DRS), BET surface area analyses. Boehmite is successfully applied as catalyst for the condensation reaction between 4-nitrobenzaldehyde and acetone as a model substrate giving α, β-unsaturated ketones without any side product. The scope of the reaction is extended for various substituted aldehydes. A probable mechanism has been suggested to explain the cooperative behavior of the acidic and basic sites. The catalyst is environmentally friendly and easily recovered from the reaction mixture. Also the catalyst is reusable up to 3 catalytic cycles.

  15. Probing the Rate-Determining Step of the Claisen-Schmidt Condensation by Competition Reactions

    Science.gov (United States)

    Mak, Kendrew K. W.; Chan, Wing-Fat; Lung, Ka-Ying; Lam, Wai-Yee; Ng, Weng-Cheong; Lee, Siu-Fung

    2007-01-01

    Competition experiments are a useful tool for preliminary study of the linear free energy relationship of organic reactions. This article describes a physical organic experiment for upper-level undergraduates to identify the rate-determining step of the Claisen-Schmidt condensation of benzaldehyde and acetophenone by studying the linear free…

  16. Reaction of the condensation of alkylphenols with formaldehyde and ammonia. [Mannich base

    Energy Technology Data Exchange (ETDEWEB)

    Sopkina, A.K.; Gordash, Iu.T.; Grechko, A.N.; Marusiak, O.V.; Sukhoverkhov, V.D.; Zriakov, I.N.

    1980-01-01

    The Mannich base, which is produced by the condensation of alkylphenols with formaldehyde and ammonia, is used as an additive or as an intermediate product in the production of additives. With condensation according to Mannich, the yield of the bases depends on the structure of the original alkylphenol and the conditions of the condensations. It is shown, that with the use of monoalkylphenols, having linear or a ramified radical, it is possible to produces practically a complete conversion of alkylphenols. As a rule, the yield of the Mannich bases in these conditions is greater than 80%. For the dialkylphenols, the yield of the Mannich bases in analogous conditions does not exceed 50%. The attempt to find the optimal conditions of the condensation reaction according to Mannich with the help of the method of nonlinear programming showed, that the yield of the Mannich bases is affected not only by the concentration, the duration of the reaction, and temperature, but also more complex factors of the paired effect of the concentration, the duration of the reaction, concentration and temperature.

  17. Chemical reactions in organic monomolecular layers. Condensation of hydrazine on carbonyl functions

    International Nuclear Information System (INIS)

    Rosilio, Charles; Ruaudel-Teixier, Annie.

    1976-01-01

    Evidence is given for chemical reactions of hydrazine (NH 2 -NH 2 ) with different carbonyl functional groups of organic molecules in the solid state, in monomolecular layer structures. The condensation of hydrazine with these molecules leads to conjugated systems by bridging the N-N links, to cyclizations, and also to polycondensations. The reactions investigated were followed up by infrared spectrophotometry, by transmission and metallic reflection. These chemical reactions revealed in the solid phase constitute a polycondensation procedure which is valuable in obtaining organized polymers in monomolecular layers [fr

  18. Microwave Assisted Condensation Reactions of 2-Aryl Hydrazonopropanals with Nucleophilic Reagents and Dimethyl Acetylenedicarboxylate

    Directory of Open Access Journals (Sweden)

    Rita M. Borik

    2007-08-01

    Full Text Available The reaction of methyl ketones 1a-g with dimethylformamide dimethylacetal (DMFDMA afforded the enaminones 2a-g, which were coupled with diazotized aromatic amines 3a,b to give the corresponding aryl hydrazones 6a-h. Condensation of compounds 6a-h with some aromatic heterocyclic amines afforded iminoarylhydrazones 9a-m. Enaminoazo compounds 12a,b could be obtained from condensation of 6c with secondary amines. The reaction of 6e,h with benzotriazolylacetone yielded 14a,b. Also, the reaction of 6a,b,d-f,h with glycine and hippuric acid in acetic anhydride afforded pyridazinone derivatives 17a-f. Synthesis of pyridazine carboxylic acid derivatives 22a,b from the reaction of 6b,e with dimethyl acetylenedicarboxylate (DMAD in the presence of triphenylphosphine at room temperature is also reported. Most of these reactions were conducted under irradiation in a microwave oven in the absence of solvent in an attempt to improve the product yields and to reduce the reaction times.

  19. Catalytic performance of Metal-Organic-Frameworks vs.extra-large porezeolite UTL in condensation reactions

    Czech Academy of Sciences Publication Activity Database

    Shamzhy, Mariya; Opanasenko, Maksym; Shvets, O. V.; Čejka, Jiří

    2013-01-01

    Roč. 1, AUG 2013 (2013), s. 1-11 ISSN 2296-2646 R&D Projects: GA ČR GBP106/12/G015 Grant - others:European Commission(XE) FP7/2007-2013, contract 228862 Institutional support: RVO:61388955 Keywords : condensation reactions * MOFs * zeolites Subject RIV: CF - Physical ; Theoretical Chemistry http://www.frontiersin.org/Journal/10.3389/fchem.2013.00011/abstract

  20. Metal Organic Frameworks as Solid Catalysts in Condensation Reactions of Carbonyl Groups

    Czech Academy of Sciences Publication Activity Database

    Dhakshinamoorthy, A.; Opanasenko, Maksym; Čejka, Jiří; Garcia, H.

    2013-01-01

    Roč. 355, 2-3 (2013), s. 247-268 ISSN 1615-4150 R&D Projects: GA ČR GBP106/12/G015 Grant - others:European Commission(XE) FP7/2007-2013, contract 228862 Institutional support: RVO:61388955 Keywords : alcohol condensation * green chemistry * Henry reaction Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.542, year: 2013

  1. Bilayer sheet protrusions and budding from bilayer membranes induced by hydrolysis and condensation reactions

    Science.gov (United States)

    Nakagawa, Koh M.; Noguchi, Hiroshi

    Shape transformations of flat bilayer membranes and vesicles induced by hydrolysis and condensation reactions of amphiphilic molecules are studied using coarse-grained molecular dynamics simulations. The hydrolysis and condensation reactions result in the formation and dissociation of amphiphilic molecules, respectively. Asymmetric reactions between the inner and outer leaflets of a vesicle can transport amphiphilic molecules between the leaflets. It is found that the resulting area difference between the two leaflets induces bilayer sheet protrusion~(BP) and budding at low reduced volumes of the vesicles, whereas BP only occurs at high reduced volumes. The probabilities of these two types of transformations depend on the shear viscosity of the surrounding fluids compared to the membrane as well as the reaction rates. A higher surrounding fluid viscosity leads to more BP formation. The inhomogeneous spatial distribution of the hydrophobic reaction products forms the nuclei of BP formation, and faster diffusion of the products enhances BP formation. Our results suggest that adjustment of the viscosity is important to control membrane shape transformations in experiments.

  2. Acute Adverse Reactions to Nonionic Iodinated Contrast Media for CT: Prospective Randomized Evaluation of the Effects of Dehydration, Oral Rehydration, and Patient Risk Factors.

    Science.gov (United States)

    Motosugi, Utaroh; Ichikawa, Tomoaki; Sano, Katsuhiro; Onishi, Hiroshi

    2016-11-01

    The objective of our study was to determine the effects of dehydration and oral rehydration on the incidence of acute adverse reactions to iodinated contrast media administered during abdominal and pelvic CT in outpatients. For our prospective randomized study performed at a single institution, adult outpatients undergoing contrast-enhanced abdominal CT were randomly divided into a rehydration group (n = 2244 patients [1379 men and 865 women]; mean age, 65.2 years; age range, 18-90 years) and a control group (n = 3715 [2112 male patients and 1603 female patients]; mean age, 65.8 years; age range, 17-96 years), which included an age- and sex-matched subgroup (adjusted control group, n = 2244). The rehydration group received an oral rehydration solution (500 mL of liquid in which osmotic pressure is adjusted to enhance gastrointestinal absorption) before abdominal and pelvic CT. Patients were also divided into subclinically dehydrated (n = 997) and hydrated (n = 4962) groups according to their answers to a questionnaire that they completed before the CT examination. The patients were interviewed about contrast-induced adverse reactions before they left the CT room, and the reactions were categorized as allergiclike or physiologic. The incidence of reactions was compared between the rehydration and control groups and between the subclinical dehydration and hydrated groups. The rehydration and control groups were compared with an unpaired t test or a chi-square or Fisher test. The overall incidence of an acute adverse reaction was 4.3% (254/5959); the acute adverse reactions included 136 allergiclike and 118 physiologic reactions. Fourteen allergiclike and nine physiologic reactions were moderate grade, and none was severe. There was no significant difference between the rehydration group and adjusted control group in the overall incidence of adverse reactions (99/2244 [4.4%] vs 100/2244 [4.5%], respectively; p = 0.9422) or between the subclinically dehydrated group

  3. Toward a reaction rate model of condensed-phase RDX decomposition under high temperatures

    Science.gov (United States)

    Schweigert, Igor

    2015-06-01

    Shock ignition of energetic molecular solids is driven by microstructural heterogeneities, at which even moderate stresses can result in sufficiently high temperatures to initiate material decomposition and chemical energy release. Mesoscale modeling of these ``hot spots'' requires a reaction rate model that describes the energy release with a sub-microsecond resolution and under a wide range of temperatures. No such model is available even for well-studied energetic materials such as RDX. In this presentation, I will describe an ongoing effort to develop a reaction rate model of condensed-phase RDX decomposition under high temperatures using first-principles molecular dynamics, transition-state theory, and reaction network analysis. This work was supported by the Naval Research Laboratory, by the Office of Naval Research, and by the DoD High Performance Computing Modernization Program Software Application Institute for Multiscale Reactive Modeling of Insensitive Munitions.

  4. Synthesis, characterization and catalytic properties of nanocrystaline Y{sub 2}O{sub 3}-coated TiO{sub 2} in the ethanol dehydration reaction

    Energy Technology Data Exchange (ETDEWEB)

    Fajardo, Humberto Vieira [Universidade Federal de Ouro Preto (UFOP), MG (Brazil). Departamento de Quimica; Longo, Elson [Universidade Estadual Paulista (UNESP), Araraquara, SP (Brazil). Departamento de Fisico-Quimica; Leite, Edson Roberto; Libanori, Rafael [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Quimica; Probst, Luiz Fernando Dias [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Departamento de Quimica; Carreno, Neftali Lenin Villarreal [Universidade Federal de Pelotas (UFPel), RS (Brazil). Departamento de Quimica Analitica e Inorganica

    2012-03-15

    In the present study, TiO{sub 2} nano powder was partially coated with Y{sub 2}O{sub 3} precursors generated by a sol-gel modified route. The system of nanocoated particles formed an ultra thin structure on the TiO{sub 2} surfaces. The modified nanoparticles were characterized by high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD) analysis, Zeta potential and surface area through N{sub 2} physisorption measurements. Bioethanol dehydration was used as a probe reaction to investigate the modifications on the nanoparticles surface. The process led to the obtainment of nanoparticles with important surface characteristics and catalytic behavior in the bioethanol dehydration reaction, with improved activity and particular selectivity in comparison to their non-coated analogs. The ethylene production was disfavored and selectivity toward acetaldehyde, hydrogen and ethane increased over modified nanoparticles. (author)

  5. Synthesis, characterization and catalytic properties of nanocrystaline Y2O3-coated TiO2 in the ethanol dehydration reaction

    Directory of Open Access Journals (Sweden)

    Humberto Vieira Fajardo

    2012-04-01

    Full Text Available In the present study, TiO2 nanopowder was partially coated with Y2O3 precursors generated by a sol-gel modified route. The system of nanocoated particles formed an ultra thin structure on the TiO2 surfaces. The modified nanoparticles were characterized by high resolution transmission electron microscopy (HR-TEM, X-ray diffraction (XRD analysis, Zeta potential and surface area through N2 fisisorption measurements. Bioethanol dehydration was used as a probe reaction to investigate the modifications on the nanoparticles surface. The process led to the obtainment of nanoparticles with important surface characteristics and catalytic behavior in the bioethanol dehydration reaction, with improved activity and particular selectivity in comparison to their non-coated analogs. The ethylene production was disfavored and selectivity toward acetaldehyde, hydrogen and ethane increased over modified nanoparticles.

  6. Closure of the condensed-phase organic-nitrate reaction unreviewed safety question at Hanford site

    International Nuclear Information System (INIS)

    COWLEY, W.L.

    1999-01-01

    A discovery Unreviewed Safety Question (USQ) was declared on the underground waste storage tanks at the Hanford Site in May 1996. The USQ was for condensed-phase organic-nitrate reactions (sometimes called organic complexant reactions) in the tanks. This paper outlines the steps taken to close the USQ, and resolve the related safety issue. Several processes were used at the Hanford Site to extract and/or process plutonium. These processes resulted in organic complexants (for chelating multivalent cations) and organic extraction solvents being sent to the underground waste storage tanks. This paper addresses the organic complexant hazard. The organic complexants are in waste matrices that include inert material, diluents, and potential oxidizers. In the presence of oxidizing material, the complexant salts can be made to react exothermically by heating to high temperatures or by applying an external ignition source of sufficient energy. The first organic complexant hazard assessments focused on determining whether a hulk runaway reaction could occur, similar to the 1957 accident at Kyshtm (a reprocessing plant in the former U.S.S.R.). Early analyses (1977 through 1994) examined organic-nitrate reaction onset temperatures and concluded that a bulk runaway reaction could not occur at the Hanford Site because tank temperatures were well below that necessary for bulk runaway. Therefore, it was believed that organic-nitrate reactions were adequately described in the then current Authorization Basis (AB). Subsequent studies examined a different accident scenario, propagation resulting from an external ignition source (e.g., lightning or welding slag) that initiates a combustion front that propagates through the organic waste. A USQ evaluation determined that localized high energy ignition sources were credible, and that point source ignition of organic complexant waste was not adequately addressed i n the then existing AB. Consequently, the USQ was declared on the

  7. Closure of the condensed-phase organic-nitrate reaction USQ at hanford

    Energy Technology Data Exchange (ETDEWEB)

    COWLEY, W.L.

    1999-06-24

    A discovery Unreviewed Safety Question (USQ) was declared on the underground waste storage tanks at the Hanford Site in May 1996. The USQ was for condensed-phase organic-nitrate reactions (sometimes called organic complexant reactions) in the tanks. This paper outlines the steps taken to close the USQ, and resolve the related safety issue. Several processes were used at the Hanford Site to extract and/or process plutonium. These processes resulted in organic complexants (for chelating multivalent cations) and organic extraction solvents being sent to the underground waste storage tanks. This paper addresses the organic complexant hazard. The organic complexants are in waste matrices that include inert material, diluents, and potential oxidizers. In the presence of oxidizing material, the complexant salts can be made to react exothermically by heating to high temperatures or by applying an external ignition source of sufficient energy. The first organic complexant hazard assessments focused on determining whether a hulk runaway reaction could occur, similar to the 1957 accident at Kyshtm (a reprocessing plant in the former U.S.S.R.). Early analyses (1977 through 1994) examined organic-nitrate reaction onset temperatures and concluded that a bulk runaway reaction could not occur at the Hanford Site because tank temperatures were well below that necessary for bulk runaway. Therefore, it was believed that organic-nitrate reactions were adequately described in the then current Authorization Basis (AB). Subsequent studies examined a different accident scenario, propagation resulting from an external ignition source (e.g., lightning or welding slag) that initiates a combustion front that propagates through the organic waste. A USQ evaluation determined that localized high energy ignition sources were credible, and that point source ignition of organic complexant waste was not adequately addressed i n the then existing AB. Consequently, the USQ was declared on the

  8. A route to hydroxylfluorenes: TsOH-mediated condensation reactions of 1,3-diketones with propargylic alcohols

    KAUST Repository

    Yao, Liangfeng

    2012-01-01

    An efficient method of preparing hydroxylfluorenes by TsOH-mediated tandem alkylation/rearrangements of propargylic alcohols with 1,3-diketones is described. These reactions are accomplished in moderate to good yields under mild conditions to offer a straightforward and convenient one step synthetic route to hydroxylfluorene derivatives through a plausible mechanism involving a sequence of dehydration, addition, rearrangement and aromatization. This journal is © The Royal Society of Chemistry 2012.

  9. The role of boronic acids in accelerating condensation reactions of [small alpha]-effect amines with carbonyls

    OpenAIRE

    Gillingham, Dennis

    2016-01-01

    A broad palette of bioconjugation reactions are available for chemical biologists, but an area that still requires investigation is high-rate constant reactions. These are indispensable in certain applications, particularly for in vivo labelling. Appropriately positioned boronic acids accelerate normally sluggish Schiff base condensations of α-effect nucleophiles by five orders of magnitude – providing a new entry to the rare set of reactions that have a rate constant above 100 M−1 s−1 under ...

  10. Search for enhancements due to pion condensation precursors in (p,p') reactions on 12C

    International Nuclear Information System (INIS)

    Escudie, J.; Austin, S.M.; Boudard, A.; Bruge, G.; Chaumeaux, A.; Farvacque, L.; Legrand, D.; Lugol, J.C.; Mayer, B.; Belery, P.; Debevec, P.T.; Delbar, T.; Deutsch, J.; Gregoire, G.; Prieels, R.; Cameron, J.M.; Glashausser, C.; Whitten, C.A.

    1981-01-01

    Cross sections for the 12 C(p,p') reaction leading to the 1 + states at 15.1 MeV(T = 1) and 12.7 MeV(T = 0) were measured at a bombarding energy of 402 MeV. These data, covering a range of momentum transfer q from 0.45 to 2.65 fm -1 (0.6 --3.7m/sub π/) provide a test of the effects, precursor to a pion condensate, predicted to be important for the T = 1 state near q = 2--3m/sub π/. The cross sections for the two 1 + states are very similar fro large q, perhaps indicating that the precursor effects are small

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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.

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

    Science.gov (United States)

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

    2013-12-01

    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.

  13. Modeling reaction histories to study chemical pathways in condensed phase detonation

    International Nuclear Information System (INIS)

    Scott Stewart, D.; Hernández, Alberto; Lee, Kibaek

    2016-01-01

    The estimation of pressure and temperature histories, which are required to understand chemical pathways in condensed phase explosives during detonation, is discussed. We argue that estimates made from continuum models, calibrated by macroscopic experiments, are essential to inform modern, atomistic-based reactive chemistry simulations at detonation pressures and temperatures. We present easy to implement methods for general equation of state and arbitrarily complex chemical reaction schemes that can be used to compute reactive flow histories for the constant volume, the energy process, and the expansion process on the Rayleigh line of a steady Chapman-Jouguet detonation. A brief review of state-of-the-art of two-component reactive flow models is given that highlights the Ignition and Growth model of Lee and Tarver [Phys. Fluids 23, 2362 (1980)] and the Wide-Ranging Equation of State model of Wescott, Stewart, and Davis [J. Appl. Phys. 98, 053514 (2005)]. We discuss evidence from experiments and reactive molecular dynamic simulations that motivate models that have several components, instead of the two that have traditionally been used to describe the results of macroscopic detonation experiments. We present simplified examples of a formulation for a hypothetical explosive that uses simple (ideal) equation of state forms and detailed comparisons. Then, we estimate pathways computed from two-component models of real explosive materials that have been calibrated with macroscopic experiments.

  14. Modeling reaction histories to study chemical pathways in condensed phase detonation

    Science.gov (United States)

    Scott Stewart, D.; Hernández, Alberto; Lee, Kibaek

    2016-03-01

    The estimation of pressure and temperature histories, which are required to understand chemical pathways in condensed phase explosives during detonation, is discussed. We argue that estimates made from continuum models, calibrated by macroscopic experiments, are essential to inform modern, atomistic-based reactive chemistry simulations at detonation pressures and temperatures. We present easy to implement methods for general equation of state and arbitrarily complex chemical reaction schemes that can be used to compute reactive flow histories for the constant volume, the energy process, and the expansion process on the Rayleigh line of a steady Chapman-Jouguet detonation. A brief review of state-of-the-art of two-component reactive flow models is given that highlights the Ignition and Growth model of Lee and Tarver [Phys. Fluids 23, 2362 (1980)] and the Wide-Ranging Equation of State model of Wescott, Stewart, and Davis [J. Appl. Phys. 98, 053514 (2005)]. We discuss evidence from experiments and reactive molecular dynamic simulations that motivate models that have several components, instead of the two that have traditionally been used to describe the results of macroscopic detonation experiments. We present simplified examples of a formulation for a hypothetical explosive that uses simple (ideal) equation of state forms and detailed comparisons. Then, we estimate pathways computed from two-component models of real explosive materials that have been calibrated with macroscopic experiments.

  15. Ethanol dehydration

    OpenAIRE

    Ana María Uyazán; Iván Dario Gil; J L Aguilar; Gerardo Rodríguez Niño; Luis Alfonso Caicedo

    2004-01-01

    This review outlines ethanol dehydration processes and their most important characteristics. It also deals with the main operating variables and some criteria used in designing the separation scheme. A differentiation is made between processes involving liquid steam balance in separation operations and those doing it by screening the difference in molecule size. The last part presents a comparison between the three main industrial processes, stressing their stengths and weaknesses from the op...

  16. Ethanol dehydration

    Directory of Open Access Journals (Sweden)

    Ana María Uyazán

    2004-09-01

    Full Text Available This review outlines ethanol dehydration processes and their most important characteristics. It also deals with the main operating variables and some criteria used in designing the separation scheme. A differentiation is made between processes involving liquid steam balance in separation operations and those doing it by screening the difference in molecule size. The last part presents a comparison between the three main industrial processes, stressing their stengths and weaknesses from the operational, energy consumption and industrial services points of view.

  17. Photochemical reactions in dehydrated photosynthetic organisms, leaves, chloroplasts and photosystem II particles: reversible reduction of pheophytin and chlorophyll and oxidation of {beta}-carotene

    Energy Technology Data Exchange (ETDEWEB)

    Shuvalov, Vladimir A.; Heber, Ulrich

    2003-11-01

    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{sub 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 {beta}-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 {beta}-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{sup -} or Car{sup +} in close proximity to P680, the primary electron donor. Appreciable photoaccumulation of reduced pheophytin was only observed in dry leaves after Q{sub 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{sup +} with consequent recombination of

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

    International Nuclear Information System (INIS)

    Shuvalov, Vladimir A.; Heber, Ulrich

    2003-01-01

    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 β-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 β-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

  19. Amine-Functionalized Sugarcane Bagasse: A Renewable Catalyst for Efficient Continuous Flow Knoevenagel Condensation Reaction at Room Temperature.

    Science.gov (United States)

    Qiao, Yanhui; Teng, Junjiang; Wang, Shuangfei; Ma, Hao

    2017-12-24

    A biomass-based catalyst with amine groups (-NH₂), viz., amine-functionalized sugarcane bagasse (SCB-NH₂), was prepared through the amination of sugarcane bagasse (SCB) in a two-step process. The physicochemical properties of the catalyst were characterized through FT-IR, elemental analysis, XRD, TG, and SEM-EDX techniques, which confirmed the -NH₂ group was grafted onto SCB successfully. The catalytic performance of SCB-NH₂ in Knoevenagel condensation reaction was tested in the batch and continuous flow reactions. Significantly, it was found that the catalytic performance of SCB-NH₂ is better in flow system than that in batch system. Moreover, the SCB-NH₂ presented an excellent catalytic activity and stability at the high flow rate. When the flow rate is at the 1.5 mL/min, no obvious deactivation was observed and the product yield and selectivity are more than 97% and 99% after 80 h of continuous reaction time, respectively. After the recovery of solvent from the resulting solution, a white solid was obtained as a target product. As a result, the SCB-NH₂ is a promising catalyst for the synthesis of fine chemicals by Knoevenagel condensation reaction in large scale, and the modification of the renewable SCB with -NH₂ group is a potential avenue for the preparation of amine-functionalized catalytic materials in industry.

  20. Purification and Characterization of OleA from Xanthomonas campestris and Demonstration of a Non-decarboxylative Claisen Condensation Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Frias, JA; Richman, JE; Erickson, JS; Wackett, LP

    2011-03-25

    OleA catalyzes the condensation of fatty acyl groups in the first step of bacterial long-chain olefin biosynthesis, but the mechanism of the condensation reaction is controversial. In this study, OleA from Xanthomonas campestris was expressed in Escherichia coli and purified to homogeneity. The purified protein was shown to be active with fatty acyl-CoA substrates that ranged from C(8) to C(16) in length. With limiting myristoyl-CoA (C(14)), 1 mol of the free coenzyme A was released/mol of myristoyl-CoA consumed. Using [(14)C] myristoyl-CoA, the other products were identified as myristic acid, 2-myristoylmyristic acid, and 14-heptacosanone. 2-Myristoylmyristic acid was indicated to be the physiologically relevant product of OleA in several ways. First, 2-myristoylmyristic acid was the major condensed product in short incubations, but over time, it decreased with the concomitant increase of 14-heptacosanone. Second, synthetic 2-myristoylmyristic acid showed similar decarboxylation kinetics in the absence of OleA. Third, 2-myristoylmyristic acid was shown to be reactive with purified OleC and OleD to generate the olefin 14-heptacosene, a product seen in previous in vivo studies. The decarboxylation product, 14-heptacosanone, did not react with OleC and OleD to produce any demonstrable product. Substantial hydrolysis of fatty acyl-CoA substrates to the corresponding fatty acids was observed, but it is currently unclear if this occurs in vivo. In total, these data are consistent with OleA catalyzing a non-decarboxylative Claisen condensation reaction in the first step of the olefin biosynthetic pathway previously found to be present in at least 70 different bacterial strains.

  1. Condensed tannins: Reactions of model compounds with furfuryl alcohol and furfuraldehyde

    Science.gov (United States)

    L. Foo; Richard W. Hemingway

    1985-01-01

    Reaction products of phloroglucinol or catechin with furfuryl alcohol and furfuraldehyde were studied. In reactions of furfuryl alcohol with phloroglucinol, only 2-furyl-(11, 31, 51-trihydroxyphenyl) methane was obtained as product, and 53% of the phloroglucinol was recovered. Reactions of furfuryl...

  2. Intermolecular Dehydrative Coupling Reaction of Arylketones with Cyclic Alkenes Catalyzed by a Well-Defined Cationic Ruthenium-Hydride Complex: A Novel Ketone Olefination Method via Vinyl C–H Bond Activation

    Science.gov (United States)

    Yi, Chae S.; Lee, Do W.

    2010-01-01

    Summary The cationic ruthenium-hydride complex [(η6-C6H6)(PCy3)(CO)RuH]+BF4− was found to be a highly effective catalyst for the intermolecular olefination reaction of arylketones with cycloalkenes. The preliminary mechanistic analysis revealed that electrophilic ruthenium-vinyl complex is the key species for mediating both vinyl C–H bond activation and the dehydrative olefination steps of the coupling reaction. PMID:20567607

  3. Dehydration (For Teens)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Dehydration KidsHealth / For Teens / Dehydration What's in this article? ... the Doctor? Print en español Deshidratación What Is Dehydration? Dehydration is when someone loses more fluids than ...

  4. 4-metalated condensed pyrimidines: their preparation and reaction with aldehydes under Barbier-type conditions.

    Science.gov (United States)

    Therkelsen, Frans D; Rottländer, Mario; Thorup, Niels; Pedersen, Erik Bjerregaard

    2004-06-10

    [reaction: see text] The organometallic intermediate obtained from halogen-metal exchanges of 4-iodo-6-phenylthieno[2,3-d]pyrimidine under Barbier-type conditions was reacted with aldehydes to form the corresponding alcohols in moderate yields. The reaction involving an organolithium intermediate proceeded only at low temperature, whereas the reaction involving a magnesium ate intermediate also proceeded at room temperature. A crystal structure confirms that the expected constitutional alcohol isomer is formed, where no migration has taken place. The conditions were also suitable for 9-benzyl-6-iodopurine.

  5. Bifunctional nanocrystalline MgO for chiral epoxy ketones via Claisen-Schmidt condensation-asymmetric epoxidation reactions.

    Science.gov (United States)

    Choudary, Boyapati M; Kantam, Mannepalli L; Ranganath, Kalluri V S; Mahendar, Koosam; Sreedhar, Bojja

    2004-03-24

    Design and development of a truly nanobifunctional heterogeneous catalyst for the Claisen-Schmidt condensation (CSC) of benzaldehydes with acetophenones to yield chalcones quantitatively followed by asymmetric epoxidation (AE) to afford chiral epoxy ketones with moderate to good yields and impressive ee's is described. The nanomagnesium oxide (aerogel prepared) NAP-MgO was found to be superior over the NA-MgO and CM-MgO in terms of activity and enantioselectivity as applicable in these reactions. An elegant strategy for heterogenization of homogeneous catalysts is presented here to evolve single-site chiral catalysts for AE by a successful transfer of molecular chemistry to surface metal-organic chemistry with the retention of activity, selectivity/enantioselectivity. Brønsted hydroxyls are established as sole contributors for the epoxidation reaction, while they add on to the CSC, which is largely driven by Lewis basic O2-sites. Strong hydrogen-bond interactions between the surface -OH on MgO and -OH groups of diethyl tartrate are found inducing enantioselectivity in the AE reaction. Thus, the nanocrystalline NAP-MgO with its defined shape, size, and accessible OH groups allows the chemisorption of TBHP, DET, and olefin on its surface to accomplish single-site chiral catalysts to provide optimum ee's in AE reactions.

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

    Science.gov (United States)

    Weber, A. L.

    1986-01-01

    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.

  7. Reaction engineering of co-condensing (methyl)ethoxysilane mixtures: Kinetic characterization and modeling

    Energy Technology Data Exchange (ETDEWEB)

    RANKIN,STEPHEN E.; MCCORMICK,ALON V.

    2000-01-26

    Molecular homogeneity frequently plays a decisive role in the effective application of organically modified silicate copolymers. However, methods of directly characterizing copolymerization extent in siloxanes generated from mixed alkoxysilanes are not always available or convenient. The authors present an alternative tool for determining kinetic parameters for models of alkoxysilane hydrolytic copolycondensation. Rather than restricting attention to single step batch reactors, they use a semibatch reactor with varying time of injection of one component. They describe the fitting method and show that all necessary kinetic parameters can be determined from a series of ordinary {sup 29}Si NMR data in a straightforward case study: copolymerization of dimethyldiethoxy silane and trimethylethoxysilane. Under conditions providing no direct {sup 29}Si NMR signature of copolymerization, they find kinetic trends consistent with those previously reported. As further validation, the results of a new series of experiments (varying the ratio of mono-functional to difunctional monomer) are predicted by the semibatch copolymerization model and measured parameters. Based on these results, they are able to calculate the molecular homogeneity in the copolymer products investigated. Even for this relatively simple system, the optimal injection time is a complex function of residence time, but early injection of the faster-condensing monomer gives the best homogeneity at long residence times.

  8. The Role of Metal Oxides in Nanothermite Reactions: Evidence of Condensed Phase Initiation

    Science.gov (United States)

    2010-01-01

    1-5] Given the central role that nanoaluminum plays, much attention has been given to understanding the transport of aluminum with respect to its...Piekiel, S. Chowdhury, M.R. Zachariah, Time Resolved Mass Spectrometry of the Exothermic Reaction between Nanoaluminum and Metal Oxides: The Role of... Nanoaluminum and Metal Oxides: The Role of Oxygen Release, Journal of Physical Chemistry C, 114 (2010) 14269-14275. [15] R. Siriwardane, H.J. Tian, D

  9. Kinetics of photochemical reactions in condensed phases. What can be borrowed from methods of dielectric physics

    Czech Academy of Sciences Publication Activity Database

    Sworakowski, J.; Janus, K.; Nešpůrek, Stanislav

    2001-01-01

    Roč. 8, č. 3 (2001), s. 543-548 ISSN 1070-9878. [International Conference on Dielectrics and Related Phenomena /6./. Spala, 06.09.2000-10.09.2000] R&D Projects: GA AV ČR IAA1050901; GA AV ČR KSK2050602 Institutional research plan: CEZ:AV0Z4050913 Keywords : kinetics * photochromic reaction * crown-ether Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.778, year: 2001

  10. Sensitive inexpensive spectrophotometric and spectrofluorimetric analysis of ezogabine, levetiracetam and topiramate in tablet formulations using Hantzsch condensation reaction

    Science.gov (United States)

    Ibrahim, F. A.; El-Yazbi, A. F.; Wagih, M. M.; Barary, M. A.

    2017-09-01

    Two highly sensitive, simple and selective spectrophotometric and spectrofluorimetric assays have been investigated for the analysis of ezogabine, levetiracetam and topiramate in their pure and in pharmaceutical dosage forms. The suggested methods depend on the condensation of the primary amino-groups in the three drugs with acetylacetone and formaldehyde according to Hantzsch reaction yielding highly fluorescent yellow colored dihydropyridine derivatives. The reaction products of ezogabine, levetiracetam and topiramate were measured spectrophotometrically at 418, 390 and 380 nm or spectrofluorimetrically at λem/ex of 495/425 nm, 490/415 nm and 488/410 nm, respectively. Various experimental conditions have been carefully studied to maximize the reaction yield. At the optimum reaction conditions, the calibration curves were rectilinear over the concentration ranges of 8-25, 60-180 and 80-200 μg/mL spectrophotometrically and 0.02-0.2, 0.2-1.2 and 0.2-1.5 μg/mL spectrofluorimetrically for ezogabine, levetiracetam and topiramate, respectively with good correlation coefficients. The suggested methods were applied successfully for the analysis of ezogabine, levetiracetam and topiramate in their commercial tablets with high percentage recoveries and negligible interference from various excipients in pharmaceutical dosage forms. The results were statistically analyzed and showed the absence of any significant difference between both developed and published methods. The procedures were validated and evaluated by the ICH guidelines revealing good reproducibility and accuracy. Therefore, the two proposed methods may be considered of high interest for practical and reliable analysis of ezogabine, levetiracetam and topiramate in pharmaceutical dosage forms.

  11. Dehydration and Rehydration

    Science.gov (United States)

    2012-01-01

    causes “salt depletion dehydration .” Dehydration increases physiological strain as measured by core temperature, heart rate, and perceived exertion...increase daily urine output or cause dehydration .10 Maughan et al.111 performed a review of literature concerning the effect of caffeine ingestion on...PR, et al: Dehydration markedly impairs cardiovascular function in hyperthermic endur- ance athletes during exercise, J Appl Physiol 82:1229-1236

  12. Sports Dehydration Safety Tips

    Science.gov (United States)

    Sports Dehydration Safety Tips Everything you need to know to keep your kids safe from dehydration when playing sports. To keep kids in top ... to stay hydrated by drinking plenty of fluids. Dehydration occurs when a body loses more water than ...

  13. Dehydration (For Parents)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Dehydration KidsHealth / For Parents / Dehydration What's in this article? ... Be Prevented? Print en español Deshidratación What Is Dehydration? We all lose some body water every day ...

  14. Thermal dehydration kinetics of phosphogypsum

    OpenAIRE

    López Gómez, Félix Antonio; Tayibi, Hanan; García-Díaz, Irene; Alguacil, Francisco José

    2015-01-01

    Phsophogypsum is a by-product from the processing phosphate rock. Before the use of it in cement industry such as setting regulator is necessary a study of dehydration reaction of phosphogypsum to avoid the false setting during the milling. The aim is to study the thermal behavior of two different phosphogypsum sources (Spain and Tunisia) under non-isothermal conditions in argon atmosphere by using Thermo-Gravimetriy, Differential Thermal Analysis (TG-DTA) and Differential Scanning Calori...

  15. Hydrous mineral dehydration around heat-generating nuclear waste in bedded salt formations.

    Science.gov (United States)

    Jordan, Amy B; Boukhalfa, Hakim; Caporuscio, Florie A; Robinson, Bruce A; Stauffer, Philip H

    2015-06-02

    Heat-generating nuclear waste disposal in bedded salt during the first two years after waste emplacement is explored using numerical simulations tied to experiments of hydrous mineral dehydration. Heating impure salt samples to temperatures of 265 °C can release over 20% by mass of hydrous minerals as water. Three steps in a series of dehydration reactions are measured (65, 110, and 265 °C), and water loss associated with each step is averaged from experimental data into a water source model. Simulations using this dehydration model are used to predict temperature, moisture, and porosity after heating by 750-W waste canisters, assuming hydrous mineral mass fractions from 0 to 10%. The formation of a three-phase heat pipe (with counter-circulation of vapor and brine) occurs as water vapor is driven away from the heat source, condenses, and flows back toward the heat source, leading to changes in porosity, permeability, temperature, saturation, and thermal conductivity of the backfill salt surrounding the waste canisters. Heat pipe formation depends on temperature, moisture availability, and mobility. In certain cases, dehydration of hydrous minerals provides sufficient extra moisture to push the system into a sustained heat pipe, where simulations neglecting this process do not.

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

    Science.gov (United States)

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

  17. Kinetic multi-layer model of gas-particle interactions in aerosols and clouds (KM-GAP): linking condensation, evaporation and chemical reactions of organics, oxidants and water

    Science.gov (United States)

    Shiraiwa, M.; Pfrang, C.; Koop, T.; Pöschl, U.

    2012-03-01

    We present a novel kinetic multi-layer model for gas-particle interactions in aerosols and clouds (KM-GAP) that treats explicitly all steps of mass transport and chemical reaction of semi-volatile species partitioning between gas phase, particle surface and particle bulk. KM-GAP is based on the PRA model framework (Pöschl-Rudich-Ammann, 2007), and it includes gas phase diffusion, reversible adsorption, surface reactions, bulk diffusion and reaction, as well as condensation, evaporation and heat transfer. The size change of atmospheric particles and the temporal evolution and spatial profile of the concentration of individual chemical species can be modeled along with gas uptake and accommodation coefficients. Depending on the complexity of the investigated system and the computational constraints, unlimited numbers of semi-volatile species, chemical reactions, and physical processes can be treated, and the model shall help to bridge gaps in the understanding and quantification of multiphase chemistry and microphysics in atmospheric aerosols and clouds. In this study we demonstrate how KM-GAP can be used to analyze, interpret and design experimental investigations of changes in particle size and chemical composition in response to condensation, evaporation, and chemical reaction. For the condensational growth of water droplets, our kinetic model results provide a direct link between laboratory observations and molecular dynamic simulations, confirming that the accommodation coefficient of water at ~270 K is close to unity (Winkler et al., 2006). Literature data on the evaporation of dioctyl phthalate as a function of particle size and time can be reproduced, and the model results suggest that changes in the experimental conditions like aerosol particle concentration and chamber geometry may influence the evaporation kinetics and can be optimized for efficient probing of specific physical effects and parameters. With regard to oxidative aging of organic aerosol

  18. Silica functionalized Cu(II) acetylacetonate Schiff base complex: An efficient catalyst for the oxidative condensation reaction of benzyl alcohol with amines

    Science.gov (United States)

    Anbarasu, G.; Malathy, M.; Karthikeyan, P.; Rajavel, R.

    2017-09-01

    Silica functionalized Cu(II) acetylacetonate Schiff base complex via the one pot reaction of silica functionalized 3-aminopropyltriethoxysilane with acetyl acetone and copper acetate has been reported. The synthesized material was well characterized by analytical techniques such as FT-IR, UV-DRS, XRD, SEM-EDX, HR-TEM, EPR, ICP-AES and BET analysis. The characterization results confirmed the grafting of Cu(II) Schiff base complex on the silica surface. The catalytic activity of synthesized silica functionalized Cu(II) acetylacetonate Schiff base complex was evaluated through the oxidative condensation reaction of benzyl alcohol to imine.

  19. One-Pot Synthesis of N-(α-Peroxy)Indole/Carbazole via Chemoselective Three-Component Condensation Reaction in Open Atmosphere

    KAUST Repository

    Wang, Xinbo

    2015-11-06

    A facile one-pot synthesis of N-(α-peroxy)indole and N-(α-peroxy)carbazole has been developed using metal-free, organo-acid-catalyzed three-component condensation reactions of indole/carbazole, aldehyde, and peroxide. Based on the reaction discovered, a new synthetic proposal for Fumitremorgin A and Verruculogen is introduced. Such a protocol could be easily handled and scaled up in an open atmosphere with a wide substrate scope, enabling the construction of a new molecule library.

  20. Study of defects in solids. I. Chemical effects related to the (n,γ) reaction and electron capture. II. dehydration of Ba(ClO3)2,H2O

    International Nuclear Information System (INIS)

    Mathieu, J.-P.

    1975-01-01

    The first part of this work concerns the Moessbauer effect study of two groups of phenomena: those related to the (n,γ) reaction and those connected with radioactive disintegration of 57 Co by electron capture. Hf compounds were chosen for the first group, and a chemical study was also devoted to the effects of the (n,γ) reaction in organic complexes of Cr(III). Nuclear recoil and thermal annealing of these compounds were investigated. For the second group an attempt was made to show the effects of the environment on the chemical state of the 57 Fe detected. In part two the Ba(ClO 3 ) 2 ,H 2 O dehydratation mechanism was examined by quadrupolar nuclear resonance. By this technique, combined with X-ray diffraction and Raman spectroscopy, the effects of dehydration on the characteristics of the quadrupolar interaction and on the crystal structure of the compound were demonstrated. A model of the dehydration process is proposed [fr

  1. Transport-induced shifts in condensate dew-point and composition in multicomponent systems with chemical reaction

    Science.gov (United States)

    Rosner, D. E.; Nagarajan, R.

    1985-01-01

    Partial heterogeneous condensation phenomena in multicomponent reacting systems are analyzed taking into consideration the chemical element transport phenomena. It is demonstrated that the dew-point surface temperature in chemically reactive systems is not a purely thermodynamic quantity, but is influenced by the multicomponent diffusion and Soret-mass diffusion phenomena. Several distinct dew-points are shown to exist in such systems and, as a result of transport constraints, the 'sharp' locus between two chemically distinct condensates is systematically moved to a difference mainstream composition.

  2. Electrolyte Concentrates Treat Dehydration

    Science.gov (United States)

    2009-01-01

    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.

  3. Permeability of gypsum samples dehydrated in air

    Science.gov (United States)

    Milsch, Harald; Priegnitz, Mike; Blöcher, Guido

    2011-09-01

    We report on changes in rock permeability induced by devolatilization reactions using gypsum as a reference analog material. Cylindrical samples of natural alabaster were dehydrated in air (dry) for up to 800 h at ambient pressure and temperatures between 378 and 423 K. Subsequently, the reaction kinetics, so induced changes in porosity, and the concurrent evolution of sample permeability were constrained. Weighing the heated samples in predefined time intervals yielded the reaction progress where the stoichiometric mass balance indicated an ultimate and complete dehydration to anhydrite regardless of temperature. Porosity showed to continuously increase with reaction progress from approximately 2% to 30%, whilst the initial bulk volume remained unchanged. Within these limits permeability significantly increased with porosity by almost three orders of magnitude from approximately 7 × 10-19 m2 to 3 × 10-16 m2. We show that - when mechanical and hydraulic feedbacks can be excluded - permeability, reaction progress, and porosity are related unequivocally.

  4. Mechanism of the self-condensation of GlcNH2

    DEFF Research Database (Denmark)

    Jia, Lingyu; Liu, Xingchen; Qiao, Yan

    2017-01-01

    A combined experimental and computational study on the imidazolium ionic liquid-promoted conversion of d-Glucosamine (GlcNH2) to deoxyfructosazine (DOF) and fructosazine (FZ) was performed. The pathways for the formation of DOF and FZ via self-condensation of GlcNH2 were investigated by in situ13C...... significant influences on the energy barriers associated with dehydration reaction. In addition, a critical role of counteranion AcO− is to facilitate dehydrogenation process, leading to the formation of hydrogen. A comparison between the two reaction channels, after the formation of intermediate...

  5. Thermal dehydration kinetics of phosphogypsum

    Directory of Open Access Journals (Sweden)

    López, F. A.

    2015-09-01

    Full Text Available Phsophogypsum is a by-product from the processing phosphate rock. Before the use of it in cement industry such as setting regulator is necessary a study of dehydration reaction of phosphogypsum to avoid the false setting during the milling. The aim is to study the thermal behavior of two different phosphogypsum sources (Spain and Tunisia under non-isothermal conditions in argon atmosphere by using Thermo-Gravimetriy, Differential Thermal Analysis (TG-DTA and Differential Scanning Calorimetry (DSC. DSC experiments were carried out at temperatures ranging from ambient to 350 °C at different heating rates. The temperatures of conversion from gypsum to hemihydrate and anhydrite states and heat of dehydration were determined. Various methods were used to analyze the DSC data for reaction kinetics determination. The activation energy and frequency factor were calculated for dehydration of phosphogypsum. Activation energy values of the main dehydration reaction of phosphogypsum were calculated to be approximately 61–118 kJ/mol.El fosfoyeso es un subproducto procedente del procesado de la roca fosfato. Una de las posibles vías de reutilización y revalorización es su uso como regulador del fraguado en la industria cementera. Debido a los posibles problemas de falso fraguado asociado a los procesos de deshidratación que tienen lugar durante la molienda del cemento, esta investigación estudió el comportamiento térmico, bajo condiciones no-isotérmicas en atmósfera de argón, de dos fosfoyesos, mediante TG-DTA y DSC. Los ensayos de DSC se realizaron hasta los 350 °C a diferentes velocidades de calentamiento. La temperatura de conversión del yeso a las formas de hemihidrato y anhidrita y el calor de hidratación fueron determinados. Las cinéticas de reacción fueron obtenidas analizando los datos de DSC mediante varios métodos. Se calculó la energía de activación y el factor de frecuencia para las reacciones de deshidratación del

  6. Kinetic multi-layer model of gas-particle interactions in aerosols and clouds (KM-GAP: linking condensation, evaporation and chemical reactions of organics, oxidants and water

    Directory of Open Access Journals (Sweden)

    M. Shiraiwa

    2012-03-01

    Full Text Available We present a novel kinetic multi-layer model for gas-particle interactions in aerosols and clouds (KM-GAP that treats explicitly all steps of mass transport and chemical reaction of semi-volatile species partitioning between gas phase, particle surface and particle bulk. KM-GAP is based on the PRA model framework (Pöschl-Rudich-Ammann, 2007, and it includes gas phase diffusion, reversible adsorption, surface reactions, bulk diffusion and reaction, as well as condensation, evaporation and heat transfer. The size change of atmospheric particles and the temporal evolution and spatial profile of the concentration of individual chemical species can be modeled along with gas uptake and accommodation coefficients. Depending on the complexity of the investigated system and the computational constraints, unlimited numbers of semi-volatile species, chemical reactions, and physical processes can be treated, and the model shall help to bridge gaps in the understanding and quantification of multiphase chemistry and microphysics in atmospheric aerosols and clouds.

    In this study we demonstrate how KM-GAP can be used to analyze, interpret and design experimental investigations of changes in particle size and chemical composition in response to condensation, evaporation, and chemical reaction. For the condensational growth of water droplets, our kinetic model results provide a direct link between laboratory observations and molecular dynamic simulations, confirming that the accommodation coefficient of water at ~270 K is close to unity (Winkler et al., 2006. Literature data on the evaporation of dioctyl phthalate as a function of particle size and time can be reproduced, and the model results suggest that changes in the experimental conditions like aerosol particle concentration and chamber geometry may influence the evaporation kinetics and can be optimized for efficient probing of specific physical effects and parameters. With regard to oxidative

  7. From cation to oxide: hydroxylation and condensation of aqueous complexes

    International Nuclear Information System (INIS)

    Jolivet, J.P.

    1997-01-01

    Hydroxylation, condensation and precipitation of metal cations in aqueous solution are briefly reviewed. Hydroxylation of aqueous complexes essentially depends on the format charge (oxidation state), the size and the pH of the medium. It is the step allowing the condensation reaction. Depending on the nature of complexes (aqua-hydroxo, oxo-hydroxo), the. mechanism of condensation is different, olation or ox-olation respectively. The first one leads to poly-cations or hydroxides more or less stable against dehydration. The second one leads to poly-anions or oxides. Oligomeric species (poly-cations, poly-anions) are form from charged monomer complexes while the formation of solid phases requires non-charged precursors. Because of their high lability, charged oligomers are never the precursors of solids phases. The main routes for the formation of solid phases from solution are studied with two important and representative elements, Al and Si. For Al 3+ ions, different methods (base addition in solution, thermo-hydrolysis, hydrothermal synthesis) are discussed in relation to the crystal structure of the solid phase obtained. For silicic species condensing by ox-olation, the role of acid or base catalysis on the morphology of gels is studied. The influence of complexing ligands on the processes and on the characteristics of solids (morphology of particles, basic salts and polymetallic oxides formation) is studied. (author)

  8. Charge-dependent non-bonded interaction methods for use in quantum mechanical modeling of condensed phase reactions

    Science.gov (United States)

    Kuechler, Erich R.

    Molecular modeling and computer simulation techniques can provide detailed insight into biochemical phenomena. This dissertation describes the development, implementation and parameterization of two methods for the accurate modeling of chemical reactions in aqueous environments, with a concerted scientific effort towards the inclusion of charge-dependent non-bonded non-electrostatic interactions into currently used computational frameworks. The first of these models, QXD, modifies interactions in a hybrid quantum mechanical/molecular (QM/MM) mechanical framework to overcome the current limitations of 'atom typing' QM atoms; an inaccurate and non-intuitive practice for chemically active species as these static atom types are dictated by the local bonding and electrostatic environment of the atoms they represent, which will change over the course of the simulation. The efficacy QXD model is demonstrated using a specific reaction parameterization (SRP) of the Austin Model 1 (AM1) Hamiltonian by simultaneously capturing the reaction barrier for chloride ion attack on methylchloride in solution and the solvation free energies of a series of compounds including the reagents of the reaction. The second, VRSCOSMO, is an implicit solvation model for use with the DFTB3/3OB Hamiltonian for biochemical reactions; allowing for accurate modeling of ionic compound solvation properties while overcoming the discontinuous nature of conventional PCM models when chemical reaction coordinates. The VRSCOSMO model is shown to accurately model the solvation properties of over 200 chemical compounds while also providing smooth, continuous reaction surfaces for a series of biologically motivated phosphoryl transesterification reactions. Both of these methods incorporate charge-dependent behavior into the non-bonded interactions variationally, allowing the 'size' of atoms to change in meaningful ways with respect to changes in local charge state, as to provide an accurate, predictive and

  9. Steam generators, turbines, and condensers. Volume six

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    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)

  10. Preparation of neuroprotective condensed 1,4-benzoxazepines by regio- and diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization reaction

    Directory of Open Access Journals (Sweden)

    László Tóth

    2014-11-01

    Full Text Available Condensed O,N-heterocycles containing tetrahydro-1,4-benzoxazepine and tetrahydroquinoline moieties were prepared by a regio- and diastereoselective domino Knoevenagel–[1,5]-hydride shift cyclization reaction of a 4-aryl-2-phenyl-1,4-benzoxazepine derivative obtained from flavanone. The relative configuration of products were determined by the correlation of 3JH,H coupling data with the geometry of major conformers accessed by DFT conformational analysis. Separated enantiomers of the products were characterized by HPLC-ECD data, which allowed their configurational assignment on the basis of TDDFT-ECD calculation of the solution conformers. Two compounds showed neuroprotective activities against hydrogen peroxide (H2O2 or β-amyloid25–35 (Aβ25–35-induced cellular injuries in human neuroblastoma SH-SY5Y cells in the range of those of positive controls.

  11. Water Condensation

    DEFF Research Database (Denmark)

    Jensen, Kasper Risgaard; Fojan, Peter; Jensen, Rasmus Lund

    2014-01-01

    The condensation of water is a phenomenon occurring in multiple situations in everyday life, e.g., when fog is formed or when dew forms on the grass or on windows. This means that this phenomenon plays an important role within the different fields of science including meteorology, building physics......, and chemistry. In this review we address condensation models and simulations with the main focus on heterogeneous condensation of water. The condensation process is, at first, described from a thermodynamic viewpoint where the nucleation step is described by the classical nucleation theory. Further, we address...

  12. Fruits and vegetables dehydration

    Science.gov (United States)

    de Ita, A.; Flores, G.; Franco, F.

    2015-01-01

    Dehydration diagrams were determined by means of Differential Thermal Analysis, DTA, and Thermo Gravimetric Analysis, TGA, curves of several simultaneous fruits and vegetables, all under the same conditions. The greater mass loss is associated with water containing in the structure of the investigated materials at low temperature. In poblano chile water is lost in a single step. The banana shows a very sharply two stages, while jicama can be observed although with a little difficulty three stages. The major mass loss occurs in the poblano chile and the lower in banana. The velocity and temperature of dehydration vary within a small range for most materials investigated, except for banana and cactus how are very different.

  13. Onion dehydration: a review

    OpenAIRE

    Mitra, Jayeeta; Shrivastava, S. L.; Rao, P. S.

    2011-01-01

    Onion (Allium cepa), a very commonly used vegetable, ranks third in the world production of major vegetables. Apart from imparting a delicious taste and flavour due to its pungency in many culinary preparations, it serves several medicinal purposes also. Processing and preservation of onion by suitable means is a major thrust area since a long time. The various kinds of treatments followed for dehydration of onion such as convective air drying, solar drying, fluidized bed drying, vacuum micro...

  14. Condensed tannins: The formation of a diarylpropanol-catechinic acid dimer from base-catalyzed reactions of (+)-catechin

    Science.gov (United States)

    Seiji Ohara; Richard W. Hemingway

    1991-01-01

    Reaction of (+ )-catechin at pH 12 and 40 DC results in the stereoselective (if not stereospecific) formation of an enolic form of 1-[6-(3',4'-dihydroxyphenyl)-7-hydroxybicyclo[3.3.1]nonane-2,4,9-trione-3-yl]-1-(3,4-dihyroxyphenyl)-3-(2,-4,6-trihydroxyphenyl)-propan-2-ol. The n.m.r. chemical shift assignments determined by a variety of two-dimensional...

  15. Experimental investigation of processes responsible for dehydration weakening and embrittlement

    Science.gov (United States)

    Hirth, G.; Okazaki, K.; Proctor, B.

    2016-12-01

    We have conducted suites of experiments designed to test the efficacy of dehydration embrittlement for inducing intermediate depth earthquakes. Deformation experiments have been conducted in a Griggs apparatus at 1 to 2 GPa on both antigorite and lawsonite gouge. To scale experimental results to natural conditions, we conducted experiments where we use temperature ramps to induce dehydration while the samples deform at a constant strain rate. The weakening rate of the samples scales with the ratio of the temperature ramp rate over the strain rate. We also conducted experiments at these conditions where the pore fluid pressure is either drained or undrained. In this poster, we will describe the following observations: (1) Experiments on antigorite demonstrate that weakening is associated with an increase in pore-fluid pressure. However, weakening is always stable even when the weakening rate is the same as the apparatus stiffness. Strain rate stepping experiments on both antigorite, and dehydrating antigorite indicate velocity strengthening behavior and no AEs are resolvable during the dehydration reaction. (2) Experiments on lawsonite show unstable weakening (i.e. stick slip behavior) at all ratios of temperature ramp rate over strain rate. Experiments within the lawsonite stability field exhibit stick-slip behavior and AEs are detected both during deformation within the lawsonite stability field and during the dehydration reaction. These results indicate that dehydration embrittlement is suppressed when the reacting phase shows velocity strengthening frictional behavior. The results of the experiments on dehydration of antigorite also suggest that embrittlement of the reaction products is suppressed by enhancement of solution-precipitation processes. This observation provides a possible explanation for why dehydration of antigorite induces embrittlement at lower confining pressures (i.e. 200 MPa), where the dehydration temperature is lower and hence the

  16. Some concepts in condensed phase chemical kinetics

    International Nuclear Information System (INIS)

    Adelman, S.A.

    1986-01-01

    Some concepts in condensed phase chemical kinetics which have emerged from a recent rigorous statistical mechanical treatment of condensed phase chemical reaction dynamics (S.A. Adelman, Adv. Chem. Phys.53:61 (1983)) are discussed in simple physical terms

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

    Science.gov (United States)

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

    2009-03-01

    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.

  18. Iron Oxide-Supported Copper Oxide Nanoparticles (Nanocat-Fe-CuO): Magnetically Recyclable Catalysts for the Synthesis of Pyrazole Derivatives, 4-Methoxyaniline, and Ullmann-type Condensation Reactions

    Science.gov (United States)

    An efficient and benign protocol is reported for the synthesis of 4-methoxyaniline, medicinally important pyrazole derivatives, and Ullmann-type condensation reaction using magnetically separable and reusable magnetite-supported copper (nanocat-Fe-CuO) nanoparticles under mild co...

  19. Steam condenser

    International Nuclear Information System (INIS)

    Masuda, Fujio

    1980-01-01

    Purpose: To enable safe steam condensation by providing steam condensation blades at the end of a pipe. Constitution: When high temperature high pressure steam flows into a vent pipe having an opening under water in a pool or an exhaust pipe or the like for a main steam eacape safety valve, non-condensable gas filled beforehand in the steam exhaust pipe is compressed, and discharged into the water in the pool. The non-condensable gas thus discharged from the steam exhaust pipe is introduced into the interior of the hollow steam condensing blades, is then suitably expanded, and thereafter exhausted from a number of exhaust holes into the water in the pool. In this manner, the non-condensable gas thus discharged is not directly introduced into the water in the pool, but is suitable expanded in the space of the steam condensing blades to suppress extreme over-compression and over-expansion of the gas so as to prevent unstable pressure vibration. (Yoshihara, H.)

  20. Dehydration in the Older Adult.

    Science.gov (United States)

    Miller, Hayley J

    2015-09-01

    Dehydration affects 20% to 30% of older adults. It has a greater negative outcome in this population than in younger adults and increases mortality, morbidity, and disability. Dehydration is often caused by water deprivation in older adults, although excess water loss may also be a cause. Traditional markers for dehydration do not take into consideration many of the physiological differences present in older adults. Clinical assessment of dehydration in older adults poses different findings, yet is not always diagnostic. Treatment of dehydration should focus on prevention and early diagnosis before it negatively effects health and gives rise to comorbidities. The current article discusses what has most thoroughly been studied; the best strategies and assessment tools for evaluation, diagnosis, and treatment of dehydration in older adults; and what needs to be researched further. [Journal of Gerontological Nursing, 41(9), 8-13.]. Copyright 2015, SLACK Incorporated.

  1. Kinetics and mechanism of the condensation of pyridoxal hydrochloride with L-tryptophan and D-tryptophan, and the chemical transformation of their products

    Science.gov (United States)

    Pishchugin, F. V.; Tuleberdiev, I. T.

    2017-10-01

    The kinetics and mechanism of interaction between pyridoxal and L-tryptophan, D-tryptophan, and their derivatives are studied. It is found that condensation reactions proceed via three kinetically distinguishable stages: (1) the rapid intraplanar addition of the NH2 groups of the amino acids to pyridoxal with the formation of amino alcohols; (2) the rotational isomerism of amino alcohol fragments with their subsequent dehydration and the formation of a Schiff base with a specific configuration; (3) the abstraction of α-hydrogen in the product of condensation of pyridoxal with L-tryptophan, or the abstraction of CO2 in the product of condensation of pyridoxal with D-tryptophan with the formation of quinoid structures, hydrolysis of which results in the preparation of pyridoxamine and keto acid or pyridoxal and tryptamine, respectively. Schiff bases resistant to further chemical transformations are formed in the reaction with tryptophan methyl ester.

  2. Formation of new stable pigments from condensation reaction between malvidin 3-glucoside and (-)-epicatechin mediated by acetaldehyde: Effect of tartaric acid concentration.

    Science.gov (United States)

    Sun, Baoshan; Barradas, Tania; Leandro, Conceição; Santos, Cláudia; Spranger, Isabel

    2008-09-15

    The objective of this work was to study the effect of tartaric acid concentration on the condensation reaction between malvidin 3-glucoside (Mv-glc) and flavanols mediated by acetaldehyde in the model solution. The model wine solutions were prepared by 12% ethanol in water (v/v) with two different l-tartaric acid concentrations (5g/l and 25g/l, respectively) and at two different pH values (3.2 and 1.7, respectively). Four new pigments were detected in model wine solutions containing Mv-glc, (-)-epicatechin and acetaldehyde. By reverse-phase HPLC-DAD, ESI-MS and MS(n) fragmentation analysis, the four new pigments were tentatively identified as four isomers of hydroxyethyl malvidin-3-glucoside-ethyl-flavanol. The decrease in the concentration of Mv-glc and (-)-epicatechin and the increase in the concentration of the new identified pigments were more pronounced at higher tartaric acid concentration. At pH 1.7, although the two well-recognized ethyl-linked Mv-glc-flavanol isomers were quantitatively the major pigmented products in the reaction solution throughout the assay period, they appeared less stable than the four new pigments. At pH 3.2, the rate of formation of ethyl-linked Mv-glc-flavanol pigments was much slower than at pH 1.7, whereas the four new pigments were quantitatively the predominant pigmented products at the latter stage of the reaction. Copyright © 2008 Elsevier Ltd. All rights reserved.

  3. Survey of quality indicators in commercial dehydrated fruits.

    Science.gov (United States)

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

    2014-05-01

    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Natural gas dehydration by desiccant materials

    Directory of Open Access Journals (Sweden)

    Hassan A.A. Farag

    2011-12-01

    Increasing water vapor concentration in inlet feed gas leads to a marked decrease in dehydration efficiency. As expected, a higher inlet flow rate of natural gas decrease dehydration efficiency. Increasing feed pressure leads to higher dehydration efficiency.

  5. Eyring parameters of dehydration processes

    International Nuclear Information System (INIS)

    Olszak-Humienik, Magdalena; Mozejko, Janina

    2003-01-01

    Thermogravimetry was used in the study of the kinetics of dehydration of MnSO 4 ·5H 2 O, CuSO 4 ·5H 2 O and 3CdSO 4 ·8H 2 O under static air atmosphere. The values of the kinetic and thermodynamic parameters for each stage of thermal dehydration were calculated from α(T) data by using the integral method, applying the Coats-Redfern approximation. The best model for all stages of dehydration is random nucleation model F1. The dependencies of enthalpy on entropy of activated complexes for different kinetic models were described. The linear relation was calculated between the Gibbs energy of activated complexes and the maximum dehydration rate temperature for analysed dehydration processes

  6. Onion dehydration: a review.

    Science.gov (United States)

    Mitra, Jayeeta; Shrivastava, S L; Rao, P S

    2012-06-01

    Onion (Allium cepa), a very commonly used vegetable, ranks third in the world production of major vegetables. Apart from imparting a delicious taste and flavour due to its pungency in many culinary preparations, it serves several medicinal purposes also. Processing and preservation of onion by suitable means is a major thrust area since a long time. The various kinds of treatments followed for dehydration of onion such as convective air drying, solar drying, fluidized bed drying, vacuum microwave drying, infrared drying and osmotic drying are reviewed here. These techniques are mainly used for preservation and value addition of onion. Several researchers have tried for decades to model the drying kinetics and quality parameters, which are also compiled here briefly.

  7. Temperature dependence on addition of urea and its related compounds on formation of neodymium condensed phosphates

    International Nuclear Information System (INIS)

    Onoda, Hiroaki; Takenaka, Atsushi; Kojima, Kazuo; Nariai, Hiroyuki

    2005-01-01

    Urea (CO(NH 2 ) 2 ) and its related compounds (biuret: NH(CONH 2 ) 2 and cyanuric acid: (CONH) 3 ) were mixed with phosphoric acid (H 3 PO 4 ) and neodymium oxide (Nd 2 O 3 ). The thermal behavior of these dried mixtures was estimated by differential thermal analyses, X-ray diffraction, and Fourier-transform infrared spectroscopy. Furthermore, specific surface area of phosphates was calculated by BET method using nitrogen adsorption. The addition of urea prevented the crystal growth of Monazite-type NdPO 4 in samples at P/Nd = 2 heated at 450 and 550 deg C, and promoted the dehydration-condensation reaction of phosphate. Urea was considered to be decomposed at 400-450 deg C in these systems. The decomposition of urea was considered to be related to the formation of neodymium dihydrogenphosphate and then this phosphate transformed to neodymium polyphosphate. The ratio of urea and phosphorus had influence on the promotion of the dehydration-condensation reaction. Thermal behavior of sample added with biuret or cyanuric acid was also investigated

  8. Temperature dependence on addition of urea and its related compounds on formation of neodymium condensed phosphates

    Energy Technology Data Exchange (ETDEWEB)

    Onoda, Hiroaki [Department of Applied Chemistry, Faculty of Science and Engineering, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, Shiga 525-8577 (Japan)]. E-mail: onoda@se.ritsumei.ac.jp; Takenaka, Atsushi [Department of Materials Science, Yonago National College of Technology, 4448, Hikona-cho, Yonago, Tottori 683-8502 (Japan); Kojima, Kazuo [Department of Applied Chemistry, Faculty of Science and Engineering, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Nariai, Hiroyuki [Department of Molecular Science, Graduate School of Science and Technology, Kobe University, 1-1, Rokkodai-cho, Nada-ku, Kobe 657-8501 (Japan)

    2005-07-01

    Urea (CO(NH{sub 2}){sub 2}) and its related compounds (biuret: NH(CONH{sub 2}){sub 2} and cyanuric acid: (CONH){sub 3}) were mixed with phosphoric acid (H{sub 3}PO{sub 4}) and neodymium oxide (Nd{sub 2}O{sub 3}). The thermal behavior of these dried mixtures was estimated by differential thermal analyses, X-ray diffraction, and Fourier-transform infrared spectroscopy. Furthermore, specific surface area of phosphates was calculated by BET method using nitrogen adsorption. The addition of urea prevented the crystal growth of Monazite-type NdPO{sub 4} in samples at P/Nd = 2 heated at 450 and 550 deg C, and promoted the dehydration-condensation reaction of phosphate. Urea was considered to be decomposed at 400-450 deg C in these systems. The decomposition of urea was considered to be related to the formation of neodymium dihydrogenphosphate and then this phosphate transformed to neodymium polyphosphate. The ratio of urea and phosphorus had influence on the promotion of the dehydration-condensation reaction. Thermal behavior of sample added with biuret or cyanuric acid was also investigated.

  9. Dehydration kinetics of boehmite in the temperature range 723–873 K

    International Nuclear Information System (INIS)

    Xu, Bingan; Smith, Peter

    2012-01-01

    Highlights: ► The dehydration of boehmite is a complex topotactic process. ► The process is chemical control with a diffusion complication as the reaction progresses. ► Al cation diffusion is the rate-limiting step. ► The reaction rates predicted by the model-free method agree well with the measured values. - Abstract: The dehydration kinetics of boehmite prepared from the hydrothermal transformation of gibbsite has been comprehensively studied to clarify the mechanism of the dehydration process using a thermogravimetric technique under both isothermal and non-isothermal conditions. Selected residues were examined by XRD, SEM, TEM and selected area electron diffraction (SAED). Results indicate that the dehydration process is a topotactic reaction which brings about γ-Al 2 O 3 with porous microstructure and poor crystallinity. The kinetic data were analysed using the model-free (isoconversional) methods. The results indicate that the activation energy of the dehydration process depends on the reaction extent, signifying the dehydration process is chemical controlled with a diffusion complication as the reaction extent increases. Prediction of the dehydration extent was accomplished using the kinetic parameter of the non-isothermal process and the isoconversional method. The predicted rate is in a reasonably good agreement with the measured values. Finally the mechanism of the dehydration process is discussed based on the auxiliary results from the physical examination of the reacted residues and the kinetic behaviour.

  10. Dehydration kinetics of boehmite in the temperature range 723-873 K

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Bingan, E-mail: bingan.xu@csiro.au [A.J. Parker Cooperative Research Centre for Integrated Hydrometallurgy Solutions, CSIRO Light Metals Flagship (Division of Process Science and Engineering), PO Box 7229, Karawara, WA 6152 (Australia); Smith, Peter [A.J. Parker Cooperative Research Centre for Integrated Hydrometallurgy Solutions, CSIRO Light Metals Flagship (Division of Process Science and Engineering), PO Box 7229, Karawara, WA 6152 (Australia)

    2012-03-10

    Highlights: Black-Right-Pointing-Pointer The dehydration of boehmite is a complex topotactic process. Black-Right-Pointing-Pointer The process is chemical control with a diffusion complication as the reaction progresses. Black-Right-Pointing-Pointer Al cation diffusion is the rate-limiting step. Black-Right-Pointing-Pointer The reaction rates predicted by the model-free method agree well with the measured values. - Abstract: The dehydration kinetics of boehmite prepared from the hydrothermal transformation of gibbsite has been comprehensively studied to clarify the mechanism of the dehydration process using a thermogravimetric technique under both isothermal and non-isothermal conditions. Selected residues were examined by XRD, SEM, TEM and selected area electron diffraction (SAED). Results indicate that the dehydration process is a topotactic reaction which brings about {gamma}-Al{sub 2}O{sub 3} with porous microstructure and poor crystallinity. The kinetic data were analysed using the model-free (isoconversional) methods. The results indicate that the activation energy of the dehydration process depends on the reaction extent, signifying the dehydration process is chemical controlled with a diffusion complication as the reaction extent increases. Prediction of the dehydration extent was accomplished using the kinetic parameter of the non-isothermal process and the isoconversional method. The predicted rate is in a reasonably good agreement with the measured values. Finally the mechanism of the dehydration process is discussed based on the auxiliary results from the physical examination of the reacted residues and the kinetic behaviour.

  11. The independent influences of heat strain and dehydration upon cognition.

    Science.gov (United States)

    van den Heuvel, Anne M J; Haberley, Benjamin J; Hoyle, David J R; Taylor, Nigel A S; Croft, Rodney J

    2017-05-01

    Many researchers have addressed the potential effects of hyperthermia and dehydration on cognition, often revealing contradictory outcomes. A possible reason for this inconsistency is that experiments may have been inadequately designed for such effects. In this study, the impact of hyperthermia, dehydration and their combination on cognition were evaluated in eight young males, after accounting for a range of experimental limitations. Passive heating and thermal clamping at two mean body temperatures (36.5, 38.5 °C) were performed under three hydration states (euhydrated, 3 and 5% dehydrated) to assess their effects on difficulty-matched working memory and visual perception tasks, and on a difficulty manipulated perceptual task. Data were analysed according to signal detection theory to isolate changes in response sensitivity, bias and speed. Neither moderate hyperthermia (P = 0.141) nor dehydration (P > 0.604) modified response sensitivity, nor did they significantly interact (P > 0.698). Therefore, the ability to distinguish correct from incorrect responses was unaffected. Nevertheless, hyperthermia, but not dehydration (P = 0.301), reduced the response bias (-0.08 versus 2.2 [normothermia]; P = 0.010) and reaction time (mean reduction 49 ms; P dehydration and their combined effects had insufficient impact to impair cognition within the memory and perceptual domains tested. Nonetheless, moderate hyperthermia elicited more liberal and rapid responses.

  12. Dehydration Kinetics of Chlorite at High Temperatures and Geophysical Implications

    Science.gov (United States)

    Shen, K.; Wang, D.; Liu, T.

    2017-12-01

    A significant amount of water is released from hydrous phases in subduction zones and the brought into the earth's interior. The resulting flux may trigger earthquakes and arc magmatism. Chlorite is one of the most important hydrous minerals with a high water content of 13.0 wt.% in the deep subduction zones, and the dehydration of chlorites are thought to be associated with many anomalies geophysical observations. To understand the nature of the geology and geophysical phenomenon, further research on the dehydration of chlorite should be carried out. Here we report the new results on dehydration kinetics of chlorite at high temperatures. We investigated the dehydration kinetics of chlorite using thermogravimetric analyses (TGA) and X-ray diffraction. The dehydration experiments were conducted with heating rates of 15, 20, 25 K/min up to 1466K. The fitted TGA data results indicate that the probable dehydroxylation mechanism of chlorite is a three-dimensional diffusion reaction with the Fick's second law. The results reveal that the dehydroxylation reaction can be divided into two stages corresponding to the hydroxyls in the two different layers: the first stage between 853 K and 973 K is related to the dehydroxylation of the interlayer hydroxide with the activation energy (Ea) of 159 kJ/ mol and pre-exponential factor (D0) value of 1.53x10-5 m2/s; the second stage between 973 K and 1093 K with an Ea value of 189 kJ/mol and D0 of 2.1x10-5 m2/s is due to the dehydroxylation of the `talc' layer. The mineral reactions and products were observed by high-temperature X-ray diffraction. There are metastable phases during reactions and product phases exhibited a topotactic relationship. The dehydroxylation reaction of chlorite is controlled by an inhomogeneous mechanism. We determine that the fluid production rates of chlorite are 2.7x10-4s-1, 4.5x10-4s-1, 7.3x10-4s-1, 1.2x10-3s-1, 1.7x10-4s-1, at 863 K, 883 K, 903 K, 923 K, 943 K for isothermal dehydration reaction. Our

  13. Emergency condensator

    International Nuclear Information System (INIS)

    Hamazaki, Ryoichi.

    1992-01-01

    The condensator of the present invention has a condensate return pipe for returning condensates formed by concentration of steams in a bundle of heat transfer tubes. A flow rate control valve is disposed to the return pipe, and the opening degree of the control valve is controlled by a valve opening degree control device which receives a reactor pressure signal under control. The valve opening degree control device outputs a control signal of 0% valve opening degree when reactor pressure is lower than the lowermost control value and outputs control signal of 100% value opening degree if it is greater than the uppermost control value. On the other hand, when it is between the lowermost value and the uppermost value, it outputs a control signal for demanding an opening degree in proportion to the difference between the reactor pressure and the lowermost control value. Since it is thus controlled, even if steams and condensaes are circulated as they are by natural convection, there is no worry that reactor pressure lowers excessively and no operator's manual handling is necessary. (T.M.)

  14. Dehydration-driven topotaxy in subduction zones

    Science.gov (United States)

    Padrón-Navarta, José Alberto; Tommasi, Andréa; Garrido, Carlos J.

    2014-05-01

    Mineral replacement reactions play a fundamental role in the chemistry and the strength of the lithosphere. When externally or internally derived fluids are present, interface-coupled dissolution-precipitation is the driving mechanism for such reactions [1]. One of the microstructural features of this process is a 3D arrangement of crystallographic axes across internal interfaces (topotaxy) between reactant and product phases. Dehydration reactions are a special case of mineral replacement reaction that generates a transient fluid-filled porosity. Among others, the dehydration serpentinite is of special relevance in subduction zones because of the amount of fluids involved (potentially up to 13 wt.%). Two topotatic relationships between olivine and antigorite (the serpentine mineral stable at high temperature and pressure) have been reported in partially hydrated mantle wedge xenoliths [2]. Therefore, if precursor antigorite serpentine has a strong crystallographic preferred orientation (CPO) its dehydration might result in prograde peridotite with a strong inherited CPO. However for predicting the importance of topotactic reactions for seismic anisotropy of subduction zones we also need to consider the crystallization orthopyroxene + chlorite in the prograde reaction and, more importantly, the fact that this dehydration reaction produces a transient porosity of ca. 20 % vol. that results in local fluctuations of strain during compaction and fluid migration. We address this issue by a microstructural comparison between the CPO developed in olivine, orthopyroxene and chlorite during high-pressure antigorite dehydration in piston cylinder experiments (at 750ºC and 20 kbar and 1000ºC and 30 kbar, 168 h) and that recorded in natural samples (Cerro del Almirez, Betic Cordillera, Spain). Experimentally developed CPOs are strong. Prograde minerals show a significant inheritance of the former antigorite foliation. Topotactic relations are dominated by (001)atg//(100)ol

  15. The dehydration of SrTeO3(H2O)--a topotactic reaction for preparation of the new metastable strontium oxotellurate(IV) phase ε-SrTeO3.

    Science.gov (United States)

    Stöger, Berthold; Weil, Matthias; Baran, Enrique J; González-Baró, Ana C; Malo, Sylvie; Rueff, Jean Michel; Petit, Sebastien; Lepetit, Marie Bernadette; Raveau, Bernard; Barrier, Nicolas

    2011-05-28

    Microcrystalline single-phase strontium oxotellurate(IV) monohydrate, SrTeO(3)(H(2)O), was obtained by microwave-assisted hydrothermal synthesis under alkaline conditions at 180 °C for 30 min. A temperature of 220 °C and longer reaction times led to single crystal growth of this material. The crystal structure of SrTeO(3)(H(2)O) was determined from single crystal X-ray diffraction data: P2(1)/c, Z = 4, a = 7.7669(5), b = 7.1739(4), c = 8.3311(5) Å, β = 107.210(1)°, V = 443.42(5) Å(3), 1403 structure factors, 63 parameters, R[F(2)>2σ(F(2))] = 0.0208, wR(F(2) all) = 0.0516, S = 1.031. SrTeO(3)(H(2)O) is isotypic with the homologous BaTeO(3)(H(2)O) and is characterised by a layered assembly parallel to (100) of edge-sharing [SrO(6)(H(2)O)] polyhedra capped on each side of the layer by trigonal-prismatic [TeO(3)] units. The cohesion of the structure is accomplished by moderate O-H···O hydrogen bonding interactions between donor water molecules and acceptor O atoms of adjacent layers. In a topochemical reaction, SrTeO(3)(H(2)O) condensates above 150 °C to the metastable phase ε-SrTeO(3) and transforms upon further heating to δ-SrTeO(3). The crystal structure of ε-SrTeO(3), the fifth known polymorph of this composition, was determined from combined electron microscopy and laboratory X-ray powder diffraction studies: P2(1)/c, Z = 4, a = 6.7759(1), b = 7.2188(1), c = 8.6773(2) Å, β = 126.4980(7)°, V = 341.20(18) Å(3), R(Fobs) = 0.0166, R(Bobs) = 0.0318, Rwp = 0.0733, Goof = 1.38. The structure of ε-SrTeO(3) shows the same basic set-up as SrTeO(3)(H(2)O), but the layered arrangement of the hydrous phase transforms into a framework structure after elimination of water. The structural studies of SrTeO(3)(H(2)O) and ε-SrTeO(3) are complemented by thermal analysis and vibrational spectroscopic measurements.

  16. May eclogite dehydration cause slab fracturation ?

    Science.gov (United States)

    Loury, Chloé; Lanari, Pierre; Rolland, Yann; Guillot, Stéphane; Ganino, Clément

    2015-04-01

    Petrological and geophysical evidences strongly indicate that fluids releases play a fundamental role in subduction zones as in subduction-related seismicity and arc magmatism. It is thus important to assess quantitatively their origin and to try to quantify the amount of such fluids. In HP metamorphism, it is well known that pressure-dependent dehydration reactions occur during the prograde path. Many geophysical models show that the variations in slab physical properties along depth could be linked to these fluid occurrences. However it remains tricky to test such models on natural sample, as it is difficult to assess or model the water content evolution in HP metamorphic rocks. This difficulty is bound to the fact that these rocks are generally heterogeneous, with zoned minerals and preservation of different paragenesis reflecting changing P-T conditions. To decipher the P-T-X(H2O) path of such heterogeneous rocks the concept of local effective bulk (LEB) composition is essential. Here we show how standardized X-ray maps can be used to constrain the scale of the equilibration volume of a garnet porphyroblast and to measure its composition. The composition of this equilibrium volume may be seen as the proportion of the rock likely to react at a given time to reach a thermodynamic equilibrium with the growing garnet. The studied sample is an eclogite coming from the carboniferous South-Tianshan suture (Central Asia) (Loury et al. in press). Compositional maps of a garnet and its surrounding matrix were obtained from standardized X-ray maps processed with the program XMapTools (Lanari et al, 2014). The initial equilibration volume was modeled using LEB compositions combined together with Gibbs free energy minimization. P-T sections were calculated for the next stages of garnet growth taking into account the fractionation of the composition at each stage of garnet growth. The modeled P-T-X(H2O) path indicates that the rock progressively dehydrates during the

  17. Evaluation and Management of Dehydration in Children.

    Science.gov (United States)

    Santillanes, Genevieve; Rose, Emily

    2018-05-01

    The article discusses the evaluation of dehydration in children and reviews the literature on physical findings of dehydration. Pediatric dehydration is a common problem in emergency departments and wide practice variation in treatment exists. Dehydration can be treated with oral, nasogastric, subcutaneous, or intravenous fluids. Although oral rehydration is underutilized in the United States, most children with dehydration can be successfully rehydrated via the oral route. Selection of oral rehydration solution and techniques for successful oral rehydration are presented. Appropriate selection and rate of administration of intravenous fluids are also discussed for isonatremic, hyponatremic, and hypernatremic dehydration. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Dehydration and hydration behavior of metal-salt-modified materials for chemical heat pumps

    International Nuclear Information System (INIS)

    Ishitobi, Hirokazu; Uruma, Keirei; Takeuchi, Masato; Ryu, Junichi; Kato, Yukitaka

    2013-01-01

    Lithium chloride (LiCl) modified magnesium hydroxide (Mg(OH) 2 ) is a potential new material for chemical heat pumps. However, there is insufficient information concerning its dehydration and hydration behavior. In this study, the dehydration and hydration reactions, corresponding to the heat storage and the heat output operations, respectively, of authentic Mg(OH) 2 and LiCl-modified Mg(OH) 2 were investigated by thermogravimetric methods and near infrared spectroscopy. The dehydration of authentic Mg(OH) 2 proceeded as a one-step reaction. In contrast, the dehydration of LiCl-modified Mg(OH) 2 occurred in two steps. The dehydration reaction rates were increased by LiCl modification of the Mg(OH) 2 surface, while the activation energy for the first-order dehydration reaction was lowered. The mechanism for the hydration reaction of magnesium oxide (MgO) was different to that for the hydration of LiCl-modified MgO. This difference was explained by the effect of the LiCl on the MgO particle surface. - Highlights: ► LiCl-modified Mg(OH) 2 is a candidate material for chemical heat pumps. ► The dehydration reaction of LiCl-modified Mg(OH) 2 is a two-step reaction. ► The dehydration reaction of Mg(OH) 2 was enhanced by LiCl modification. ► The hydration mechanisms of authentic MgO and LiCl-modified MgO were different.

  19. Dehydration: physiology, assessment, and performance effects.

    Science.gov (United States)

    Cheuvront, Samuel N; Kenefick, Robert W

    2014-01-01

    This article provides a comprehensive review of dehydration assessment and presents a unique evaluation of the dehydration and performance literature. The importance of osmolality and volume are emphasized when discussing the physiology, assessment, and performance effects of dehydration. The underappreciated physiologic distinction between a loss of hypo-osmotic body water (intracellular dehydration) and an iso-osmotic loss of body water (extracellular dehydration) is presented and argued as the single most essential aspect of dehydration assessment. The importance of diagnostic and biological variation analyses to dehydration assessment methods is reviewed and their use in gauging the true potential of any dehydration assessment method highlighted. The necessity for establishing proper baselines is discussed, as is the magnitude of dehydration required to elicit reliable and detectable osmotic or volume-mediated compensatory physiologic responses. The discussion of physiologic responses further helps inform and explain our analysis of the literature suggesting a ≥ 2% dehydration threshold for impaired endurance exercise performance mediated by volume loss. In contrast, no clear threshold or plausible mechanism(s) support the marginal, but potentially important, impairment in strength, and power observed with dehydration. Similarly, the potential for dehydration to impair cognition appears small and related primarily to distraction or discomfort. The impact of dehydration on any particular sport skill or task is therefore likely dependent upon the makeup of the task itself (e.g., endurance, strength, cognitive, and motor skill). © 2014 American Physiological Society.

  20. Condensed Matter Nuclear Science

    Science.gov (United States)

    Biberian, Jean-Paul

    2006-02-01

    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

  1. Dehydration related abdominal pain (drap)

    International Nuclear Information System (INIS)

    Shah, S.I.; Aurangzeb; Khan, I.; Bhatti, A.M.; Khan, A.A.

    2004-01-01

    Objective: To describe the frequency of dehydration as a medical cause of acute abdomen. Subjects and Methods: All the patients reporting with abdominal pain to the surgical outpatient department or the emergency department were reviewed in the study. The clinical findings in all these cases were studied along with the mode of their management and outcome. Results: Of all the patients presenting with abdominal pain, 3.3% (n=68) were suffering from dehydration related abdominal pain. They were predominantly males in a ratio of 8.7: 1, mostly in the 2nd and 3rd decades of their lives. All these cases were suffering from acute or chronic dehydration were provisionally diagnosed by general practitioners as 'acute abdomen' and referred for surgical consultation. Associated symptoms included vomiting in 42.6%, backache in 91.2%, headache in 95.6%, and pain in lower limbs in 97.1 % of the cases. 83.8% required indoor management with intravenous fluids. All the patients became asymptomatic with rehydration therapy. Conclusion: Dehydration is a possible cause of severe abdominal pain. There is a need to educate the general public about the benefits of adequate fluid intake. (author)

  2. Dehydration of (Perfluoroalkyl)tetramethylcyclopentenols

    Czech Academy of Sciences Publication Activity Database

    Čermák, Jan; Nguyen Thi, T.H.; Včelák, Jaroslav; Krupková, Alena

    2011-01-01

    Roč. 16, č. 5 (2011), s. 4031-4044 ISSN 1420-3049 R&D Projects: GA AV ČR IAA4072203; GA MŠk(CZ) LC06070 Institutional research plan: CEZ:AV0Z40720504 Keywords : dehydration * fluorous cyclopentadienes * cyclopentenols Subject RIV: CC - Organic Chemistry Impact factor: 2.386, year: 2011

  3. A small scale honey dehydrator.

    Science.gov (United States)

    Gill, R S; Hans, V S; Singh, Sukhmeet; Pal Singh, Parm; Dhaliwal, S S

    2015-10-01

    A small scale honey dehydrator has been designed, developed, and tested to reduce moisture content of honey below 17 %. Experiments have been conducted for honey dehydration by using drying air at ambient temperature, 30 and 40 °C and water at 35, 40 and 45 °C. In this dehydrator, hot water has been circulated in a water jacket around the honey container to heat honey. The heated honey has been pumped through a sieve to form honey streams through which drying air passes for moisture removal. The honey streams help in increasing the exposed surface area of honey in contact with drying air, thus resulting in faster dehydration of honey. The maximum drying rate per square meter area of honey exposed to drying air was found to be 197.0 g/h-m(2) corresponding to the drying air and water temperature of 40 and 45 °C respectively whereas it was found to be minimum (74.8 g/h-m(2)) corresponding to the drying air at ambient temperature (8-17 °C) and water at 35 °C. The energy cost of honey moisture content reduction from 25.2 to 16.4 % was Rs. 6.20 to Rs. 17.36 (US $ 0.10 to US $ 0.28 (One US $ = 62.00 Indian Rupee on February, 2014) per kilogram of honey.

  4. Effect of leaf dehydration duration and dehydration degree on PSII photochemical activity of papaya leaves.

    Science.gov (United States)

    Liu, Meijun; Zhang, Zishan; Gao, Huiyuan; Yang, Cheng; Fan, Xingli; Cheng, Dandan

    2014-09-01

    Although the effect of dehydration on photosynthetic apparatus has been widely studied, the respective effect of dehydration duration and dehydration degree was neglected. This study showed that, when leaves dehydrated in air, the PSII activities of leaves decreased with the decline of leaf relative water content (RWC). Unexpectedly, when leaves dehydrated to same RWC, the decreases in Fv/Fm, Ψo and RC/CSm were lower in leaves dehydrating at 43 °C than those at 25 °C. However, to reach the same RWC, leaves dehydrating at 43 °C experienced 1/6 of the dehydration duration for leaves dehydrating at 25 °C. To distinguish the respective effect of dehydration degree and dehydration duration on photosynthetic apparatus, we studied the PSII activities of leaves treated with different concentration of PEG solutions. Increasing dehydration degree aggravated the decline of Fv/Fm, Ψo and RC/CSm in leaves with the same dehydration duration, while prolonging the dehydration duration also exacerbated the decline of Fv/Fm, Ψo and RC/CSm in leaves with identical dehydration degree. With the same dehydration degree and duration, high temperature enhanced the decrease of Fv/Fm, Ψo and RC/CSm in the leaves. When leaves dehydrated in air, the effect of high temperature was underestimated due to reduction of dehydration duration. The results demonstrated that, dehydration degree and duration both play important roles in damage to photosynthetic apparatus. We suggest that, under combined stresses, the effects of dehydration degree and duration on plants should be considered comprehensively, otherwise, partial or incorrect results may be obtained. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  5. Illustrating the Utility of X-Ray Crystallography for Structure Elucidation through a Tandem Aldol Condensation/Diels-Alder Reaction Sequence

    Science.gov (United States)

    Hoang, Giang T.; Kubo, Tomohiro; Young, Victor G., Jr.; Kautzky, Jacob A.; Wissinger, Jane E.

    2015-01-01

    Two introductory organic chemistry laboratory experiments are described based on the Diels-Alder reaction of 2,3,4,5-tetraphenylcyclopentadienone, which is synthesized prior to or in a one-pot reaction, with styrene. Students are presented with three possible products, the "endo" and "exo" diastereomers and the decarbonylated…

  6. Towards the sustainable production of acrolein by glycerol dehydration.

    Science.gov (United States)

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

    2009-01-01

    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.

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

    Science.gov (United States)

    Israel, S.

    1981-01-01

    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.

  8. Dropwise condensation originating

    International Nuclear Information System (INIS)

    Croix, J.-M.

    1975-01-01

    Both principal modes of steam condensation (film or dropwise condensation) are surveyed. Available results are exposed as for contact angle measurements, and the heat transfer mechanisms proposed. The efficiency of the dropwise condensation mode is illustrated from the excellent results obtained in the laboratory by J.M. NIEZBORALA, using an organic compound (fluorinated disulfide) for originating the condensation [fr

  9. Isomerization and self-condensation reactions subsequent the. beta. -decay of tritiated naphthalene in the presence of liquid and gaseous benzene

    Energy Technology Data Exchange (ETDEWEB)

    Angelini, G.; Keheyan, Y.; Lilla, E.; Perez, G. (Consiglio Nazionale delle Ricerche, Rome (Italy). Ist. di Chimica Nucleare)

    1990-01-01

    Tritiated napththylium ions, generated by spontaneous {beta}-decay of (1,4-{sup 3}H) naphthalene, have been allowed to react with benzene molecules in gaseous and liquid phase. The isomeric phenylnaphthalenes and fluoranthene have been found among the reaction products. The differences between the reactivity pattern of naphthylium ion in the two phases can be explained by the different efficiency of collisional stabilization of the excited reaction intermediates. (orig.).

  10. Formaldehyde condensation products of model phenols for conifer bark tannins

    Science.gov (United States)

    Richard W. Hemingway; Gerald W. McGraw

    1978-01-01

    Gel permeation chromatography of the condensation products of phenols and formaldehyde proved effective in understanding the reactions of condensed tannins with formaldehyde. Rates of condensation of phloroglucinols, resorcinols, catechols, (+)catechins, and (-)epicatechin were examined to determine if methylol-tannins from southern pine bark could be prepared as resin...

  11. Dehydration

    Science.gov (United States)

    ... M, eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018:chap 172. Review Date 9/5/2017 Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, ...

  12. Dehydration

    Science.gov (United States)

    ... to conserve water is reduced and your thirst sense becomes less acute. These problems are compounded by chronic illnesses such as diabetes and dementia, and by the use of certain medications. Older ...

  13. The dehydration of uranyl nitrate hexahydrate

    International Nuclear Information System (INIS)

    Badalov, A.; Kamalov, D.D.; Khamidov, B.O.; Mirsaidov, I.U.; Eshbekov, N.R.

    2010-01-01

    Present article is devoted to study of dehydration process of uranyl nitrate hexahydrate. The dehydration process of uranyl nitrate hexahydrate was studied by means of tensimeter method with membrane zero-manometer. The research was carried out under equilibrium conditions. It was defined that in studied temperature ranges (300-450 K) the dehydration process of UO 2 (NO 3 ) 2 has a three stage character.

  14. Condensate treatment system

    International Nuclear Information System (INIS)

    Masumitsu, Isao; Ito, Tomoaki; Kajio, Shozo; Takayama, Toshio; Ishikawa, Yasuyuki

    1992-01-01

    Condensate treatment system is installed for purifying condensate in thermal and nuclear power stations. Once-through boilers appeared, and in order to maintain the high purity water quality of condensate, condensate desalting facilities were installed in 1962 in Japan. There are the single type using condensate desalting facility only and the combined type of condensate prefilter and condensate desalting facility. The purpose of installing condensate treatment system is to remove corrosion products and ion components generated from the structural materials of plants and to remove sea water composition if it leaks. The general steam-condensate system in thermal power plants is explained. A standard JIS B 8223 'Quality of feedwater and boiler water for boilers' is instituted. The water treatment for boilers is carried out by the treatment of makeup feed, chemical treatment in boilers and blow. In the case of once-through boilers, blow cannot be done, accordingly, very high purity water is required. Condensate prefilter, condensate desalting facility, the watching of condensate treatment system and the operation in combined water treatment are reported. Also the condensate prefilters and the condensate desalting facilities for BWR and PWR plants are described. (K.I.)

  15. Clusters: Elucidating the dynamics of ionization events and ensuing reactions in the condensed phase. Final technical report, March 1, 1991--February 28, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Castleman, A.W. Jr.

    1994-10-01

    Chemical reactions that proceed following either a photophysical or ionizing event, are directly influenced by the mechanisms of energy transfer and dissipation away from the site of absorption. Neighboring solvent or solute molecules can affect this by collisional deactivation (removal of energy), through effects in which dissociating molecules are kept in relatively close proximity for comparatively long periods of time due to the presence of the solvent, and in other ways where the solvent influences the energetics of the reaction coordinate. Research on clusters offers promise of elucidating the molecular details of these processes. The studies have focused on providing critical information on problems in radiation biology through investigations of reactions of molecules which simulate functional groups in biological systems, as they proceed following the absorption of ionizing radiation. The overall objective of the program has been to undertake basic underpinning research that contributes to a quantification of the behavior of radionuclides and pollutants associated with advanced energy activities after these materials emanate from their source and are transferred through the environment to the biota and human receptor. Some of the studies have dealt with the interaction of electromagnetic radiation with matter yielding new data that finds value in assessing photoinduced transformation of pollutants including reactions which take place on aerosol particles, as well as those of species which become transformed into aerosols as a result of their chemical and physical interactions.

  16. Synthesis of pyrazole containing α-amino acids via a highly regioselective condensation/aza-Michael reaction of β-aryl α,β-unsaturated ketones

    NARCIS (Netherlands)

    Gilfillan, Lynne; Artschwager, Raik; Harkiss, Alexander H.; Liskamp, Rob M J; Sutherland, Andrew

    2015-01-01

    A synthetic approach for the preparation of a new class of highly conjugated unnatural α-amino acids bearing a 5-arylpyrazole side-chain has been developed. Horner-Wadsworth-Emmons reaction of an aspartic acid derived β-keto phosphonate ester with a range of aromatic aldehydes gave β-aryl

  17. Low-temperature Condensation of Carbon

    Science.gov (United States)

    Krasnokutski, S. A.; Goulart, M.; Gordon, E. B.; Ritsch, A.; Jäger, C.; Rastogi, M.; Salvenmoser, W.; Henning, Th.; Scheier, P.

    2017-10-01

    Two different types of experiments were performed. In the first experiment, we studied the low-temperature condensation of vaporized graphite inside bulk liquid helium, while in the second experiment, we studied the condensation of single carbon atoms together with H2, H2O, and CO molecules inside helium nanodroplets. The condensation of vaporized graphite leads to the formation of partially graphitized carbon, which indicates high temperatures, supposedly higher than 1000°C, during condensation. Possible underlying processes responsible for the instant rise in temperature during condensation are discussed. This suggests that such processes cause the presence of partially graphitized carbon dust formed by low-temperature condensation in the diffuse interstellar medium. Alternatively, in the denser regions of the ISM, the condensation of carbon atoms together with the most abundant interstellar molecules (H2, H2O, and CO), leads to the formation of complex organic molecules (COMs) and finally organic polymers. Water molecules were found not to be involved directly in the reaction network leading to the formation of COMs. It was proposed that COMs are formed via the addition of carbon atoms to H2 and CO molecules ({{C}}+{{{H}}}2\\to {HCH},{HCH}+{CO}\\to {{OCCH}}2). Due to the involvement of molecular hydrogen, the formation of COMs by carbon addition reactions should be more efficient at high extinctions compared with the previously proposed reaction scheme with atomic hydrogen.

  18. Mobility of chemisorbed molecules and surface regeneration of active centers during dehydration of isopropanol on aluminium oxide and aluminosilicate

    International Nuclear Information System (INIS)

    Makhlis, L.A.; Vasserberg, V.Eh.

    1976-01-01

    By a differential isotope method involving 14 C the authors have investigated the surface mobility of chemisorbed molecules of isopropanol during its dehydration in an adsorption layer on aluminium oxide and aluminosilicate. The chemisorbed alcohol molecules possess marked surface mobility which plays a decisive part in the mechanism of surface regeneration of the active catalyst centers in the process of dehydration. The cessation of the reaction long before the adsorbed alcohol is completely used up is explained by the hypothesis that there is local overpopulation of the active sectors by water formed by the reaction; this hinders further surface regeneration and repetition of the elementary events of dehydration

  19. Physicochemical characteristics of osmotically dehydrated tomato ...

    African Journals Online (AJOL)

    Physicochemical characteristics of osmotically dehydrated tomato (Lycopersicon esculentum) under different common drying methods. JAV Famurewa, AO Raji. Abstract. This study investigated the effect of different common drying methods on the chemical composition of osmotically dehydrated tomato. The quality of ...

  20. Kinetics of dehydration of zirconium disulfate tetrahydrate

    International Nuclear Information System (INIS)

    Prozorovskaya, Z.N.; Erokhina, O.I.; Spitsyn, V.I.

    1977-01-01

    The dehydration process of zirconium disulphate tetrahydrate has been studied by the methods of isothermal and polythermal kinetics. The rate constants of dehydration have been determined in the temperature range from 170 to 210 deg C. The apparent energy values have been calculated under polythermal and isothermal conditions in air and under isothermal conditions in vacuum

  1. Kinetic study of dehydration of heteropolyacids

    International Nuclear Information System (INIS)

    Mokhosoev, M.V.; Khakhinov, V.V.; Tumurova, L.V.

    1988-01-01

    The thermogravimetric method has been applied to investigate the kinetics of dehydration and decomposition of heteropolyacid hydrates of molybdenum and tungsten of the 12-th series. The obtained values of kinetic parameters of dehydration processes well agree with structural representations on composition of crystal hydrates of heteropolyacids, data on IR spectroscopy and X-ray phase analysis

  2. Assessment of extracellular dehydration using saliva osmolality.

    Science.gov (United States)

    Ely, Brett R; Cheuvront, Samuel N; Kenefick, Robert W; Spitz, Marissa G; Heavens, Kristen R; Walsh, Neil P; Sawka, Michael N

    2014-01-01

    When substantial solute losses accompany body water an isotonic hypovolemia (extracellular dehydration) results. The potential for using blood or urine to assess extracellular dehydration is generally poor, but saliva is not a simple ultra-filtrate of plasma and the autonomic regulation of salivary gland function suggests the possibility that saliva osmolality (Sosm) may afford detection of extracellular dehydration via the influence of volume-mediated factors. This study aimed to evaluate the assessment of extracellular dehydration using Sosm. In addition, two common saliva collection methods and their effects on Sosm were compared. Blood, urine, and saliva samples were collected in 24 healthy volunteers during paired euhydration and dehydration trials. Furosemide administration and 12 h fluid restriction were used to produce extracellular dehydration. Expectoration and salivette collection methods were compared in a separate group of eight euhydrated volunteers. All comparisons were made using paired t-tests. The diagnostic potential of body fluids was additionally evaluated. Dehydration (3.1 ± 0.5% loss of body mass) decreased PV (-0.49 ± 0.12 L; -15.12 ± 3.94% change), but Sosm changes were marginal ( 0.05). Extracelluar dehydration was not detectable using plasma, urine, or saliva measures. Salivette and expectoration sampling methods produced similar, consistent results for Sosm, suggesting no methodological influence on Sosm.

  3. Influence of the precursors in the chemical preparation of {gamma} - Al{sub 2}O{sub 3} in reactions of alcohols dehydration; Influencia de los precursores en la preparacion quimica de {gamma} - Al{sub 2}O{sub 3} en reacciones de deshidratacion de alcoholes

    Energy Technology Data Exchange (ETDEWEB)

    Salmones, J.; Limon, M.T.; Mayagoitia, V.; Rojas, F.; Kornhauser, I.; Morales, J.; Acosta, D. [Instituto Mexicano del Petroleo, Subdireccion General de Investigacion Aplicada, Apartado Postal 14-805, 07730, Mexico D.F. (Mexico)

    1998-12-31

    A chemical method for the synthesis of alumina substrates based on a microscopic morphological control, is presented. The influence of the precursor alcohol used for the synthesis of Al(OR){sub 3} is studied too. This latter compound is the raw material to synthesize the alumina materials treated here. The effects of alcohols such as ethanol, isopropanol and ter butanol are analyzed. Results show that an early formation (i.e. at low temperature) of the porous structure is reached in the case of {gamma} -Al{sub 2}O{sub 3} synthesized from ethanol. On the other hand, pore formation for alumina obtained from isopropanol and ter butanol, occurs until appearance of the {gamma} phase (at approximately 500 Centigrade). The different alumina substrates were used as catalysts in dehydration reactions of primary, secondary and tertiary alcohols. Decreasing catalytic activity corresponds to the sequence: (R-OH){sub 3} < (R-OH){sub 2} < (R-OH) in the case of ethanol; while for isopropanol and ter butanol the sequence is: (R-OH) < (R-OH){sub 2} < (R-OH){sub 3}. These results are explained by means of a reaction mechanism which is associated with the textural properties of the catalysts. (Author)

  4. Dehydration Comes on Fast and Can Be Fatal

    Science.gov (United States)

    ... Share this! Home » Health Tips » Holiday and Seasonal Dehydration comes on fast and can be fatal During ... at a higher risk ofbecoming dehydrated. Causes of Dehydration: Excessive sweating (from heat and/or exercise) with ...

  5. In situ dehydration of yugawaralite

    DEFF Research Database (Denmark)

    Artioli, G.; Ståhl, Kenny; Cruciani, G.

    2001-01-01

    -temperature monoclinic structure [Pc, a = 6.73200(9), b = 14.0157(2), c = 10.0607(1) Angstrom, beta = 111.189(1) degrees, Z = 2, at 315 K] has the Ca cations in the channels coordinated to four framework O atoms and to four water molecules, with two of the water sites (OW1 and OW4) showing positional disorder...... of the cell parameters in the measured temperature range. This model involves a sixfold coordination of the Ca cations (five framework O atoms and one water molecule). There is no indication of significant structure changes before collapse, likely occurring when the last water molecule is expelled from...... progressively disappearing as the dehydration proceeds. The yugawaralite structure reacts to the release of water molecules with small changes in the Ca-O bond distances and minor distortions of the tetrahedral framework up to about 695 K. Above this temperature the Ca coordination falls below 7 (four framework...

  6. From Rate Measurements to Mechanistic Data for Condensed Matter Reactions: A Case Study Using the Crystallization of [Zn(OH26][ZnCl4

    Directory of Open Access Journals (Sweden)

    Berkley G. Hillis

    2016-12-01

    Full Text Available The kinetics of crystallization of the R = 3 hydrate of zinc chloride, [Zn(OH26][ZnCl4], is measured by time-resolved synchrotron x-ray diffraction, time-resolved neutron diffraction, and by differential scanning calorimetry. It is shown that analysis of the rate data using the classic Kolmogorov, Johnson, Mehl, Avrami (KJMA kinetic model affords radically different rate constants for equivalent reaction conditions. Reintroducing the amount of sample measured by each method into the kinetic model, using our recently developed modified-KJMA model (M-KJMA, it is shown that each of these diverse rate measurement techniques can give the intrinsic, material specific rate constant, the velocity of the phase boundary, vpb. These data are then compared to the velocity of the crystallization front directly measured optically. The time-resolved diffraction methods uniquely monitor the loss of the liquid reactant and formation of the crystalline product demonstrating that the crystallization of this hydrate phase proceeds through no intermediate phases. The temperature dependent vpb data are then well fit to transition zone theory to extract activation parameters. These demonstrate that the rate-limiting component to this crystallization reaction is the ordering of the waters (or protons of hydration into restricted positions of the crystalline lattice resulting in large negative entropy of activation.

  7. Condensation in insulated homes

    Energy Technology Data Exchange (ETDEWEB)

    Wiley, R A

    1978-05-28

    A research proposal on condensation in insulated homes is presented. Information is provided on: justification for condensation control; previous work and present outlook (good vapor barrier, condensation and retrofit insulation, vapor barrier decreases condensation, brick-veneer walls, condensation in stress-skin panels, air-conditioned buildings, retrofitting for conservation, study on mobile homes, high indoor relative humidity, report on various homes); and procedure (after funding has been secured). Measures are briefly described on opening walls, testing measures, and retrofitting procedures. An extensive bibliography and additional informative citations are included. (MCW)

  8. Modelling of condensation phenomena

    International Nuclear Information System (INIS)

    Jeong, Jae Jun; Chang, Won Pyo

    1996-07-01

    Condensation occurs when vapor is cooled sufficiently below the saturation temperature to induce the nucleation of droplets. Such nucleation may occur homogeneously within the vapor or heterogeneously on entrained particular matter. Heterogeneous nucleation may occur on the walls of the system, where the temperature is below the saturation temperature. There are two forms of heterogeneous condensation, drop-wise and film-wise. Another form of condensation occurs when vapor directly contacts to subcooled liquid. In nuclear power plant systems, all forms of condensation may occur during normal operation or accident conditions. In this work the modelling of condensation is surveyed, including the Nusselts' laminar film condensation theory in 1916, Rohsenow's turbulent film condensation model in 1950s, and Chen's models in 1987. Major attention is paid on the film condensation models among various research results because of its importance in engineering applications. It is found that theory, experiment, and empirical correlations for film condensation are well established, but research for drop-wise and direct-contact condensation are not sufficient yet. Condensation models in the best-estimate system codes such as RELAP5/MOD3 and CATHARE2 are also investigated. 3 tabs., 11 figs., 36 refs. (Author)

  9. Bimodal condensation silicone elastomers as dielectric elastomers

    DEFF Research Database (Denmark)

    Yu, Liyun; Madsen, Frederikke Bahrt; Skov, Anne Ladegaard

    unimodal refers to that there is one polymer only in the system. As an alternative to unimodal networks there are the bimodal networks where two polymers with significantly different molecular weights are mixed with one crosslinker. [2]Silicone rubber can be divided into condensation type and addition type...... according to the curing reaction. The advantages of condensation silicones compared to addition are the relatively low cost, the curing rate largely being independent of temperature, the excellent adhesion, and the catalyst being nontoxic. [3]In this work, a series of bimodal condensation silicone...

  10. Production of Clean Transportation Fuel Dimethylether by Dehydration of Methanol Over Nafion Catalyst

    OpenAIRE

    Varışlı, Dilek; Doğu, Timur

    2010-01-01

    Dimethylether (DME) which is a very attractive synthetic transportation fuel alternate is synthesized by the dehydration reaction of methanol over nafion as the catalyst. The objective is to test the activity of this catalyst in methanol dehydration reaction. Experiments carried out in a vapor phase flow reactor in a temperature range of 120-220oC and with a space time of 1.35 s.g/cm3 showed quite high activity of Nafion to produce DME, giving conversion values of about 0.4 at 220oC. An incre...

  11. Water-loss dehydration and aging.

    Science.gov (United States)

    Hooper, Lee; Bunn, Diane; Jimoh, Florence O; Fairweather-Tait, Susan J

    2014-01-01

    This review defines water-loss and salt-loss dehydration. For older people serum osmolality appears the most appropriate gold standard for diagnosis of water-loss dehydration, but clear signs of early dehydration have not been developed. In older adults, lower muscle mass, reduced kidney function, physical and cognitive disabilities, blunted thirst, and polypharmacy all increase dehydration risk. Cross-sectional studies suggest a water-loss dehydration prevalence of 20-30% in this population. Water-loss dehydration is associated with higher mortality, morbidity and disability in older people, but evidence is still needed that this relationship is causal. There are a variety of ways we may be able to help older people reduce their risk of dehydration by recognising that they are not drinking enough, and being helped to drink more. Strategies to increase fluid intake in residential care homes include identifying and overcoming individual and institutional barriers to drinking, such as being worried about not reaching the toilet in time, physical inability to make or to reach drinks, and reduced social drinking and drinking pleasure. Research needs are discussed, some of which will be addressed by the FP7-funded NU-AGE (New dietary strategies addressing the specific needs of elderly population for a healthy ageing in Europe) trial. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  12. Dehydration in adults and old people

    Directory of Open Access Journals (Sweden)

    Ivo Casagranda

    2007-06-01

    Full Text Available Dehydration is a decrease in total body water, reflected in altered serum sodium, osmolality and BUN elevation. There are three types of dehydration: hypertonic, hypotonic and isotonic. The common signs and symtoms of dehydration are: thirst, dry mucous membranes and skin, poor skin turgor, dry tongue with longitudinal furrows, decreased saliva, muscle weakness, weight loss of 3-5% and oliguria. The therapy is based first on fluid replacement in hypovolemic states and after on balancing the hydro-electrolyte disorders with crystalloid solutions according to the Adrogué and Madias formula.

  13. Freeze dehydration of milk using microwave energy

    International Nuclear Information System (INIS)

    Souda, K.B.; Akyel, C.; Bilgen, E.

    1989-01-01

    This paper presents the results of experimental studies on heat and mass transfer during a microwave freeze dehydration process. An experimental system and procedure was developed to freeze dry milk. A 2500-W microwave system with an appropriate wave guide was set up and instrumented, and a procedure was experimentally developed to obtain milk powder first by freezing milk and then dehydrating it at low pressure using microwave energy. An unsteady-state analysis was used to derive a one-dimensional mathematical model of the freeze dehydration process in a microwave electromagnetic field

  14. From a smokehouse to a vacuum dehydrator

    OpenAIRE

    Zlatković Branislav; Vulić Todor

    2004-01-01

    The tradition of fruit dehydration in Serbia has been long and anviable. It seems that Serbian machine-building in the area of fruit processing technology has given its greatest contribution in this field. It has been one 100 years since the smoking house of Mr Stokovic, PhD was announced to be the best and the most promising plum dehydrator at the open competition organized in Topčider by the Ministry of Agriculture. It was the first real almost continual fruit dehydrator where plums were mo...

  15. Proceedings: Condenser technology conference

    International Nuclear Information System (INIS)

    Tsou, J.L.; Mussalli, Y.G.

    1991-08-01

    Seam surface condenser and associated systems performance strongly affects availability and heat rate in nuclear and fossil power plants. Thirty-six papers presented at a 1990 conference discuss research results, industry experience, and case histories of condenser problems and solutions. This report contains papers on life extension, performance improvement, corrosion and failure analysis, fouling prevention, and recommendation for future R ampersand D. The information represents recent work on condenser problems and solutions to improve the procurement, operation, and maintenance functions of power plant personnel. Several key points follow: A nuclear and a fossil power plant report show that replacing titanium tube bundles improves condenser availability and performance. One paper reports 10 years of experience with enhanced heat transfer tubes in utility condensers. The newly developed enhanced condenser tubes could further improve condensing heat transfer. A new resistance summation method improves the accuracy of condenser performance prediction, especially for stainless steel and titanium tubed condensers. Several papers describe improved condenser fouling monitoring techniques, including a review of zebra mussel issues

  16. Anisotropic dehydration of hydrogel surfaces.

    Science.gov (United States)

    Kaklamani, Georgia; Cheneler, David; Grover, Liam M; Adams, Michael J; Anastasiadis, Spiros H; Bowen, James

    2017-12-01

    Efforts to develop tissue-engineered skin for regenerative medicine have explored natural, synthetic, and hybrid hydrogels. The creation of a bilayer material, with the stratification exhibited by native skin, is a complex problem. The mechanically robust, waterproof epidermis presents the stratum corneum at the tissue/air interface, which confers many of these protective properties. In this work, we explore the effect of high temperatures on alginate hydrogels, which are widely employed for tissue engineering due to their excellent mechanical properties and cellular compatibility. In particular, we investigate the rapid dehydration of the hydrogel surface which occurs following local exposure to heated surfaces with temperatures in the range 100-200 °C. We report the creation of a mechanically strengthened hydrogel surface, with improved puncture resistance and increased coefficient of friction, compared to an unheated surface. The use of a mechanical restraint during heating promoted differences in the rate of mass loss; the rate of temperature increase within the hydrogel, in the presence and absence of restraint, is simulated and discussed. It is hoped that the results will be of use in the development of processes suitable for preparing skin-like analogues; application areas could include wound healing and skin restoration.

  17. Condensate cleaning systems

    International Nuclear Information System (INIS)

    Yamamoto, Michiyoshi; Oosumi, Katsumi; Takashima, Yoshie; Mitani, Shinji.

    1982-01-01

    Purpose: To decrease the frequency for the backwash and regeneration operations due to the increase in the differential pressure resulted from claddings captured in a mixed floor type desalter, and decrease the amount of radioactive liquid wastes of claddings from the condensate systems by removing claddings with electromagnetic filters. Constitution: In an existent plant, a valves is disposed between a condensate pump and a mixed floor type desalter. A pipeway is branched from a condensate pipe between the condensate pipe and the valve, through which condensates are transferred by a pump to an electromagnetic filter such as of a high gradient type electromagntic filter to remove claddings, then returned to a condensate pipe between the valve and the mixed floor type desalter and, thereafter, are removed with ionic components in the mixed floor type desalter and fed to the reactor. (Yoshino, Y.)

  18. Effect of Si/Al2 Ratio on 2-butanol Dehydration over HY Zeolite Catalysts

    International Nuclear Information System (INIS)

    Jung, Euna; Choi, Hyeonhee; Jeon, Jong-Ki

    2015-01-01

    Synthesis of butenes through dehydration of 2-butanol was investigated over HY zeolite catalysts. 2-Butanol dehydration reaction was carried out in a fixed bed catalytic reactor. 2-Butanol conversion was increased with increase of Si/Al 2 ratio of HY zeolite catalysts, which can be ascribed to increase of acid strength with increase of Si/Al 2 ratio. Selectivities to 1-butene, trans-2-butene, and cis-2-butene were not greatly influenced by the change of the Si/Al 2 ratio of HY zeolite. As a result, it was advantageous to use a HY zeolite catalyst with 60 Si/Al 2 ratio for maximizing the yield of 1-butene in the dehydration of 2-butanol. The optimal reaction temperature for maximizing the yield of 1-butene was 250 .deg. C over HY (60) catalyst

  19. Diagnosing dehydration? Blend evidence with clinical observations.

    Science.gov (United States)

    Armstrong, Lawrence E; Kavouras, Stavros A; Walsh, Neil P; Roberts, William O

    2016-11-01

    The purpose of the review is to provide recommendations to improve clinical decision-making based on the strengths and weaknesses of commonly used hydration biomarkers and clinical assessment methods. There is widespread consensus regarding treatment, but not the diagnosis of dehydration. Even though it is generally accepted that a proper clinical diagnosis of dehydration can only be made biochemically rather than relying upon clinical signs and symptoms, no gold standard biochemical hydration index exists. Other than clinical biomarkers in blood (i.e., osmolality and blood urea nitrogen/creatinine) and in urine (i.e., osmolality and specific gravity), blood pressure assessment and clinical symptoms in the eye (i.e., tear production and palpitating pressure) and the mouth (i.e., thirst and mucous wetness) can provide important information for diagnosing dehydration. We conclude that clinical observations based on a combination of history, physical examination, laboratory values, and clinician experience remain the best approach to the diagnosis of dehydration.

  20. DEHYDRATION OF LOW WATER CONTENT ETHANOL

    Science.gov (United States)

    Pervaporation has emerged as an economically viable alternative technology for the dehydration of organic solvents, removal of organic compounds from water and organic/organic separations. Development of a membrane system with suitable flux and selectivity characteristics plays a...

  1. Microglassification™: a Novel Technique for Protein Dehydration

    DEFF Research Database (Denmark)

    Aniket; Gaul, David; Rickard, Deborah

    2014-01-01

    he dehydration of biologics is commonly employed to achieve solid-dose formulation and enhanced stability during long-term preservation. We have developed a novel process, MicroglassificationTM, which can rapidly and controllably dehydrate protein solutions into solid amorphous microspheres at room...... 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 MicroglassifiedTM BSA reverted to native-like conformation upon rehydration with only minor irreversible aggregation (2.7%). Results of the study establish the efficacy of the MicroglassificationTM for the successful dehydration of biologics....

  2. Pelagic sea snakes dehydrate at sea

    OpenAIRE

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

    2014-01-01

    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 sna...

  3. Dehydration processes using membranes with hydrophobic coating

    Science.gov (United States)

    Huang, Yu; Baker, Richard W; Aldajani, Tiem; Ly, Jennifer

    2013-07-30

    Processes for removing water from organic compounds, especially polar compounds such as alcohols. The processes include a membrane-based dehydration step, using a membrane that has a dioxole-based polymer selective layer or the like and a hydrophilic selective layer, and can operate even when the stream to be treated has a high water content, such as 10 wt % or more. The processes are particularly useful for dehydrating ethanol.

  4. GOHAL!: sustainable membranes for alcohol dehydration

    DEFF Research Database (Denmark)

    Boffa, Vittorio

    2017-01-01

    the pristine graphene oxide membrane. The enhanced water permeability along with the good water/ethanol selectivity makes the GO-HAL membranes promising devices for alcohol dehydration technologies. This study provides a new basis for the rational design of the future generation of GO-based membranes......Treat, H2020-MSCA-RISE-2014 (n. 64555). [1] V. Boffa et. al., Carbon-based building blocks for alcohol dehydration membranes with disorder-enhanced water permeability, Carbon, under review....

  5. The mechanism of dehydration in chromophore maturation of wild-type green fluorescent protein: A theoretical study

    Science.gov (United States)

    Ma, Yingying; Yu, Jian-Guo; Sun, Qiao; Li, Zhen; Smith, Sean C.

    2015-07-01

    An interesting aspect of the green fluorescent protein (GFP) is its autocatalytic chromophore maturation. Numerous experimental studies have indicated that dehydration is the last step in the chromophore maturation process of wild-type GFP. Based on the crystal structure of wild-type GFP, the mechanism of the reverse reaction of dehydration was investigated by using density functional theory (DFT) in this study. Our results proposed that the dehydration is exothermic. Moreover, the rate-limiting step of the mechanism is the proton on guanidinium of Arg96 transferring to the β-carbon anion of Tyr66, which is consistent with the experimental observation.

  6. Condensed phase preparation of 2,3-pentanedione

    Science.gov (United States)

    Miller, D.J.; Perry, S.M.; Fanson, P.T.; Jackson, J.E.

    1998-11-03

    A condensed phase process for the preparation of purified 2,3-pentanedione from lactic acid and an alkali metal lactate is described. The process uses elevated temperatures between about 200 to 360 C for heating a reaction mixture of lactic acid and an alkali metal lactate to produce the 2,3-pentanedione in a reaction vessel. The 2,3-pentanedione produced is vaporized from the reaction vessel and condensed with water. 5 figs.

  7. Dehydration of Glucose to 5-Hydroxymethylfurfural Using Nb-doped Tungstite

    KAUST Repository

    Yue, Chaochao

    2016-08-05

    Dehydration of glucose to 5-hydroxymethylfurfural (HMF) remains a significant problem in the context of the valorization of lignocellulosic biomass. Hydrolysis of WCl6 and NbCl5 leads to precipitation of Nb-containing tungstite (WO3H2O) at low Nb content and mixtures of tungstite and niobic acid at higher Nb content. Tungstite is a promising catalyst for the dehydration of glucose to HMF. Compared with Nb2O5, fewer by-products are formed because of the low BrOnsted acidity of the (mixed) oxides. In water, an optimum yield of HMF was obtained for Nb-W oxides with low Nb content owing to balanced Lewis and BrOnsted acidity. In THF/water, the strong Lewis acidity and weak BrOnsted acidity caused the reaction to proceed through isomerization to fructose and dehydration of fructose to a partially dehydrated intermediate, which was identified by LC-ESI-MS. The addition of HCl to the reaction mixture resulted in rapid dehydration of this intermediate to HMF. The HMF yield obtained in this way was approximately 56% for all tungstite catalysts. Density functional theory calculations show that the Lewis acid centers on the tungstite surface can isomerize glucose into fructose. Substitution of W by Nb lowers the overall activation barrier for glucose isomerization by stabilizing the deprotonated glucose adsorbate.

  8. Condensed Matter Nuclear Science

    Science.gov (United States)

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

    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

  9. Systematic text condensation

    DEFF Research Database (Denmark)

    Malterud, Kirsti

    2012-01-01

    To present background, principles, and procedures for a strategy for qualitative analysis called systematic text condensation and discuss this approach compared with related strategies.......To present background, principles, and procedures for a strategy for qualitative analysis called systematic text condensation and discuss this approach compared with related strategies....

  10. Rhenium-Catalyzed Dehydration of Nonbenzylic and Terpene Alcohols to Olefins

    NARCIS (Netherlands)

    Korstanje, T.J.; de Waard, E.F.; Jastrzebski, J.T.B.H.; Klein Gebbink, R.J.M.

    2012-01-01

    With the increasing importance of research into biomass as a feedstock for the chemical industry, new methods to reduce the oxygen content of biomass are required. Here, we present our progress in the field of the dehydration reaction, using various rhenium-based catalysts, with rhenium(VII) oxide

  11. Chromosome condensation and segmentation

    International Nuclear Information System (INIS)

    Viegas-Pequignot, E.M.

    1981-01-01

    Some aspects of chromosome condensation in mammalians -humans especially- were studied by means of cytogenetic techniques of chromosome banding. Two further approaches were adopted: a study of normal condensation as early as prophase, and an analysis of chromosome segmentation induced by physical (temperature and γ-rays) or chemical agents (base analogues, antibiotics, ...) in order to show out the factors liable to affect condensation. Here 'segmentation' means an abnormal chromosome condensation appearing systematically and being reproducible. The study of normal condensation was made possible by the development of a technique based on cell synchronization by thymidine and giving prophasic and prometaphasic cells. Besides, the possibility of inducing R-banding segmentations on these cells by BrdU (5-bromodeoxyuridine) allowed a much finer analysis of karyotypes. Another technique was developed using 5-ACR (5-azacytidine), it allowed to induce a segmentation similar to the one obtained using BrdU and identify heterochromatic areas rich in G-C bases pairs [fr

  12. Condensation in complex geometries

    International Nuclear Information System (INIS)

    Lauro, F.

    1975-01-01

    A mathematical evaluation of the condensation exchange coefficient can only succeds for well specified cases: small upright or inclined plates, horizontal tubes, small height vertical tubes. Among the main hypotheses accounted for this mathematical development in the case of the condensate, a laminar flow and uniform surface temperature are always considered. In practice certain shapes of surfaces significantly increase the heat transfer during the vapor condensation on a surface wet by the condensate. Such surfaces are rough surfaces such as the condensate is submitted to surface tension effects, negligeable for plane or large curvature surfaces, and the nature of the material may play an important role (temperature gradients). Results from tests on tubes with special shapes, performed in France or out of France, are given [fr

  13. Quartet condensation of fermions.

    Science.gov (United States)

    Talukdar, Aseem; Ma, Michael; Zhang, Fu-Chun

    2007-10-01

    We investigate quartet condensation in fermion systems with four internal states. This is the generalization of the well known BCS superconductor formed by Cooper pair (CP) condensation. Physical examples include spin-3/2 fermionic atoms, bi-layered systems with electrons and holes, quadra-layer spin polarized electron hole system, and two band electronic system. We derive the Landau Ginzberg (LG) free energy for such system in terms of the CP amplitudes. The LG free energy is found to contain attractive interactions among different types of CP's. This will allow them to form bound states of CP's called Cooper quartets (CQ). Using a variational calculation based on the Bogoliubov inequality, we find that CQ condensation may be favored over pair condensation at low temperature. We also study the pairing structures in such systems when pair condensation is preferred.

  14. Dehydration-induced instabilities at intermediate depths in subduction zones

    Science.gov (United States)

    Brantut, Nicolas; Stefanou, Ioannis; Sulem, Jean

    2017-08-01

    We formulate a model for coupled deformation and dehydration of antigorite, based on a porosity-dependent yield criterion and including shear-enhanced compaction. A pore pressure and compaction instability can develop when the net volume change associated with the reaction is negative, i.e., at intermediate depth in subduction zones. The instability criterion is derived in terms of the dependence of the yield criterion on porosity: if that dependence is strong, instabilities are more likely to occur. We also find that the instability is associated with strain localization, over characteristic length scales determined by the hydraulic diffusivity, the elasto-plastic parameters of the rock, and the reaction rate. Typical lower bounds for the localization length are of the order of 10 to 100 for antigorite dehydration and deformation at 3 GPa. The fluid pressure and deformation instability is expected to induce stress buildup in the surrounding rocks forming the subducted slab, which provides a mechanism for the nucleation and propagation of intermediate-depth earthquakes.

  15. Dehydration kinetics of talc at 1 bar

    Science.gov (United States)

    Ganguly, J.; Bose, K.

    1991-01-01

    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.

  16. Physics of condensed matter

    CERN Document Server

    Misra, Prasanta K

    2012-01-01

    Physics of Condensed Matter is designed for a two-semester graduate course on condensed matter physics for students in physics and materials science. While the book offers fundamental ideas and topic areas of condensed matter physics, it also includes many recent topics of interest on which graduate students may choose to do further research. The text can also be used as a one-semester course for advanced undergraduate majors in physics, materials science, solid state chemistry, and electrical engineering, because it offers a breadth of topics applicable to these majors. The book be

  17. Ethylene Formation by Catalytic Dehydration of Ethanol with Industrial Considerations

    Directory of Open Access Journals (Sweden)

    Ho-Shing Wu

    2012-12-01

    Full Text Available Ethylene is the primary component in most plastics, making it economically valuable. It is produced primarily by steam-cracking of hydrocarbons, but can alternatively be produced by the dehydration of ethanol, which can be produced from fermentation processes using renewable substrates such as glucose, starch and others. Due to rising oil prices, researchers now look at alternative reactions to produce green ethylene, but the process is far from being as economically competitive as using fossil fuels. Many studies have investigated catalysts and new reaction engineering technologies to increase ethylene yield and to lower reaction temperature, in an effort to make the reaction applicable in industry and most cost-efficient. This paper presents various lab synthesized catalysts, reaction conditions, and reactor technologies that achieved high ethylene yield at reasonable reaction temperatures, and evaluates their practicality in industrial application in comparison with steam-cracking plants. The most promising were found to be a nanoscale catalyst HZSM-5 with 99.7% ethylene selectivity at 240 °C and 630 h lifespan, using a microreactor technology with mechanical vapor recompression, and algae-produced ethanol to make ethylene.

  18. Geothermal demonstration: Zunil food dehydration facility

    Energy Technology Data Exchange (ETDEWEB)

    Maldonado, O. (Consultecnia, Guatemala City (Guatemala)); Altseimer, J.; Thayer, G.R. (Los Alamos National Lab., NM (United States)); Cooper, L. (Energy Associates International, Albuquerque, NM (United States)); Caicedo, A. (Unidad de Desarrollo Geotermico, Guatemala City (Guatemala). Inst. Nacional de Electrificacion)

    1991-08-01

    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 able to use geothermal energy, a temporary diesel-fueled boiler provided the energy to test dehydration on seven other crops available in this area. The system demonstrates that geothermal heat can be used successfully for dehydrating food products. Many other industrial applications of geothermal energy could be considered for Zunil since a considerable amount of moderate-temperature heat will become available when the planned geothermal electrical facility is constructed there. 6 refs., 15 figs., 7 tabs.

  19. Methods for Converter Sludge Dehydration Intensification

    Science.gov (United States)

    Vakhromeev, M. I.; Moreva, Y. A.; Starkova, L. G.

    2017-11-01

    The article considers the intensification methods for converter sludge dehydration exemplified by the sludges of the Oxygen Converter Workshop (OCW) of the Open Joint-Stock Company “Magnitogorsk Iron and Steel Works” (MMK, OJSC), one of the largest metallurgical companies in the Southern Urals. Converter sludges can contain up to 45-70% of ferrum [21] which is interesting in terms of their use as an addition to a sinter-feed mixture. Sludge intensifies the sintering process. It positively influences pelletizing and fusion mixture melting dynamics at sintering. Over the period of the converter sludge dehydration complex operation at the OCW, MMK, OJSC, it was revealed that processing results in obtaining of high humidity sludge. It causes sludge freezing during the winter period, thus, its transportation involves extra costs for sludge warming up. To resolve the above-mentioned problem, the following works were performed in 2016: - experimental studies of how the application of the low-molecular anionic flocculate “SEURVEY” FL-3 influences sludge humidity reduction. - experimental studies of how the filtering press process operation parameters influence sludge humidity reduction. The new flocculate application didn't lower the dehydrated sludge humidity (the objective was the humidity of not more than 15%). Basing upon the conducted research results, we can make a conclusion that putting into operation the sewage water reactant treatment technology with the use of “SEURVEY”, FL-3 (H-10) is not recommended. The research of the influence the filtering press process parameters have on the dehydration process intensification demonstrated that reaching of the obtained residue humidity value lower than 15% is possible under the reduction of the filtering press chamber depths to 30 mm and with the application of additional operation “Residue drying” with compressed air. This way of the sludge dehydration problem resolving at filtering presses of the

  20. Condensation in Microchannels

    National Research Council Canada - National Science Library

    Ameel, Timothy

    1999-01-01

    .... Evaporators and condensers for meso-scale energy systems will most likely be constructed of microchannels due to the microfabrication constraints that limit most structures to two-dimensional planar geometries...

  1. Coseismic Dehydration and Amorphisation of Serpentinite in a Creeping Shear Zone

    Science.gov (United States)

    Tarling, M.; Smith, S. A. F.; Viti, C.; Rooney, J. S.; Gordon, K. C.

    2017-12-01

    Recent experiments show that coseismic heating in serpentinite-bearing faults can produce dehydration assemblages consisting of olivine + enstatite or talc, as well as amorphous material and melt. Identification of these coseismic products has not been made in natural serpentinite shear zones, possibly because the reaction products would be quickly altered or rehydrated to form serpentine. Magnetite-coated slip surfaces within the serpentinite mélange of the Livingstone Fault, New Zealand, contain microstructural and mineralogical evidence for coseismic dehydration and amorphization of serpentine due to frictional heating. The bulk serpentinite mélange has a scaly fabric that contains abundant evidence for pressure-solution creep. These fabrics are crosscut by multi-layered, magnetite-coated slip surfaces up to 1.5 mm thick that enclose numerous thin (products (nanocrystalline olivine, enstatite, amorphous silica) are restricted to a zone 500 um from the main slip surface, no products of dehydration or amorphisation are identifiable. Encapsulated within the magnetite layers and protected from subsequent hydration, the thin selvages of serpentinite provide the first evidence of highly localised dehydration and amorphisation of serpentinite in a natural shear zone. Interpreted in the context of recent experiments, our results suggest that 1) the slip surfaces experienced extreme dynamic weakening associated with coseismic dehydration and amorphisation and, 2) localized rupture and coseismic slip can propagate through serpentinite mélange deforming by bulk pressure-solution creep.

  2. Effect of enzyme dehydration on alcalase-catalyzed dipeptide synthesis in near-anhydrous organic media.

    Science.gov (United States)

    Vossenberg, Petra; Beeftink, Rik; Stuart, Martien Cohen; Tramper, Hans

    2013-01-01

    The effect of enzyme dehydration by molecular sieves on the coupling of phenylalanine amide and the carbamoylmethyl ester of N-protected phenylalanine in near-anhydrous tetrahydrofuran was investigated. This coupling was catalyzed by Alcalase covalently immobilized onto macroporous acrylic beads (Cov); these immobilized enzymes were hydrated prior to use. The dehydration kinetics of Cov by molecular sieve powder were determined by incubating Cov with different amounts of molecular sieve powder for different periods of time (0-80 h). Subsequently, the remaining coupling activity of Cov was measured. Dehydration-induced inactivation of Cov by molecular sieve powder was found to occur in three phases: (1) an initial, rapid, major dehydration-induced inactivation that takes place during the first activity measurement, (2) a phase of first-order inactivation, and (3) a plateau phase in activity. These dehydration kinetics were incorporated into a previously found reaction kinetics model. The resulting model was then used to fit progress curve data of the coupling in the presence of different amounts of molecular sieve powder. Upon establishment of parameter values, the model was used to predict independent data sets and found to work well. © 2013 American Institute of Chemical Engineers.

  3. Metal organic framework MIL-101 (Cr) for dehydration reactions

    Indian Academy of Sciences (India)

    Porous chromium terephthalate MIL-101 (Cr-MIL-101) has been prepared by direct method under hydrothermal conditions and characterized using X-ray diffraction, N2 sorption, TGA and FT-IR. The nitrogen adsorption-desorption isotherm shows that the Cr-MIL-101 possesses BET specific surface area of 2563 m2/g.

  4. Metal organic framework MIL-101(Cr) for dehydration reactions

    Indian Academy of Sciences (India)

    aration, catalysis and drug delivery.1 MOFs possess unique two or three dimensional structures formed by the self-assembly of metal ions or metal clusters. (the connectors) are bridged with polytopic organic ligands as linkers, which allows the design of spe- cific nanometer-scale framework geometries with pore structures.

  5. Metal organic framework MIL-101(Cr) for dehydration reactions

    Indian Academy of Sciences (India)

    Porous chromium terephthalate MIL-101 (Cr-MIL-101) has been prepared by direct method under hydrothermal conditions and characterized using X-ray diffraction, N2 sorption, TGA and FT-IR. The nitrogen adsorption-desorption isotherm shows that the Cr-MIL-101 possesses BET specific surface area of 2563 m2/g.

  6. Degradation and contamination of perfluorinated sulfonic acid membrane due to swelling-dehydration cycles

    DEFF Research Database (Denmark)

    Andersen, Shuang Ma; Morgen, Per; Skou, Eivind Morten

    Formation of sulfonic anhydride S-O-S (from the condensation of sulfonic acids) was known one of the important degradation mechanisms [i] for Nafion membrane under hydrothermal aging condition, which is especially critical for hydrogen fuel cells. Similar mechanism would also have be desirable...... to the membrane degradation in direct methanol fuel cells (DMFCs), where liquid water has direct contact with the electrolyte. An ex-situ experiment was established with swelling-dehydration cycles on the membrane. However, formation of sulfonic anhydride was not detected during the entire treatment; instead...

  7. Gold( i )-catalysed dehydrative formation of ethers from benzylic alcohols and phenols

    KAUST Repository

    Veenboer, Richard M. P.

    2015-01-01

    © The Royal Society of Chemistry 2015. We report the cross-dehydrative reaction of two alcohols to form unsymmetrical ethers using NHC-gold(i) complexes (NHC = N-heterocyclic carbene). Our progress in developing this reaction into a straightforward procedure is discussed in detail. The optimised methodology proceeds under mild reaction conditions and produces water as the sole by-product. The synthetic utility of this environmentally benign methodology is exemplified by the formation of a range of new ethers from readily available phenols bearing electron withdrawing substituents and secondary benzylic alcohols with various substituents. Finally, we present experimental results to account for the chemoselectivity obtained in these reactions.

  8. Drinks to Prevent Dehydration in a Vomiting Child

    Science.gov (United States)

    ... Text Size Email Print Share Drinks to Prevent Dehydration in a Vomiting Child Page Content Article Body ... children, the main risk is water loss, or dehydration , especially if fever causes them to sweat more ...

  9. DEHYDRATION IN CHILDREN WITH ACUTE DIARRHEA

    Directory of Open Access Journals (Sweden)

    S. V. Khaliullina

    2014-01-01

    Full Text Available The article is focused on the main issues of the regulation of water-electrolyte metabolism in children, possible variants of its disorder in acute diarrhoeal diseases. The clinical features of dehydration depending on the severity and qualitative component of losses are described, recommendations on laboratory diagnosis and treatment are provided. 

  10. Pelagic sea snakes dehydrate at sea.

    Science.gov (United States)

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

    2014-05-07

    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.

  11. Fluid Bed Dehydration of Magnesium Chloride

    Science.gov (United States)

    Adham, K.; Lee, C.; O'Keefe, K.

    Molten salt electrolysis of MgCl2 is commonly used for the production of magnesium metal. However, the electrolysis feed must be completely dry with minimum oxygen content. Therefore, complete dehydration of the MgCl2 brine or the hydrated prill is a required process, which is very challenging because of the ease of thermal degradation due to hydrolysis of magnesium chloride.

  12. Dehydrated rare earth halides and production process

    International Nuclear Information System (INIS)

    Picard, F.

    1990-01-01

    Rare earth chlorides, bromides or iodides containing less than 1 wt% water and less than 3 wt% oxyhalide are dehydrated by a gas flow of hydrogen halide through the halide bed. Structural water can interfer in some applications for instance metal preparation by chemical or electrochemical reduction [fr

  13. Chronic dehydration affects hydroelectrolytic equilibrium and ...

    African Journals Online (AJOL)

    Shortage of water supply is the most stressful condition that can meet man and animals. Since the adrenal gland plays a pivotal role in the stress response, the objective of this work is to study, in the male Wistar rat, the repercussions of chronic dehydration on adrenal gland structure compared to that of a desert rodent: ...

  14. Dehydration transformation in Ca-montmorillonite

    Indian Academy of Sciences (India)

    Unknown

    pore pressure in rock, affects rock strength and con- tributes to sub-surface fluid migration (Wu et al 1997) and diagenetic process (Ransom and Helgeson 1995). In addition, dehydration of smectites may also be important in predicting their behaviour while they are being trans- ported down subduction zones at continental ...

  15. chronic dehydration affects hydroelectrolytic equilibrium and adrenal

    African Journals Online (AJOL)

    A. Dekar-Madoui

    2017-05-01

    May 1, 2017 ... ABSTRACT. Shortage of water supply is the most stressful condition that can meet man and animals. Since the adrenal gland plays a pivotal role in the stress response, the objective of this work is to study, in the male Wistar rat, the repercussions of chronic dehydration on adrenal gland structure compared ...

  16. Pig skin apposite dehydrated by lyophilization

    International Nuclear Information System (INIS)

    Reyes F, M.L.; Gonzalez V, C.; Flores A, M.; Peralta R, J.; Reboyo B, D.; Rodriguez U, M.D.

    2007-01-01

    Taking like base a work carried out in 2001 in the Radio sterilized Tissue Bank (BTR) in which lyophilized apposite of pig skin were obtained at laboratory scale, this work is presented that had as purpose to process pig skin to produce temporary covers of skin (apposite) dehydrated by lyophilization to commercial scale. (Author)

  17. Pelagic sea snakes dehydrate at sea

    Science.gov (United States)

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

    2014-01-01

    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

  18. Nanocrack Formation in Hematite through the Dehydration of Goethite and the Carbon Infiltration from Biotar

    Directory of Open Access Journals (Sweden)

    Yoshiaki Kashiwaya

    2010-01-01

    Full Text Available The cracks in nano-order are generated and propagated when the combined water is released during the dehydration. If the nanopore can be utilized for a reaction site, the overall reaction can be extremely accelerated. On the other hand, it is well known that woody biomass is an attractive alternative fuel for the reduction of CO2 emission. However, the process of biomass pyrolysis is disturbed by the tar which causes a clogging in gas tubing system. Hata et al. found that the tar was consumed almost 100% in the iron ore layer having nanocrack or nanopore. The nanocracks formed in hematite crystals after dehydration of goethite were about 4 nm in width, which is in excellent agreement with the result of BET measurement. When the carbon deposited from tar into the nanocracks, reduction reactions were occurred simultaneously. The deposited carbons completely infilled into the nanocracks and the void in the sample.

  19. Economic burden associated with hospital postadmission dehydration.

    Science.gov (United States)

    Pash, Elizabeth; Parikh, Niraj; Hashemi, Lobat

    2014-11-01

    Development of dehydration after hospital admission can be a measure of quality care, but evidence describing the incidence, economic burden, and outcomes of dehydration in hospitalized patients is lacking. The objective of this study was to compare costs and resource utilization of U.S. patients experiencing postadmission dehydration (PAD) with those who do not in a hospital setting. All adult inpatient discharges, excluding those with suspected dehydration present on admission (International Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM] codes for dehydration: 276.0, 276.1, 276.5), were identified from the Premier database using ICD-9-CM codes. PAD and no-PAD (NPAD) groups were matched on propensity score adjusting for demographics (age, sex, race, medical, elective patients), patient severity (All Patient Refined Diagnosis-Related Groups severity scores), and hospital characteristics (geographic location, bed size, teaching and urban hospital). Costs, length of stay (LOS), and incidence of mortality and catheter-associated urinary tract infection (CAUTI) were compared between groups using the t test for continuous variables and the χ(2) test for categorical variables. In total, 86,398 (2.1%) of all the selected patients experienced PAD. Postmatching mean total costs were significantly higher for the PAD group compared with the NPAD group ($33,945 vs $22,380; P < .0001). Departmental costs were also significantly higher for the PAD group (all P < .0001). Compared with the NPAD group, the PAD group had a higher mean LOS (12.9 vs 8.2 days), a higher incidence of CAUTI (0.6% vs 0.5%), and higher in-hospital mortality (8.6% vs 7.8%) (all P < .05). The results for subgroup analysis also showed significantly higher total cost and longer LOS days for patients with PAD (all P < .05). The economic burden associated with hospital PAD in medical and surgical patients was substantial. © 2014 American Society for Parenteral and Enteral

  20. Dehydration and rehydration of a tuff vitrophyre

    International Nuclear Information System (INIS)

    Vaniman, D.; Bish, D., Chipera, S.

    1993-01-01

    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 (∼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 ≤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

  1. Salmonella survival during thermal dehydration of fresh garlic and storage of dehydrated garlic products.

    Science.gov (United States)

    Zhang, Hongmei; Qi, Yan; Wang, Lei; Zhang, Shaokang; Deng, Xiangyu

    2017-12-18

    Salmonella survival was characterized and modeled during thermal dehydration of fresh garlic and storage of dehydrated garlic products. In our experiments that simulated commercial dehydration processing at 80±5°C, moderate level of Salmonella contamination (4-5logCFU/g) on fresh garlic was reduced below the enumeration limit (1.7logCFU/g) after 4.5h of dehydration and not detectable by culture enrichment after 7h. With high level of contamination (7-8logCFU/g), the Salmonella population persisted at 3.6logCFU/g after 8h of processing. By increasing the dehydration temperature to 90±5°C, the moderate and high levels of initial Salmonella load on fresh garlic dropped below the enumeration limit after 1.5 and 3.75h of processing and became undetectable by culture enrichment after 2.5 and 6h, respectively. During the storage of dried garlic products, Salmonella was not able to grow under all tested combinations of temperature (25 and 35°C) and water activity (0.56-0.98) levels, suggesting active inhibition. Storage temperature played a primary role in determining Salmonella survival on dehydrated garlic flakes. Under a typical storage condition at 25°C and ambient relative humidity, Salmonella could persist over months with the population gradually declining (4.3 log reduction over 88days). Granular size of dehydrated garlic had an impact on Salmonella survival, with better survival of the pathogen observed in bigger granules. At the early stage of dehydrated garlic storage (until 7days), rising water activity appeared to initially promote but then inhibited Salmonella survival, resulting in a water activity threshold at 0.73 where Salmonella displayed strongest persistence. However, this phenomenon was less apparent during extended storage (after 14days). Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Kinetics of thermal dehydration of zirconium and thorium hydroxide hydrogels

    International Nuclear Information System (INIS)

    Mitra, N.K.; Sinhamahapatra, S.

    1983-01-01

    Kinetics of thermal dehydration of synthetic zirconium and thorium hydroxide hydrogels have been studied by thermogravimetric method. Dehydration followed first order kinetics upto a certain stage. The rate constants for the initial and final stages of dehydration were related to the water content of the gels. Textural change on heat treatment also contributes to it. (author)

  3. What's the Big Sweat about Dehydration? (For Kids)

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Dehydration KidsHealth / For Kids / Dehydration Print en español ¿Por qué es tan peligroso deshidratarse? What Is Dehydration? When it's hot outside and you've been ...

  4. Reattachment of dehydrated tooth fragments: Two case reports ...

    African Journals Online (AJOL)

    Delayed reattachment may lead to unesthetic results because of the dehydration of fragments. The purpose of this study was to present 1-year follow-ups of reattachment of dehydrated fragments using dentin bondings and flowable composites in two different cases. The color of the dehydrated fragments was natural in the ...

  5. Studying of the dehydration process of uranyl nitrate hexahydrate (Unh)

    International Nuclear Information System (INIS)

    Badalov, A.; Kamalov, J.J.; Homidov, B.J.; Mirsaidov, I.U.; Eshbekov, N.R.

    2005-01-01

    By the tensimeteric method is studying the dehydration process of uranyl nitrate hexahydrate (Unh). It is shown, that the temperature interval 300-400 K in equilibrium conditions the dehydration process of Unh runs in three stages. According to the equations of dependence of saturated steam pressure from temperature, the thermodynamic characteristics of each stage of the dehydration process of Unh are calculated

  6. Comparison of gas dehydration methods based on energy ...

    African Journals Online (AJOL)

    Comparison of gas dehydration methods based on energy consumption. ... This study compares three conventional methods of natural gas (Associated Natural Gas) dehydration to carry out the dehydration process and suitability of use on the basis of energy requirement. These methods are Triethylene Glycol (TEG) ...

  7. Condensate feeding system

    International Nuclear Information System (INIS)

    Iwami, Hiroshi.

    1981-01-01

    Purpose: To control the dissolved oxygen concentration in water of a condensate feeding system to a desired level. Constitution: Coolant is fed to a nuclear reactor through a route from the steam exit of the reactor and by way of turbine, turbine condensator, condensate pump, condensate desalinator, feedwater heater and feed pump. Steam extraction lines are branched from the turbines, and pipeways are further branched from the steam extraction lines for feeding steam by way of extraction steam injection valves to steam-water mixers disposed on the upstream of the feedwater heater. On the downstream of the feedwater heater, is provided a dissolved oxygen concentration meter, the indication value of which controls the opening degree of the steam injection valves which, in turn, controls the opening degree of the steam feed valves for the feedwater heater to adjust the amount for the injection steams. Accordingly, the dissolved oxygen concentration in the water of the condensate feeding system can be controlled by the inclusion of steams with high dissolved oxygen concentration into the feedwater system from the turbine steam extraction lines by way of the mixers. (Furukawa, Y.)

  8. Mechanistic insights into aqueous phase propanol dehydration in H-ZSM-5 zeolite

    Energy Technology Data Exchange (ETDEWEB)

    Mei, Donghai [Pacific Northwest National Laboratory, Physical and Computational Sciences Directorate & Institute for Integrated Catalysis, Richland WA 99352; Lercher, Johannes A. [Pacific Northwest National Laboratory, Physical and Computational Sciences Directorate & Institute for Integrated Catalysis, Richland WA 99352; Dept. of Chemistry and Catalysis Research Institute, TU München, Lichtenbergstrasse 4 Garching 85748 Germany

    2016-10-06

    Aqueous phase dehydration of 1-propanol over H-ZSM-5 zeolite was investigated using density functional theory (DFT) calculations. The water molecules in the zeolite pores prefer to aggregate via the hydrogen bonding network and be protonated at the Brønsted acidic sites (BAS). Two typical configurations, i.e., dispersed and clustered, of water molecules were identified by ab initio molecular dynamics simulation of the mimicking aqueous phase H-ZSM-5 zeolite unit cell with 20 water molecules per unit cell. DFT calculated Gibbs free energies suggest that the dimeric propanol-propanol, the propanol-water complex, and the trimeric propanol-propanol-water are formed at high propanol concentrations, which provide a kinetically feasible dehydration reaction channel of 1-propanol to propene. However, calculation results also indicate that the propanol dehydration via the unimolecular mechanism becomes kinetically discouraged due to the enhanced stability of the protonated dimeric propanol and the protonated water cluster acting as the BAS site for alcohol dehydration reaction. This work was supported by the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences. Pacific Northwest National Laboratory (PNNL) is a multiprogram national laboratory operated for DOE by Battelle. Computing time was granted by the grand challenge of computational catalysis of the William R. Wiley Environmental Molecular Sciences Laboratory (EMSL). EMSL is a national scientific user facility located at Pacific Northwest National Laboratory (PNNL) and sponsored by DOE’s Office of Biological and Environmental Research.

  9. Dehydration of alcohols over oxide catalysts: γ-eliminations -- stereospecificity and selectivity

    International Nuclear Information System (INIS)

    Siddhan, S.; Narayanan, K.

    1979-01-01

    The effect of alkali impregnation on alumina catalysts has been investigated by a physicochemical study of pure and modified alumina catalyst samples. The stereospecificity and selectivity of dehyration reactions, as well as the incidence of γ-elimination, have been studied by passing suitable substrates over catalyst samples. There was a change in the acidity-basicity balance in the sodium-impregnated alumina samples vis a vis pure alumina, while the surface area virtually remained constant. A higher propensity for γ-elimination was noticed with increases in basicity of the catalyst. 1-Olefin formation was found to be larger in more basic alumina- and thoria-catalyzed dehydration reactions. Thoria was strikingly unique in its capacity to dehydrate only alcohols, which have at least one β-hydrogen atom. Neopentyl alcohol could not be dehydrated even under drastic conditions. The modes of elimination in the case of alumina and thoria have been shown to be anti and syn, respectively, from the results of the dehydration studies with threo-3-methyl-2-pentanol. Studies of alcohols with proper β-substituents revealed that the cis preference is not universal in all catalytic eliminations but, in fact, depends on the mode of elimination. While cis-preference was noticed in alumina-catalyzed anti eliminations, trans-olefin was formed to a major amount in thoria-catalyzed syn-elimination processes. 9 figures, 13 tables

  10. Basic Study on Sludge Concentration and Dehydration with Ultrasonic Exposure

    Science.gov (United States)

    Sawada, Yuta; Nagashima, Satoshi; Uchida, Takeyoshi; Kawashima, Norimichi; Takeuchi, Shinichi; Akita, Masashi; Nagaoka, Hiroshi

    2005-06-01

    We study the condensation of sludge and the improvement of the dehydration efficiency of sludge by acoustic cavitation for efficiency improvement and cost reduction in water treatment. An ultrasound wave was irradiated into activated sludge in the water tank of our ultrasound exposure system and a standing wave acoustic field was formed using a vibrating disk driven by a Langevin-type transducer. The vibrating disk was mounted on the bottom of the water tank. Acoustic cavitation was generated in the activated sludge suspension and the sludge was floated to the water surface by ultrasound exposure with this system. We observed B-mode ultrasound images of the activated sludge suspension before ultrasound exposure and that of the floated sludge and treated water after ultrasound exposure. The ultrasound diagnostic equipment was used for the observation of the B-mode ultrasound images of the sludge. It was found that the sludge floated to the water surface because of adhesion of microbubbles generated by acoustic cavitation to the sludge particles, which decreased the sludge density. It can be expected that the drifting sludge in water can be recovered by the flotation thickening method of sludge as an application of the results of this study. It is difficult to recover the drifting sludge in water by the conventional gravity thickening method.

  11. Muonic Chemistry in Condensed Matter

    CERN Multimedia

    2002-01-01

    When polarized muons (@m|+) stop in condensed matter, muonic atoms are formed in the final part of their range, and direct measurements of the @m|+-spin polarization are possible via the asymmetric decay into positrons. The hyperfine interaction determines the characteristic precession frequencies of the @m|+ spin in muonium, @w(Mu). Such frequencies can be altered by the interactions of the muonium's electron spin with the surrounding medium. The measurement of @w(Mu) in a condensed system is known often to provide unique information regarding the system. \\\\ \\\\ In particular, the use of muonium atoms as a light isotope of the simple reactive radical H|0 allows the investigation of fast reactions of radicals over a typical time scale 10|-|9~@$<$~t~@$<$~10|-|5~sec, which is determined by the instrumental resolution at one end and by the @m|+ lifetime at the other. \\\\ \\\\ In biological macromolecules transient radicals, such as the constituents of DNA itself, exist on a time scale of sub-microseconds, acco...

  12. Condensed matter physics

    CERN Document Server

    Isihara, A

    2007-01-01

    More than a graduate text and advanced research guide on condensed matter physics, this volume is useful to plasma physicists and polymer chemists, and their students. It emphasizes applications of statistical mechanics to a variety of systems in condensed matter physics rather than theoretical derivations of the principles of statistical mechanics and techniques. Isihara addresses a dozen different subjects in separate chapters, each designed to be directly accessible and used independently of previous chapters. Topics include simple liquids, electron systems and correlations, two-dimensional

  13. Evolution of microstructure and elastic wave velocities in dehydrated gypsum samples

    Science.gov (United States)

    Milsch, Harald; Priegnitz, Mike

    2012-12-01

    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.

  14. Characterization and Neutron Shielding Behavior of Dehydrated Magnesium Borate Minerals Synthesized via Solid-State Method

    Directory of Open Access Journals (Sweden)

    Azmi Seyhun Kipcak

    2013-01-01

    Full Text Available Magnesium borates are one of the major groups of boron minerals that have good neutron shielding performance. In this study, dehydrated magnesium borates were synthesized by solid-state method using magnesium oxide (MgO and boron oxide (B2O3, in order to test their ability of neutron shielding. After synthesizing the dehydrated magnesium borates, characterizations were done by X-ray Diffraction (XRD, fourier transform infrared (FT-IR, Raman spectroscopy, and scanning electron microscopy (SEM. Also boron oxide (B2O3 contents and reaction yields (% were calculated. XRD results showed that seven different types of dehydrated magnesium borates were synthesized. 1000°C reaction temperature, 240 minutes of reaction time, and 3 : 2, 1 : 1 mole ratios of products were selected and tested for neutron transmission. Also reaction yields were calculated between 84 and 88% for the 3 : 2 mole ratio products. The neutron transmission experiments revealed that the 3 : 2 mole ratio of MgO to B2O3 neutron transmission results (0.618–0.655 was better than the ratio of 1 : 1 (0.772–0.843.

  15. Dehydration kinetics of a natural montmorillonite

    International Nuclear Information System (INIS)

    Andreotti, G.; Loria, A.; Mazzega, E.; Valeri, S.

    1978-01-01

    The dehydration mass loss of samples of montmorillonite (a layered hydrated silicate) was measured in an environment at constant temperature and at constant undersatured water vapour content. The hydration curves were analyzed by assuming the model of thermally activated, monoenergetic and first-order process compatible with the experimental results. Two dehydration kinetics with activation energies (0.21+-0.02) eV and (0.34+-0.02) eV were found that can be related to the existence of two kinds of water (structured and nonstructured) in the hydrated silicate interlayers. The possibility of an icelike structure of a fraction of the adsorbed molecules is briefly discussed. The experimental results show, furthermore, that in the investigated hydration range (up to about 10% in mass) the fraction of structured water has a maximum when the hydration is about 6%. (author)

  16. Condensed matter physics

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    The condensed matter physics research in the Physics Department of Risoe National Laboratory is predominantly experimental utilising diffraction of neutrons and x-rays. The research topics range from studies of structure, excitations and phase transitions in model systems to studies of ion transport, texture and recrystallization kinetics with a more applied nature. (author)

  17. Modular invariant gaugino condensation

    Energy Technology Data Exchange (ETDEWEB)

    Gaillard, M.K.

    1991-05-09

    The construction of effective supergravity lagrangians for gaugino condensation is reviewed and recent results are presented that are consistent with modular invariance and yield a positive definite potential of the noscale type. Possible implications for phenomenology are briefly discussed. 29 refs.

  18. Bose-Einstein Condensation

    Indian Academy of Sciences (India)

    have quoted, London noted that at the density of liquid helium, the temperature for Bose-Einstein condensation of an ideal gas would be about three degrees above absolute zero.4 Liquid helium shows new properties below 2.1 degrees Kelvin [3]. London boldly suggested that these new properties were a consequence of ...

  19. Bose-Einstein Condensation

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 12. Bose-Einstein Condensation - Birds of a Feather Flock Together. Rajaram Nityananda. Volume 10 Issue 12 December 2005 pp 142-147. Fulltext. Click here to view fulltext PDF. Permanent link:

  20. Bose-Einstein Condensation

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 5; Issue 4. Bose–Einstein Condensation - Birds of a Feather Flock Together. Rajaram Nityananda. General Article Volume 5 Issue 4 April 2000 pp 46-51. Fulltext. Click here to view fulltext PDF. Permanent link:

  1. Bose-Einstein condensation

    Indian Academy of Sciences (India)

    Bose-Einstein Condensation. Vasant Natarajan is at the. Department of Physics,. Indian Institute of. Science. His current research involves trapping of atoms to carry out high precision tests of fundamental physics. He has earlier worked on high precision mass spectrom- etry and on the focussing of atomic beams by laser.

  2. Confinement contains condensates

    DEFF Research Database (Denmark)

    Brodsky, S. J.; Roberts, C. D.; Shrock, R.

    2012-01-01

    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 common...... evidence and incidentally expose misconceptions in a recent Comment....

  3. Condensed matter physics

    International Nuclear Information System (INIS)

    1990-01-01

    This is a summary of condensed matter physics in Brazil. It discusses as well, the perspectives and financing evolved in this research area for the next decade. It is specially concerned with semiconductors, magnetic materials, superconductivity, polymers, glasses, crystals ceramics, statistical physics, magnetic resonance and Moessbauer spectroscopy. (A.C.A.S.)

  4. Electrons in Condensed Matter

    Indian Academy of Sciences (India)

    Electrons in Condensed Matter. T V Ramakrishnan. Introduction. A hundred years ago, J J Thomson tore light negatively charged particles out of many different kinds of atoms by subjecting them to strong electric fields in discharge tubes. He showed that the same particle (with identical charge e and charge to mass ratio ...

  5. Simple Simulations of DNA Condensation

    Energy Technology Data Exchange (ETDEWEB)

    STEVENS,MARK J.

    2000-07-12

    Molecular dynamics simulations of a simple, bead-spring model of semiflexible polyelectrolytes such as DNA are performed. All charges are explicitly treated. Starting from extended, noncondensed conformations, condensed structures form in the simulations with tetravalent or trivalent counterions. No condensates form or are stable for divalent counterions. The mechanism by which condensates form is described. Briefly, condensation occurs because electrostatic interactions dominate entropy, and the favored Coulombic structure is a charge ordered state. Condensation is a generic phenomena and occurs for a variety of polyelectrolyte parameters. Toroids and rods are the condensate structures. Toroids form preferentially when the molecular stiffness is sufficiently strong.

  6. Dehydration transformation in Ca-montmorillonite

    Indian Academy of Sciences (India)

    These investigations revealed that sample underwent transformation from hydrated phase to dehydrated phase at 200°C, and as a consequence, its basal spacing collapsed from 16.02 Å (30°C) to around 10 Å (200°C). This transformation occurred through a wide range of temperature, i.e. within the range 120°–200°C. The ...

  7. Improving the process of dehydration uchuva

    OpenAIRE

    Rafael Giraldo; Tulio Vargas; Humberto Gil

    2009-01-01

    In the drying of food is essential to know the time required to achieve the dry bulb temperature, with the goal of reducing energy consumption without affecting product quality. Appropriate estimate is required to determine in advance the heat transfer coefficient by forced convection between air and product. In this paper we developed a procedure for a drying system in the form of Gooseberry hemispherical and four helmets in a pilot dehydrator trays. The heating time was determined by measur...

  8. High-temperature dehydration of talc: a kinetics study using in situ X-ray powder diffraction

    Science.gov (United States)

    Wang, Duojun; Yi, Li; Huang, Bojin; Liu, Chuanjiang

    2015-06-01

    High-temperature in situ X-ray powder diffraction patterns were used to study the dehydration kinetics of natural talc with a size of 10-15 µm. The talc was annealed from 1073 to 1223 K, and the variations in the characteristic peaks corresponding to talc with the time were recorded to determine the reaction progress. The decomposition of talc occurred, and peaks corresponding to talc and peaks corresponding to enstatite and quartz were observed. The enstatite and talc exhibited a topotactic relationship. The dehydration kinetics of talc was studied as a function of temperature between 1073 and 1223 K. The kinetics data could be modeled using an Avrami equation that considers nucleation and growth processes ? where n varies from 0.4 to 0.8. The rate constant (k) equation for the natural talc is ? The reaction mechanism for the dehydration of talc is a heterogeneous nucleation and growth mechanism.

  9. Hyponatraemia and dehydration in severe malaria.

    Science.gov (United States)

    English, M C; Waruiru, C; Lightowler, C; Murphy, S A; Kirigha, G; Marsh, K

    1996-01-01

    The prevalence and likely cause of hyponatraemia in severe childhood malaria were investigated. One hundred and thirty two children, 47 of whom had cerebral malaria, were prospectively recruited and serial simple indices of fluid and electrolyte balance and renal function monitored during admission. In 55%, hyponatraemia (sodium < 135 mmol/l) was present on admission. Hyponatraemia was pronounced (sodium < or = 130 mmol/l) in 21%, and these children gained less weight during admission (mean weight gain 2.4% v 4.3%) than children with a normal sodium (135-145 mmol/l). Overall, 31% of survivors were at least moderately dehydrated on admission (5% weight gain by discharge). These children had higher plasma urea concentrations on admission (6.1 v 4.5 mmol/l) and were more acidotic (mean base excess -12.1 v -8.0) than children who were not dehydrated. There were changes in simple indices of renal function between admission and discharge in children who survived (creatinine 65.7 v 37.9 mumol/l and urea 5.5 v 1.9 mmol/l). The results suggest that dehydration is common in severe childhood malaria, that it may contribute to mild impairment in renal function, and that hyponatraemic children are less water depleted, showing appropriate rather than inappropriate secretion of antidiuretic hormone. PMID:8787422

  10. Dehydration and endurance performance in competitive athletes.

    Science.gov (United States)

    Goulet, Eric D B

    2012-11-01

    The field of research examining the link between dehydration and endurance performance is at the dawn of a new era. This article reviews the latest findings describing the relationship between exercise-induced dehydration and endurance performance and provides the knowledge necessary for competitive, endurance-trained athletes to develop a winning hydration strategy. Acute, pre-exercise body weight loss at or above 3% may decrease subsequent endurance performance. Therefore, endurance athletes should strive to start exercise well hydrated, which can be achieved by keeping thirst sensation low and urine color pale and drinking approximately 5-10 mL/kg body weight of water 2 h before exercise. During exercise lasting 1 h or less, dehydration does not decrease endurance performance, but athletes are encouraged to mouth-rinse with sports drinks. During exercise lasting longer than 1 h, in which fluid is readily available, drinking according to the dictates of thirst maximizes endurance performance. In athletes whose thirst sensation is untrustworthy or when external factors such as psychological stress or repeated food intake may blunt thirst sensation, it is recommended to program fluid intake to maintain exercise-induced body weight loss around 2% to 3%. © 2012 International Life Sciences Institute.

  11. Could Neonatal Hypernatremia Dehydration Influence Hearing Status?

    Directory of Open Access Journals (Sweden)

    Hassan Boskabadi

    2014-01-01

    Full Text Available 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.  

  12. Development status of condensed cluster fusion theory

    International Nuclear Information System (INIS)

    Takahashi, Akito

    2015-01-01

    The condensed cluster fusion theory has been developed since 1989, under the view that dynamic ordering processes of confined transient clusters of D(H)-particles in catalytic surface sites, vacancies and global mesoscopic potential well of metal nanoparticles may induce simultaneous multi-body fusion reactions. One thorough answer is obtained for the condensation motion of clusters under platonic symmetry like 4D(H)/TSC, 6D(H)/RDC and 8D(H)/RDC and their fusion reaction rates. Theoretical analysis for initial dynamic clustering process on/in catalytic sites is still speculative and under searching a technique to combine the electron density functional method and the QM Langevin method. (author)

  13. Dehydration of Sodium Carbonate Decahydrate to Monohydrate in a Fluidized Bed

    Czech Academy of Sciences Publication Activity Database

    Hartman, Miloslav; Veselý, Václav; Svoboda, Karel; Trnka, Otakar; Beran, Z.

    2001-01-01

    Roč. 47, č. 10 (2001), s. 2333-2340 ISSN 0001-1541 R&D Projects: GA ČR GA203/98/0101; GA AV ČR IAA4072711 Institutional research plan: CEZ:AV0Z4072921 Keywords : gas -solid reactions * sulfur-dioxide * thermal dehydration Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.793, year: 2001

  14. Reaction mechanisms and kinetics of processing glucose, xylose and glucose-xylose mixtures under hot compressed water conditions for predicting bio-crude composition

    DEFF Research Database (Denmark)

    Grigoras, Ionela; Toor, Saqib Sohail; Rosendahl, Lasse Aistrup

    Mechanisms for bio-crude formation during the conversion of glucose, xylose and glucose-xylose mixtures as biomass model compounds under hot compressed water conditions are investigated. Studies in literature have shown that the diverse products formed at the early stages of glucose or xylose...... conversion are 5-HMF, erythrose, glyceraldehyde, dihydroxyacetone, pyruvaldehyde, and saccharinic acids resulted through reactions such as dehydration, retro-aldol condensation and isomerization. However, these compounds are mostly water soluble compounds and lack the final steps towards formation of water...... insoluble components at longer reaction times. The effects of pressure, pH, catalyst and reaction time on the main products are examined thoroughly. The possible routes for the formation of oil compounds are developed....

  15. Downhole dehydration - status report and implementation study; Downhole Dehydration - Statusbericht und Umsetzungsstudie

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, D.; Schmidt, D. [BEB Erdgas und Erdoel GmbH, Hannover (Germany)

    1998-12-31

    Downhole dehydration, i.e. in-situ separation of water and oil, is an interesting new technology. The contribution describes the technology and the results of a field experiment. (orig.) [Deutsch] Die Tail-End Foerderphase in der deutschen Erdoelproduktion, welche durch hohe Wasserhebekosten gekennzeichnet ist, erfordert zur Aufrechterhaltung der Wirtschaftlichkeit neue Gedankenansaetze. Ein aus wirtschaftlicher und technischer Sicht reizvoller Optimierungsgedanke ist die untertaegige Wasser/Oel Separation, auch Downhole Dehydration genannt. Unter Downhole Dehydration (DHD) versteht man also die untertaegige (teilweise) Separation des Lagerstaettenwassers vom Nassoel, kurz nachdem das Gemisch untertaegig in das Bohrloch eingetreten ist. Dabei wird das abgetrennte Lagerstaettenwasser untertage in einen geeigneten Horizont unmittelbar wieder injiziert und das Oel (wie bei der konventionellen Foerderung) zutage gepumpt, mit dem Ziel der Nutzung der daraus resultierenden Kosten- und Investitionsersparnis. Ziel dieses Vortrages ist es, einen kurzen Einblick in die erstmalig in Europa angewandte Technik zu geben und von den Erfahrungen des praktizierten Feldversuches zu berichten. (orig.)

  16. Theoretical investigation of the selective dehydration and dehydrogenation of ethanol catalyzed by small molecules.

    Science.gov (United States)

    Wang, Yanqun; Tang, Yizhen; Shao, Youxiang

    2017-09-01

    Catalytic dehydration and dehydrogenation reactions of ethanol have been investigated systematically using the ab initio quantum chemistry methods The catalysts include water, hydrogen peroxide, formic acid, phosphoric acid, hydrogen fluoride, ammonia, and ethanol itself. Moreover, a few clusters of water and ethanol were considered to simulate the catalytic mechanisms in supercritical water and supercritical ethanol. The barriers for both dehydration and dehydrogenation can be reduced significantly in the presence of the catalysts. It is revealed that the selectivity of the catalytic dehydration and dehydrogenation depends on the acidity and basicity of the catalysts and the sizes of the clusters. The acidic catalyst prefers dehydration while the basic catalysts tend to promote dehydrogenation more effectively. The calculated water-dimer catalysis mechanism supports the experimental results of the selective oxidation of ethanol in the supercritical water. It is suggested that the solvent- and catalyst-free self-oxidation of the supercritical ethanol could be an important mechanism for the selective dehydrogenation of ethanol on the theoretical point of view. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Dehydration survival of crop plants and its measurement.

    Science.gov (United States)

    Blum, Abraham; Tuberosa, Roberto

    2018-01-08

    Dehydration survival under drought stress is defined in this review as the transition from plant activity into a quiescent state of life preservation, which will be terminated by either recovery or death, depending on the stress regime and the plant's resilience. Dehydration survival is a popular phenotype by which functional genomics attempts to test gene function in drought resistance and survival. The available reports on phenotyping and genotyping of dehydration survival in genomic studies indicate that the measurement of this trait is often biased to the extent that misguided interpretations are likely to occur. This review briefly discusses the physiological basis of dehydration survival in resurrection plants and crop plants, and concludes that in phenotyping dehydration survival there is a need to distinguish between dehydration avoidance and dehydration tolerance (also termed desiccation tolerance) in affecting survival and recovery. Without this distinction, functional genomics studies of the trait might be biased. Survival due to dehydration avoidance is expressed by the capacity to maintain a relatively high plant water status as the plant is desiccated. Survival due to dehydration tolerance is expressed by delayed mortality (mortality at a relatively low plant water status) as affected by the resilience of plant metabolism. The common test of dehydration survival, using the relative recovery after a given number of stress days, is therefore insufficient because it is mainly driven by dehydration avoidance and so ignores a possible role for dehydration tolerance. Conceivable methods for more accurate phenotyping of the two components of dehydration survival are proposed and discussed. © The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  18. Influence of non condensable gases on condenser performance. Bibliographical study

    International Nuclear Information System (INIS)

    Phong, Vinh

    1970-09-01

    The author proposes a synthesis of a bibliographical study on condenser performance, and more particularly on the influence of non-condensables on these performance. He distinguishes experimental studies, and analytical or theoretical studies. As far as experimental studies are concerned, he discusses various factors: influence of the rate of non condensables and of scan rate, influence of condenser geometry, influence of the exchanged heat flow, influence of the operational pressure, empirical correlations. As far as analytical studies on the influence of non-condensables are concerned, the author discusses and comments diffusion laws, and some specific studies [fr

  19. Dehydration of lawsonite could directly trigger earthquakes in subducting oceanic crust

    Science.gov (United States)

    Okazaki, Keishi; Hirth, Greg

    2016-02-01

    Intermediate-depth earthquakes in cold subduction zones are observed within the subducting oceanic crust, as well as the mantle. In contrast, intermediate-depth earthquakes in hot subduction zones predominantly occur just below the Mohorovičić discontinuity. These observations have stimulated interest in relationships between blueschist-facies metamorphism and seismicity, particularly through dehydration reactions involving the mineral lawsonite. Here we conducted deformation experiments on lawsonite, while monitoring acoustic emissions, in a Griggs-type deformation apparatus. The temperature was increased above the thermal stability of lawsonite, while the sample was deforming, to test whether the lawsonite dehydration reaction induces unstable fault slip. In contrast to similar tests on antigorite, unstable fault slip (that is, stick-slip) occurred during dehydration reactions in the lawsonite and acoustic emission signals were continuously observed. Microstructural observations indicate that strain is highly localized along the fault (R1 and B shears), and that the fault surface develops slickensides (very smooth fault surfaces polished by frictional sliding). The unloading slope during the unstable slip follows the stiffness of the apparatus at all experimental conditions, regardless of the strain rate and temperature ramping rate. A thermomechanical scaling factor for the experiments is within the range estimated for natural subduction zones, indicating the potential for unstable frictional sliding within natural lawsonite layers.

  20. Research Status of Evaporative Condenser

    Science.gov (United States)

    Wang, Feifei; Yang, Yongan

    2018-02-01

    Reducing energy consumption, saving water resources, recycling cool water are main directions of China’s development. Evaporative condenser using latent heat reduces water resources waste, with energy-saving advantages. This paper reviews the research status of evaporative condenser at home and abroad, and introduces the principle, classification, various influencing factors of evaporative condenser, and puts forward the future research direction.

  1. Recovery of condensate water quality in power generator's surface condenser

    Science.gov (United States)

    Kurniawan, Lilik Adib

    2017-03-01

    In PT Badak NGL Plant, steam turbines are used to drive major power generators, compressors, and pumps. Steam exiting the turbines is condensed in surface condensers to be returned to boilers. Therefore, surface condenser performance and quality of condensate water are very important. One of the recent problem was caused by the leak of a surface condenser of Steam Turbine Power Generator. Thesteam turbine was overhauled, leaving the surface condenser idle and exposed to air for more than 1.5 years. Sea water ingress due to tube leaks worsens the corrosionof the condenser shell. The combination of mineral scale and corrosion product resulting high conductivity condensate at outlet condenser when we restarted up, beyond the acceptable limit. After assessing several options, chemical cleaning was the best way to overcome the problem according to condenser configuration. An 8 hour circulation of 5%wt citric acid had succeed reducing water conductivity from 50 μmhos/cm to below 5 μmhos/cm. The condensate water, then meets the required quality, i.e. pH 8.3 - 9.0; conductivity ≤ 5 μmhos/cm, therefore the power generator can be operated normally without any concern until now.

  2. Condensed matter physics

    CERN Document Server

    Marder, Michael P

    2010-01-01

    This Second Edition presents an updated review of the whole field of condensed matter physics. It consolidates new and classic topics from disparate sources, teaching not only about the effective masses of electrons in semiconductor crystals and band theory, but also about quasicrystals, dynamics of phase separation, why rubber is more floppy than steel, granular materials, quantum dots, Berry phases, the quantum Hall effect, and Luttinger liquids.

  3. Asymmetric condensed dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre, Anthony; Diez-Tejedor, Alberto, E-mail: aguirre@scipp.ucsc.edu, E-mail: alberto.diez@fisica.ugto.mx [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA, 95064 (United States)

    2016-04-01

    We explore the viability of a boson dark matter candidate with an asymmetry between the number densities of particles and antiparticles. A simple thermal field theory analysis confirms that, under certain general conditions, this component would develop a Bose-Einstein condensate in the early universe that, for appropriate model parameters, could survive the ensuing cosmological evolution until now. The condensation of a dark matter component in equilibrium with the thermal plasma is a relativistic process, hence the amount of matter dictated by the charge asymmetry is complemented by a hot relic density frozen out at the time of decoupling. Contrary to the case of ordinary WIMPs, dark matter particles in a condensate must be lighter than a few tens of eV so that the density from thermal relics is not too large. Big-Bang nucleosynthesis constrains the temperature of decoupling to the scale of the QCD phase transition or above. This requires large dark matter-to-photon ratios and very weak interactions with standard model particles.

  4. Catalytic Upgrading of Biomass-Derived Compounds via C-C Coupling Reactions. Computational and Experimental Studies of Acetaldehyde and Furan Reactions in HZSM-5

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Cong [Argonne National Lab. (ANL), Argonne, IL (United States); Evans, Tabitha J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Cheng, Lei [Argonne National Lab. (ANL), Argonne, IL (United States); Nimlos, Mark R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Mukarakate, Calvin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Robichaud, David J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Assary, Rajeev S. [Argonne National Lab. (ANL), Argonne, IL (United States); Curtiss, Larry A. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-10-02

    These catalytic C–C coupling and deoxygenation reactions are essential for upgrading of biomass-derived oxygenates to fuel-range hydrocarbons. Detailed understanding of mechanistic and energetic aspects of these reactions is crucial to enabling and improving the catalytic upgrading of small oxygenates to useful chemicals and fuels. Using periodic density functional theory (DFT) calculations, we have investigated the reactions of furan and acetaldehyde in an HZSM-5 zeolite catalyst, a representative system associated with the catalytic upgrading of pyrolysis vapors. Comprehensive energy profiles were computed for self-reactions (i.e., acetaldehyde coupling and furan coupling) and cross-reactions (i.e., acetaldehyde + furan) of this representative mixture. Major products proposed from the computations are further confirmed using temperature controlled mass spectra measurements. Moreover, the computational results show that furan interacts with acetaldehyde in HZSM-5 via an alkylation mechanism, which is more favorable than the self-reactions, indicating that mixing furans with aldehydes could be a promising approach to maximize effective C–C coupling and dehydration while reducing the catalyst deactivation (e.g., coke formation) from aldehyde condensation.

  5. Dehydration of isobutanol to isobutene in a slurry reactor

    Energy Technology Data Exchange (ETDEWEB)

    Latshaw, B.E.

    1994-02-01

    The April 1990 Alternative Fuels Proposal to the Department of Energy involved the development of new technology, based on the liquid phase process, for conversion of coal-derived synthesis gas to oxygenated hydrocarbon fuels, fuel additives, and fuel intermediates. The objective of this work was to develop a slurry reactor based process for the dehydration of isobutanol to isobutene. The isobutene can serve as a feedstock for the high octane oxygenated fuel additive methyl tertiary-butyl either (MTBE). Alumina catalysts were investigated because of their wide use as a dehydration catalyst. Four commercially available alumina catalysts (Catapal B, Versal B, Versal GH, and Al-3996R) were evaluated for both activity and selectivity to the branched olefin. All four catalysts demonstrated conversions greater than 80% at 290 C, while conversions of near 100% could be obtained at 330 C. The reaction favors low pressures and moderate to low space velocities. A yield of 0.90 mole isobutene per mole reacted isobutanol or better was obtained at conversions of 60--70% and higher. From 75 to 98% conversion, the four catalysts all provide isobutene yields ranging from 0.92 to 0.94 with the maximum occurring around 90% conversion. At low conversions, the concentration of diisobutyl ether becomes significant while the concentration of linear butenes is essentially a linear function of isobutanol conversion. Doping the catalyst with up to 0.8 wt % potassium showed a modest increase in isobutene selectivity; however, this increase was more than offset by a reduction in activity. Investigations using a mixed alcohols feed (consistent with isobutanol synthesis from syngas) demonstrated a small increase in the C4 iso-olefin selectivity over that observed for a pure isobutanol feed. 55 refs.

  6. Dehydration of football referees during a match.

    Science.gov (United States)

    Da Silva, A I; Fernandez, R

    2003-12-01

    To study hydration status in referees (main) and assistant referees (linesmen) during official football matches. 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. 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%. Referees are moderately dehydrated after a football match (2%), whereas assistants show a non-significant dehydration of 1% of their body weight.

  7. Dehydration of plutonium or neptunium trichloride hydrate

    Science.gov (United States)

    Foropoulos, J. Jr.; Avens, L.R.; Trujillo, E.A.

    1992-03-24

    A process is described for preparing anhydrous actinide metal trichlorides of plutonium or neptunium by reacting an aqueous solution of an actinide metal trichloride selected from the group consisting of plutonium trichloride or neptunium trichloride with a reducing agent capable of converting the actinide metal from an oxidation state of +4 to +3 in a resultant solution, evaporating essentially all the solvent from the resultant solution to yield an actinide trichloride hydrate material, dehydrating the actinide trichloride hydrate material by heating the material in admixture with excess thionyl chloride, and recovering anhydrous actinide trichloride.

  8. Thermodynamics of dehydration process of uranyl nitrate pentahydrate of thorium

    International Nuclear Information System (INIS)

    Khamidov, F.A.; Mirsaidov, I.U.; Nazarov, K.M.; Nasriddinov, S.K.; Badalov, A.B.

    2010-01-01

    Present article is devoted to thermodynamics of dehydration process of uranyl nitrate pentahydrate of thorium. The results of researches of dehydration process of uranyl nitrate pentahydrate of thorium Th(NO 3 ) 4 ·5H 2 O were considered. The researches were carried out by means of tensimeter method with membrane zero-manometer under equilibrium conditions and at 300-450 K temperature ranges. The thermodynamic characteristics of dehydration process of initial crystalline hydrate was defined.

  9. Diagnostic accuracy of clinical dehydration scales in children.

    Science.gov (United States)

    Falszewska, Anna; Dziechciarz, Piotr; Szajewska, Hania

    2017-08-01

    The aim of this study was to evaluate the diagnostic accuracy of the Clinical Dehydration Scale (CDS), the World Health Organization (WHO) scale, and the Gorelick scale for dehydration assessment in children. A prospective, observational study was carried out between October 2014 and December 2016. Eligible participants were children aged 1 month to 5 years with acute diarrhea. After hospital admission, each patient's weight was recorded and the degree of dehydration based on three scales was assessed. The reference standard was the percentage weight change between the discharge and admission weights. The main outcomes were the sensitivity, specificity, positive likelihood ratio (LR), and negative LR. Of 128 children enrolled in the study, complete data were available from 118 patients for analysis. Most of children presented with no or mild dehydration. Only the CDS showed limited value in confirming a diagnosis of dehydration ≥6% (positive LR 3.9, 95% CI 1.1 to 9.1), with no value in ruling it out (negative LR 0.6, 95% CI 0.2 to 0.99). In our cohort, the CDS was of limited diagnostic value in ruling in severe dehydration in children with acute gastroenteritis. The WHO and Gorelick scales were not helpful in the assessment of dehydration. What is Known : • Treatment of acute gastroenteritis (AGE) is based on assessing and correcting the degree of dehydration. • Several scales combining various signs and symptoms have been developed, including the Clinical Dehydration Scale (CDS), and the World Health Organization (WHO) scale, and the Gorelick scale. None of these scales is internationally accepted for best accuracy in diagnosing dehydration in children. What is New: • The CDS was of limited diagnostic value in ruling in severe dehydration in children with AGE. • The WHO and Gorelick scales were not helpful in the assessment of dehydration.

  10. Effect of feeding dehydrated and ensiled tanniferous sainfoin (Onobrychis viciifolia) on nitrogen and mineral digestion and metabolism of lambs.

    Science.gov (United States)

    Scharenberg, Anna; Arrigo, Yves; Gutzwiller, Andreas; Wyss, Ueli; Hess, Hans D; Kreuzer, Michael; Dohme, Frigga

    2007-10-01

    The effects of tanniferous sainfoin on digestion and metabolism have been investigated in 12 lambs in an incomplete cross-over design (n = 6). Effects of condensed tannins (CT) were evaluated by comparing dehydrated and ensiled sainfoin treated with and without polyethylene glycol (PEG). Dehydrated and ensiled grass-clover mixtures served as controls. The lambs were fed the treatment diets, including a mineral supplement, for 21 d. During the last 7 d excreta, rumen fluid and blood were sampled. The CT of sainfoin decreased rumen fluid ammonia concentration (p Ensiling of sainfoin led to the lowest N-retention. In conclusion, the reduction in ruminal ammonia and urine-N losses by sainfoin CT did not improve N-retention.

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

    Science.gov (United States)

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

    2013-05-01

    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. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Soft Condensed Matter

    International Nuclear Information System (INIS)

    Jones, Richard A L

    2002-01-01

    The author states in the preface of the book that the aim is '...to give a unified overview of the various aspects of the physics of soft condensed matter'. The book succeeds in fulfilling this aim in many respects. The style is fluent and concise and gives the necessary explanations to make its content understandable to people with some knowledge of the basic principles of physics. The content of the book is complete enough to give a panoramic view of the landscape of soft condensed matter. The first two chapters give, respectively, a short introduction and a presentation of forces, energies and timescales, giving a general overview and pointing out the particular importance of different aspects such as timescales, which are much more important in soft condensed matter than in traditional or 'hard' condensed matter. The next chapter, devoted to phase transition, recalls that the equilibrium between two phases is controlled by free energy considerations. Spinodal decomposition is presented as a counterpart of nucleation and growth. Again, characteristic length scales are considered and applied to a phase separation mixture of polymers in a common solvent. The following three chapters are devoted respectively to specific topics: colloidal dispersion, polymers and gelation. The stability and phase behaviour of colloids are related to the interaction between colloidal particles. Properties of colloidal crystals as well as colloidal dispersion are depicted in terms of stabilization of crystalline colloids. The flow properties of colloidal dispersion are presented in terms of free energy minimization and the structure of the dispersion. After a brief introduction to polymer chemistry and architecture, the coil-globule transition is discussed. Viscoelasticity of polymers is described and discussed by introducing the notion of entanglement. This leads to the introduction of the tube model and the theory of reptation. The sol-gel transition is presented phenomenologically

  13. Comparison of clinical and biochemical markers of dehydration with the clinical dehydration scale in children: a case comparison trial.

    Science.gov (United States)

    Tam, Ron K; Wong, Hubert; Plint, Amy; Lepage, Nathalie; Filler, Guido

    2014-06-16

    The clinical dehydration scale (CDS) is a quick, easy-to-use tool with 4 clinical items and a score of 1-8 that serves to classify dehydration in children with gastroenteritis as no, some or moderate/severe dehydration. Studies validating the CDS (Friedman JN) with a comparison group remain elusive. We hypothesized that the CDS correlates with a wide spectrum of established markers of dehydration, making it an appropriate and easy-to-use clinical tool. This study was designed as a prospective double-cohort trial in a single tertiary care center. Children with diarrhea and vomiting, who clinically required intravenous fluids for rehydration, were compared with minor trauma patients who required intravenous needling for conscious sedation. We compared the CDS with clinical and urinary markers (urinary electrolytes, proteins, ratios and fractional excretions) for dehydration in both groups using receiver operating characteristic (ROC) curves to determine the area under the curve (AUC). We enrolled 73 children (male = 36) in the dehydration group and 143 (male = 105) in the comparison group. Median age was 32 months (range 3-214) in the dehydration and 96 months (range 2.6-214 months, p dehydration group and 0 in the comparison group (p dehydrated group: difference in heart rate, diastolic blood pressure, urine sodium/potassium ratio, urine sodium, fractional sodium excretion, serum bicarbonate, and creatinine measurements. The best markers for dehydration were urine Na and serum bicarbonate (ROC AUC = 0.798 and 0.821, respectively). CDS was most closely correlated with serum bicarbonate (Pearson r = -0.3696, p = 0.002). Although serum bicarbonate is not the gold standard for dehydration, this study provides further evidence for the usefulness of the CDS as a dehydration marker in children. Registered at ClinicalTrials.gov (NCT00462527) on April 18, 2007.

  14. [Severe rhabdomyolysis secondary to severe hypernatraemic dehydration].

    Science.gov (United States)

    Mastro-Martínez, Ignacio; Montes-Arjona, Ana María; Escudero-Lirio, Margarita; Hernández-García, Bárbara; Fernández-Cantalejo Padial, José

    2015-01-01

    Rhabdomyolysis is a rare paediatric condition. The case is presented of a patient in whom this developed secondary to severe hypernatraemic dehydration following acute diarrhoea. Infant 11 months of age who presented with vomiting, fever, diarrhoea and anuria for 15 hours. Parents reported adequate preparation of artificial formula and oral rehydration solution. He was admitted with malaise, severe dehydration signs and symptoms, cyanosis, and low reactivity. The laboratory tests highlighted severe metabolic acidosis, hypernatraemia and pre-renal kidney failure (Sodium [Na] plasma 181 mEq/L, urine density> 1030). He was managed in Intensive Care Unit with gradual clinical and renal function improvement. On the third day, slight axial hypotonia and elevated cell lysis enzymes (creatine phosphokinase 75,076 IU/L) were observed, interpreted as rhabdomyolysis. He was treated with intravenous rehydration up to 1.5 times the basal requirements, and he showed a good clinical and biochemical response, being discharged 12 days after admission without motor sequelae. Severe hypernatraemia is described as a rare cause of rhabdomyolysis and renal failure. In critically ill patients, it is important to have a high index of suspicion for rhabdomyolysis and performing serial determinations of creatine phosphokinase for early detection and treatment. Copyright © 2015 Sociedad Chilena de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

  15. The condensed matter physics

    International Nuclear Information System (INIS)

    Sapoval, B.

    1988-01-01

    The 1988 progress report of the laboratory of the Condensed Matter Physics (Polytechnic School, France), is presented. The Laboratory activities are related to the physics of semiconductors and disordered phases. The electrical and optical properties of the semiconductors, mixed conductor, superionic conductors and ceramics, are studied. Moreover, the interfaces of those systems and the sol-gel inorganic polymerization phenomena, are investigated. The most important results obtained, concern the following investigations: the electrochemical field effect transistor, the cathodoluminescence, the low energy secondary electrons emission, the fluctuations of a two-dimensional diffused junction and the aerogels [fr

  16. Topology in Condensed Matter

    CERN Document Server

    Monastyrsky, M I

    2006-01-01

    This book reports new results in condensed matter physics for which topological methods and ideas are important. It considers, on the one hand, recently discovered systems such as carbon nanocrystals and, on the other hand, new topological methods used to describe more traditional systems such as the Fermi surfaces of normal metals, liquid crystals and quasicrystals. The authors of the book are renowned specialists in their fields and present the results of ongoing research, some of it obtained only very recently and not yet published in monograph form.

  17. Ice condenser experimental plan

    International Nuclear Information System (INIS)

    Kannberg, L.D.; Piepel, G.F.; Owczarski, P.C.; Liebetrau, A.M.

    1986-01-01

    An experimental plan is being developed to validate the computer code ICEDF. The code was developed to estimate the extent of aerosol retention in the ice compartments of pressurized water reactor ice condenser containment systems during severe accidents. The development of the experimental plan began with review of available information on the conditions under which the code will be applied. Computer-generated estimates of thermohydraulic and aerosol conditions entering the ice condenser were evaluated and along with other information, used to generate design criteria. The design criteria have been used for preliminary test assembly design and for generation of statistical test designs. Consideration of the phenomena to be evaluated in the testing program, as well as equipment and measurement limitations, have led to changes in the design criteria and to subsequent changes in the test assembly design and statistical test design. The overall strategy in developing the experimental plan includes iterative generation and evaluation of candidate test designs using computer codes for statistical test design and ICEDF for estimation of experimental results. Estimates of experimental variability made prior to actual testing will be verified by replicate testing at preselected design points

  18. Dehydration and drinking responses in a pelagic sea snake.

    Science.gov (United States)

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

    2012-08-01

    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.

  19. Production and evaluation of precooked dehydrated unripe banana ...

    African Journals Online (AJOL)

    No significant change in total aerobic counts or yeasts and moulds counts occurred in dehydrated banana slices packaged in 250 gauge polyethylene bags and stored at ambient temperature for 3 months. The slices were found to be high in starch (~68.5%) and minerals. When shallow fried, the dehydrated banana slices ...

  20. Production and evaluation of precooked dehydrated unripe banana ...

    African Journals Online (AJOL)

    This study was aimed at developing a process for production of easy to prepare dehydrated banana slices. Steaming unripe bananas for 7 minutes followed by hand peel stripping, slicing and dehydration in air dryers produced slices with better rehydration properties than slices produced without steaming, even when the ...

  1. Straightforward uranium-catalyzed dehydration of primary amides to nitriles

    International Nuclear Information System (INIS)

    Enthaler, Stephan

    2011-01-01

    The efficient uranium-catalyzed dehydration of a variety of primary amides, using N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) as a dehydration reagent, to the corresponding nitriles has been investigated. With this catalyst system, extraordinary catalyst activities and selectivities were feasible. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Regulation of plant stress response by dehydration responsive ...

    African Journals Online (AJOL)

    Plant growth and productivity are greatly affected by environmental stresses such as dehydration, high salinity, low temperature and biotic pathogen infection. Plant adaptation to these environmental stresses is controlled by cascades of molecular networks. The dehydration responsive element binding (DREB) transcription ...

  3. Ferminoic physics in dipolariton condensates.

    Science.gov (United States)

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

    2014-03-21

    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.

  4. A study on dehydration of rare earth chloride hydrate

    International Nuclear Information System (INIS)

    Cho, Yong Zun; Eun, Hee Chul; Son, Sung Mo; Lee, Tae Kyo; Hwang, Taek Sung

    2012-01-01

    The dehydration schemes of rare earth (La, Ce, Nd, Pr, Sm. Eu, Gd, Y) chloride hydrates was investigated by using a dehydration apparatus. To prevent the formation of the rare earth oxychlorides, the operation temperature was changed step by step (80→150→230 degree C) based on the TGA (thermo-gravimetric analysis) results of the rare earth chloride hydrates. A vacuum pump and preheated Ar gas were used to effectively remove the evaporated moisture and maintain an inert condition in the dehydration apparatus. The dehydration temperature of the rare earth chloride hydrate was increased when the atomic number of the rare earth nuclide was increased. The content of the moisture in the rare earth chloride hydrate was decreased below 10% in the dehydration apparatus.

  5. Two-stage dehydration of sugars

    Science.gov (United States)

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

    2009-11-10

    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.

  6. Microgravity condensing heat exchanger

    Science.gov (United States)

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

    2011-01-01

    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.

  7. Bose-Einstein Condensation

    International Nuclear Information System (INIS)

    Jaksch, D

    2003-01-01

    The Gross-Pitaevskii equation, named after one of the authors of the book, and its large number of applications for describing the properties of Bose-Einstein condensation (BEC) in trapped weakly interacting atomic gases, is the main topic of this book. In total the monograph comprises 18 chapters and is divided into two parts. Part I introduces the notion of BEC and superfluidity in general terms. The most important properties of the ideal and the weakly interacting Bose gas are described and the effects of nonuniformity due to an external potential at zero temperature are studied. The first part is then concluded with a summary of the properties of superfluid He. In Part II the authors describe the theoretical aspects of BEC in harmonically trapped weakly interacting atomic gases. A short and rather rudimentary chapter on collisions and trapping of atomic gases which seems to be included for completeness only is followed by a detailed analysis of the ground state, collective excitations, thermodynamics, and vortices as well as mixtures of BECs and the Josephson effect in BEC. Finally, the last three chapters deal with topics of more recent interest like BEC in optical lattices, low dimensional systems, and cold Fermi gases. The book is well written and in fact it provides numerous useful and important relations between the different properties of a BEC and covers most of the aspects of ultracold weakly interacting atomic gases from the point of view of condensed matter physics. The book contains a comprehensive introduction to BEC for physicists new to the field as well as a lot of detail and insight for those already familiar with this area. I therefore recommend it to everyone who is interested in BEC. Very clearly however, the intention of the book is not to provide prospects for applications of BEC in atomic physics, quantum optics or quantum state engineering and therefore the more practically oriented reader might sometimes wonder why exactly an equation is

  8. Supersymmetry is afraid of condensates

    Directory of Open Access Journals (Sweden)

    G. Domokos

    1983-01-01

    Full Text Available Supersymmetry is never broken by pair condensates of chiral superfields: the supersymmetry breaking part of Green's functions satisfies an equation which always has an identically vanishing solution. Hence any phase containing pair condensates is unstable due to its positive vacuum energy.

  9. Potentially Prebiotic Syntheses of Condensed Phosphates

    Science.gov (United States)

    Keefe, Anthony D.; Miller, Stanley L.

    1996-01-01

    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.

  10. Computational Dehydration of Crystalline Hydrates Using Molecular Dynamics Simulations

    DEFF Research Database (Denmark)

    Larsen, Anders Støttrup; Rantanen, Jukka; Johansson, Kristoffer E

    2017-01-01

    Molecular dynamics (MD) simulations have evolved to an increasingly reliable and accessible technique and are today implemented in many areas of biomedical sciences. We present a generally applicable method to study dehydration of hydrates based on MD simulations and apply this approach to the de......Molecular dynamics (MD) simulations have evolved to an increasingly reliable and accessible technique and are today implemented in many areas of biomedical sciences. We present a generally applicable method to study dehydration of hydrates based on MD simulations and apply this approach...... to the dehydration of ampicillin trihydrate. The crystallographic unit cell of the trihydrate is used to construct the simulation cell containing 216 ampicillin and 648 water molecules. This system is dehydrated by removing water molecules during a 2200 ps simulation, and depending on the computational dehydration...... rate, different dehydrated structures were observed. Removing all water molecules immediately and removing water relatively fast (10 water molecules/10 ps) resulted in an amorphous system, whereas relatively slow computational dehydration (3 water molecules/10 ps) resulted in a crystalline anhydrate...

  11. A Study on the Condensation Reaction of 4-Amino-3,5-dimethyl-1,2,4-triazole with Benzaldehydes: Structure and Spectroscopic Properties of Some New Stable Hemiaminals

    Directory of Open Access Journals (Sweden)

    Katarzyna Wajda-Hermanowicz

    2015-09-01

    Full Text Available Studies on the stable hemiaminals and Schiff bases formation in the reaction of substituted benzaldehydes with primary 3,5-dimethyl-1,2,4-triazole 4-amine were carried out under neutral conditions. These products were investigated by IR, Raman, MS, 1H- and 13C-NMR spectra as well as by X-ray crystallography. The effect of reaction conditions: temperature, polarity of the solvents utilized, substrate concentration and the ortho and para benzaldehyde substituents on the yield of products was also examined.

  12. Kinetics of Maleic Acid and Aluminum Chloride Catalyzed Dehydration and Degradation of Glucose

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ximing; Hewetson, Barron B.; Mosier, Nathan S.

    2015-04-16

    We report the positive effect of maleic acid, a dicarboxylic acid, on the selectivity of hexose dehydration to 5-hydroxymethyfurfural (HMF) and subsequent hydrolysis to levulinic and formic acids. We also describe the kinetic analysis of a Lewis acid (AlCl3) alone and in combination with HCl or maleic acid to catalyze the isomerization of glucose to fructose, dehydration of fructose to HMF, hydration of HMF to levulinic and formic acids, and degradation of these compounds to humins. The results show that AlCl3 significantly enhances the rate of glucose conversion to HMF and levulinic acid in the presence of both maleic acid and HCl. In addition, the degradation of HMF to humins, rather than levulinic and formic acids, is reduced by 50% in the presence of maleic acid and AlCl3 compared to HCl combined with AlCl3. The results suggest different reaction mechanisms for the dehydration of glucose and rehydration of HMF between maleic acid and HCl.

  13. Rehydration Capacities and Rates for Various Porcine Tissues after Dehydration

    Science.gov (United States)

    Meyer, Jacob P.; McAvoy, Kieran E.; Jiang, Jack

    2013-01-01

    The biphasic effects of liquid on tissue biomechanics are well known in cartilage and vocal folds, yet not extensively in other tissue types. Past studies have shown that tissue dehydration significantly impacts biomechanical properties and that rehydration can restore these properties in certain tissue types. However, these studies failed to consider how temporal exposure to dehydrating or rehydrating agents may alter tissue rehydration capacity, as overexposure to dehydration may permanently prevent rehydration to the initial liquid volume. Select porcine tissues were dehydrated until they reached between 100% and 40% of their initial mass. Each sample was allowed to rehydrate for 5 hours in a 0.9% saline solution, and the percent change between the initial and rehydrated mass values was calculated. Spearman correlation tests indicated a greater loss in mass despite rehydration when tissues were previously exposed to greater levels of dehydration. Additionally, Pearson correlation tests indicated the total liquid mass of samples after complete rehydration decreased when previously exposed to higher levels of dehydration. Rehydration rates were found by dehydrating tissues to 40% of their initial mass followed by rehydration in a 0.9% saline solution for 60 minutes, with mass measurements occurring in 15 minute intervals. All tissues rehydrated nonlinearly, most increasing significantly in mass up to 30 minutes after initial soaking. This study suggests the ability for tissues to rehydrate is dependent on the level of initial dehydration exposure. In vitro rehydration experiments therefore require controlled dosage and temporal exposure to dehydrating and rehydrating agents to avoid incomplete rehydration, and caution should be taken when combining different tissue types in models of hydration. PMID:24023753

  14. Methods for assessing the effects of dehydration on cognitive function.

    Science.gov (United States)

    Lieberman, Harris R

    2012-11-01

    Studying the effects of dehydration on cognitive function presents a variety of unique and difficult challenges to investigators. These challenges, which are addressed in this article, can be divided into three general categories: 1) choosing an appropriate method of generating a consistent level of dehydration; 2) determining and effectively employing appropriate and sensitive measures of cognitive state; and 3) adequately controlling the many confounding factors that interfere with assessment of cognitive function. The design and conduct of studies on the effects of dehydration on cognitive function should carefully consider various methodological issues, and investigators should carefully weigh the benefits and disadvantages of particular methods and procedures. © 2012 International Life Sciences Institute.

  15. Peculiarities of dehydration of calcium dodeca- and hexavanadates

    International Nuclear Information System (INIS)

    Koryakova, O.V.; Perelyaeva, L.A.; Zabolotskaya, E.V.; Medvedeva, N.I.; Ivakin, A.A.

    1982-01-01

    Infrared spectroscopic, electron paramagentic resonance, X-ray diffraction and thermogravimetric methods were used to study the process and dehydration products of CaV 12 O 31 x12H 2 O and CaV 6 O 16 x6H 2 O calcium dodeca-and hexavanadates. The dependence of chemical composition on dehydration temperature was established. It was revealed that investigated polyvanadates contain two types of water crystallization and coordinationally linked-one. Complete dehydration (300-400 deg C) leads to irreversible structural changes and formation of oxide vanadium bronze. The ''final'' product (t > 500 deg C) is the mixture of vanadium pentaoxide and calcium metavanadate

  16. The diagnostic accuracy of Clinical Dehydration Scale in identifying dehydration in children with acute gastroenteritis: a systematic review.

    Science.gov (United States)

    Falszewska, Anna; Dziechciarz, Piotr; Szajewska, Hania

    2014-10-01

    To systematically update diagnostic accuracy of the Clinical Dehydration Scale (CDS) in clinical recognition of dehydration in children with acute gastroenteritis. Six databases were searched for diagnostic accuracy studies in which population were children aged 1 to 36 months with acute gastroenteritis; index test was the CDS; and reference test was post-illness weight gain. Three studies involving 360 children were included. Limited evidence showed that in high-income countries the CDS provides strong diagnostic accuracy for ruling in moderate and severe (>6%) dehydration (positive likelihood ratio 5.2-6.6), but has limited value for ruling it out (negative likelihood ratio 0.4-0.55). In low-income countries, the CDS has limited value either for ruling moderate or severe dehydration in or out. In both settings, the CDS had limited value for ruling in or out dehydration dehydration 3% to 6%. The CDS can help assess moderate to severe dehydration in high-income settings. Given the limited data, the evidence should be viewed with caution. © The Author(s) 2014.

  17. Renal tubular vasopressin receptors downregulated by dehydration

    International Nuclear Information System (INIS)

    Steiner, M.; Phillips, M.I.

    1988-01-01

    Receptors for arginine vasopressin (AVP) were characterized in tubular epithelial basolateral membranes (BL membranes) prepared from the kidneys of male Spraque-Dawley rats. Association of [ 3 H]AVP was rapid, reversible, and specific. Saturation studies revealed a single class of saturable binding sites with a maximal binding (B max ) of 184 ± 15 fmol/mg protein. The V 2 receptor antagonist was more than 3,700 times as effective in displacing [ 3 H]AVP than was the V 1 antagonist. To investigate the physiological regulation of vasopressin receptors, the effects of elevated levels of circulating AVP on receptor characteristics were studied. Seventy-two-hour water deprivation significantly elevated plasma osmolality and caused an 11.5-fold increase in plasma [AVP]. Scatchard analysis revealed a 38% decreased in the number of AVP receptors on the BL membranes from dehydrated animals. The high-affinity binding sites on the BL membranes fit the pharmacological profile for adenylate cyclase-linked vasopressin receptors (V 2 ), which mediate the antidiuretic action of the hormone. The authors conclude that physiologically elevated levels of AVP can downregulate vasopressin receptors in the kidney

  18. Improving the process of dehydration uchuva

    Directory of Open Access Journals (Sweden)

    Rafael Giraldo

    2009-08-01

    Full Text Available In the drying of food is essential to know the time required to achieve the dry bulb temperature, with the goal of reducing energy consumption without affecting product quality. Appropriate estimate is required to determine in advance the heat transfer coefficient by forced convection between air and product. In this paper we developed a procedure for a drying system in the form of Gooseberry hemispherical and four helmets in a pilot dehydrator trays. The heating time was determined by measuring the moisture loss vs. drying time. Based on statistics reported by the company which conducted the research, significant variables were selected as follows: temperature 58 ° C, inlet velocity 3.55 m / s, presentation of two helmets and a temperature of 62 ° C , velocity of 5.85 m / s presentation at four feet, respectively. These values provided the combinations of different variables and it was concluded by a 23 factorial design as favorable conditions, the presentation in four hooves, a dry bulb temperature of 62°C and inlet velocity of 3.55 m / s.With these results, the drying conditions scaled by a dimensionless analysis on industrial equipment, maintaining the temperature of 62 ° C and the presentation of four feet, giving a result for the air inlet velocity of 8m / s. The above conditions allow to reduce the drying process in 4 hours, with a final moisture content of 13.8% without significantly affecting the quality of the product.

  19. Condenser retubing-criteria manual

    International Nuclear Information System (INIS)

    Impagliazzo, A.M.; Bell, R.J.; Curlett, P.L.; Gordon, H.L.

    1982-05-01

    The objective of this document is to provide engineering assistance to utilities involved in retubing steam surface condensers with corrosion-resistant materials, such as titanium, and the recently developed high alloy pit-resistant steels. Field tests and recent operating experience have shown titanium and at least one of the high alloy pit-resistant steels to be virtually immune to the usual forms of corrosion occurring in steam surface condensers. This, together with the trend toward elimination of copper alloys in the circulating water system, has caused many utilities to retube their condensers with these materials

  20. Bose condensation in (random traps

    Directory of Open Access Journals (Sweden)

    V.A. Zagrebnov

    2009-01-01

    Full Text Available We study a non-interacting (perfect Bose-gas in random external potentials (traps. It is shown that a generalized Bose-Einstein condensation in the random eigenstates manifests if and only if the same occurs in the one-particle kinetic-energy eigenstates, which corresponds to the generalized condensation of the free Bose-gas. Moreover, we prove that the amounts of both condensate densities are equal. This statement is relevant for justification of the Bogoliubov approximation} in the theory of disordered boson systems.

  1. Ice condensation on sulfuric acid tetrahydrate: Implications for polar stratospheric ice clouds

    Directory of Open Access Journals (Sweden)

    T. J. Fortin

    2003-01-01

    Full Text Available The mechanism of ice nucleation to form Type 2 PSCs is important for controlling the ice particle size and hence the possible dehydration in the polar winter stratosphere. This paper probes heterogeneous ice nucleation on sulfuric acid tetrahydrate (SAT. Laboratory experiments were performed using a thin-film, high-vacuum apparatus in which the condensed phase is monitored via Fourier transform infrared spectroscopy and water pressure is monitored with the combination of an MKS baratron and an ionization gauge. Results show that SAT is an efficient ice nucleus with a critical ice saturation ratio of S*ice = 1.3 to 1.02 over the temperature range 169.8-194.5 K. This corresponds to a necessary supercooling of 0.1-1.3 K below the ice frost point. The laboratory data is used as input for a microphysical/photochemical model to probe the effect that this heterogeneous nucleation mechanism could have on Type 2 PSC formation and stratospheric dehydration. In the model simulations, even a very small number of SAT particles (e.g., 10-3 cm-3 result in ice nucleation on SAT as the dominant mechanism for Type 2 PSC formation. As a result, Type 2 PSC formation is more widespread, leading to larger-scale dehydration. The characteristics of the clouds are controlled by the assumed number of SAT particles present, demonstrating that a proper treatment of SAT is critical for correctly modeling Type 2 PSC formation and stratospheric dehydration.

  2. Condensation coefficient of water in a weak condensation state

    International Nuclear Information System (INIS)

    Kobayashi, Kazumichi; Watanabe, Shunsuke; Yamano, Daigo; Yano, Takeru; Fujikawa, Shigeo

    2008-01-01

    The condensation coefficient of water at a vapor-liquid interface is determined by combining shock tube experiments and numerical simulations of the Gaussian-BGK Boltzmann equation. The time evolution in thickness of a liquid film, which is formed on the shock tube endwall behind the shock wave reflected at the endwall, is measured with an optical interferometer consisting of the physical beam and the reference one. The reference beam is utilized to eliminate systematic noises from the physical beam. The growth rate of the film is evaluated from the measured time evolution and it is incorporated into the kinetic boundary condition for the Boltzmann equation. From a numerical simulation using the boundary condition, the condensation coefficient of water is uniquely deduced. The results show that, in a condition of weak condensation near a vapor-liquid equilibrium state, the condensation coefficient of water is almost equal to the evaporation coefficient estimated by molecular dynamics simulations near a vapor-liquid equilibrium state and it decreases as the system becomes a nonequilibrium state. The condensation coefficient of water is nearly identical with that of methanol [Mikami, S., Kobayashi, K., Ota, T., Fujikawa, S., Yano, T., Ichijo, M., 2006. Molecular gas dynamics approaches to interfacial phenomena accompanied with condensation. Exp. Therm. Fluid Sci. 30, 795-800].

  3. Condensation coefficient of water in a weak condensation state

    Science.gov (United States)

    Kobayashi, Kazumichi; Watanabe, Shunsuke; Yamano, Daigo; Yano, Takeru; Fujikawa, Shigeo

    2008-07-01

    The condensation coefficient of water at a vapor-liquid interface is determined by combining shock tube experiments and numerical simulations of the Gaussian-BGK Boltzmann equation. The time evolution in thickness of a liquid film, which is formed on the shock tube endwall behind the shock wave reflected at the endwall, is measured with an optical interferometer consisting of the physical beam and the reference one. The reference beam is utilized to eliminate systematic noises from the physical beam. The growth rate of the film is evaluated from the measured time evolution and it is incorporated into the kinetic boundary condition for the Boltzmann equation. From a numerical simulation using the boundary condition, the condensation coefficient of water is uniquely deduced. The results show that, in a condition of weak condensation near a vapor-liquid equilibrium state, the condensation coefficient of water is almost equal to the evaporation coefficient estimated by molecular dynamics simulations near a vapor-liquid equilibrium state and it decreases as the system becomes a nonequilibrium state. The condensation coefficient of water is nearly identical with that of methanol [Mikami, S., Kobayashi, K., Ota, T., Fujikawa, S., Yano, T., Ichijo, M., 2006. Molecular gas dynamics approaches to interfacial phenomena accompanied with condensation. Exp. Therm. Fluid Sci. 30, 795-800].

  4. Hospital Admissions for Malnutrition and Dehydration in Patients With Dementia.

    Science.gov (United States)

    Marshall, Katherine A; Burson, Rosanne; Gall, Kristyn; Saunders, Mitzi M

    2016-01-01

    Dehydration and malnutrition are commonly experienced by patients with dementia and can result in hospitalizations and decreased quality of life. The purpose of this study was to explore and describe retrospectively, the incidence and correlations of variables that may precede hospitalizations for dehydration/malnutrition in the community-dwelling patient with dementia. Data from the Outcome and Assessment Information Set (OASIS) Start of Care (SOC) on 44 patients served by a Michigan home care agency were retrieved for analysis. This study did not reveal any single or collection of variables that would predict risk for hospitalization for dehydration/malnutrition. With the lack of specific predictors of hospitalization related to dehydration and malnutrition, clinicians need to place high priority on risk-lowering strategies and preventive education for patients, family, and caregivers.

  5. Theoretical Considerations Governing the Dehydration of Fuels by Gas Blowing

    National Research Council Canada - National Science Library

    Krynitsky, John A

    1957-01-01

    .... A number of solutions applicable to the dehydration of JP-5 fuel under a variety of operating conditions are included to demonstrate the relative importance of the above parameters and to illustrate the type of performance possible.

  6. Pervaporation : membranes and models for the dehydration of ethanol

    NARCIS (Netherlands)

    Spitzen, Johannes Wilhelmus Franciscus

    1988-01-01

    In this thesis the dehydration of ethanol/water mixtures by pervaporation using homogeneous membranes is studied. Both the general transport mechanism as well as the development of highly selective membranes for ethanol/water separation are investigated.

  7. NOVEL POLYMERIC MEMBRANE FOR DEHYDRATION OF ORGANIC SOLVENTS

    Science.gov (United States)

    Pervaporation has emerged as an economically viable alternative technology for dehydration of organic solvents, removal of organic compounds and organic/organic separations. Development of a membrane system with suitable flux and selectivity characteristics plays a critical role...

  8. Radioactive waste slurry dehydrating and drum filling device

    International Nuclear Information System (INIS)

    Ichihashi, Toshio; Abe, Kazuaki; Hasegawa, Akira

    1981-01-01

    Purpose: To obtain a device for simultaneously filling and dehydrating radioactive waste in a waste can without the necessity of a special device for dehydration. Constitution: This device includes a radioactive waste storage tank, a pump for supplying the waste from the tank to a can, a drain tube having a filter at the lower end and installed displaceable in the axial direction of the can, and a drain pump. The slurry stored in the radioactive waste storage tank is supplied by the pump to the can, and the feedwater in the slurry is removed by another pump through a drain pipe having a filter which does not pass solid content from the can. Accordingly, as the slurry is filled in the can, the feedwater contained therein is removed. Consequently, it can simultaneously dehydrate and fill the dehydrated waste in the can. (Yoshihara, H.)

  9. Efficient, Long-Life Biocidal Condenser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Environmental control systems for manned lunar and planetary bases will require condensing heat exchangers to control humidity in manned modules. Condensing surfaces...

  10. Condenser assembly system for an appliance

    Energy Technology Data Exchange (ETDEWEB)

    Litch, Andrew David

    2017-10-17

    An appliance includes a compact condenser assembly formed with at least two separately and independently produced wire on tube condensers. Each of the at least two wire on tube condensers has a condenser inlet and a condenser outlet. The at least two wire on tube condensers are at least substantially locked and positioned in a matingly engaged configuration forming a compact condenser assembly. The at least two wire on tube condensers are configured to be operationally connected in at least one of a parallel configuration, a series configuration, a selectable configuration, and a bypass configuration.

  11. External validation and comparison of three pediatric clinical dehydration scales.

    Directory of Open Access Journals (Sweden)

    Joshua Jauregui

    Full Text Available 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.

  12. Rationalization of Sucrose Solution Using During the Fruit Osmotic Dehydration

    OpenAIRE

    Babić, Mirko; Babić, Ljiljana; Pavkov, Ivan; Radojčin, Milivoj

    2009-01-01

    The model of sustainable energy production of dried fruit conducted by using combined technology – the model that has been developed at the Faculty of Agriculture in Novi Sad – includes osmotic dehydration of fruit in sucrose solution. During the process of dehydration the moisture content of the solution is increased due to mass transfer of moisture from fruit. This article examines different models of recycling and concentrating of the solution. Thus, the model for concentrating of the solu...

  13. External validation and comparison of three pediatric clinical dehydration scales.

    Science.gov (United States)

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

    2014-01-01

    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. 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. 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. 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.

  14. Cryopreservation of coffee zygotic embryos: dehydration and osmotic rehydration

    Directory of Open Access Journals (Sweden)

    Maísa de Siqueira Pinto

    Full Text Available ABSTRACT Conservation of plant genetic resources is important to prevent genetic erosion. Seed banks are the most common method of ex situ conservation; however, coffee seeds can not be stored by conventional methods. Cryopreservation is a viable alternative for long-term conservation of species that produce intermediate or recalcitrant seeds, as coffee. The aim of this work was to cryopreserve Coffea arabica L. cv Catuaí Vermelho IAC 144 zygotic embryos, and analyse the effects of dehydration prior cryopreservation and osmotic rehydration after thawing, in embryos germination and seedlings formation after cryopreservation. Prior to cryopreservation, different dehydration times (0, 15, 30, 60 and 120 min were tested. Dehydrated embryos were cryopreserved in liquid nitrogen for 1 hour, and after thawing were rehydrated by osmotic solutions. Dehydrated and non-cryopreserved embryos were also analysed. The test with 2,3,5 triphenyl tetrazolium chloride (TTC was used to evaluate the embryos viability. Non-dehydrated embryos did not survive after freezing. Embryos that were dehydrated until 20% of the moisture content did not germinate when osmotic rehydration was not performed. In contrast, cryopreserved embryos with the same moisture content presented 98% germination when they were rehydrated slowly in osmotic solution. According to tetrazolium tests, embryos presented maximum viability (75% after dehydration for 60 minutes (23% moisture content. Therefore, coffee zygotic embryos (Coffea arabica L. cv. Catuaí Vermelho can be successfully cryopreserved using physical dehydration in silica gel for 60 minutes (23% moisture content, followed by osmotic rehydration after thawing. This method allowed a germination of 98% of cryopreserved zygotic embryos.

  15. Highly condensed aromatics and their connection to hydrogenation asphalts

    Energy Technology Data Exchange (ETDEWEB)

    Boente, L.

    1944-11-22

    An attempt is made to account for the structure of asphalts and resins which arose in residues upon hydrogenation of coal. The main assumption is that most of these asphalts consisted of highly condensed aromatics, which are considered as derivatives of the substance coronene, which could be described as having the structure consisting of six benzene rings arranged around a central seventh benzene ring. Part of the discussion is speculative, but evidence is given which had led to that speculation. The asphalts had been very hard to analyze exactly, partly because of their very low solubility in most solvents and their very high boiling points. Possible mechanisms for the formation of such highly condensed aromatics during the hydrogenation process are described along with experimental work aimed in part at hydrogenating these aromatics and in part at producing them by condensation reactions of aluminum chloride on coronene. Some of the products of the condensation reactions even resembled coke or soot, while others were red substances which fluoresced green in phenanthrene solution. It is hypothesized that coronene could be looked upon as the basic nucleus for a whole series of highly condensed aromatic molecules, in the same way that benzene is looked upon as the basic nucleus for a whole series of aromatic compounds.

  16. OPTIMAL EVAPORATING AND CONDENSING TEMPERATURES ...

    African Journals Online (AJOL)

    ORC) in a hot and humid environment. A theoretical procedure is proposed for the determination of the optimal evaporation temperature (OET) and optimal condensing temperature (OCT) of a subcritical ORC plant, which is based on ...

  17. Solar engineering - a condensed course

    Energy Technology Data Exchange (ETDEWEB)

    Broman, Lars

    2011-11-15

    The document represents the material covered in a condensed two-week course focusing on the most important thermal and PV solar energy engineering topics, while also providing some theoretical background.

  18. Whole transcriptome organisation in the dehydrated supraoptic nucleus

    Directory of Open Access Journals (Sweden)

    C.C.T. Hindmarch

    2013-12-01

    Full Text Available The supraoptic nucleus (SON is part of the central osmotic circuitry that synthesises the hormone vasopressin (Avp and transports it to terminals in the posterior lobe of the pituitary. Following osmotic stress such as dehydration, this tissue undergoes morphological, electrical and transcriptional changes to facilitate the appropriate regulation and release of Avp into the circulation where it conserves water at the level of the kidney. Here, the organisation of the whole transcriptome following dehydration is modelled to fit Zipf's law, a natural power law that holds true for all natural languages, that states if the frequency of word usage is plotted against its rank, then the log linear regression of this is -1. We have applied this model to our previously published euhydrated and dehydrated SON data to observe this trend and how it changes following dehydration. In accordance with other studies, our whole transcriptome data fit well with this model in the euhydrated SON microarrays, but interestingly, fit better in the dehydrated arrays. This trend was observed in a subset of differentially regulated genes and also following network reconstruction using a third-party database that mines public data. We make use of language as a metaphor that helps us philosophise about the role of the whole transcriptome in providing a suitable environment for the delivery of Avp following a survival threat like dehydration.

  19. Dehydration in the Elderly: A Review Focused on Economic Burden.

    Science.gov (United States)

    Frangeskou, M; Lopez-Valcarcel, B; Serra-Majem, L

    2015-06-01

    Dehydration is the most common fluid and electrolyte problem among elderly patients. It is reported to be widely prevalent and costly to individuals and to the health care system. The purpose of this review is to summarize the literature on the economic burden of dehydration in the elderly. A comprehensive search of several databases from database inception to November 2013, only in English language, was conducted. The databases included Pubmed and ISI Web of Science. The search terms «dehydration» / "hyponaremia" / "hypernatremia" AND «cost» AND «elderly» were used to search for comparative studies of the economic burden of dehydration. A total of 15 papers were identified. Dehydration in the elderly is an independent factor of higher health care expenditures. It is directly associated with an increase in hospital mortality, as well as with an increase in the utilization of ICU, short and long term care facilities, readmission rates and hospital resources, especially among those with moderate to severe hyponatremia. Dehydration represents a potential target for intervention to reduce healthcare expenditures and improve patients' quality of life.

  20. Fructokinase activity mediates dehydration-induced renal injury.

    Science.gov (United States)

    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

    2014-08-01

    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.

  1. Dehydration and fluid volume kinetics before major open abdominal surgery.

    Science.gov (United States)

    Hahn, R G; Bahlmann, H; Nilsson, L

    2014-11-01

    Assessment of dehydration in the preoperative setting is of potential clinical value. The present study uses urine analysis and plasma volume kinetics, which have both been validated against induced changes in body water in volunteers, to study the incidence and severity of dehydration before open abdominal surgery begins. Thirty patients (mean age 64 years) had their urine analysed before major elective open abdominal surgery for colour, specific weight, osmolality and creatinine. The results were scored and the mean taken to represent a 'dehydration index'. Thereafter, the patients received an infusion of 5 ml/kg of Ringer's acetate intravenously for over 15 min. Blood was sampled for 70 min and the blood haemoglobin concentration used to estimate the plasma volume kinetics. Distribution of fluid occurred more slowly (P dehydrated as compared with euhydrated patients. The dehydration index indicated that the fluid deficit in these patients corresponded to 2.5% of the body weight, whereas the deficit in the others was 1%. In contrast, the 11 patients who later developed postoperative nausea and vomiting had a very short elimination half-life, only 9 min (median, P dehydration before major surgery was modest as evidenced both by urine sampling and volume kinetic analysis. © 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  2. Upstream petroleum industry glycol dehydrator benzene emissions status report

    International Nuclear Information System (INIS)

    1999-07-01

    The population of dehydrators referred to are located in the Western Sedimentary Basin in northeast British Columbia, Alberta and Saskatchewan, and includes units installed at wellsites, compressor stations, gas plants, central crude oil treating facilities, and reservoir or salt cavern gas storage facilities. Benzene emissions from the still column vent on glycol dehydrators occur as a result of glycol's strong affinity for aromatic hydrocarbons, including benzene. A study was carried out to: 1) develop a list of oil and gas companies operating in Canada, 2) develop an equipment and benzene emissions inventory of glycol dehydrators, 3) develop a database in Microsoft Access format to gather and maintain inventory and emission data, 4) evaluate and validate at least 10% of the reported data, 5) develop a list of companies that manufacture dehydrators and incinerators to determine how many new dehydrators were sold for use in Canada in 1998, and 6) prepare a report summarizing findings and recommendations. The companies included in the survey were the oil and gas companies identified by the Nickels' Oil and Gas Index and others provided by CAPP, CGA, and SEPAC. The project was carried out to gather glycol dehydrator equipment and still column vent benzene emissions information. 8 refs

  3. Non-Stomatal Inhibition Associated with Inactivation of Rubisco in Dehydrated Coffee Leaves under Unshaded and Shaded Conditions

    OpenAIRE

    Michio, Kanechi; Naotsugu, Uchida; Takeshi, Yasuda; Tadashi, Yamaguchi; Faculty of Agriculture, Kobe University; Faculty of Agriculture, Kobe University; Faculty of Agriculture, Kobe University; Faculty of Agriculture, Kobe University

    1996-01-01

    The effect of rapid dehydration due to withholding of irrigation on leaf photosynthesis in coffee (Coffea arabica L.) was studied by comparing the CO_2-dependent rate of photosynthesis in intact leaves (A/Ci curve), the amounts of Chl, total soluble protein and ribulose-1,5-bisphosphate carboxylase (Rubisco) in leaves, and the activities of photo-chemical reactions of isolated chloroplasts and of Rubisco under unshaded and shaded conditions. The CO_2-saturated rate of photosynthesis and the c...

  4. The functional architecture of dehydration-anorexia.

    Science.gov (United States)

    Watts, Alan G; Boyle, Christina N

    2010-07-14

    The anorexia that accompanies the drinking of hypertonic saline (DE-anorexia) is a critical adaptive behavioral mechanism that helps protect the integrity of fluid compartments during extended periods of cellular dehydration. Feeding is rapidly reinstated once drinking water is made available again. The relative simplicity and reproducibility of these behaviors makes DE-anorexia a very useful model for investigating how the various neural networks that control ingestive behaviors first suppress and then reinstate feeding. We show that DE-anorexia develops primarily because the mechanisms that terminate ongoing meals are upregulated in such a way as to significantly reduce meal size. At the same time however, signals generated by the ensuing negative energy balance appropriately activate neural mechanisms that can increase food intake. But as the output from these two competing processes is integrated, the net result is an increasing reduction of nocturnal food intake, despite the fact that spontaneous meals are initiated with the same frequency as in control animals. Furthermore, hypothalamic NPY injections also stimulate feeding in DE-anorexic animals with the same latency as controls, but again meals are prematurely terminated. Comparing Fos expression patterns across the brain following 2-deoxyglucose administration to control and DE-anorexic animals implicates neurons in the descending part of the parvicellular paraventricular nucleus of the hypothalamus and the lateral hypothalamic areas as key components of the networks that control DE-anorexia. Finally, DE-anorexia generates multiple inhibitory processes to suppress feeding. These are differentially disengaged once drinking water is reinstated. The paper represents an invited review by a symposium, award winner or keynote speaker at the Society for the Study of Ingestive Behavior [SSIB] Annual Meeting in Portland, July 2009. 2010 Elsevier Inc. All rights reserved.

  5. Thermogravimetric study of the dehydration and reduction of red mud

    Science.gov (United States)

    Teplov, O. A.; Korenovskii, N. L.; Lainer, Yu. A.

    2015-01-01

    The processes of drying and reduction of red mud in the pure state and with coal additions in vacuum or in gaseous media (helium, hydrogen) have been experimentally studied by thermogravimetry using a Setaram TAG24 thermogravimetric analyzer. The minimum total weight loss (˜20%) is observed for red mud samples without additives in forevacuum, and the maximum loss (˜38%) is detected in samples with coal. It is demonstrated that, for this type of red mud with iron oxide Fe2O3, water molecules are bonded in the form of iron hydroxide Fe2O3 · 3H2O rather than goethite FeOOH. The peak of magnetite formation is observed in differential thermogravimetry (DTG) curve in the range 270-400°C. The simulation of the magnetite dehydration and formation rates under experimental conditions in the relevant temperature ranges agrees with the experimental data. A peak of wustite formation in hydrogen above ˜600°C is recorded in a DTG curve, and the removal of one-third of sodium oxide, which is likely not to be fixed into strong sodium alumosilicate, is observed in the range 800-1000°C. The peak detected in the DTG curve of the mud with charcoal in helium in the range 350-450°C is similar to the peak of hematite reduction in magnetite in a hydrogen atmosphere. The most probable source of hydrogen-containing gases in this temperature range consists of the residual hydrocarbons of charcoal. The reduction reactions of disperse iron oxides with coal proceed only at temperatures above 600°C. These processes occur in the same temperature range (600-900°C) both in forevacuum and in a helium atmosphere. It is experimentally demonstrated that sintering process occurs in the mud in the temperature range 450-850°C.

  6. Integrated Rig for the Production of Boron Nitride Nanotubes via the Pressurized Vapor-Condenser Method

    Science.gov (United States)

    Smith, Michael W. (Inventor); Jordan, Kevin C. (Inventor)

    2014-01-01

    An integrated production apparatus for production of boron nitride nanotubes via the pressure vapor-condenser method. The apparatus comprises: a pressurized reaction chamber containing a continuously fed boron containing target having a boron target tip, a source of pressurized nitrogen and a moving belt condenser apparatus; a hutch chamber proximate the pressurized reaction chamber containing a target feed system and a laser beam and optics.

  7. Condensation of amino acids to form peptides in aqueous solution induced by the oxidation of sulfur(iv): an oxidative model for prebiotic peptide formation.

    Science.gov (United States)

    Chen, Fei; Yang, Dan

    2007-02-01

    Condensation of amino acids to peptides is an important step during the origin of life. However, up to now, successful explanations for plausible prebiotic peptide formation pathways have been limited. Here we report that the oxidation of sulfur (IV) can induce the condensation reaction of carboxylic acids and amines to form amides, and the condensation reaction of amino acids to form peptides. This might be a general reaction contributing to prebiotic peptide formation.

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

    Science.gov (United States)

    Clennan, Malgorzata M.; Clennan, Edward L.

    2011-01-01

    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…

  9. Condensation: the new deal; Condensation: la nouvelle donne

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-06-01

    The principle of condensation boilers is based on the recovery of the latent heat of the steam generated by the combustion of natural gas. This technology was introduced in France at the end of the 80's but failed in its promise because of the complexity of the equipments available at that time. Today, constructors' offer is more mature and reliable and the context has changed. This technology can conciliate three goals: a mastery of energy consumptions, the comfort of the user and the respect of environment. This meeting organized by the research center of Gaz de France (Cegibat), was a good opportunity to makes a status of the market of individual condensation systems in France and in Europe, to present the situation of this technology today and the 10 golden rules for the fitting and maintenance of individual condensation boilers, and to present some technical references, examples and results of today's offer. (J.S.)

  10. Research progress of control of condensate depression for condenser

    Science.gov (United States)

    Liu, Ying; Liang, Run; Li, Fengyu

    2017-08-01

    It is introduced that significance and structure of the condensate depression control system. In accordance with controller devised procedure, we analyze and elaborate how to construct the lumped parameter and dynamic mathematical model which possesses distinct physics significance. Neural network model being called black-box model is also introduced. We analyze and contrast the control technique of condensate depression as conventional PI control, fuzzy PI control and fuzzy control. It is indicated that if the controller of condensate depression were devised inappropriate, while the steam discharged of turbine varying by a large margin, would result in the rotation rate of cooling water circulating pump accelerating at a great lick even to trigger the galloping danger which is less impressive for the units operating safely.

  11. Tetradentate-arm Schiff base derived from the condensation reaction of 3,3′-dihydroxybenzidine, glyoxal/diacetyl and 2-aminophenol: Designing, structural elucidation and properties of their binuclear metal(II complexes

    Directory of Open Access Journals (Sweden)

    E. Akila

    2017-05-01

    Full Text Available The novel binuclear Schiff base complexes were prepared by the reaction of 3,3′-dihydroxybenzidine, glyoxal/diacetyl and 2-aminophenol in 1:2:2 M ratio. The binucleating Schiff base ligand and its complexes of Cu(II, Ni(II and VO(II ions were characterized by elemental analysis, molar conductance, 1H NMR, infrared, electronic spectra, cyclic voltammetry, thermal, magnetic and EPR studies. The low molar conductance values of the complexes support the non-electrolytic in nature. In IR spectra, the comparison of shift in frequency of the complexes with the ligand reveals the coordination of donor atom to the metal atom. The binuclear nature of the complexes is assessed from their magnetic susceptibility values. The electronic and EPR spectra of the metal complexes provide information about the geometry of the complexes and are in good agreement with the proposed square planar geometry for Cu(II, Ni(II and square pyramidal for VO(II complexes. Molecular modeling has been used to suggest the structure of the complexes. The DNA cleavage ability of the complexes was monitored by gel electrophoresis using supercoiled pUC18 DNA. The metal complexes were screened for their antibacterial activities against pathogenic bacteria like Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Bacillus subtilis. The activity data show that the metal complexes are more potent activity than the parent Schiff base ligand against microorganisms.

  12. Using Dehydrated Vegetables in Some Brown Bread Types

    Directory of Open Access Journals (Sweden)

    Simona Man

    2013-11-01

    Full Text Available Normal 0 false false false MicrosoftInternetExplorer4 Expanding the range of bakery products in terms of producing supplemented or dietetic products has been an increasingly important trend in contemporary baking. Bakery products as basic and popular food, could be used in the prevention of nutritive deficiencies of many important nutrients, by supplementing the products with biologically valuable ingredients. Such ingredients are dehydrated vegetables in the form of powder. For establishing the bread quality, a special importance shows it’s chemical composition, because the substances that enter in it’s constitution serve to obtaining the energy necessary to the human body. Beside the chemical composition, the bread quality and alimentary use, respectively, depends a large measure on a series of signs: flavor and taste, external appearance, crumb porosity and texture, breads’ volume. This paper belongs to a more complex study, which aims are obtaining some bread assortments with high nutritional value, and improving their sensorial and rheological features, by adding dehydrated vegetables at different levels 4% potato flakes, 2% dehydrated onion, 0.5% dehydrated garlic and 2% dehydrated leek.

  13. Dehydration during exercise: what are the real dangers?

    Science.gov (United States)

    Noakes, T D

    1995-01-01

    The belief that dehydration poses significant health risks for endurance athletes, especially marathon and ultramarathon runners, stems from the classical 1969 study of Wyndham and Strydom entitled "The Danger of an Inadequate Water Intake During Marathon Running." The subsequent influence of the paper relates more to its incorrect title than to its scientific content. For the authors did not study nor did they identify any dangers resulting from an inadequate water intake during marathon running. In fact, the most dehydrated runners in their studies were also the most successful, as they won the competitive races that were studied. The positive result of the study was to influence international rule changes to allow increased fluid intake during competitive running races. The less desirable effect was to induce a dogmatic zeal among sports medicine practitioners who began to extol the dangers of dehydration during exercise. The (il)logic spurring this zeal seems to have been the conclusion that progressive dehydration during exercise will cause heatstroke, which is the most important cause of collapse during exercise. Hence, (i) heatstroke during running can only be avoided if dehydration is prevented, and (ii) all persons who collapse in association with exercise will have a heat disorder, which must be treated with intravenous fluid therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

  14. Influences of Different Conditioners on Dehydration Ratio of Activated Sludge

    Science.gov (United States)

    Zhuo, Qiongfang; Zheng, Wenli; Yi, Hao; Chen, Sili; Xu, Zhencheng; Jin, Zhong; Lan, Yongzhe; Guo, Qingwei

    2017-11-01

    Excess sludge contains a large quantity of water with water content reaching about 97%-99%. Besides microorganisms and germs, the sludge is of complicated composition, including heavy metals, persistent organic pollutants, PPCPs, endocrine disrupters, etc. It covers a large area with harmfulness, so it needs further treatment. However, due to existence of extracellular polymeric substances in the sludge, the sludge has poor dehydration property, so how to improve dehydration of sludge is a difficult point in water treatment industry. Chemical conditioning—mechanical dehydration method is sludge dehydration technology which has been widely applied in China. Most sludge treatment plants use organic and inorganic conditioners like polyacrylamide (PAM), polyaluminum chloride (PAC) and polymerized ferrous sulfate (PFS), etc. With characteristics of low toxicity and degradation resistance, these conditioners pose potential risks to the environment and they are adverse to follow-up resource utilization. Therefore, influences of 17 conditioners on sludge dehydration ratio were discussed in this paper, expecting to seek for green, environmentally friendly and highly efficient conditioner so as to improve resource utilization ratio of sludge.

  15. Features of the Treatment for the Syndrome of Dehydration in Infants and Older Children, Newborns: Fundamentals of Parenteral Rehydration

    Directory of Open Access Journals (Sweden)

    V.I. Snisar

    2016-04-01

    Full Text Available In pediatric practice, the syndrome of dehydration is quite common. In children, the most likely cause of the fluid loss is gastroenteritis syndrome and diarrhea of various origins. These causes are often associated with diarrhea and vomiting that results in the loss of water and electrolytes in various proportions. In contrast to the treatment of critical conditions, such as hypovolemic and septic shock, there is no standardized approach to the correction of mild to moderate syndrome of dehydration. The role of oral rehydration in the prehospital and hospital stage is significantly underestimated. This article is a sign of interest in the unification of approaches to the treatment of such conditions, makes it possible to get acquainted with a generalized view of the treatment and prevention of a variety of adverse reactions on the background of oral and/or parenteral rehydration. Our survey reminds the practitioner about the features of dehydration syndrome in children of different age groups, the importance of taking into account the pathogenesis of various types of dehydration during the diagnosis, de­monstrates the importance of knowledge in the field of infusion media in the context of the therapy balanced in terms of the volume and components, as well as considers the target fluid spaces of the body under pathological losses. We investigate the concept of physiological infusion solution on the basis of evidence-based medicine. This review is advisory, it is based both on the national experience in the treatment of the syndrome of dehydration and foreign resources analysis.

  16. Introduction. Cosmology meets condensed matter.

    Science.gov (United States)

    Kibble, T W B; Pickett, G R

    2008-08-28

    At first sight, low-temperature condensed-matter physics and early Universe cosmology seem worlds apart. Yet, in the last few years a remarkable synergy has developed between the two. It has emerged that, in terms of their mathematical description, there are surprisingly close parallels between them. This interplay has been the subject of a very successful European Science Foundation (ESF) programme entitled COSLAB ('Cosmology in the Laboratory') that ran from 2001 to 2006, itself built on an earlier ESF network called TOPDEF ('Topological Defects: Non-equilibrium Field Theory in Particle Physics, Condensed Matter and Cosmology'). The articles presented in this issue of Philosophical Transactions A are based on talks given at the Royal Society Discussion Meeting 'Cosmology meets condensed matter', held on 28 and 29 January 2008. Many of the speakers had participated earlier in the COSLAB programme, but the strength of the field is illustrated by the presence also of quite a few new participants.

  17. Condensational theory of stationary tornadoes

    International Nuclear Information System (INIS)

    Makarieva, A.M.; Gorshkov, V.G.; Nefiodov, A.V.

    2011-01-01

    Using the Bernoulli integral for air streamline with condensing water vapor a stationary axisymmetric tornado circulation is described. The obtained profiles of vertical, radial and tangential velocities are in agreement with observations for the Mulhall tornado, world's largest on record and longest-lived among the three tornadoes for which 3D velocity data are available. Maximum possible vortex velocities are estimated. -- Highlights: → Water vapor condensation causes a logarithmic drop of air pressure towards tornado center. → The first ever theoretical description of tornado velocities is obtained. → The maximum vortex velocity grows logarithmically with decreasing tornado eye radius. → Air motion with high velocities can only develop in sufficiently large condensation areas.

  18. On topotaxy and compaction during antigorite and chlorite dehydration: an experimental and natural study

    Science.gov (United States)

    Padrón-Navarta, José Alberto; Tommasi, Andréa; Garrido, Carlos J.; Mainprice, David

    2015-04-01

    Dehydration reactions result in minerals' replacement and a transient fluid-filled porosity. These reactions involve interface-coupled dissolution-precipitation and might therefore lead to fixed crystallographic orientation relations between reactant (protolith) and product phases (i.e. topotaxy). We investigate these two phenomena in the dehydration of a foliated antigorite (atg) serpentinite by comparing the crystallographic preferred orientation (CPO) developed by olivine (ol), orthopyroxene (opx) and chlorite (chl) during high-pressure antigorite and chlorite dehydration in piston-cylinder experiments and in natural samples recording the dehydration of antigorite (Cerro del Almirez, Betic Cordillera, Spain). Experiments were performed under undrained conditions resulting in fluid-filled porosity and in strong CPO of the prograde minerals, controlled by the pre-existing antigorite CPO in the reactant foliated serpentinite. The orientation of a ol,opx and is parallel to from the protolith. The Cerro del Almirez samples show similar, locally well-developed topotactic relations between orthopyroxene, chlorite and antigorite, but the product CPOs are weaker and more complex at the thin section scale. In contrast to the experiments, olivine from natural samples shows a weak correlation between b ol and the former . We relate the strengthening of local topotactic relations and the weakening of the inherited CPO at a larger scale in natural samples to compaction and associated fluid migration. Microstructural features that might be related to compaction in the natural samples include: (1) smooth bending of the former foliation, (2) gradual crystallographic misorientation (up to 16°) of prismatic orthopyroxene due to buckling by dislocation creep, (3) inversion of enstatite to low clinoenstatite (P21/c) along lamellae and (4) brittle fracturing of prismatic orthopyroxene enclosed by plastically deformed chlorite. The coexistence of orthopyroxene buckling and

  19. Dehydration of MoO 3 · 2H 2O: A Neutron Thermodiffractometry Study

    Science.gov (United States)

    Boudjada, N.; Rodríguez-Carvajal, J.; Anne, M.; Figlarz, M.

    1993-07-01

    A neutron powder thermodiffractometric study of the dehydration reactions MoO 3 · 2H 2O → MoO 3 · H 2O → MoO 3 has been carried out in order to investigate the topotactic mechanism previously reported. The topotactic character of the reactions is confirmed and an approximate model for the crystal structure of MoO 3 · H 2O is proposed. Quantitative data about the relative amount of the existing phases, as a function of temperature, have been deduced from multiphase profile analysis. The anomalous behavior of the cell parameters of MoO 3 · H 2O, at about 100°C, indicates the existence of a new phase transition. The evolution of the crystallite size of MoO 3 has also been obtained from the broadening of Bragg reflections at high temperature. The preferred direction of growth is along [021].

  20. Scrutinizing the pion condensed phase

    Energy Technology Data Exchange (ETDEWEB)

    Carignano, Stefano; Mammarella, Andrea; Mannarelli, Massimo [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Lepori, Luca [Universita di Padova, Dipartimento di Fisica e Astronomia, Padova (Italy); Universita dell' Aquila, Dipartimento di Scienze Fisiche e Chimiche, Coppito-L' Aquila (Italy); Pagliaroli, Giulia [INFN, Laboratori Nazionali del Gran Sasso, Assergi (Italy); Gran Sasso Science Institute, L' Aquila (Italy)

    2017-02-15

    When the isospin chemical potential exceeds the pion mass, charged pions condense in the zero-momentum state forming a superfluid. Chiral perturbation theory provides a very powerful tool for studying this phase. However, the formalism that is usually employed in this context does not clarify various aspects of the condensation mechanism and makes the identification of the soft modes problematic. We re-examine the pion condensed phase using different approaches within the chiral perturbation theory framework. As a first step, we perform a low-density expansion of the chiral Lagrangian valid close to the onset of the Bose-Einstein condensation. We obtain an effective theory that can be mapped to a Gross-Pitaevskii Lagrangian in which, remarkably, all the coefficients depend on the isospin chemical potential. The low-density expansion becomes unreliable deep in the pion condensed phase. For this reason, we develop an alternative field expansion deriving a low-energy Lagrangian analog to that of quantum magnets. By integrating out the ''radial'' fluctuations we obtain a soft Lagrangian in terms of the Nambu-Goldstone bosons arising from the breaking of the pion number symmetry. Finally, we test the robustness of the second-order transition between the normal and the pion condensed phase when next-to-leading-order chiral corrections are included. We determine the range of parameters for turning the second-order phase transition into a first-order one, finding that the currently accepted values of these corrections are unlikely to change the order of the phase transition. (orig.)

  1. Structural ordering of disordered ligand-binding loops of biotin protein ligase into active conformations as a consequence of dehydration.

    Directory of Open Access Journals (Sweden)

    Vibha Gupta

    Full Text Available Mycobacterium tuberculosis (Mtb, a dreaded pathogen, has a unique cell envelope composed of high fatty acid content that plays a crucial role in its pathogenesis. Acetyl Coenzyme A Carboxylase (ACC, an important enzyme that catalyzes the first reaction of fatty acid biosynthesis, is biotinylated by biotin acetyl-CoA carboxylase ligase (BirA. The ligand-binding loops in all known apo BirAs to date are disordered and attain an ordered structure only after undergoing a conformational change upon ligand-binding. Here, we report that dehydration of Mtb-BirA crystals traps both the apo and active conformations in its asymmetric unit, and for the first time provides structural evidence of such transformation. Recombinant Mtb-BirA was crystallized at room temperature, and diffraction data was collected at 295 K as well as at 120 K. Transfer of crystals to paraffin and paratone-N oil (cryoprotectants prior to flash-freezing induced lattice shrinkage and enhancement in the resolution of the X-ray diffraction data. Intriguingly, the crystal lattice rearrangement due to shrinkage in the dehydrated Mtb-BirA crystals ensued structural order of otherwise flexible ligand-binding loops L4 and L8 in apo BirA. In addition, crystal dehydration resulted in a shift of approximately 3.5 A in the flexible loop L6, a proline-rich loop unique to Mtb complex as well as around the L11 region. The shift in loop L11 in the C-terminal domain on dehydration emulates the action responsible for the complex formation with its protein ligand biotin carboxyl carrier protein (BCCP domain of ACCA3. This is contrary to the involvement of loop L14 observed in Pyrococcus horikoshii BirA-BCCP complex. Another interesting feature that emerges from this dehydrated structure is that the two subunits A and B, though related by a noncrystallographic twofold symmetry, assemble into an asymmetric dimer representing the ligand-bound and ligand-free states of the protein, respectively. In

  2. Study of the dehydration of Portland cement by Moessbauer spectrometry

    International Nuclear Information System (INIS)

    Hassaan, M.Y.; Salah, S.H.; Eissa, N.A.

    1989-01-01

    Egyptian Portland Cement in the form of one inch cube was hydrated at different times of hydration. Nine cubes of each period of hydration were heated for five minutes 200, 300, 400 up to 1000 0 C then were quenched in air. The compressive strength was measured for these samples and related to unheated ones. These cubes were ground and measured by Moessbauer spectrometry to correlate the effect of dehydration of cement pastes on the states of iron, with the decrease of compressive strength. It was observed that starting from 400 0 C the central doublet characteristic of the hydration process decreased as the dehydration temperature was increased. At 1000 0 C the dehydration process was complete, the central doublet disappeared and the compressive strength vanished. The hydration process was found to be reversible. The application of Moessbauer spectrometry to estimate the degree of fire in concrete building was demonstrated. (orig.)

  3. Isothermal dehydration of thin films of water and sugar solutions

    International Nuclear Information System (INIS)

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

    2014-01-01

    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

  4. Studying thermal dehydration of double nickel alkali metal pyrophosphates

    International Nuclear Information System (INIS)

    Bykanova, T.A.; Lavrov, A.V.; AN SSSR, Moscow. Inst. Obshchej i Neorganicheskoj Khimii)

    1978-01-01

    The methods of thermogravimetry, paper chromatography, infrared spectroscopy and X-ray phase analysis were used in studying the process of thermal dehydration of pyrophosphates of the M 2 Ni 3 (P 2 O 7 ) 2 xnH 2 O type (where n=6, 10; M=Na, K, Rb, Cs, NH 4 ). The dehydration of Cs 2 Ni 3 (P 2 O 7 ) 2 x10H 2 O proceeds in a single stage (endothermal effect at 210 deg C). The exothermal effects at 730 and 690 deg C correspond to the crystallization of the amorphous dehydration products. It has been established that binary pyrophosphates of nickel with alkali metals decompose when heated into Ni 3 (PO 4 ) 2 +MPO 4

  5. Isothermal dehydration of thin films of water and sugar solutions

    Energy Technology Data Exchange (ETDEWEB)

    Heyd, R. [Centre de Recherche sur la Matière Divisée, University of Orleans and CNRS, rue de la Férollerie 1B, 45071 Orléans Cedex 2 (France); Rampino, A. [Centre de Recherche sur la Matière Divisée, University of Orleans and CNRS, rue de la Férollerie 1B, 45071 Orléans Cedex 2 (France); Laboratory of Physical and Macromolecular Chemistry, University of Trieste, Via Giorgieri 1, 34127 Trieste (Italy); Bellich, B.; Elisei, E. [Laboratory of Physical and Macromolecular Chemistry, University of Trieste, Via Giorgieri 1, 34127 Trieste (Italy); Cesàro, A. [Laboratory of Physical and Macromolecular Chemistry, University of Trieste, Via Giorgieri 1, 34127 Trieste (Italy); Elettra Sincrotrone Trieste, Area Science Park, I-34149 Trieste (Italy); Saboungi, M.-L. [Centre de Recherche sur la Matière Divisée, University of Orleans and CNRS, rue de la Férollerie 1B, 45071 Orléans Cedex 2 (France); Institut de Minéralogie, de Physique des Matériaux, et de Cosmochimie (IMPMC), Sorbonne Univ-UPMC, Univ Paris 06, UMR CNRS 7590, Museum National d’Histoire Naturelle, IRD UMR 206, 4 Place Jussieu, F-75005 Paris (France)

    2014-03-28

    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.

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

    Science.gov (United States)

    Bērziņš, Agris; Actiņš, Andris

    2014-06-01

    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. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  7. EPR study on gamma-irradiated fruits dehydrated via osmosis

    Energy Technology Data Exchange (ETDEWEB)

    Yordanov, N.D. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)]. E-mail: ndyepr@bas.bg; Aleksieva, K. [Laboratory EPR, Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

    2007-06-15

    The shape and time stability of the electron paramagnetic resonance (EPR) spectra of non- and {gamma}-irradiated papaya, melon, cherry and fig samples dehydrated via osmosis are reported. It is shown that non-irradiated samples are generally EPR silent whereas {gamma}-irradiated exhibit 'sugar-like' EPR spectra. The recorded EPR spectra are monitored for a period of 7 months after irradiation (stored at low humidity and in the dark). The results suggest longer period of unambiguous identification of the radiation processing of osmose dehydrated fruits. Therefore, the Protocol EN 13708,2001 issued by CEN is fully applicable for the studied fruit samples.

  8. The chiral condensate in matter

    International Nuclear Information System (INIS)

    Brockmann, R.; Weise, W.

    1995-01-01

    The change of the chiral condensate in dense matter is discussed. Especially the higher order terms in the density of nuclear matter are evaluated (in the relativistic Brueckner-Hartree-Fock approach). Implications for nuclear physics and relativistic heavy ion collisions are discussed, such as the strong Dirac scalar mean field that results from the density dependence of . (orig.)

  9. KAON CONDENSATION IN NEUTRON STARS.

    Energy Technology Data Exchange (ETDEWEB)

    RAMOS,A.; SCHAFFNER-BIELICH,J.; WAMBACH,J.

    2001-04-24

    We discuss the kaon-nucleon interaction and its consequences for the change of the properties of the kaon in the medium. The onset of kaon condensation in neutron stars under various scenarios as well its effects for neutron star properties are reviewed.

  10. Approaching Bose-Einstein Condensation

    Science.gov (United States)

    Ferrari, Loris

    2011-01-01

    Bose-Einstein condensation (BEC) is discussed at the level of an advanced course of statistical thermodynamics, clarifying some formal and physical aspects that are usually not covered by the standard pedagogical literature. The non-conventional approach adopted starts by showing that the continuum limit, in certain cases, cancels out the crucial…

  11. Kinetic isotope effect in dehydration of ionic solids. II. The kinetics of dehydration of calcium oxalate monohydrate

    International Nuclear Information System (INIS)

    Manche, E.P.; Carroll, B.

    1977-01-01

    The kinetics of the isothermal dehydration of the protonated and deuterated monohydrate of calcium oxalate has been investigated at 120, 150, and 170 0 C. The rate of dehydration for these salts was found to be k/sub H//k/sub D/ = 1.025 +- 0.012. This result rules out the enormous kinetic isotope effect as given in the literature. An isotope effect of a few percent is not ruled out; this magnitude is in keeping with that found by Heinzinger in other dehydration processes. An estimated difference of about 150 cal/mol between the heat of desorption for H 2 O and D 2 O should have led to a ratio, k/sub h//k/sub D/ = 1.20. The smaller observed ratio has been explained on the basis of a compensation effect and may be considered an example of the Barclay--Butler correlation

  12. Comparative study between microwave and conventional dehydration of okra.

    Directory of Open Access Journals (Sweden)

    Shams El Din, M. H. A.

    1999-12-01

    Full Text Available This study was conducted to evaluate different pre-treatments and dehydration methods on the quality of okra. No significant differences were found among pretreatments and dehydration methods for the chemical composition of dehydrated okra samples. Dipping in 0.1 % sodium metabisulphite solution at room temperature and immersion in 0.1 % sodium metabisulphite solution at 92-95 °C improved the retention of ascorbic acid of okra samples after dehydration by either conventional or microwave oven. Also, the reduced dehydration time required for microwave dehydration produced far less destruction of ascorbic acid. The highest rehydration ratio was found in unwashed okra sample and dehydrated by microwave after immersion in 0.1 % sodium metabisulphite solution at 92-95 °C. Dehydrated okra samples by sun drying and conventional oven had lower retention percentages of total chlorophyll and carotenoids than those of dehydrated okra samples by microwave oven. The general appearance and colour scores of dehydrated okra samples by microwave were significantly different from those of conventionally dehydrated or sun dried okra samples.

    Este estudio se ha realizado para evaluar los diferentes pretratamientos y métodos de deshidratación en la calidad del kimbombó. No se encontraron diferencias significativas entre ellos respecto a la composición química de las muestras de kimbombó deshidratadas. La inmersión en solución de metabisulfito sódico al 0.1 % a temperatura ambiente y la inmersión en solución de metabisulfito sódico al 0.1 % a 92-95 °C mejoraron la retención de ácido ascórbico de las muestras de kimbombó después de la deshidratación tanto utilizando el homo convencional como el horno microondas. Además el menor tiempo necesario para la deshidratación usando el horno microondas produjo menos destrucción de ácido ascórbico. La mayor relación de rehidratación fue encontrada en muestras de kimbombó no tratadas o

  13. Modeling of Kerena Emergency Condenser

    Science.gov (United States)

    Bryk, Rafał; Schmidt, Holger; Mull, Thomas; Wagner, Thomas; Ganzmann, Ingo; Herbst, Oliver

    2017-12-01

    KERENA is an innovative boiling water reactor concept equipped with several passive safety systems. For the experimental verification of performance of the systems and for codes validation, the Integral Test Stand Karlstein (INKA) was built in Karlstein, Germany. The emergency condenser (EC) system transfers heat from the reactor pressure vessel (RPV) to the core flooding pool in case of water level decrease in the RPV. EC is composed of a large number of slightly inclined tubes. During accident conditions, steam enters into the tubes and condenses due to the contact of the tubes with cold water at the secondary side. The condensed water flows then back to the RPV due to gravity. In this paper two approaches for modeling of condensation in slightly inclined tubes are compared and verified against experiments. The first approach is based on the flow regime map. Depending on the regime, heat transfer coefficient is calculated according to specific semi-empirical correlation. The second approach uses a general, fully-empirical correlation. The models are developed with utilization of the object-oriented Modelica language and the open-source OpenModelica environment. The results are compared with data obtained during a large scale integral test, simulating loss of coolant accident performed at Integral Test Stand Karlstein (INKA). The comparison shows a good agreement.Due to the modularity of models, both of them may be used in the future in systems incorporating condensation in horizontal or slightly inclined tubes. Depending on his preferences, the modeller may choose one-equation based approach or more sophisticated model composed of several exchangeable semi-empirical correlations.

  14. Modeling of Kerena Emergency Condenser

    Directory of Open Access Journals (Sweden)

    Bryk Rafał

    2017-12-01

    Full Text Available KERENA is an innovative boiling water reactor concept equipped with several passive safety systems. For the experimental verification of performance of the systems and for codes validation, the Integral Test Stand Karlstein (INKA was built in Karlstein, Germany. The emergency condenser (EC system transfers heat from the reactor pressure vessel (RPV to the core flooding pool in case of water level decrease in the RPV. EC is composed of a large number of slightly inclined tubes. During accident conditions, steam enters into the tubes and condenses due to the contact of the tubes with cold water at the secondary side. The condensed water flows then back to the RPV due to gravity. In this paper two approaches for modeling of condensation in slightly inclined tubes are compared and verified against experiments. The first approach is based on the flow regime map. Depending on the regime, heat transfer coefficient is calculated according to specific semi-empirical correlation. The second approach uses a general, fully-empirical correlation. The models are developed with utilization of the object-oriented Modelica language and the open-source OpenModelica environment. The results are compared with data obtained during a large scale integral test, simulating loss of coolant accident performed at Integral Test Stand Karlstein (INKA. The comparison shows a good agreement.Due to the modularity of models, both of them may be used in the future in systems incorporating condensation in horizontal or slightly inclined tubes. Depending on his preferences, the modeller may choose one-equation based approach or more sophisticated model composed of several exchangeable semi-empirical correlations.

  15. Condensed tannin-resorcinol adducts in laminating adhesives

    Science.gov (United States)

    Richard W. Hemingway; Roland E. Kreibich

    1985-01-01

    A condensed tannin-resorcinol adduct made by co-reaction of an extract from southern pine bark with resorcinol at a 2 to 1 weight ratio was used to prepare a laminating resin in which the entire amount of resorcinol normally used was replaced by this adduct. The resin was formulated into a room temperature setting adhesive that meets the basic criteria of product...

  16. Dehydration kinetics of Portland cement paste at high temperature

    NARCIS (Netherlands)

    Zhang, Q.; Ye, G.

    2012-01-01

    Portland cement paste is a multiphase compound mainly consisting of calcium-silicate-hydrate (CSH) gel, calcium hydroxide (CH) crystal, and unhydrated cement core. When cement paste is exposed to high temperature, the dehydration of cement paste leads to not only the decline in strength, but also

  17. Partial dehydration of 'Niagara Rosada' GRAPES ( Vitis labrusca L ...

    African Journals Online (AJOL)

    The partial dehydration of grapes after harvest and aimed wine-making, has been shown to be a process that brings increased concentration of sugar and phenolic compounds in the must, which results in the quality of the wines produced. However, the works developed so far studied the process for temperatures up to a ...

  18. Comparison of Gas Dehydration Methods based on Energy ...

    African Journals Online (AJOL)

    PROF HORSFALL

    Hydrocarbon Engineering 5: 71-74. Kumar, S (1987) Gas Production Engineering. Houston: Gulf Professional Publishing 239. NET4GAS (2011) Gas quality parameters. Available at:http://extranet.transgas.cz/caloricity_spec.aspx . Netusil, M. and Ditl, P. (2010). Comparison of. Methods for Dehydration of Natural Gas Stored.

  19. Water-activity of dehydrated guava slices sweeteners

    International Nuclear Information System (INIS)

    Ayub, M.; Zeb, A.; Ullah, J.

    2005-01-01

    A study was carried out to investigate the individual and combined effect of caloric sweeteners (sucrose, glucose and fructose) and non-caloric sweeteners (saccharine, cyclamate and aspartame) along with antioxidants (citric acid and ascorbic acid) and chemical preservatives (potassium metabisulphite and potassium sorbate) on the water-activity (a/sub w/) of dehydrated guava slices. Different dilutions of caloric sweeteners (20, 30, 40 and 50 degree brix (bx) and non-caloric sweeteners (equivalent to sucrose sweetness) were used. Guava slices were osmotically dehydrated in these solutions and then dehydrated initially at 0 and then at 60 degree C to final moisture-content of 20-25%. Guava slices prepared with sucrose: glucose 7:3 potassium metabisulphite, ascorbic acid and citric acid produced best quality products, which have minimum (a/sub w/) and best overall sensory characteristics. The analysis showed that treatments and their various concentrations had a significant effect (p=0.05) on (a/sub w/) of dehydrated guava slices. (author)

  20. A fatal case of hypernatraemic dehydration in a neonate.

    Science.gov (United States)

    Staub, Eveline; Wilkins, Barry

    2012-09-01

    Problems with lactation can result in hypernatraemic dehydration in the neonate, with potentially severe adverse consequences. This is illustrated in this fatal case of a 10 day old neonate who presented with excessive hypernatraemic dehydration due to insufficient breast milk intake, resulting in cerebral sinus vein thrombosis with cerebral haemorrhage and infarction. Differential diagnosis included excessive sodium intake (through inappropriately mixed formula or house remedies or through hyperaldosteronism) and high water deficit (renal or gastrointestinal losses, nephrogenic or central diabetes insipidus), all of which were ruled out by specific investigations or history. No evidence was found for inborn error of metabolism. The dehydration in this baby, however, was accentuated by trans-epidermal water loss due to an ichthyosiform skin condition. This first ever reported Australian fatality from neonatal hypernatraemic dehydration supports the concern of health care professionals over rising incidences of this entity in exclusively breastfed infants, and should encourage endorsement of improved monitoring of weight loss in newborns and breastfeeding support for their mothers. © 2012 The Authors. Journal of Paediatrics and Child Health © 2012 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

  1. DEHYDRATION OF ALCOHOLS VIA PREVAPORATION USING A NOVEL HYDROPHILIC MEMBRANE

    Science.gov (United States)

    Pervaporation has emerged as an economically viable alternative technology for the dehydration of organic solvents, removal of organic compounds from water and organic/organic separations. Development of a suitable membrane system with high flux and high selectivity plays a criti...

  2. Science Study Aids 1: Dehydration for Food Preservation.

    Science.gov (United States)

    Boeschen, John; And Others

    This publication is the first of a series of seven supplementary investigative materials for use in secondary science classes providing up-to-date research-related investigations. This unit is structured for grades 9 through 12. It is concerned with the osmatic dehydration of fruits. The guide provides students with information about food…

  3. Process modelling and optimization of osmotic dehydration assisted ...

    African Journals Online (AJOL)

    Osmotic dehydration (pretreatment) of red bell pepper in hypertonic salt (NaCl) solution and drying was studied. A 4X4X4 factorial experiment in a Randomized Complete Block Design (RCBD) was used for the pretreatment and pretreated samples were later dried in a fabricated laboratory dryer. Process variables ...

  4. Physico-chemical changes during storage of dehydrated plantain ...

    African Journals Online (AJOL)

    The changes in some physico-chemical properties of dehydrated plantain slices packaged in polyethylene and polypropylene pouches and stored, at 37 oC and 75 per cent RH, for 6 months were studied. Moisture gain, non-enzymatic browning, colour changes, puncture force, pH, ascorbic acid and total acidity were ...

  5. NONCHEMICAL DEHYDRATION OF FIXED TISSUE COMBINING MICROWAVES AND VACUUM

    NARCIS (Netherlands)

    KOK, LP; BOON, ME

    A novel histoprocessing method for paraffin and plastic sections is presented in which dehydration of fixed tissue blocks is achieved within 5 minutes by microwaving under vacuum. Exploiting the decrease in boiling temperature under vacuum, we succeed in evaporating liquid molecules in the tissues

  6. Mechanisms by Which Dehydration May Lead to Chronic Kidney Disease.

    Science.gov (United States)

    Roncal-Jimenez, C; Lanaspa, M A; Jensen, T; Sanchez-Lozada, L G; Johnson, R J

    2015-01-01

    Dehydration, a condition that characterizes excessive loss of body water, is well known to be associated with acute renal dysfunction; however, it has largely been considered reversible and to be associated with no long-term effects on the kidney. Recently, an epidemic of chronic kidney disease has emerged in Central America in which the major risk factor seems to be recurrent heat-associated dehydration. This has led to studies investigating whether recurrent dehydration may lead to permanent kidney damage. Three major potential mechanisms have been identified, including the effects of vasopressin on the kidney, the activation of the aldose reductase-fructokinase pathway, and the effects of chronic hyperuricemia. The discovery of these pathways has also led to the recognition that mild dehydration may be a risk factor in progression of all types of chronic kidney diseases. Furthermore, there is some evidence that increasing hydration, particularly with water, may actually prevent CKD. Thus, a whole new area of investigation is developing that focuses on the role of water and osmolarity and their influence on kidney function and health. © 2015 S. Karger AG, Basel.

  7. DEHYDRATION OF ALCOHOLS VIA PERVAPORATION USING A NOVEL HYDROHILIC MEMBRANE

    Science.gov (United States)

    Pervaporation has emerged as an economically viable alternative technology for the dehydration of organic solvents, removal of organic compounds from water and organic/organic separations. Development of a suitable membrane system with high flux and high selectivity plays a criti...

  8. Thirst perception in dehydrated sickle cell disease patients in steady ...

    African Journals Online (AJOL)

    Using the Visual Analogue Scale we studied thirst perception (TP) in 20 euhydrated SCA patients and 28 control (HbA) subjects, as well as during dehydration in 13 SCA patients and 9 HbA subjects. Serum and urine samples were collected and analyzed for Na, K ions, creatinine concentrations and haematocrit and ...

  9. Hypernatraemic dehydration in infants with acute gastroenteritis at ...

    African Journals Online (AJOL)

    however, describes a higher HIV exposure prevalence in relation to hypernatraemic dehydration, warranting ... Bangladesh reported that 28% of their hypernatraemic patients had severe wasting.This finding could be ... [8] In contrast, a Chinese study concluded that a faster rate of Na correction was a significant risk factor for ...

  10. Osmotic dehydration - a pre-treatment for pineapple drying

    CSIR Research Space (South Africa)

    Lombard, GE

    2006-02-01

    Full Text Available Cayenne- type pineapple pieces. The effects of osmotic dehydration on mass transfer properties such as water loss, solids gain and weight reduction were investigated. The results obtained were also analysed in terms of WL/SG ratio since this parameter can...

  11. Carbon-based building blocks for alcohol dehydration

    DEFF Research Database (Denmark)

    Boffa, Vittorio; Mallon, Peter E.; Magnacca, Giuliana

    A biopolymer (HAL), extracted from organic compost with yield ~20%, was used to fabricate composite HAL-graphene oxide (GO) membranes. Upon thermal stabilization, HAL brings high disorder in the membrane structure, thus increasing water permeability. This feature together with the good water/etha....../ethanol perm-selectivity make GO-HAL membranes promising devices for alcohol dehydration....

  12. Drying of carrots in slices with osmotic dehydration

    African Journals Online (AJOL)

    SAM

    2014-07-23

    Jul 23, 2014 ... According to Torreggiani (1993), osmotic dehydration is a special method of drying which is based on the principle that when cellular material are immersed in a hypertonic aqueous solution, a driving force for water removal sets up because of the higher osmotic pressure of the hypertonic solution.

  13. Replacement of barley grains and dehydrated alfalfa by Sulla Hay ...

    African Journals Online (AJOL)

    Replacement of barley grains and dehydrated alfalfa by Sulla Hay (Hedysarum flexuosum) and common reed leaves (Phragmites australis) in fattening rabbits diet. S.A. Kadi, A. Mouhous, F. Djellal, ... was valuable for fattening rabbit. Keywords: Rabbit, Growth performances, Phragmites australis, Hedysarum flexuosum.

  14. Reduction of air pollution with new dehydration concepts

    International Nuclear Information System (INIS)

    Khoi, V.V.

    1991-01-01

    The conference paper deals with the new dehydration concepts being designed for preventing hydrate formation during the transport of gas for a group of fields being under development in the North Sea. The development comprises a central production platform consisting of a gas treatment system using triethylene and/or diethylene glycol in the process. 4 figs., 3 tabs

  15. POTENTIAL DIMETHYLMERCURY CONCENTRATION IN WATER & ORGANIC CONDENSATE

    Energy Technology Data Exchange (ETDEWEB)

    MEACHAM, J.E.

    2004-12-28

    This document bounds potential dimethylmercury concentration in water or organic condensate that might form in ventilation systems or cooler tank regions. Dimethylmercury concentrations were extremely low and would be below drinking water standards in the water condensate.

  16. Mantle wedge infiltrated with saline fluids from dehydration and decarbonation of subducting slab.

    Science.gov (United States)

    Kawamoto, Tatsuhiko; Yoshikawa, Masako; Kumagai, Yoshitaka; Mirabueno, Ma Hannah T; Okuno, Mitsuru; Kobayashi, Tetsuo

    2013-06-11

    Slab-derived fluids play an important role in heat and material transfer in subduction zones. Dehydration and decarbonation reactions of minerals in the subducting slab have been investigated using phase equilibria and modeling of fluid flow. Nevertheless, direct observations of the fluid chemistry and pressure-temperature conditions of fluids are few. This report describes CO2-bearing saline fluid inclusions in spinel-harzburgite xenoliths collected from the 1991 Pinatubo pumice deposits. The fluid inclusions are filled with saline solutions with 5.1 ± 1.0% (wt) NaCl-equivalent magnesite crystals, CO2-bearing vapor bubbles, and a talc and/or chrysotile layer on the walls. The xenoliths contain tremolite amphibole, which is stable in temperatures lower than 830 °C at the uppermost mantle. The Pinatubo volcano is located at the volcanic front of the Luzon arc associated with subduction of warm oceanic plate. The present observation suggests hydration of forearc mantle and the uppermost mantle by slab-derived CO2-bearing saline fluids. Dehydration and decarbonation take place, and seawater-like saline fluids migrate from the subducting slab to the mantle wedge. The presence of saline fluids is important because they can dissolve more metals than pure H2O and affect the chemical evolution of the mantle wedge.

  17. Kinetic Isotopic Fractionation of Cd and Zn During Condensation

    Science.gov (United States)

    Cloquet, C.; Carignan, J.; Libourel, G.

    2005-12-01

    The development of MC-ICPMS allowed to measure precisely isotopic compositions of transitional metals with a resolution generally better than +/- 0.15 per mil per atomic mass unit. The isotopic composition of such metals (Zn, Cd, Cu) varies in terrestrial and extra-terrestrial samples resulting most probably from phase transformations (solid-gas-solid) and/or biogenic fractionation. Up to now, very few experiments were conducted in order to document isotope fractionation during evaporation and condensation of metals. In this study, we report Cd and Zn elemental and isotopic variations measured in fly ashes collected from an urban waste combustor (UWC) equipped with various ash and flue gas filtration devices, including a heat transfer system. In the evacuation system, temperature drop from ca. 900 to 250 degree Celsius. This temperature range allows the evaporation and then condensation of Cd and Zn and probably fusion and oxido-reduction reactions. Indeed, the composition of combustion residues clearly indicates that most of the cadmium and part of the zinc were evacuated in the flue gases. Chemical analysis of the fly ashes collected along the thermal gradient suggest a massive condensation of semi-volatile elements such as Cd and Zn just above the heat transfer plate, which behave as a cold point in the evacuation system. As a first approximation, Cd and Zn contents are directly related to the amount metal condensates on more refractory particles. Leaching experiments on different fly ashes thermodynamic calculations confirmed the occurrence of soluble Cd and Zn salt condensates. The cadmium and Zn isotopic composition of bulk, leachate and residue samples provided variations as large as 1 per mil for delta 114Cd (114Cd/110Cd ratio) and up to 0.5 per mil for delta 66Zn (66Zn/64Zn ratio). Both Cd and Zn delta values are positively correlated to concentrations. According to the position of samples in the thermal gradient of the evacuation system, we suggest that

  18. Dehydrated melon containing antioxidants and calcium from grape juice

    Directory of Open Access Journals (Sweden)

    Hulda N. M. Chambi

    2016-11-01

    Full Text Available Background: Grape juice has a high antioxidant potential, capable of fighting oxidative processes in the body. The juice is mainly marketed in its concentrated form, which has a high content of glucose and fructose. The juice concentrate may then be used as an osmotic agent to dehydrated fruit with a relatively short shelf-life at room temperature, such as melon. The osmotic dehydration process can also be combined with conventional drying in order to further reduce the water activity (a w of the product. Finally, the antioxidant-rich melon meets the consumers’ demand for foods which contain ingredients that may impart health benefits. Results: Melon dehydrated by osmotic process at 200, 400 and 600 mbar, using grape juice concentrate (GJC, showed no significant differences in physical characteristics (a w , °Brix, and moisture content. Higher efficiency was observed when dehydration was performed at 200 mbar. After osmotic dehydration with GJC, both plasmolysis of the melon cells and an increase in intercellular spaces were observed by optical microscopy, with no negative impact on the mechanical properties (True stress, Hencky’s strain and deformability modulus. Calcium present in GJC was impregnated into the melon matrix, thus contributing with the mineral composition and mechanical properties of the final product. No significant differences were observed for the antioxidant capacity of melon dehydrated both with GJC and GJC followed by air-drying at 50 and 70°C. This demonstrates that it is possible to combine the two processes to obtain a product with intermediate moisture without decreasing its antioxidant capacity. The samples scored above the acceptable limit (>5 varying between like slightly to like moderately, resulting in a purchase intent with average scores between 3 (maybe/maybe not buy and 4 (probably would buy. Conclusions: A product with intermediate water activity, acidic, firm, high antioxidant capacity, rich in calcium

  19. Pion condensation and neutron star dynamics

    International Nuclear Information System (INIS)

    Kaempfer, B.

    1983-01-01

    The question of formation of pion condensate via a phase transition in nuclear matter, especially in the core of neutron stars is reviewed. The possible mechanisms and the theoretical restrictions of pion condensation are summarized. The effects of ultradense equation of state and density jumps on the possible condensation phase transition are investigated. The possibilities of observation of condensation process are described. (D.Gy.)

  20. Condensed matter analogues of cosmology

    Science.gov (United States)

    Kibble, Tom; Srivastava, Ajit

    2013-10-01

    It is always exciting when developments in one branch of physics turn out to have relevance in a quite different branch. It would be hard to find two branches farther apart in terms of energy scales than early-universe cosmology and low-temperature condensed matter physics. Nevertheless ideas about the formation of topological defects during rapid phase transitions that originated in the context of the very early universe have proved remarkably fruitful when applied to a variety of condensed matter systems. The mathematical frameworks for describing these systems can be very similar. This interconnection has led to a deeper understanding of the phenomena in condensed matter systems utilizing ideas from cosmology. At the same time, one can view these condensed matter analogues as providing, at least in a limited sense, experimental access to the phenomena of the early universe for which no direct probe is possible. As this special issue well illustrates, this remains a dynamic and exciting field. The basic idea is that when a system goes through a rapid symmetry-breaking phase transition from a symmetric phase into one with spontaneously broken symmetry, the order parameter may make different choices in different regions, creating domains that when they meet can trap defects. The scale of those domains, and hence the density of defects, is constrained by the rate at which the system goes through the transition and the speed with which order parameter information propagates. This is what has come to be known as the Kibble-Zurek mechanism. The resultant scaling laws have now been tested in a considerable variety of different systems. The earliest experiments illustrating the analogy between cosmology and condensed matter were in liquid crystals, in particular on the isotropic-to-nematic transition, primarily because it is very easy to induce the phase transition (typically at room temperature) and to image precisely what is going on. This field remains one of the

  1. mPGES-1-derived PGE2 mediates dehydration natriuresis

    Science.gov (United States)

    Jia, Zhanjun; Liu, Gang; Sun, Ying; Kakizoe, Yutaka; Guan, Guangju; Zhang, Aihua; Zhou, Shu-Feng

    2013-01-01

    PGE2 is a natriuretic factor whose production is elevated after water deprivation (WD) but its role in dehydration natriuresis is not well-defined. The goal of the present study was to investigate the role of microsomal prostaglandin E synthase-1 (mPGES-1) in dehydration natriuresis. After 24-h WD, wild-type (WT) mice exhibited a significant increase in 24-h urinary Na+ excretion accompanied with normal plasma Na+ concentration and osmolality. In contrast, WD-induced elevation of urinary Na+ excretion was completely abolished in mPGES-1 knockout (KO) mice in parallel with increased plasma Na+ concentration and a trend increase in plasma osmolality. WD induced a 1.8-fold increase in urinary PGE2 output and a 1.6-fold increase in PGE2 content in the renal medulla of WT mice, both of which were completely abolished by mPGES-1 deletion. Similar patterns of changes were observed for urinary nitrate/nitrite and cGMP. The natriuresis in dehydrated WT mice was associated with a significant downregulation of renal medullary epithelial Na channel-α mRNA and protein, contrasting to unaltered expressions in dehydrated KO mice. By quantitative RT-PCR, WD increased the endothelial nitric oxide synthase (eNOS), inducible NOS, and neuronal NOS expressions in the renal medulla of WT mice by 3.9-, 1.48-, and 2.6-fold, respectively, all of which were significantly blocked in mPGES-1 KO mice. The regulation of eNOS expression was further confirmed by immunoblotting. Taken together, our results suggest that mPGES-1-derived PGE2 contributes to dehydration natriuresis likely via NO/cGMP. PMID:23171554

  2. Charge Screening in a Charged Condensate

    International Nuclear Information System (INIS)

    Gabadadze, Gregory; Rosen, Rachel A.

    2009-01-01

    We consider a highly dense system of helium-4 nuclei and electrons in which the helium-4 nuclei have condensed. We present the condensation mechanism in the framework of low energy effective field theory and discuss the screening of electric charge in the condensate.

  3. Computations for a condenser. Experimental results

    International Nuclear Information System (INIS)

    Walden, Jean.

    1975-01-01

    Computations for condensers are presented with experimental results. The computations are concerned with the steam flux at the condenser input, and inside the tube bundle. Experimental results are given for the flux inside the condenser sleeve and the flow passing through the tube bundle [fr

  4. Direct, nondestructive observation of a Bose condensate

    NARCIS (Netherlands)

    Andrews, M.R.; Mewes, M.O.; van Druten, N.J.; Durfee, D.S.; Kurn, D.M.; Ketterle, W.

    1996-01-01

    The spatial observation of a Bose condensate is reported. Dispersive light scattering was used to observe the separation between the condensed and normal components of the Bose gas inside a magnetic trap. This technique is nondestructive, and about a hundred images of the same condensate can be

  5. Droplet size distribution in condensing flow

    NARCIS (Netherlands)

    Sidin, R.S.R.

    2009-01-01

    In this thesis, the problem of predicting the droplet size distribution in condensing ow is in- vestigated numerically and analytically. The work focuses on two types of problems: one where condensation occurs during the transonic expansion of a vapor-mixture, and a second one where condensation

  6. Influence of iodine on the treatment of spacecraft humidity condensate to produce potable water

    Science.gov (United States)

    Symons, James M.; Muckle, Susan V.

    1990-01-01

    Several compounds in the ersatz humidity condensate do react with iodine to form iodine-substituted organic compounds (TOI), most notably phenol, acetaldehyde, ethanol, and sodium formate. Iodination of the ersatz humidity condensate produced 3.0 to 3.5 mg/L of TOI within 24 hours. The TOI that was produced by the passage of the ersatz humidity condensate through the first iodinated resin (IR) in the adsorption system was removed by the granular activated carbon that followed. TOI detected in the final effluent was formed by the reaction of the non-adsorbable condensate compounds with the final IR in the treatment series. The activated carbon bed series in the adsorption system performed poorly in its removal of TOC. The rapid breakthrough of TOC was not surprising, as the ersatz humidity condensate contained several highly soluble organic compounds, alcohols and organic acids.

  7. Modelling of film condensation in presence of non condensable gases

    International Nuclear Information System (INIS)

    Genevieve Geffraye; Dominique Bestion; Vladimir Kalitvianski

    2005-01-01

    Full text of publication follows: This paper presents recent developments in the modelling of the condensation due to heat removal from a wall with a possible presence of hydrogen, nitrogen, or air. This work is mainly concerned with nuclear reactor safety with particular reference to situations related to new reactor design, cold shutdown state and severe accident analysis. Film condensation of steam in presence of nitrogen and helium in a tube has been investigated in the COTURNE experiment in a rather large range of parameters, pressure (from 0.1 to 7 Mpa), heat flux (0.1 to 6 W/cm 2 ), mass fraction of noncondensable gas (0 to 1) and also in presence of superheated steam. The experiment represents a Steam Generator tube of a Pressurised Water Reactor and can simulate both co-current or countercurrent flow of steam and water.The models are implemented in the CATHARE code used for nuclear reactor thermal-hydraulics. The code uses two mass balance equations for liquid and gas, two momentum balance equations for liquid and gas and two energy balance equations for liquid and gas. Additional mass transport equations can be added for each non condensable gas. Heat transfers from wall to liquid film, from liquid to interface and gas to interface are modelled. The liquid film heat transfer coefficient is first investigated in pure saturated steam conditions in the pressure range from 0.1 to 7 Mpa. The CATHARE film condensation model in pure steam conditions is derived from Chen's correlation. Chen proposes a general correlation for the film condensation, covering the wavy-laminar and the turbulent film regimes and taking into account the interfacial friction effect. A large data base of laminar film regime was used including COTURNE data other available data found in the literature. The analysis of these data base suggests an influence of the liquid Reynolds number, according to the Nusselt theory, and also of the Eoetvoes number, with surface tension effects. A

  8. Fundamentals of condensed matter physics

    CERN Document Server

    Cohen, Marvin L

    2016-01-01

    Based on an established course and covering the fundamentals, central areas, and contemporary topics of this diverse field, Fundamentals of Condensed Matter Physics is a much-needed textbook for graduate students. The book begins with an introduction to the modern conceptual models of a solid from the points of view of interacting atoms and elementary excitations. It then provides students with a thorough grounding in electronic structure as a starting point to understand many properties of condensed matter systems - electronic, structural, vibrational, thermal, optical, transport, magnetic and superconductivity - and methods to calculate them. Taking readers through the concepts and techniques, the text gives both theoretically and experimentally inclined students the knowledge needed for research and teaching careers in this field. It features 200 illustrations, 40 worked examples and 150 homework problems for students to test their understanding. Solutions to the problems for instructors are available at w...

  9. 40 CFR 63.1275 - Glycol dehydration unit process vent standards.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Glycol dehydration unit process vent... Facilities § 63.1275 Glycol dehydration unit process vent standards. (a) This section applies to each glycol dehydration unit subject to this subpart with an actual annual average natural gas flowrate equal to or...

  10. 40 CFR 63.765 - Glycol dehydration unit process vent standards.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Glycol dehydration unit process vent... Facilities § 63.765 Glycol dehydration unit process vent standards. (a) This section applies to each glycol dehydration unit subject to this subpart with an actual annual average natural gas flowrate equal to or...

  11. 21 CFR 573.400 - Ethoxyquin in certain dehydrated forage crops.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ethoxyquin in certain dehydrated forage crops. 573... DRINKING WATER OF ANIMALS Food Additive Listing § 573.400 Ethoxyquin in certain dehydrated forage crops. Ethoxyquin (1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline) may be safely used in the dehydrated forage crops...

  12. DESIGNING AND EFFICIENCY EFFECT OF AUTOMATIC BALL-CLEANING SYSTEM FOR CONDENSER 180-KTsS-1 OF TURBINE Т-180/210-130-1 LMZ. Part 1

    Directory of Open Access Journals (Sweden)

    Yu. A. Zenovich-Leshkevich-Ol’pinskiy

    2015-01-01

    Full Text Available In order to reduce losses in the cooling source (condenser and to increase effectiveness of fuel-and-power resources utilization, the authors present a modern automatic ball-cleaning system for the pipes of condenser 180-KTsS-1 of turbine unit Т-180/210-130-1 LMZ of Gomel CHP-2. The article examines exploitation challenges of the steam turbine condensers and methods of clearing them from sedimentations. Depending on the sedimentation character and composition, and the quality of cooling water at the power plant, they apply various methods of the condenser tubes clearing: heat drying, vacuum dehydration, acid-washing, pipes-shooting with water and water-air pistols, ablution with high-pressure water jet etc. All the applied cleaning methods are the periodical means to fight the sedimentations and require the turbine halting or unloading, predetermine the equipment operating between clearings with constantly smearing cooling surfaces of the condensers, i.e. with reduced efficiency of equipment operation.The installation of the ball-cleaning system practically excludes defects of the chemical and mechanical cleaning methods, which leads to the condenser pipes life-in-service increase, the full-flow condensate quality improvement, reliability and efficient performance enhancement of the steam turbines equipment. The authors consider developed algorithms of data processing and designed system control of the condenser cleaning that allowed realizing its operation in automatic mode.

  13. LOFCON-LOFT condenser program

    International Nuclear Information System (INIS)

    Lemmon, E.C.; MacKay, D.B.

    1978-01-01

    LOFCON is a program developed for the LOFT air condenser system contained in the secondary coolant system. Although the basic theory described herein is general, the program given is not--it is specifically for the LOFT configuration. LOFCON is presented in subroutine form so that it may be easily incorporated into a larger program describing the complete secondary side. Specifically LOFCON was written to be incorporated into the detailed CSMP model of the LOFT secondary coolant system simulation

  14. LOFCON-LOFT condenser program

    Energy Technology Data Exchange (ETDEWEB)

    Lemmon, E.C.; MacKay, D.B.

    1978-05-26

    LOFCON is a program developed for the LOFT air condenser system contained in the secondary coolant system. Although the basic theory described herein is general, the program given is not--it is specifically for the LOFT configuration. LOFCON is presented in subroutine form so that it may be easily incorporated into a larger program describing the complete secondary side. Specifically LOFCON was written to be incorporated into the detailed CSMP model of the LOFT secondary coolant system simulation.

  15. Advances in condensed matter optics

    CERN Document Server

    Chen, Liangyao; Jiang, Xunya; Jin, Kuijuan; Liu, Hui; Zhao, Haibin

    2015-01-01

    This book describes some of the more recent progresses and developmentsin the study of condensed matter optics in both theoretic and experimental fields.It will help readers, especially graduate students and scientists who are studying and working in the nano-photonic field, to understand more deeply the characteristics of light waves propagated in nano-structure-based materials with potential applications in the future.

  16. Accelerators for condensed matter research

    International Nuclear Information System (INIS)

    Williams, P.R.

    1990-01-01

    The requirement for high energy, high luminosity beams has stimulated the science and engineering of accelerators to a point where they open up opportunities for new areas of scientific application to benefit from the advances driven by particle physics. One area of great importance is the use of electron or positron storage rings as a source of intense VUV or X-ray synchrotron radiation. An accelerator application that has grown in prominence over the last 10 years has been spallation neutron sources. Neutrons offer an advantage over X-rays as a condensed matter probe because the neutron energy is usually of the same order as the room temperature thermal energy fluctuations in the sample being studied. Another area in which accelerators are playing an increasingly important role in condensed matter research concerns the use of Mu mesons, Muons, as a probe. This paper also presents a description of the ISIS Spallation Neutron Source. The design and status of the facility are described, and examples are given of its application to the study of condensed matter. (N.K.)

  17. Theory of laminar film condensation

    CERN Document Server

    Fujii, Tetsu

    1991-01-01

    Since the petroleum crisis in the 1970s, a lot of effort to save energy was made in industry, and remarkable achievements have been made. In the research and development concerning thermal energy, however, it was clar­ ified that one of the most important problems was manufacturing con­ densing systems with smaller size and higher performance. To solve this problem we need a method which synthesizes selections_ of the type of con­ denser, cooling tube and its arrangement, assessment of fouling on the cooling surfaces, consideration of transient characteristics of a condenser, etc. The majority of effort, however, has been to devise a surface element which enhances the heat transfer coefficient in condensation of a single or multicomponent vapor. Condensation phenomena are complexly affected by a lot of physical property values, and accordingly the results of theo­ retical research are expressed with several dimensionless parameters. On the other hand, the experimental research is limited to those with som...

  18. A DFT-based comparative equilibrium study of thermal dehydration and hydrolysis of CaCl₂ hydrates and MgCl₂ hydrates for seasonal heat storage.

    Science.gov (United States)

    Pathak, Amar Deep; Nedea, Silvia; Zondag, Herbert; Rindt, Camilo; Smeulders, David

    2016-04-21

    Salt hydrates store solar energy in chemical form via a reversible dehydration-hydration reaction. However, as a side reaction to dehydration, hydrolysis (HCl formation) may occur in chloride based salt hydrates (specially in MgCl2 hydrates), affecting the durability of the storage system. The mixture of CaCl2 and MgCl2 hydrates has been shown experimentally to have exceptional cycle stability and improved kinetics. However, the optimal operating conditions for the mixture are unknown. To understand the appropriate balance between dehydration and hydrolysis kinetics in the mixtures, it is essential to gain in-depth insight into the mixture components. We present a GGA-DFT level study to investigate the various gaseous structures of CaCl2 hydrates and to understand the relative stability of their conformers. The hydration strength and relative stability of conformers are dominated by electrostatic interactions. A wide network of intramolecular homonuclear and heteronuclear hydrogen bonds is observed in CaCl2 hydrates. Equilibrium product concentrations are obtained during dehydration and hydrolysis reactions under various temperature and pressure conditions. The trend of the dehydration curve with temperature in CaCl2 hydrates is similar to the experiments. Comparing these results to those of MgCl2 hydrates, we find that CaCl2 hydrates are more resistant towards hydrolysis in the temperature range of 273-800 K. Specifically, the present study reveals that the onset temperatures of HCl formation, a crucial design parameter for MgCl2 hydrates, are lower than for CaCl2 hydrates except for the mono-hydrate.

  19. Catalytic dehydration of ethanol to ethylene

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ying; Jin, Zhaosheng; Shen, Wei [SINOPEC Shanghai Research Institute of Petrochemical Technology, Shanghai (China)

    2011-07-01

    The different routes of ethylene production were briefly introduced and the advantage of ethanol to ethylene (ETE) route was explained. Followed by that, the upgraded catalyst applied in this route developed by SINOPEC Shanghai Research Institute of Petrochemical Technology (SRIPT) was introduced together with the development of the ethanol to ethylene process. The core technologies involved in this process development were discussed, such as isothermal fixed-bed reactor, water scrubber and alkaline wash column, two columns of low-temperature separation as well as process heat integration. Furthermore, the performance of one of ethanol industrial plants licensed by SRIPT was reviewed. It is as follows, conversion of ethanol reaches 99% while selectivity of ethylene is over 96% at the reaction temperature of 350{approx}450 C, the liquid hourly space velocity (LHSV)of 0.5{approx}1.0 h{sup -1} and atmosphere pressure. Meanwhile, the catalyst shows its life time of one year. This route is considered not only as an economical and practical process but also as an environmentfriendly path to ethylene production. (orig.)

  20. Preparation of Mesoporous SiO2-Pillared Lamellar Titanoniobate Catalysts for Bioethanol Dehydration

    Directory of Open Access Journals (Sweden)

    Olivalter Pergentino

    2014-01-01

    Full Text Available The lamellar perovskite K0,8Ti0,8Nb1,2O5 was prepared by solid state reaction, and its protonic form was used in a sequence of intercalation steps with n-butylamine, cetyltrimethylammonium bromide (CTABr, and tetraethyl orthosilicate (TEOS. After calcination, a high surface area, mesoporous SiO2-pillared titanoniobate, was obtained. The samples were characterized by XRD, EDX, TG-DTG, N2 adsorption isotherms, and NH3-TPD. The pillarization procedure affected the textural properties, the amount, and strength distribution of acid sites. The influence of the pillarization procedure on the catalytic properties of the lamellar titanoniobates was investigated on ethanol dehydration. High ethanol conversions and ethylene yields (>90% were obtained in the presence of the SiO2-pillared titanoniobate catalyst, at 350–450°C.

  1. Boronic acids facilitate rapid oxime condensations at neutral pH

    OpenAIRE

    Schmidt, Pascal; Stress, Cedric; Gillingham, Dennis

    2015-01-01

    We report here the discovery and development of boron-assisted oxime formation as a powerful connective reaction for chemical biology. Oximes proximal to boronic acids form in neutral aqueous buffer with rate constants of more than 104 M−1 s−1, the largest to date for any oxime condensation. Boron's dynamic coordination chemistry confers an adaptability that seems to aid a number of elementary steps in the oxime condensation. In addition to applications in bioconjugation, the emerging importa...

  2. Gastric emptying of liquids in rats dehydrated by water deprivation

    Directory of Open Access Journals (Sweden)

    Baracat E.C.E.

    1997-01-01

    Full Text Available The gastric emptying of liquids was investigated in male Wistar rats (8 to 10 weeks old, 210-300 g dehydrated by water deprivation. In this model of dehydration, weight loss, hematocrit and plasma density were significantly higher in the dehydrated animals than in the control groups after 48 and 72 h of water deprivation (P<0.05. Three test meals (saline (N = 10, water (N = 10 and a WHO rehydrating solution containing in one liter 90 mEq sodium, 20 mEq potassium, 80 mEq chloride and 30 mEq citrate (N = 10 were used to study gastric emptying following water deprivation for 24, 48 and 72 h. After 72 h, gastric emptying of the water (39.4% retention and rehydrating solution (49.2% retention test meals was significantly retarded compared to the corresponding control groups (P<0.05, Mann-Whitney test. The 72-h period of deprivation was used to study the recovery from dehydration, and water was supplied for 60 or 120 min after 67 h of deprivation. Body weight loss, hematocrit and plasma density tended to return to normal when water was offered for 120 min. In the animals supplied with water for 60 min, there was a recovery in the gastric emptying of water while the gastric emptying of the rehydrating solution was still retarded (53.1% retention; P<0.02, Kruskal-Wallis test. In the group supplied with water for 120 min, the gastric emptying of the rehydrating (51.7% retention and gluco-saline (46.0% retention solutions tended to be retarded (P = 0.04, Kruskal-Wallis test. In this model of dehydration caused by water deprivation, with little alteration in the body electrolyte content, gastric emptying of the rehydrating solution was retarded after rehydration with water. We conclude that the mechanisms whereby receptors in the duodenal mucosa can modify gastric motility are altered during dehydration caused by water deprivation

  3. Universal Themes of Bose-Einstein Condensation

    Science.gov (United States)

    Proukakis, Nick P.; Snoke, David W.; Littlewood, Peter B.

    2017-04-01

    Foreword; List of contributors; Preface; Part I. Introduction: 1. Universality and Bose-Einstein condensation: perspectives on recent work D. W. Snoke, N. P. Proukakis, T. Giamarchi and P. B. Littlewood; 2. A history of Bose-Einstein condensation of atomic hydrogen T. Greytak and D. Kleppner; 3. Twenty years of atomic quantum gases: 1995-2015 W. Ketterle; 4. Introduction to polariton condensation P. B. Littlewood and A. Edelman; Part II. General Topics: Editorial notes; 5. The question of spontaneous symmetry breaking in condensates D. W. Snoke and A. J. Daley; 6. Effects of interactions on Bose-Einstein condensation R. P. Smith; 7. Formation of Bose-Einstein condensates M. J. Davis, T. M. Wright, T. Gasenzer, S. A. Gardiner and N. P. Proukakis; 8. Quenches, relaxation and pre-thermalization in an isolated quantum system T. Langen and J. Schmiedmayer; 9. Ultracold gases with intrinsic scale invariance C. Chin; 10. Berezinskii-Kosterlitz-Thouless phase of a driven-dissipative condensate N. Y. Kim, W. H. Nitsche and Y. Yamamoto; 11. Superfluidity and phase correlations of driven dissipative condensates J. Keeling, L. M. Sieberer, E. Altman, L. Chen, S. Diehl and J. Toner; 12. BEC to BCS crossover from superconductors to polaritons A. Edelman and P. B. Littlewood; Part III. Condensates in Atomic Physics: Editorial notes; 13. Probing and controlling strongly correlated quantum many-body systems using ultracold quantum gases I. Bloch; 14. Preparing and probing chern bands with cold atoms N. Goldman, N. R. Cooper and J. Dalibard; 15. Bose-Einstein condensates in artificial gauge fields L. J. LeBlanc and I. B. Spielman; 16. Second sound in ultracold atomic gases L. Pitaevskii and S. Stringari; 17. Quantum turbulence in atomic Bose-Einstein condensates N. G. Parker, A. J. Allen, C. F. Barenghi and N. P. Proukakis; 18. Spinor-dipolar aspects of Bose-Einstein condensation M. Ueda; Part IV. Condensates in Condensed Matter Physics: Editorial notes; 19. Bose

  4. On the dehydration mechanism of Mg(OH)2 by a high-energy electron beam

    International Nuclear Information System (INIS)

    Su Dong; Jiang, Nan; Spence, John C. H.; He Feng; Petuskey, William T.

    2008-01-01

    The dehydration process in Mg(OH) 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 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

  5. Hydration and dehydration cycles in polymer electrolyte fuel cells operated with wet anode and dry cathode feed: A neutron imaging and modeling study

    Science.gov (United States)

    García-Salaberri, P. A.; Sánchez, D. G.; Boillat, P.; Vera, M.; Friedrich, K. A.

    2017-08-01

    Proper water management plays an essential role in the performance and durability of Polymer Electrolyte Fuel Cells (PEFCs), but it is challenged by the variety of water transport phenomena that take place in these devices. Previous experimental work has shown the existence of fluctuations between low and high current density levels in PEFCs operated with wet hydrogen and dry air feed. The alternation between both performance states is accompanied by strong changes in the high frequency resistance, suggesting a cyclic hydration and dehydration of the membrane. This peculiar scenario is examined here considering liquid water distributions from neutron imaging and predictions from a 3D two-phase non-isothermal model. The results show that the hydration-dehydration cycles are triggered by the periodic condensation and shedding of liquid water at the anode inlet. The input of liquid water humidifies the anode channel and offsets the membrane dry-out induced by the dry air stream, thus leading to the high-performance state. When liquid water is flushed out of the anode channel, the dehydration process takes over, and the cell comes back to the low-performance state. The predicted amplitude of the current oscillations grows with decreasing hydrogen and increasing air flow rates, in agreement with previous experimental data.

  6. Unstable fault slip induced by lawsonite dehydration in blueschist: Implication for the seismicity in the subducting oceanic crusts

    Science.gov (United States)

    Okazaki, K.; Hirth, G.

    2015-12-01

    Intermediate-depth earthquakes in cold subduction zones are observed within the subducting oceanic crust, as well as the subducting mantle In contrast, intermediate-depth earthquakes in hot subduction zones predominantly occur just below the Moho. These observations have stimulated interest in potential relationships between blueschist-facies metamorphism and seismicity, particularly through the dehydration reactions involving lawsonite. The rheology of these high-pressure and low-temperature metamorphic minerals is largely unknown. We conducted experiments on lawsonite accompanied by monitoring of acoustic emission (AE) in a Griggs-type deformation apparatus. Deformation was started at the confining pressure of 1.0 GPa, the temperature of 300 ˚C, and constant displacement rates of 0.16 to 0.016 μm/s, that correspond to equivalent strain rates (ɛ) of 9 × 10-5 to 9 × 10-6 1/s. In these experiments, temperature was increased at the temperature ramp rate of 0.5 to 0.05˚C/s above the thermal stability of lawsonite (600˚C) while the sample was deforming to test whether the dehydration reaction induces unstable fault slip. In contrast to similar tests on antigorite, unstable fault slip (i.e., stick-slip) occurred during dehydration reactions in the lawsonite gouge layer, and AE signals were continuously observed. Microstructural observations indicate that strain is highly localized along the fault (R1 and B shear), and the fault surface shows mirror-like slickensides. The unloading slope (i.e., rate of stress drop as a function of slip) during the unstable slip follows the stiffness of the apparatus at all experimental conditions regardless of the strain rate and temperature ramping rate. A thermal-mechanical scaling factor in the experiments covers the range estimated for natural subduction zones, indicating the potential for unstable frictional sliding within natural lawsonite layers to induce seismicity in cold subduction zones.

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    The anisotropy of crystals of glypican-1 was significantly reduced by controlled dehydration using the HC1 device, allowing the building of previously disordered parts of the structure. 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

  8. Atomic structure and dehydration mechanism of amorphous silica: Insights from 29Si and 1H solid-state MAS NMR study of SiO2 nanoparticles

    Science.gov (United States)

    Kim, Hyun Na; Lee, Sung Keun

    2013-11-01

    Detailed knowledge of the atomic structure of hydrous species on surface of amorphous silica and the effect of temperature and particle size on their atomic configurations are essential to understand the nature of fluids-amorphous silicates interactions and the dehydration processes in the amorphous oxides. Here, we report the 29Si, 1H MAS, and 1H-29Si heteronuclear correlation (HetCor) NMR spectra of 7 nm and 14 nm amorphous silica nanoparticles—a model system for natural amorphous silica—where previously unknown details of changes in their atomic structures with varying dehydration temperature and particle size are revealed. Diverse hydroxyl groups with varying atomic configurations and molecular water apparently show distinct dehydration trends. The dehydration (i.e., removal of water) of amorphous silica nanoparticles mostly results in the increase of isolated silanol by removing water molecules from hydrogen-bonded silanols associated water molecules. With further increase in dehydration temperature, the intensity of isolated silanol peak decreases above ˜873 K, suggesting that the condensation of isolated silanol may occur mainly above ˜873 K. The entire dehydration (and dehydroxylation) process completes at ˜1473 K. Both the water (i.e., physisorbed water and hydrogen-bonded water) and hydrogen-bonded silanol species show a dramatic change in the slope of intensity variation at ˜873 K, indicating that most of silanols is hydrogen-bonded to water rather than to other silanols. The fraction of hydrogen-bonded proton species is also much smaller in 14 nm amorphous silica nanoparticles than in 7 nm amorphous silica nanoparticles mainly due to the presences of larger fractions of water and hydrogen-bonded silanol species. 29Si NMR results show that with increasing dehydration temperature, the fraction of Q4 species apparently increases at the expense of Q2 and Q3 species. The fractions of Q2 and Q3 structures in 7 nm amorphous silica nanoparticles are

  9. Dehydration of sodium carbonate monohydrate with indirect microwave heating

    International Nuclear Information System (INIS)

    Seyrankaya, Abdullah; Ozalp, Baris

    2006-01-01

    In this study, dehydration of sodium carbonate monohydrate (Na 2 CO 3 .H 2 O) (SCM) in microwave (MW) field with silicon carbide (SiC) as an indirect heating medium was investigated. SCM samples containing up to 3% free moisture were placed in the microwave oven. The heating experiments showed that SCM is a poor microwave energy absorber for up to 6 min of irradiation at an 800 W of microwave power. The heat for SCM calcination is provided by SiC which absorbs microwave. The monohydrate is then converted to anhydrous sodium carbonate on the SiC plate by calcining, i.e. by removing the crystal water through heating of the monohydrate temperatures of over 120 deg. C. The calcination results in a solid phase recrystallization of the monohydrate into anhydrate. In the microwave irradiation process, dehydration of SCM in terms of indirect heating can be accelerated by increasing the microwave field power

  10. [PREVALENCE OF DEHYDRATION BEFORE TRAINING IN PROFESIONAL CHILEAN SOCCER PLAYERS].

    Science.gov (United States)

    Castro-Sepúlveda, Mauricio; Astudillo, Sebastian; Álvarez, Cristian; Zapata-Lamana, Rafael; Zbinden-Foncea, Hermann; Ramírez-Campillo, Rodrigo; Jorquera, Carlos

    2015-07-01

    there is a lack of studies concerning hydration status before training in professional soccer player. to describe hydration status before regular training practices in professional soccer players. a total of 156 male soccer players (age 25.4 ± 5.2 y) from six professional Chilean clubs were included. No hydration or food intake recommendations were made before experiment, with the aim to assess hydration status under athlete's regular "real" conditions. Body mass, height and urine specific gravity (USG) measurements were performed before training practices. 98% of athletes showed dehydration (between moderate and severe) before regular training practices. dehydration is the most prevalent hydration status in professional Chilean soccer players before training, which may negatively affect athlete's performance and may increase their risk of heat-related injuries. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  11. Apple's dehydration by the irradiation pretreatment

    International Nuclear Information System (INIS)

    Fu Junjie; Chao Yan; Shen Weiqiao; Wang Jun

    2001-01-01

    60 Co γ-ray irradiation was used as a pre-treatment method to dry the apple. The aim of this study was to discover the effect factor concerning the change of the apple cell structure which would affect the speed of drhydration and the relation between the speed of hot air dehydration and the irradiation dose. The results demonstrated that with the increasing of irradiation dose. The damage of apple's vacuole membrane increased. The positive correlation was shown in slice thickness and dehydration rate, the relation of the irradiation dose and the temperature of hot air was negatively correlated. The optimum of pre-treatment was gained for slice thickness, the irradiation dose and dry temperature of hot air. (authors)

  12. Efficiency of Osmotic Dehydration of Apples in Polyols Solutions

    Directory of Open Access Journals (Sweden)

    Joanna Cichowska

    2018-02-01

    Full Text Available The present study aimed to evaluate the influence of selected compounds from the polyol group, as well as other saccharides, on the osmotic dehydration process of apples. The following alternative solutions were examined: erythritol, xylitol, maltitol, inulin and oligofructose. Efficiency of the osmotic dehydration process was evaluated based on the kinetics of the process, and through comparison of the results obtained during the application of a sucrose solution. This innovative research utilizes alternative solutions in osmotic pretreatment, which until now, have not been commonly used in fruit processing by researchers worldwide. Results indicate that erythritol and xylitol show stronger or similar efficiency to sucrose; however, the use of inulin, as well as oligofructose, was not satisfactory due to the insufficient, small osmotic driving forces of the process, and the low values of mass transfer parameters.

  13. Interlayer Spaces Associated with Hydration and Dehydration in Synthetic Saponite

    International Nuclear Information System (INIS)

    Sato, K; Fujimoto, K; Nakata, M; Shikazono, N

    2010-01-01

    Positron annihilation lifetime spectroscopy was conducted for a synthetic saponite to investigate hydration and dehydration behaviour occurring in nanoscale interlayer spaces. Long positron lifetime of ∼ 24 ns was observed with the intensity of ∼ 8 % when the sample is evacuated at ∼ 10 -5 Torr. The radius of open nanospace evaluated from the positron lifetime is ∼ 10 A, which corresponds to the interlayer spaces of saponite. The open nanospace increases up to 13 % after baking at 423 K for 8 h under the vacuum. The present results imply that positron annihilation spectroscopy is powerful tool to investigate hydration and dehydration behavior through the local structural changes in the interlayer spaces of clay minerals.

  14. Methods for dehydration of sugars and sugar alcohols

    Science.gov (United States)

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

    2010-08-10

    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.

  15. Efficiency of Osmotic Dehydration of Apples in Polyols Solutions.

    Science.gov (United States)

    Cichowska, Joanna; Żubernik, Joanna; Czyżewski, Jakub; Kowalska, Hanna; Witrowa-Rajchert, Dorota

    2018-02-17

    The present study aimed to evaluate the influence of selected compounds from the polyol group, as well as other saccharides, on the osmotic dehydration process of apples. The following alternative solutions were examined: erythritol, xylitol, maltitol, inulin and oligofructose. Efficiency of the osmotic dehydration process was evaluated based on the kinetics of the process, and through comparison of the results obtained during the application of a sucrose solution. This innovative research utilizes alternative solutions in osmotic pretreatment, which until now, have not been commonly used in fruit processing by researchers worldwide. Results indicate that erythritol and xylitol show stronger or similar efficiency to sucrose; however, the use of inulin, as well as oligofructose, was not satisfactory due to the insufficient, small osmotic driving forces of the process, and the low values of mass transfer parameters.

  16. Evaluation of performance enhancement by condensing the anode moisture in a proton exchange membrane fuel cell stack

    International Nuclear Information System (INIS)

    Zhang, Shouzhen; Chen, Ben; Shu, Peng; Luo, Maji; Xie, Changjun; Quan, Shuhai; Tu, Zhengkai; Yu, Yi

    2017-01-01

    Highlights: • Anode Moisture condensing is introduced into a PEMFC stack. • Performance improves at high current density and high stack temperature after AMC. • MEA is dehydrated and poor performance occurs at low current density during AMC. - Abstract: Water management is an important issue for proton exchange membrane fuel cells. Back-diffusion of water from cathode to anode often occurs due to the differences in concentration and pressure during operation of fuel cell, resulting in the flooding and severe carbon corrosion in the cathode. Herein, we report a novel method of anode moisture condensing (AMC) in which a condenser is set at the outlet of the anode to cool down the anode moisture. With the help of AMC, liquid water is condensed from the moisture due to the variation of the saturated pressure of water vapor, which can accelerate the evaporating of the liquid water inside the anode and mitigate the probability of water flooding. A ten-cell stack with a condenser at the outlet of the anode is fabricated to systematically investigate the effects of the stack temperature and flow rate on the stack performance. The result shows that the PEMFC performance can be greatly improved at high current density and high operation temperature under the condition of AMC. The stack exhibits very similar performance before and after application of AMC below 500 mA cm −2 , whereas the output power increases from 405 W to 436 W at 600 mA cm −2 at 65 °C. With further increase in operation temperature to 80 °C, the average voltage increases from 0.598 V to 0.641 V even at 500 mA cm −2 . Moreover, the application of AMC can speed up the water evaporation, leading to the dehydration of the membrane and thus poor performance of PEMFC at low current density.

  17. Condensation on slippery asymmetric bumps

    Science.gov (United States)

    Park, Kyoo-Chul; Kim, Philseok; Grinthal, Alison; He, Neil; Fox, David; Weaver, James C.; Aizenberg, Joanna

    2016-03-01

    Controlling dropwise condensation is fundamental to water-harvesting systems, desalination, thermal power generation, air conditioning, distillation towers, and numerous other applications. For any of these, it is essential to design surfaces that enable droplets to grow rapidly and to be shed as quickly as possible. However, approaches based on microscale, nanoscale or molecular-scale textures suffer from intrinsic trade-offs that make it difficult to optimize both growth and transport at once. Here we present a conceptually different design approach—based on principles derived from Namib desert beetles, cacti, and pitcher plants—that synergistically combines these aspects of condensation and substantially outperforms other synthetic surfaces. Inspired by an unconventional interpretation of the role of the beetle’s bumpy surface geometry in promoting condensation, and using theoretical modelling, we show how to maximize vapour diffusion fluxat the apex of convex millimetric bumps by optimizing the radius of curvature and cross-sectional shape. Integrating this apex geometry with a widening slope, analogous to cactus spines, directly couples facilitated droplet growth with fast directional transport, by creating a free-energy profile that drives the droplet down the slope before its growth rate can decrease. This coupling is further enhanced by a slippery, pitcher-plant-inspired nanocoating that facilitates feedback between coalescence-driven growth and capillary-driven motion on the way down. Bumps that are rationally designed to integrate these mechanisms are able to grow and transport large droplets even against gravity and overcome the effect of an unfavourable temperature gradient. We further observe an unprecedented sixfold-higher exponent of growth rate, faster onset, higher steady-state turnover rate, and a greater volume of water collected compared to other surfaces. We envision that this fundamental understanding and rational design strategy can be

  18. Mechanisms of Aerobic Performance Impairment With Heat Stress and Dehydration

    Science.gov (United States)

    2010-08-01

    Hazzard MP, Quinn TJ, Castellani JW. Hypohydration effects on thermoregulation during moderate exercise in the cold . Eur J Appl Physiol 92: 565–570, 2004...compared with cold exposure (13, 41, 55). The strong modifying effect of Tsk on aerobic performance when dehydrated supports the proposed underly- ing...13. Cheuvront SN, Carter R 3rd, Castellani JW, Sawka MN. Hypohy- dration impairs endurance exercise performance in temperate but not cold air. J Appl

  19. Impact of osmotic dehydration on the encapsulated apices survival ...

    African Journals Online (AJOL)

    L-1 activated charcoal) prior to encapsulation in alginate (3%) beads with calcium chloride (1.32M). Then, the apices were exposed to osmotic dehydration with two concentrations of sucrose (0.75M and 1.25M) at two durations (24h and 40h) before their culture in M2 medium (MS + 2mg.L-1 BAP, 100?g.L-1 d'ANA and 2g.

  20. Quantum tunnelling in condensed media

    CERN Document Server

    Kagan, Yu

    1992-01-01

    The essays in this book deal with of the problem of quantum tunnelling and related behavior of a microscopic or macroscopic system, which interacts strongly with an ""environment"" - this being some form of condensed matter. The ""system"" in question need not be physically distinct from its environment, but could, for example, be one particular degree of freedom on which attention is focussed, as in the case of the Josephson junction studied in several of the papers. This general problem has been studied in many hundreds, if not thousands, of articles in the literature, in contexts as diverse

  1. Overexpression of LOV KELCH protein 2 confers dehydration tolerance and is associated with enhanced expression of dehydration-inducible genes in Arabidopsis thaliana.

    Science.gov (United States)

    Miyazaki, Yuji; Abe, Hiroshi; Takase, Tomoyuki; Kobayashi, Masatomo; Kiyosue, Tomohiro

    2015-05-01

    The overexpression of LKP2 confers dehydration tolerance in Arabidopsis thaliana ; this is likely due to enhanced expression of dehydration-inducible genes and reduced stomatal opening. LOV KELCH protein 2 (LKP2) modulates the circadian rhythm and flowering time in plants. In this study, we observed that LKP2 overexpression enhanced dehydration tolerance in Arabidopsis. Microarray analysis demonstrated that expression of water deprivation-responsive genes was higher in the absence of dehydration stress in transgenic Arabidopsis plants expressing green fluorescent protein-tagged LKP2 (GFP-LKP2) than in control transgenic plants expressing GFP. After dehydration followed by rehydration, GFP-LKP2 plants developed more leaves and roots and exhibited higher survival rates than control plants. In the absence of dehydration stress, four dehydration-inducible genes, namely DREB1A, DREB1B, DREB1C, and RD29A, were expressed in GFP-LKP2 plants, whereas they were not expressed or were expressed at low levels in control plants. Under dehydration stress, the expression of DREB2B and RD29A peaked faster in the GFP-LKP2 plants than in control plants. The stomatal aperture of GFP-LKP2 plants was smaller than that of control plants. These results suggest that the dehydration tolerance of GFP-LKP2 plants is caused by upregulation of DREB1A-C/CBF1-3 and their downstream targets; restricted stomatal opening in the absence of dehydration stress also appears to contribute to the phenotype. The rapid and high expression of DREB2B and its downstream target genes also likely accounts for some features of the GFP-LKP2 phenotype. Our results suggest that LKP2 can be used for biotechnological applications not only to adjust the flowering time control but also to enhance dehydration tolerance.

  2. Dehydration Influences Mood and Cognition: A Plausible Hypothesis?

    Directory of Open Access Journals (Sweden)

    David Benton

    2011-05-01

    Full Text Available 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.

  3. Development and Performance Evaluation of Tomato Dehydrating Machine

    Directory of Open Access Journals (Sweden)

    C. N. Nwogu

    2017-04-01

    Full Text Available Tomato (Solanum lycopersicum is a very important staple food worldwide with about 7,500 varieties consumed in diverse ways including: raw in salads, as an ingredient in many dishes, sauces, ketchup and drinks. Tomatoes deteriorate (rotten easily due to their high moisture content. A tomato dehydrating machine comprising of a spray gun, cam shaft, delivery pipe, three air blowers, drying trough, base and a speed reduction gear box was designed, fabricated and evaluated. The machine is powered by a 1.5hp electric motor. The developed machine has a dehydration efficiency of 81.45%, throughput of 3.7212kg/hr. The dehydrated tomato produced from the machine has ascorbic acid content, lycopene content, calcium content, potassium content and sugar reduction content of 10.6 mg/100g, 78.24 mg/100g, 10.6 mg/100g, 169.0 mg/100g and 2.9 mg/100g respectively which fell between acceptable ranges for the nutritional content of tomato.

  4. Recent Advances on Bioethanol Dehydration using Zeolite Membrane

    Science.gov (United States)

    Makertihartha, I. G. B. N.; Dharmawijaya, P. T.; Wenten, I. G.

    2017-07-01

    Renewable energy has gained increasing attention throughout the world. Bioethanol has the potential to replace existing fossil fuel usage without much modification in existing facilities. Bioethanol which generally produced from fermentation route produces low ethanol concentration. However, fuel grade ethanol requires low water content to avoid engine stall. Dehydration process has been increasingly important in fuel grade ethanol production. Among all dehydration processes, pervaporation is considered as the most promising technology. Zeolite possesses high potential in pervaporation of bioethanol into fuel grade ethanol. Zeolite membrane can either remove organic (ethanol) from aqueous mixture or water from the mixture, depending on the framework used. Hydrophilic zeolite membrane, e.g. LTA, can easily remove water from the mixture leaving high ethanol concentration. On the other hand, hydrophobic zeolite membrane, e.g. silicate-1, can remove ethanol from aqueous solution. This review presents the concept of bioethanol dehydration using zeolite membrane. Special attention is given to the performance of selected pathway related to framework selection.

  5. On scalar condensate baryogenesis model

    International Nuclear Information System (INIS)

    Kiriloval, D.P.; Valchanov, T.V.

    2004-09-01

    We discuss the scalar field condensate baryogenesis model, which is among the baryogenesis scenarios preferred today, compatible with inflation. According to that model a complex scalar field φ, carrying baryon charge B≠0 is generated at inflation. The baryon excess in the Universe results from the φ decay at later stages of Universe evolution (T 15 GeV). We updated the model's parameters range according to the current observational cosmological constraints and analyzed numerically φ evolution after the inflationary stage till its decay φ → qq-barlγ. During that period oscillated with a decreasing amplitude due to Universe expansion and particle production processes due to the coupling of the field to fermions gφf 1 f 2 . It was shown that particle creation processes play an essential role for evolution and its final value. It may lead to a considerable decrease of the field's amplitude for large g and/or large H values, which reflects finally into strong damping of the baryon charge carried by the condensate. The analysis suggests that for a natural range of the model's parameters the observed value of the baryon asymmetry can be obtained and the model can serve as a successful baryogenesis model, compatible with inflation. (author)

  6. Condensation induced water hammer safety

    Energy Technology Data Exchange (ETDEWEB)

    Gintner, M.A.

    1997-03-10

    Condensation induced water hammer events in piping systems can cause catastrophic steam system failures which can result in equipment damage, personal injury, and even death. As an industry, we have learned to become accustomed to the ''banging'' that we often hear in our steam piping systems, and complacent in our actions to prevent it. It is unfortunate that lives are lost needlessly, as this type of water hammer event is preventable if one only applies some basic principles when operating and maintaining their steam systems. At the U. S. Department of Energy's Hanford Site where I work, there was one such accident that occurred in 1993 which took the life of a former co-worker and friend of mine. Hanford was established as part of the Manhattan Project during World War II. it is a 560 square mile complex located along the banks of the Columbia River in Southeastern Washington State. For almost 45 years, hanford's mission was to produce weapons grade plutonium for our nations defense programs. Today, Hanford no longer produces plutonium, but is focused on site clean-up and economic diversification. Hanford still uses steam for heating and processing activities, utilizing over 20 miles of piping distribution systems similar to those found in industry. Although these aging systems are still sound, they cannot stand up to the extreme pressure pulses developed by a condensation induced water hammer.

  7. Magnon condensation and spin superfluidity

    Science.gov (United States)

    Bunkov, Yury M.; Safonov, Vladimir L.

    2018-04-01

    We consider the Bose-Einstein condensation (BEC) of quasi-equilibrium magnons which leads to spin superfluidity, the coherent quantum transfer of magnetization in magnetic material. The critical conditions for excited magnon density in ferro- and antiferromagnets, bulk and thin films, are estimated and discussed. It was demonstrated that only the highly populated region of the spectrum is responsible for the emergence of any BEC. This finding substantially simplifies the BEC theoretical analysis and is surely to be used for simulations. It is shown that the conditions of magnon BEC in the perpendicular magnetized YIG thin film is fulfillied at small angle, when signals are treated as excited spin waves. We also predict that the magnon BEC should occur in the antiferromagnetic hematite at room temperature at much lower excited magnon density compared to that of ferromagnetic YIG. Bogoliubov's theory of Bose-Einstein condensate is generalized to the case of multi-particle interactions. The six-magnon repulsive interaction may be responsible for the BEC stability in ferro- and antiferromagnets where the four-magnon interaction is attractive.

  8. Condensation induced water hammer safety

    International Nuclear Information System (INIS)

    Gintner, M.A.

    1997-01-01

    Condensation induced water hammer events in piping systems can cause catastrophic steam system failures which can result in equipment damage, personal injury, and even death. As an industry, we have learned to become accustomed to the ''banging'' that we often hear in our steam piping systems, and complacent in our actions to prevent it. It is unfortunate that lives are lost needlessly, as this type of water hammer event is preventable if one only applies some basic principles when operating and maintaining their steam systems. At the U. S. Department of Energy's Hanford Site where I work, there was one such accident that occurred in 1993 which took the life of a former co-worker and friend of mine. Hanford was established as part of the Manhattan Project during World War II. it is a 560 square mile complex located along the banks of the Columbia River in Southeastern Washington State. For almost 45 years, hanford's mission was to produce weapons grade plutonium for our nations defense programs. Today, Hanford no longer produces plutonium, but is focused on site clean-up and economic diversification. Hanford still uses steam for heating and processing activities, utilizing over 20 miles of piping distribution systems similar to those found in industry. Although these aging systems are still sound, they cannot stand up to the extreme pressure pulses developed by a condensation induced water hammer

  9. Synthesis of Acrolein from Glycerol Using FePO4 Catalyst in Liquid Phase Dehydration

    Directory of Open Access Journals (Sweden)

    Akhmad Zainal Abidin

    2016-02-01

    Full Text Available Acrolein is currently produced using propylene from crude oil while its price and scarcity are increasing. A renewable material such as glycerol is an attractive alternative for acrolein production. It can be obtained from crude palm oil (CPO and is a byproduct of biodiesel production. Besides being able to compete economically, glycerol is an environmentally friendly material. The purpose of this study is to synthesize acrolein from glycerol using FePO4 catalyst in liquid phase dehydration. The catalyst was prepared by three different methods: hydrothermal (catalyst A, deposition at Fe/P = 1.15 (catalyst B, and deposition at Fe/P = 1.20 (catalyst C. The experimental reaction temperature was varied at 220, 240 and 260 °C under constant atmospheric pressure. The results showed that catalyst C provided the best yield (91%, followed by catalyst A (90% and catalyst B (82%. The increasing reaction temperature showed a tendency to increase the yield of acrolein, while the presence of oxygen reduced the yield of acrolein and allowed the reaction to produce more side products such as glycerol propanal, acetaldehyde, and propionate. Catalyst reuse without any regeneration resulted in a yield profile of acrolein that continued to decline.

  10. Analysis of dehydration and strength in elite badminton players.

    Directory of Open Access Journals (Sweden)

    Javier Abián-Vicén

    Full Text Available 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.

  11. Bio-oil fractionation and condensation

    Science.gov (United States)

    Brown, Robert C; Jones, Samuel T; Pollard, Anthony

    2013-07-02

    A method of fractionating bio-oil vapors which involves providing bio-oil vapors comprising bio-oil constituents is described. The bio-oil vapors are cooled in a first stage which comprises a condenser having passages for the bio-oil separated by a heat conducting wall from passages for a coolant. The coolant in the condenser of the first stage is maintained at a substantially constant temperature, set at a temperature in the range of 75 to 100.degree. C., to condense a first liquid fraction of liquefied bio-oil constituents in the condenser of the first stage. The first liquid fraction of liquified bio-oil constituents from the condenser in the first stage is collected. Also described are steps for subsequently recovering further liquid fractions of liquefied bio-oil constituents. Particular compositions of bio-oil condensation products are also described.

  12. The physics of exciton-polariton condensates

    CERN Document Server

    Lagoudakis, Konstantinos

    2013-01-01

    In 2006 researchers created the first polariton Bose-Einstein condensate at 19K in the solid state. Being inherently open quantum systems, polariton condensates open a window into the unpredictable world of physics beyond the “fifth state of matter”: the limited lifetime of polaritons renders polariton condensates out-of-equilibrium and provides a fertile test-bed for non-equilibrium physics. This book presents an experimental investigation into exciting features arising from this non-equilibrium behavior. Through careful experimentation, the author demonstrates the ability of polaritons to synchronize and create a single energy delocalized condensate. Under certain disorder and excitation conditions the complete opposite case of coexisting spatially overlapping condensates may be observed. The author provides the first demonstration of quantized vortices in polariton condensates and the first observation of fractional vortices with full phase and amplitude characterization. Finally, this book investigate...

  13. THE STABILITY OF VAPOR CONDENSATION EQUILIBRIUM

    OpenAIRE

    SHIMIN ZHANG

    2005-01-01

    The system must get across an energy peak of unstable equilibrium during the condensation of pure vapor; as the supersaturated extent of vapor increases and the temperature decreases, the energy peak shortens and vapor condensation becomes easier. The system must get across an energy peak of unstable equilibrium first, and then get into an energy valley of stable equilibrium during the condensation of impure vapor; as the partial pressure of vapor decreases, the energy peak becomes taller, th...

  14. Nonlinear behavior of the radiative condensation instability

    International Nuclear Information System (INIS)

    McCarthy, D.; Drake, J.F.

    1991-01-01

    An investigation of the nonlinear behavior of the radiative condensation instability is presented in a simple one-dimensional magnetized plasma. It is shown that the radiative condensation is typically a nonlinear instability---the growth of the instability is stronger once the disturbance reaches finite amplitude. Moreover, classical parallel thermal conduction is insufficient by itself to saturate the instability. Radiative collapse continues until the temperature in the high density condensation falls sufficiently to reduce the radiation rate

  15. Physics of hollow Bose-Einstein condensates

    OpenAIRE

    Padavić, Karmela; Sun, Kuei; Lannert, Courtney; Vishveshwara, Smitha

    2016-01-01

    Bose-Einstein condensate shells, while occurring in ultracold systems of coexisting phases and potentially within neutron stars, have yet to be realized in isolation on Earth due to the experimental challenge of overcoming gravitational sag. Motivated by the expected realization of hollow condensates by the space-based Cold Atomic Laboratory in microgravity conditions, we study a spherical condensate undergoing a topological change from a filled sphere to a hollow shell. We argue that the col...

  16. Relationship of Renal Function Tests and Electrolyte Levels with Severity of Dehydration in Acute Diarrhea.

    Science.gov (United States)

    Gauchan, E; Malla, K K

    2015-01-01

    Acute diarrheal illness constitutes a major cause of morbidity and mortality in children in developing countries. Most of the complications of diarrhea occur due to excessive fluid and electrolyte loss; adverse complications are seen more with increasing severity of dehydration. This study was conducted to identify the relation of renal function and electrolyte abnormalities in children with varying severity of dehydration. This study was carried out in Manipal Teaching Hospital, Pokhara, Nepal over duration of one year. The aims were to find out the association of renal function and electrolyte disturbances with type of diarrhea, severity of dehydration and their relation to outcome. All children more than one month and less than 15 years with acute diarrhea were included in the study. Data were entered and analyzed by SPSS version 19. Statistical analysis applied was Chi-square test. A p-value of Dehydration was associated more with Acute Watery Diarrhea than with Invasive Diarrhea. Renal function and electrolyte abnormalities were seen more in Acute Watery Diarrhea with increasing levels of blood urea, serum creatinine and abnormal levels of serum sodium seen with increased severity of dehydration. Abnormalities in renal function and electrolytes correlated significantly with severity of dehydration. The outcome of patients correlated with severity of dehydration with mortality occurring in 18.1% of patients with Severe dehydration, 0.8% of Some dehydration with no mortality in the No dehydration group.

  17. Advances in modelling of condensation phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.S.; Zaltsgendler, E. [Ontario Hydro Nuclear, Toronto (Canada); Hanna, B. [Atomic Energy of Canada Limited, Pinawa, Manitoba (Canada)

    1997-07-01

    The physical parameters in the modelling of condensation phenomena in the CANDU reactor system codes are discussed. The experimental programs used for thermal-hydraulic code validation in the Canadian nuclear industry are briefly described. The modelling of vapour generation and in particular condensation plays a key role in modelling of postulated reactor transients. The condensation models adopted in the current state-of-the-art two-fluid CANDU reactor thermal-hydraulic system codes (CATHENA and TUF) are described. As examples of the modelling challenges faced, the simulation of a cold water injection experiment by CATHENA and the simulation of a condensation induced water hammer experiment by TUF are described.

  18. Strangeness condensation and ''clearing'' of the vacuum

    International Nuclear Information System (INIS)

    Brown, G.E.; Kubodera, Kuniharu; Rho, M.; State Univ. of New York, Stony Brook

    1987-01-01

    We show that a substantial amount of strange quark-antiquark pair condensates in the nucleon required by the πN sigma term implies that kaons could condense in nuclear matter at a density about three times that of normal nuclear matter. This phenomenon can be understood as the ''cleansing'' of qanti q condensates from the QCD vacuum by a dense nuclear matter, resulting in a (partial) restoration of the chiral symmetry explicitly broken in the vacuum. It is suggested that the condensation signals a new phase distinct from that of quark plasma and that of ordinary dense hadronic matter. (orig.)

  19. Combined effect of storage temperature and water activity on the antiglycoxidative properties and color of dehydrated apples.

    Science.gov (United States)

    Lavelli, Vera

    2009-12-23

    Phytochemical contents, color, and inhibition efficacy toward oxidative and glycoxidative reactions were studied in dehydrated apples following storage in the water activity range from 0.1 to 0.7 at 20, 30, and 40 degrees C, which can be considered as room conditions. Hunter colorimetric parameters were analyzed at different temperatures and time intervals, and nonenzymatic browning was modeled according to pseudo-zero-order kinetics. The effect of temperature on the browning rate followed the Arrhenius equation, with an activation energy of 64000 J/mol, which was not affected by the water activity level. The phytochemical contents, inhibition efficacy of protein glycation, and antioxidant properties were then analyzed in the products stored under selected "equivalent" conditions in terms of browning effects, namely, 120 days/20 degrees C, 50 days/30 degrees C, and 22 days/40 degrees C. After storage for 120 days/20 degrees C, the retention percentages of hydroxycinnamic acids, phloridzin, and epicatechin were >86%, but ascorbic acid, catechin, and procyanidins were less stable; concurrently dehydrated apples retained about 80% of the radical scavenging activity and 70% of the ability to inhibit protein glycation. Following storage at higher temperatures the expected browning effect occurred in a shorter time scale; however, the patterns of product degradation were different. A sharp increase in the degradation rates of all antioxidants, relative to browning rate, was observed at temperatures >or=30 degrees C, and this trend was accelerated with concurrent increase in water activity at >0.3 levels. The application of low-temperature/long-time conditions for storage of dehydrated apples corresponded to maximum retention of their efficacy to counteract oxidative and glycoxidative reactions, which have been linked to human chronic diseases.

  20. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT: NEW CONDENSATOR, INC.--THE CONDENSATOR DIESEL ENGINE RETROFIT CRANKCASE VENTILATION SYSTEM

    Science.gov (United States)

    EPA's Environmental Technology Verification Program has tested New Condensator Inc.'s Condensator Diesel Engine Retrofit Crankcase Ventilation System. Brake specific fuel consumption (BSFC), the ratio of engine fuel consumption to the engine power output, was evaluated for engine...

  1. Quasiparticles in condensed matter systems

    Science.gov (United States)

    Wölfle, Peter

    2018-03-01

    Quasiparticles are a powerful concept of condensed matter quantum theory. In this review, the appearence and the properties of quasiparticles are presented in a unifying perspective. The principles behind the existence of quasiparticle excitations in both quantum disordered and ordered phases of fermionic and bosonic systems are discussed. The lifetime of quasiparticles is considered in particular near a continuous classical or quantum phase transition, when the nature of quasiparticles on both sides of a transition into an ordered state changes. A new concept of critical quasiparticles near a quantum critical point is introduced, and applied to quantum phase transitions in heavy fermion metals. Fractional quasiparticles in systems of restricted dimensionality are reviewed. Dirac quasiparticles emerging in so-called Dirac materials are discussed. The more recent discoveries of topologically protected chiral quasiparticles in topological matter and Majorana quasiparticles in topological superconductors are briefly reviewed.

  2. Possibility of removing condensate and scattered oil from gas-condensate field during bed flooding

    Energy Technology Data Exchange (ETDEWEB)

    Belkina, N.A.; Yagubov, M.S.

    1984-01-01

    The problem is set of evaluating the possible removal from the bed of scattered oil and condensate during flooding of the bed. For this purpose, an experimental study was made of the displacement by water from the porous medium of the oil and condensate saturating it. The obtained experimental results permit evaluation of the possible removal from the gas-condensate bed of scattered oil and condensate during flooding of the bed.

  3. Reactions of phenols and alcohols over thoria: mechanism of ether formation

    International Nuclear Information System (INIS)

    Karuppannasamy, S.; Narayanan, K.; Pillai, C.N.

    1980-01-01

    The dehydration of phenols and alkylation of phenols by alcohols over thoria were studied at 400 to 500 0 C and atmospheric pressure. Phenol and cresols, when dehydrated gave diaryl ethers as main products. With para-substituted phenols such as p-methoxy, p-t-butyl, p-chloro, and p-nitrophenol no ether formation was noticed. All the reactions were accompanied by considerable amount of coke formation. Alkylation of phenols by alcohols gave a mixture of O- and C-alkylated products under the same reaction conditions. O-alkylation and C-alkylation are parallel reactions. The mechanistic aspects of the reactions are discussed. 3 figures, 3 tables

  4. Statistical physics and condensed matter

    International Nuclear Information System (INIS)

    2003-01-01

    This document is divided into 4 sections: 1) General aspects of statistical physics. The themes include: possible geometrical structures of thermodynamics, the thermodynamical foundation of quantum measurement, transport phenomena (kinetic theory, hydrodynamics and turbulence) and out of equilibrium systems (stochastic dynamics and turbulence). The techniques involved here are typical of applied analysis: stability criteria, mode decomposition, shocks and stochastic equations. 2) Disordered, glassy and granular systems: statics and dynamics. The complexity of the systems can be studied through the structure of their phase space. The geometry of this phase space is studied in several works: the overlap distribution can now be computed with a very high precision; the boundary energy between low lying states does not behave like in ordinary systems; and the Edward's hypothesis of equi-probability of low lying metastable states is invalidated. The phenomenon of aging, characteristic of glassy dynamics, is studied in several models. Dynamics of biological systems or of fracture is shown to bear some resemblance with that of disordered systems. 3) Quantum systems. The themes include: mesoscopic superconductors, supersymmetric approach to strongly correlated electrons, quantum criticality and heavy fermion compounds, optical sum rule violation in the cuprates, heat capacity of lattice spin models from high-temperature series expansion, Lieb-Schultz-Mattis theorem in dimension larger than one, quantum Hall effect, Bose-Einstein condensation and multiple-spin exchange model on the triangular lattice. 4) Soft condensed matter and biological systems. Path integral representations are invaluable to describe polymers, proteins and self-avoiding membranes. Using these methods, problems as diverse as the titration of a weak poly-acid by a strong base, the denaturation transition of DNA or bridge-hopping in conducting polymers have been addressed. The problems of RNA folding has

  5. Mushroom dehydration in a hybrid-solar dryer

    International Nuclear Information System (INIS)

    Reyes, Alejandro; Mahn, Andrea; Cubillos, Francisco; Huenulaf, Pedro

    2013-01-01

    Highlights: ► Mushrooms (Paris variety) were dehydrated in a hybrid solar dryer. ► Effective diffusivity was estimated by the Constant Diffusivity Model. ► Drying kinetics were adjusted by a semi-theoretical and the empirical Page model. ► Temperature, thickness and air recycle significantly affected critical moisture. ► The input of solar energy resulted in 3.5–12.5% electrical energy saving. - Abstract: Mushrooms (Paris variety) were dehydrated in a hybrid solar dryer (HSD) provided with a 3 m 2 solar panel and electric resistances. Mushrooms were cut in 8 mm or 4 mm thickness slices. At the outlet of the tray dryer 80–90% air was recycled and the air temperature was adjusted to the pre-defined levels (50 or 60 °C). At the outlet of the solar panel the air temperature raised between 2 and 20 °C above the ambient temperature, depending mainly of solar radiation level. Temperature, slices thickness and air recycle level had statistically significant effects on critical moisture content (X c ), as well as on the time necessary to reach a moisture content of 0.1 (wb). The color parameters of dehydrated mushroom indicate a notorious darkening, in all runs. Rehydration assays at 35 °C showed that in less than 30 min rehydrated mushrooms reached a moisture content of 0.8 (wb). Effective diffusivity (D eff ) was estimated by the Simplified Constant Diffusivity Model (SCDM), and it ranged between 6E−10 and 40E−10 m 2 /s, with R 2 higher than 0.98, agreeing with literature. The adjustment of experimental drying kinetics with the empirical Page’s model resulted in R 2 higher than 0.997. Finally, the input of solar energy resulted in 3.5–12.5% energy saving. These values could even be improved by increasing the agro-product load in the HSD

  6. Characterization of dehydration-induced luminescence of kaolinite.

    Science.gov (United States)

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

    1985-01-01

    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.

  7. Reliability of Urinary Dehydration Markers in Elite Youth Boxers.

    Science.gov (United States)

    Zubac, Damir; Cular, Drazen; Marusic, Uros

    2018-03-01

    To determine the reliability and diagnostic accuracy of noninvasive urinary dehydration markers in field-based settings on a day-to-day basis in elite adolescent amateur boxers. Sixty-nine urine samples were collected daily from 23 athletes (17.3 ± 1.9 y) during their weight-stable phase and analyzed by field and laboratory measures of hydration status. Urine osmolality (U OSM ), urine specific gravity (U SG ), total protein content (T PC ), and body-mass stability were evaluated to determine fluid balance and hydration status. Overall macronutrient and water intake were determined using dietary records. According to their anthropometric characteristics, athletes were assigned into 2 groups: lightweight (L WB ) and heavyweight (H WB ) boxers. Data presented on U OSM demonstrated a uniform increment by 11.2% ± 12.8% (L WB ) and 19.9% ± 22.7% (H WB ) (P dehydration markers. Poor correlations were found between U SG and T PC metabolites (r = .27, P = .211). Urinary dehydration markers (both U SG and U OSM ) exhibit high variability and seem to be unreliable diagnostic tools to track actual body-weight loss in real-life settings. The ad libitum fluid intake was apparently inadequate to match acute fluid loss during and after intense preparation. The applicability of a single-time-point hydration-status assessment concept may preclude accurate assessment of actual body-weight deficits in youth boxers.

  8. Dehydration of gypsum rock by solar energy: preliminary study

    OpenAIRE

    López-Delgado, Aurora; López-Andrés, Sol; Padilla, Isabel; Alvarez, M.; Galindo, R.; Váquez, A. J.

    2014-01-01

    The dehydration process of gypsum rock was studied under concentrated solar energy by using a Fresnel lens with power density of 260 Wcm-2. Temperatures higher than 700¿C were attained for 1 min of solar exposure. The effect of grain size of sample and radiation exposure time on the formation of bassanite and anhydrite was studied by XRD. The complete transformation of dihydrate into hemihydrate and/or anhydrate phases is complete for the finer size sample. Plaster composed of 92.7% of anhydr...

  9. Artificial neural network model of pork meat cubes osmotic dehydration

    OpenAIRE

    Pezo, Lato L.; Ćurčić, Biljana Lj.; Filipović, Vladimir S.; Nićetin, Milica R.; Koprivica, Gordana B.; Mišljenović, Nevena M.; Lević, Ljubinko B.

    2013-01-01

    Mass transfer of pork meat cubes (M. triceps brachii), shaped as 1x1x1 cm, during osmotic dehydration (OD) and under atmospheric pressure was investigated in this paper. The effects of different parameters, such as concentration of sugar beet molasses (60-80%, w/w), temperature (20-50ºC), and immersion time (1-5 h) in terms of water loss (WL), solid gain (SG), final dry matter content (DM), and water activity (aw), were investigated using experimental results. Five artificial neural net...

  10. PRODUCING STRAWBERRY (Fragaria chiloensis) DEHYDRATED Spray and lyophilization

    OpenAIRE

    Guevara Pérez, A.; Universidad Nacional Agraria La Melina - Lima-Perú. Facultad de Industrias Alimentarias, Departamento de Tecnología de Alimentos.; Rojas Ayerve, T.; Universidad Nacional Agraria La Melina - Lima-Perú. Facultad de Ciencias, Departamento de Química.; Araujo Vargas, J. M.; Universidad Nacional Agraria La Melina - Lima-Perú. Facultad de Industrias Alimentarias, Departamento de Ingeniería de Alimentos.; Araujo Vargas, J. M.; Facultad de Industrias Alimentarias, Departamento de Ingeniería de Alimentos.

    2014-01-01

    Two methods of dehydration of strawberries (Fragaria chiloensis 1 .) ha ve been studied: spray-drying and freezedrying. It has been found that the optimum sequence for the drying operation is as follows: selection/classification , washing, steaming, pulp-extraction, conditioning and freeze-drying. The efficiency over the total solids obtained with this method is 86.48% compared to 66.02% when using spray-drying. The strawberry pulp was conditioned by water dilution of 1:1. For spray-drying, t...

  11. Quality and sensorial characteristics of osmotically dehydrated mango with syrups of inverted sugar and sucrose

    OpenAIRE

    Bernardi,Sabrina; Bodini,Renata B.; Marcatti,Bruna; Petrus,Rodrigo Rodrigues; Favaro-Trindade,Carmen Sílvia

    2009-01-01

    Osmotic dehydration is becoming more popular as a complementary treatment in the processing of dehydrated foods, since it presents some advantages such as minimising heat damage to the colour and flavour, inhibiting enzymatic browning and thus dispensing the addition of sulphite and, mainly, reducing energy costs. The objective of the present study was to evaluate the effect of using inverted sugar and sucrose syrups as osmotic agents in the dehydration of mango. The conditions used in the de...

  12. Dehydration Behaviour of Borax Pentahydrate to Anhydrous Borax by Multi-Stage Heating in a Fluidized

    OpenAIRE

    ŞAHİN, Ömer

    2002-01-01

    In order to optimize the anhydrous borax process in a fluidized bed calcinator, it is absolutely necessary to study the dehydration behaviour of borax pentahydrate. It was found that the basic feature of the dehydration of borax pentahydrate to anhydrous borax is concerned with the conditions employed. The bulk density and sodium borate content of the end product were determined to be a function of number of stages of temperature of the dehydration period in the fluidized bed. It...

  13. Performance of Clinical Signs in the Diagnosis of Dehydration in Children with Acute Gastroenteritis

    OpenAIRE

    Hoxha, Teuta; Xhelili, Luan; Azemi, Mehmedali; Avdiu, Muharrem; Ismaili-Jaha, Vlora; Efendija-Beqa, Urata; Grajcevci-Uka, Violeta

    2015-01-01

    Background: Acute evaluation and treatment of children presenting with dehydration represent one of the most common situation in the pediatric emergency department. To identify dehydration in infants and children before treatment, a number of symptoms and clinical signs have been evaluated. The aim of the study was to describe the performance of clinical signs in detecting dehydration in children. Methods: Two hundred children aged 1 month to 5 year were involved in our prospective study. The...

  14. Connections between quantum chromodynamics and condensed ...

    Indian Academy of Sciences (India)

    Abstract. Features of QCD can be seen qualitatively in certain condensed matter systems. Recently some of the analyses that originated in condensed matter physics have found applications in QCD. Using examples we discuss some of the connections between the two fields and show how progress can be made by ...

  15. Condensate growth in trapped Bose gates

    NARCIS (Netherlands)

    Bijlsma, M.J.; Zaremba, E.; Stoof, H.T.C.

    2000-01-01

    We study the dynamics of condensate fromation in an inhomogeneous trapped Bose gas with a positive interatomic scattering length. We take into account both the nonequilibrium kinetics of the thermal cloud and the Hartree-Fock mean-field efects in the condensed and the noncondensed parts of the gas.

  16. Condensate growth in trapped Bose gases

    NARCIS (Netherlands)

    Bijlsma, M.J.; Zaremba, E.; Stoof, H.T.C.

    2000-01-01

    We study the dynamics of condensate formation in an inhomogeneous trapped Bose gas with a positive interatomic scattering length. We take into account both the nonequilibrium kinetics of the thermal cloud and the Hartree-Fock mean-field effects in the condensed and the noncondensed parts of the gas.

  17. Tunneling of trapped-atom Bose condensates

    Indian Academy of Sciences (India)

    Tunneling of trapped-atom Bose condensates. SUBODH R SHENOY. Abdus Salam International Centre for Theoretical Physics, P.O. Box 586, Trieste 34100, Italy. Abstract. We obtain the dynamics in number and phase difference, for Bose condensates that tun- nel between two wells of a double-well atomic trap, using the ...

  18. Collision of Bose Condensate Dark Matter structures

    International Nuclear Information System (INIS)

    Guzman, F. S.

    2008-01-01

    The status of the scalar field or Bose condensate dark matter model is presented. Results about the solitonic behavior in collision of structures is presented as a possible explanation to the recent-possibly-solitonic behavior in the bullet cluster merger. Some estimates about the possibility to simulate the bullet cluster under the Bose Condensate dark matter model are indicated.

  19. Soliton resonance in bose-einstein condensate

    Science.gov (United States)

    Zak, Michail; Kulikov, I.

    2002-01-01

    A new phenomenon in nonlinear dispersive systems, including a Bose-Einstein Condensate (BEC), has been described. It is based upon a resonance between an externally induced soliton and 'eigen-solitons' of the homogeneous cubic Schrodinger equation. There have been shown that a moving source of positive /negative potential induces bright /dark solitons in an attractive / repulsive Bose condensate.

  20. Effective thermal conductivity of condensed polymeric nanofluids ...

    Indian Academy of Sciences (India)

    Thermal properties of polymeric nanosolids, obtained by condensing the corresponding nanofluids, are investigated using photothermal techniques. The heat transport properties of two sets of polyvinyl alcohol (PVA) based nanosolids, TiO2/PVA and Cu/PVA, prepared by condensing the respective nanofluids, which are ...

  1. Quantum monodromy in trapped Bose condensates

    NARCIS (Netherlands)

    Waalkens, H.

    2002-01-01

    Bose-Einstein condensation of ultra cold atoms is typically realized in magnetic traps which effectively lead to an axially symmetric harmonic potential. This letter shows that the spectrum of collective vibrational modes of a repulsive condensate in a prolate potential displays a defect known as

  2. Born-Kothari Condensation for Fermions

    Directory of Open Access Journals (Sweden)

    Arnab Ghosh

    2017-09-01

    Full Text Available In the spirit of Bose–Einstein condensation, we present a detailed account of the statistical description of the condensation phenomena for a Fermi–Dirac gas following the works of Born and Kothari. For bosons, while the condensed phase below a certain critical temperature, permits macroscopic occupation at the lowest energy single particle state, for fermions, due to Pauli exclusion principle, the condensed phase occurs only in the form of a single occupancy dense modes at the highest energy state. In spite of these rudimentary differences, our recent findings [Ghosh and Ray, 2017] identify the foregoing phenomenon as condensation-like coherence among fermions in an analogous way to Bose–Einstein condensate which is collectively described by a coherent matter wave. To reach the above conclusion, we employ the close relationship between the statistical methods of bosonic and fermionic fields pioneered by Cahill and Glauber. In addition to our previous results, we described in this mini-review that the highest momentum (energy for individual fermions, prerequisite for the condensation process, can be specified in terms of the natural length and energy scales of the problem. The existence of such condensed phases, which are of obvious significance in the context of elementary particles, have also been scrutinized.

  3. Dropwise Condensation Enhancement on Geometric Features

    Science.gov (United States)

    Zhao, Yajing; Preston, Daniel J.; Lu, Zhengmao; Wang, Evelyn N.

    Dropwise condensation, which has been demonstrated to exhibit a 5-7X higher heat transfer coefficient compared with state-of-the-art filmwise condensation, contributes to energy savings in a wide range of applications such as desalination systems, steam cycles and dew harvesting. In order to enhance dropwise condensation performance, previous studies have investigated the effects of surface geometric features on droplet growth rates and found that bumps protruding from surfaces can effectively promote dropwise condensation. In this work, we show that while bumps on surfaces enable droplets to grow faster in some cases, there are also cases where bumps on surfaces actually degrade dropwise condensation. We numerically simulated and experimentally demonstrated that even the same surface geometric feature can exert completely opposite effects on dropwise condensation of water under two different working conditions (pure vapor vs. air vapor mixture). This phenomenon is explained by comparing the heat and mass transfer resistance of the surface structure to that of the vapor transport during dropwise condensation. We expect that the fundamental understanding developed in this study will provide useful guidelines for relevant condensation applications.

  4. The Influence of pH on the Melamine-Dimethylurea-Formaldehyde Co-Condensations: A Quantitative 13C-NMR Study

    Directory of Open Access Journals (Sweden)

    Ming Cao

    2017-03-01

    Full Text Available 1,3-dimethylurea (DMU was used to mimic urea and to model melamine-urea-formaldehyde (MUF co-condensation reactions. The products of 1,3-dimethylurea-formaldehyde (DMUF, melamine-formaldehyde (MF, and melamine-1,3-dimethylurea-formaldehyde (MDMUF reactions under alkaline and weak acidic conditions were compared by performing quantitative carbon-13 nuclear magnetic resonance (13C-NMR analysis. The effect of pH on the co-condensation reactions was clarified. With the presence of the methyl groups in DMU, the appearance or absence of the featured signal at 54–55 ppm can be used to identify the co-condensed methylene linkage –N(–CH3 –CH2–NH–. Under alkaline condition, MDMUF reactions produced primarily MF polymers and the featured signal at 54–55 ppm was absent. Even though the co-condensations concurrently occurred, undistinguishable and very minor condensed structures with ether linkage were formed. Differently, under weak acidic condition, the relative content of co-condensed methylene carbons accounts for over 40%, indicating the MDMUF co-condensation reactions were much more competitive than the self-condensations. The formation of reactive carbocation intermediate was proposed to rationalize the results.

  5. Assessment of the controllability of condensible emissions. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Shareef, G.S.; Waddell, J.T.

    1990-10-01

    The report gives results of a study to gain insights into the condensible emissions area from an air toxics perspective, with emphasis on controllability and chemical composition of these emissions. The study: compiled existing data on condensible emissions; determined the chemical composition of condensible emissions, where possible; identified source categories that are major emitters of condensibles; evaluated the effectiveness of various control devices in reducing condensible emissions; and evaluated how the performance of currently available control technologies can be improved to better control condensible emissions. Two data bases were developed: the Condensibles Data Base contains 43 emission source categories; the Specialized Condensibles Data Base focuses on the chemical composition of condensible emissions.

  6. Strategies for Innovation in Multicomponent Reaction Design

    OpenAIRE

    Ganem, Bruce

    2009-01-01

    By generating structural complexity in a single step from three or more reactants, multicomponent reactions (MCRs) make it possible to synthesize target compounds with greater efficiency and atom economy. The history of such reactions can be traced to the mid-nineteenth century when Strecker first produced α-aminonitriles from the condensation of aldehydes with ammonia and hydrogen cyanide.

  7. Oxygen isotopic fractionation in the condensation of refractory smokes

    Science.gov (United States)

    Nelson, R.; Thiemens, M.; Nuth, J.; Donn, B.

    1989-01-01

    This paper reports preliminary measurements of the oxygen isotopic fractionation that occurs during the condensation of refractory metal oxide smokes. Fractionation occurred at temperatures in excess of 500 K during and/or subsequent to reaction of SiH4, Fe(CO)5, Al(CH3)3, and O2 in a H2 carrier gas. Observed isotopic fractionation was as high as -15 per mil/amu. The magnitude of the isotopic fractionation suggests that the process is kinetically controlled since the effect is greatly in excess of that expected for equilibrium isotopic exchange.

  8. Capillary Condensation in 8 nm Deep Channels.

    Science.gov (United States)

    Zhong, Junjie; Riordon, Jason; Zandavi, Seyed Hadi; Xu, Yi; Persad, Aaron H; Mostowfi, Farshid; Sinton, David

    2018-02-01

    Condensation on the nanoscale is essential to understand many natural and synthetic systems relevant to water, air, and energy. Despite its importance, the underlying physics of condensation initiation and propagation remain largely unknown at sub-10 nm, mainly due to the challenges of controlling and probing such small systems. Here we study the condensation of n-propane down to 8 nm confinement in a nanofluidic system, distinct from previous studies at ∼100 nm. The condensation initiates significantly earlier in the 8 nm channels, and it initiates from the entrance, in contrast to channels just 10 times larger. The condensate propagation is observed to be governed by two liquid-vapor interfaces with an interplay between film and bridging effects. We model the experimental results using classical theories and find good agreement, demonstrating that this 8 nm nonpolar fluid system can be treated as a continuum from a thermodynamic perspective, despite having only 10-20 molecular layers.

  9. Dehydration enhances multiple physiological defense mechanisms in a desert lizard, Heloderma suspectum.

    Science.gov (United States)

    Moeller, Karla T; Demare, Guillaume; Davies, Scott; DeNardo, Dale F

    2017-06-15

    The physiological challenges associated with dehydration can induce an increase in plasma glucocorticoid concentrations, a response thought to provide the mechanism for dehydration suppressing immune function. However, a comprehensive examination of the inter-relationship of dehydration, stress and immune function has not been conducted within a single species. We previously demonstrated that Gila monsters ( Heloderma suspectum ), which inhabit a xeric environment with a predictable seasonal drought, have enhanced measures of innate immunity when dehydrated. These results suggest that, in this species, dehydration may not induce a glucocorticoid response, but, instead, enhances physiological defense mechanisms. To explore this possibility, we examined multiple measures of innate immunity as well as initial and reactive plasma concentrations of glucocorticoids in captive and free-ranging Gila monsters at various hydration states. Our results show that, in this species, dehydration alone does not cause a substantial increase in plasma glucocorticoids, and we provide broader evidence that dehydration enhances defensive mechanisms including stress reactivity and various measures of innate immune function. These findings suggest that physiological responses to dehydration may depend heavily on an organism's ecology. More research on the effects of dehydration on the glucocorticoid response and immunity will help clarify the interactive roles they play in response to hydration challenges and whether adaptations to water-limited environments influence these interactions. © 2017. Published by The Company of Biologists Ltd.

  10. (1)H nuclear magnetic resonance (NMR) as a tool to measure dehydration in mice.

    Science.gov (United States)

    Li, Matthew; Vassiliou, Christophoros C; Colucci, Lina A; Cima, Michael J

    2015-08-01

    Dehydration is a prevalent pathology, where loss of bodily water can result in variable symptoms. Symptoms can range from simple thirst to dire scenarios involving loss of consciousness. Clinical methods exist that assess dehydration from qualitative weight changes to more quantitative osmolality measurements. These methods are imprecise, invasive, and/or easily confounded, despite being practiced clinically. We investigate a non-invasive, non-imaging (1)H NMR method of assessing dehydration that attempts to address issues with existing clinical methods. Dehydration was achieved by exposing mice (n = 16) to a thermally elevated environment (37 °C) for up to 7.5 h (0.11-13% weight loss). Whole body NMR measurements were made using a Bruker LF50 BCA-Analyzer before and after dehydration. Physical lean tissue, adipose, and free water compartment approximations had NMR values extracted from relaxation data through a multi-exponential fitting method. Changes in before/after NMR values were compared with clinically practiced metrics of weight loss (percent dehydration) as well as blood and urine osmolality. A linear correlation between tissue relaxometry and both animal percent dehydration and urine osmolality was observed in lean tissue, but not adipose or free fluids. Calculated R(2) values for percent dehydration were 0.8619 (lean, P dehydration in live animals. Copyright © 2015 John Wiley & Sons, Ltd.

  11. Sewage sludge dehydration with biodegradable polyelectrolytes as flocculants. Final report. Pt. 1. Development of synthetic polyelectrolytes; Klaerschlammentwaesserung unter Einsatz biologisch abbaubarer Polyelektrolyte als Flockungshilfsmittel. Abschlussbericht. T. 1. Entwicklung der synthetischen Polyelektrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Matuschewski, H.; Gohlke, U.; Jaeger, W.

    1997-09-01

    Polyelectrolytes with improved degradability were to be developed for dehydration of uncontaminated sewage sludge. Part-project I investigated the synthesis of polymers. For this purpose, polyvinyl alcohol was functionalized into polyelectrolytes by etheration, Mannich reaction, acetalisation and graft copolymerisation. Some of the new polymers have very good flocculation and dehydration characteristics. (SR) [Deutsch] Ziel des Vorhabens war es, Ergebnisse zur Entwaesserung nicht kontaminierter Klaerschlaemme mit Polyelektrolyten mit verbesserter Abbaubarkeit zu erarbeiten. Ziel des Teilvorhabens I war die Synthese entsprechender Polymerer. Dazu wurde Polyvinylalkohol durch Veretherung, Mannichreaktion, Acetalisierung und Propfcopolymerisation zu Polyelektrolyten funktionalisiert. Die neuen Polymere weisen zum Teil sehr gute Flockungs- und Entwaesserungseigenschaften auf. (SR)

  12. Process for dehydration of oregano using propane gas as fuel

    Directory of Open Access Journals (Sweden)

    Carlos O. Velásquez-Santos

    2014-08-01

    Full Text Available The article describes two important issues, the first is the process to design, implement and validate a mechanical dryer of oregano, using propane gas as fuel, and the second is the cost of the process of dehydrated, taking into account the cost of electric energy consumption by the fan and the cost of propane gas consumption by the heat exchanger. To achieve this, it was necessary review the state of the art and the study of the raw material (oregano, were established as premises of design the necessary technical specifications and the variables involved in the process, using conceptual methods and simulation to ensure that it complies with the ISO standard 7925:1999, which defines the requirements for the marketing of dried oregano and processed. Emphasis was made on the percentage of moisture that is 10%, the moisture of the product was found by the azeotropic distillation method, subsequently was validated the functionality and efficiency, comparing the results from an experimental design, then it was obtained the drying curve of oregano with the prototype of drying and it was checked if it meets ISO 7925:1999 standard and the NTC 4423 standard in order to obtain a final product dehydrated with the percentage of humidity appropriate.

  13. Detection of Fumonisins in Fresh and Dehydrated Commercial Garlic.

    Science.gov (United States)

    Tonti, Stefano; Mandrioli, Mara; Nipoti, Paola; Pisi, Annamaria; Toschi, Tullia Gallina; Prodi, Antonio

    2017-08-16

    An epidemic fungal disease caused by Fusarium proliferatum, responsible for fumonisin production (FB1, FB2, and FB3), has been reported in the main garlic-producing countries in recent years. Fumonisins are a group of structurally related toxic metabolites produced by this pathogen. The aim of this work was to establish an enzyme-linked immunosorbent assay (ELISA) procedure, mostly applied to cereals, that is suitable for fumonisin detection in garlic and compare these results to those obtained by high-performance liquid chromatography (HPLC) and screening of fresh and dehydrated garlic for toxicological risk. The results show good correlation between the two analytical methods. In fresh symptomatic garlic, fumonisin levels were higher in the basal plates than those in the portions with necrotic spots. Among the 56 commercially dehydrated garlic samples screened, three were positive by ELISA test and only one was above the limit of quantitation. The same samples analyzed by HPLC showed the presence of FB1 in trace amounts that was below the limit of quantitation; FB2 and FB3 were absent. The results are reassuring, because no substantial contamination by fumonisins was found in commercial garlic.

  14. Physicochemical and microscopic characterization of dehydrated ostrich eggs

    Directory of Open Access Journals (Sweden)

    Jailane de Souza Aquino

    2014-09-01

    Full Text Available Approximately 20% of ostrich eggs are infertile and can be consumed by humans, however, its high volume and perishability indicate the need of appropriate technological processes. Thus, this study aimed to determine the chemical composition of in natura ostrich eggs, as well as physical, chemical and microscopic parameters of ostrich egg products after dehydration. The chemical composition of in natura ostrich and chicken eggs was determined. Ostrich egg whites, yolks and whole eggs were fermented and dried in mini spray-dryer. After dehydration, yield, composition and particle diameter of egg products collected in the cyclone and spray-dryer chamber were evaluated. In natura ostrich egg white and yolk showed higher protein (respectively 15.21% and 11.54% and fat (respectively 38.48% and 0.34% contents, when compared to chicken eggs. Samples collected from the cyclone showed a lower moisture content and better particle diameter uniformity. The ostrich egg products presented satisfactory yield, uniformity and nutritional value, demonstrating that the spray-dryer technique is another alternative for conservation and use of this food for human consumption.

  15. Phase transitions on dehydration of the natural zeolite thomsonite

    DEFF Research Database (Denmark)

    Ståhl, Kenny

    2001-01-01

    The dehydration of the natural zeolite thomsonite, Na4CasAl20Si20O80 24H(2)O, has been studied using a combination of conventional and synchrotron X-ray powder diffraction. A preliminary in situ dehydration study revealed two distinct unit cell changes at approximately 540 and 570 K, respectively...... coordinate two waters each. Thomsonite, heat treated at 523 K: Spacegroup Pncn, a = 13.0032(1), b = 12.9814(1), c = 13.2486(1) Angstrom, and 16 water/unit cell. Up to the first phase transition W3 and W4, both coordinated by the mixed CaA/Na site, are expelled. Thomsonite, heat treated at 553 K-Spacegroup Pn......2n, a = 13.0814(2), b = 13.0429(2), c = 13.2004(2) Angstrom, and 12 water/unit cell. During the phase transition at about 540 K the mixed CaA/Na site is separate into distinct CaA and Na sites. As the Na sites do not require water coordination another 1/6 of the original water contents may...

  16. Condensing boiler applications in the process industry

    International Nuclear Information System (INIS)

    Chen, Qun; Finney, Karen; Li, Hanning; Zhang, Xiaohui; Zhou, Jue; Sharifi, Vida; Swithenbank, Jim

    2012-01-01

    Major challenging issues such as climate change, energy prices and fuel security have focussed the attention of process industries on their energy efficiency and opportunities for improvement. The main objective of this research study was to investigate technologies needed to exploit the large amount of low grade heat available from a flue gas condensing system through industrial condensing boilers. The technology and application of industrial condensing boilers in various heating systems were extensively reviewed. As the condensers require site-specific engineering design, a case study was carried out to investigate the feasibility (technically and economically) of applying condensing boilers in a large scale district heating system (40 MW). The study showed that by recovering the latent heat of water vapour in the flue gas through condensing boilers, the whole heating system could achieve significantly higher efficiency levels than conventional boilers. In addition to waste heat recovery, condensing boilers can also be optimised for emission abatement, especially for particle removal. Two technical barriers for the condensing boiler application are corrosion and return water temperatures. Highly corrosion-resistant material is required for condensing boiler manufacture. The thermal design of a 'case study' single pass shell-and-tube condensing heat exchanger/condenser showed that a considerable amount of thermal resistance was on the shell-side. Based on the case study calculations, approximately 4900 m 2 of total heat transfer area was required, if stainless steel was used as a construction material. If the heat transfer area was made of carbon steel, then polypropylene could be used as the corrosion-resistant coating material outside the tubes. The addition of polypropylene coating increased the tube wall thermal resistance, hence the required heat transfer area was approximately 5800 m 2 . Net Present Value (NPV) calculations showed that the choice of a carbon

  17. Reevaluation of the phenol-sulfuric acid reaction for the estimation of hexoses and pentoses.

    Science.gov (United States)

    Rao, P; Pattabiraman, T N

    1989-08-15

    Evidence is provided to show that in the conventional phenol-sulfuric acid reaction procedure, phenol underwent sulfonation in situ and the phenolsulfonic acid formed decreased the color intensity for hydroxymethyl furfural (HMF), furfural, and many hexoses and pentoses tested. A modified method is described to overcome this problem in which phenol was added after the dehydration of carbohydrates by sulfuric acid and after cooling the system. The color intensity around 475-485 nm for different compounds was fairly proportional to the amount of furfural derivatives (absorption at 310-320 nm) formed from the sugars in the modified method unlike in the conventional procedure. The studies also show that for condensation of HMF derivatives with phenol, heat is not necessary. The color intensity in the modified method also increased compared to that in the conventional method. The increase in the modified method compared to that in the conventional method was 6.0-fold for furfural, 9.1-fold for hydroxymethyl furfural, 3.7-fold for fructose, 2.3-fold for xylose, and 2.0-fold for glucose and arabinose. The possible reasons for this differential increase are discussed.

  18. Condensing embryology teaching: alternative perspectives

    Directory of Open Access Journals (Sweden)

    Hasan M

    2018-03-01

    Full Text Available Mohammad Hasan, Syed Maaz Tariq, Syed Ali Haider Department of MBBS, Jinnah Sindh Medical University, Karachi, PakistanWe read the article “Condensing embryology teaching for medical students: can it be taught in 2 hours?” by Kazzazi and Bartlett quite attentively. The authors were successful in mentioning an effective mode of teaching embryology. Embryology is indeed an important subject that forms the base for appreciating anatomy and has immense practical implementations in different parts of medicine, for example, in pediatrics and ENT surgery. However, it is often neglected and is only taught in preclinical years.1 The authors proposed a method for teaching embryology splendidly from their perspective; therefore, we felt the need to expand the discussion from the perspective of third-year medical students who have just completed their preclinical years. Hence, we would like to mention few limitations to this study as well.Authors’ replyFawz Kazzazi, Jonathan Bartlett School of Clinical Medicine, University of Cambridge, Cambridge, UKWe read with interest the response letter by Hasan et al. We must first commend the editor and journal on their great ability to unify the medical community and extend topics for debate internationally.View the original paper by Kazzazi and Bartlett.

  19. Topology and condensed matter physics

    CERN Document Server

    Mj, Mahan; Bandyopadhyay, Abhijit

    2017-01-01

    This book introduces aspects of topology and applications to problems in condensed matter physics. Basic topics in mathematics have been introduced in a form accessible to physicists, and the use of topology in quantum, statistical and solid state physics has been developed with an emphasis on pedagogy. The aim is to bridge the language barrier between physics and mathematics, as well as the different specializations in physics. Pitched at the level of a graduate student of physics, this book does not assume any additional knowledge of mathematics or physics. It is therefore suited for advanced postgraduate students as well. A collection of selected problems will help the reader learn the topics on one's own, and the broad range of topics covered will make the text a valuable resource for practising researchers in the field.  The book consists of two parts: one corresponds to developing the necessary mathematics and the other discusses applications to physical problems. The section on mathematics is a qui...

  20. Ice-condenser aerosol tests

    International Nuclear Information System (INIS)

    Ligotke, M.W.; Eschbach, E.J.; Winegardner, W.K.

    1991-09-01

    This report presents the results of an experimental investigation of aerosol particle transport and capture using a full-scale height and reduced-scale cross section test facility based on the design of the ice compartment of a pressurized water reactor (PWR) ice-condenser containment system. Results of 38 tests included thermal-hydraulic as well as aerosol particle data. Particle retention in the test section was greatly influenced by thermal-hydraulic and aerosol test parameters. Test-average decontamination factor (DF) ranged between 1.0 and 36 (retentions between ∼0 and 97.2%). The measured test-average particle retentions for tests without and with ice and steam ranged between DF = 1.0 and 2.2 and DF = 2.4 and 36, respectively. In order to apparent importance, parameters that caused particle retention in the test section in the presence of ice were steam mole fraction (SMF), noncondensible gas flow rate (residence time), particle solubility, and inlet particle size. Ice-basket section noncondensible flows greater than 0.1 m 3 /s resulted in stable thermal stratification whereas flows less than 0.1 m 3 /s resulted in thermal behavior termed meandering with frequent temperature crossovers between flow channels. 10 refs., 66 figs., 16 tabs

  1. Ice-condenser aerosol tests

    Energy Technology Data Exchange (ETDEWEB)

    Ligotke, M.W.; Eschbach, E.J.; Winegardner, W.K. (Pacific Northwest Lab., Richland, WA (United States))

    1991-09-01

    This report presents the results of an experimental investigation of aerosol particle transport and capture using a full-scale height and reduced-scale cross section test facility based on the design of the ice compartment of a pressurized water reactor (PWR) ice-condenser containment system. Results of 38 tests included thermal-hydraulic as well as aerosol particle data. Particle retention in the test section was greatly influenced by thermal-hydraulic and aerosol test parameters. Test-average decontamination factor (DF) ranged between 1.0 and 36 (retentions between {approximately}0 and 97.2%). The measured test-average particle retentions for tests without and with ice and steam ranged between DF = 1.0 and 2.2 and DF = 2.4 and 36, respectively. In order to apparent importance, parameters that caused particle retention in the test section in the presence of ice were steam mole fraction (SMF), noncondensible gas flow rate (residence time), particle solubility, and inlet particle size. Ice-basket section noncondensible flows greater than 0.1 m{sup 3}/s resulted in stable thermal stratification whereas flows less than 0.1 m{sup 3}/s resulted in thermal behavior termed meandering with frequent temperature crossovers between flow channels. 10 refs., 66 figs., 16 tabs.

  2. Effect of Calcination Temperatures and Mo Modification on Nanocrystalline (γ-χ-Al2O3 Catalysts for Catalytic Ethanol Dehydration

    Directory of Open Access Journals (Sweden)

    Tharmmanoon Inmanee

    2017-01-01

    Full Text Available The mixed gamma and chi crystalline phase alumina (M-Al catalysts prepared by the solvothermal method were investigated for catalytic ethanol dehydration. The effects of calcination temperatures and Mo modification were elucidated. The catalysts were characterized by X-ray diffraction (XRD, N2 physisorption, transmission electron microscopy (TEM, and NH3-temperature programmed desorption (NH3-TPD. The catalytic activity was tested for ethylene production by dehydration reaction of ethanol in gas phase at atmospheric pressure and temperature between 200°C and 400°C. It was found that the calcination temperatures and Mo modification have effects on acidity of the catalysts. The increase in calcination temperature resulted in decreased acidity, while the Mo modification on the mixed phase alumina catalyst yielded increased acidity, especially in medium to strong acids. In this study, the catalytic activity of ethanol dehydration to ethylene apparently depends on the medium to strong acid. The mixed phase alumina catalyst calcined at 600°C (M-Al-600 exhibits the complete ethanol conversion having ethylene yield of 98.8% (at 350°C and the Mo-modified catalysts promoted dehydrogenation reaction to acetaldehyde. This can be attributed to the enhancement of medium to strong acid with metal sites of catalyst.

  3. Quantitative Study for the Surface Dehydration of Vocal Folds Based on High-Speed Imaging.

    Science.gov (United States)

    Li, Lin; Zhang, Yu; Maytag, Allison L; Jiang, Jack J

    2015-07-01

    From the perspective of the glottal area and mucosal wave, quantitatively estimate the differences of vocal fold on laryngeal activity during phonation at three different dehydration levels. Controlled three sets of tests. A dehydration experiment for 10 excised canine larynges was conducted at 16 cm H2O. According to the dehydration cycle time (H), dehydration levels were divided into three degrees (0% H, 50% H, 75% H). The glottal area and mucosal wave under three dehydration levels were extracted from high-speed images and digital videokymography (DKG) image sequences. Direct and non-direct amplitude components were derived from glottal areas. The amplitude and frequency of mucosal wave were calculated from DKG image sequences. These parameters in condition of three dehydration levels were compared for statistical analysis. The results showed a significant difference in direct (P = 0.001; P = 0.005) and non-direct (P = 0.005; P = 0.016) components of glottal areas between every two different dehydration levels. Considering the right-upper, right-lower, left-upper, and left-lower of vocal fold, the amplitudes of mucosal waves consistently decreased with increasing of dehydration levels. But, there was no significant difference in frequency. Surface dehydration could give rise to complex variation of vocal fold on tissues and vibratory mechanism, which should need analyzing from multiple perspectives. The results suggested that the combination of glottal area and mucosal wave could be better to research the change of vocal fold at different dehydrations. It would become a better crucial research tool for the clinical treatment of dehydration-induced laryngeal pathologies. Copyright © 2015 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  4. Intraocular pressure following 18 hours of systemic dehydration in ocular normotensive healthy subjects

    Directory of Open Access Journals (Sweden)

    Faustina K. Idu

    2015-07-01

    Full Text Available Aim: To investigate the effect of dehydration on intraocular pressure (IOP. Subjects: The study population comprised 50 subjects (27 men and 23 women with a mean age of 42.84 ± 2.64 years. Method: The subjects dehydrated for 18 hours. IOP was assessed in both eyes using the Perkins handheld applanation tonometer. Baseline measurement of IOP was taken before the subjects dehydrated for 18 hours and repeated after dehydration. Blood samples were taken before and after dehydration for the determination of plasma osmolality and plasma antidiuretic hormone (ADH concentrations. Results: A statistically significant (p < 0.001 reduction in the mean weight of subjects occurred after dehydration. There was a significant reduction in IOP from 16.68 mmHg ± 0.32 mmHg to 13.08 mmHg ± 0.31 mmHg after dehydration (p < 0.001. Mean plasma osmolality showed a statistically significant increase (p < 0.05 from baseline of 290.02 mOsmol/kg ± 1.25 mOsmol/kg to 294.96 mOsmol/kg ± 1.33 mOsmol/kg after dehydration. There was also a significant increase (p < 0.05 in mean plasma ADH concentration from 5.36 pg/mL ± 0.21 pg/mL to 6.40 pg/mL ± 0.20 pg/mL after dehydration. There were no significant differences in both systolic and diastolic blood pressures before and after dehydration. Conclusion: Dehydration decreases IOP in healthy humans; this decrease probably results from an increase in plasma osmolality and plasma ADH concentrations.

  5. Direct contact condensation in packed beds

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yi; Klausner, James F.; Mei, Renwei; Knight, Jessica [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611 (United States)

    2006-12-15

    A diffusion driven desalination process was recently described where a very effective direct contact condenser with a packed bed is used to condense water vapor out of an air/vapor mixture. A laboratory scale direct contact condenser has been fabricated as a twin tower structure with two stages, co-current and countercurrent. Experiments have been operated in each stage with respective saturated air inlet temperatures of 36, 40 and 43{sup o}C. The temperature and humidity data have been collected at the inlet and exit of the packed bed for different water to air mass flow ratios that vary between 0 and 2.5. A one-dimensional model based on conservation principles has been developed, which predicts the variation of temperature, humidity, and condensation rate through the condenser stages. Agreement between the model and experiments is very good. It is observed that the countercurrent flow stage condensation effectiveness is significantly higher than that for the co-current stage. The condensation heat and mass transfer rates were found to decrease when water blockages occur within the packed bed. Using high-speed digital cinematography, it was observed that this problem can occur at any operating condition, and is dependent on the packing surface wetting characteristics. This observation is used to explain the requirement for two different empirical constants, depending on packing diameter, suggested by Onda for the air side mass transfer coefficient correlation. (author)

  6. Emergency condensator for BWR type reactor

    International Nuclear Information System (INIS)

    Ubakai, Yoichi; Narumi, Yuichi; Sakata, Yuji.

    1992-01-01

    An emergency condensator is constituted with heat transfer pipes, a steam chamber, an upper pipe plate, a lower pipe plate and a condensate chamber. The upper pipe plate is secured by supports, and a steam pipe is connected to the upper pipe plate. A condensate pipeline and a incondensible gas vent pipe are disposed to the condensate chamber. Taking thermal expansion of the steam pipes and thermal expansion of the heat transfer pipes into consideration, the heat transfer pipe is made as an L-shaped pipe having a vertical portion and a horizontal portion so as to absorb each of the thermal expansion smoothly. The L-shaped heat transfer pipes are constituted as a bundle of pipes having the end portions thereof secured to the upper pipe plate and the lower pipe plate. The emergency condensator is disposed in a emergency condensator pool chamber. Cooling water in contact with the outer side of the L-shaped heat transfer pipes is the pool water in the pool chamber, and the condensator chamber is disposed in concrete walls of the pool chamber. With such a constitution, stress due to thermal expansion of the heat transfer pipes is mitigated, and heat transfer performance, earth quake resistance and maintenancability are improved. (I.N.)

  7. Base-catalyzed dehydration of 3-substituted benzene cis-1,2-dihydrodiols: stabilization of a cyclohexadienide anion intermediate by negative aromatic hyperconjugation.

    Science.gov (United States)

    Kudavalli, Jaya Satyanarayana; Rao, S Nagaraja; Bean, David E; Sharma, Narain D; Boyd, Derek R; Fowler, Patrick W; Gronert, Scott; Kamerlin, Shina Caroline Lynn; Keeffe, James R; More O'Ferrall, Rory A

    2012-08-29

    Evidence that a 1,2-dihydroxycyclohexadienide anion is stabilized by aromatic "negative hyperconjugation" is described. It complements an earlier inference of "positive" hyperconjugative aromaticity for the cyclohexadienyl cation. The anion is a reactive intermediate in the dehydration of benzene cis-1,2-dihydrodiol to phenol. Rate constants for 3-substituted benzene cis-dihydrodiols are correlated by σ(-) values with ρ = 3.2. Solvent isotope effects for the reactions are k(H(2)O)/k(D(2)O) = 1.2-1.8. These measurements are consistent with reaction via a carbanion intermediate or a concerted reaction with a "carbanion-like" transition state. These and other experimental results confirm that the reaction proceeds by a stepwise mechanism, with a change in rate-determining step from proton transfer to the loss of hydroxide ion from the intermediate. Hydrogen isotope exchange accompanying dehydration of the parent benzene cis-1,2-dihydrodiol was not found, and thus, the proton transfer step is subject to internal return. A rate constant of ~10(11) s(-1), corresponding to rotational relaxation of the aqueous solvent, is assigned to loss of hydroxide ion from the intermediate. The rate constant for internal return therefore falls in the range 10(11)-10(12) s(-1). From these limiting values and the measured rate constant for hydroxide-catalyzed dehydration, a pK(a) of 30.8 ± 0.5 was determined for formation of the anion. Although loss of hydroxide ion is hugely exothermic, a concerted reaction is not enforced by the instability of the intermediate. Stabilization by negative hyperconjugation is proposed for 1,2-dihydroxycyclohexadienide and similar anions, and this proposal is supported by additional experimental evidence and by computational results, including evidence for a diatropic ("aromatic") ring current in 3,3-difluorocyclohexadienyl anion.

  8. Active condensation of water by plants

    Directory of Open Access Journals (Sweden)

    Prokhorov Alexey Anatolievich

    2013-10-01

    Full Text Available This paper is devoted to some peculiarities of water condensation on the surface of plants . Arguments in support of the hypothesis that in decreasing temperature of leaves and shoots below the dew point, the plant can actively condense moisture from the air, increasing the duration of dewfall are presented. Evening dewfall on plant surfaces begins before starting the formation of fog. Morning condensation continues for some time after the air temperature exceeds the dew point . The phenomenon in question is found everywhere, but it is particularly important for plants in arid ecosystems.

  9. Quark virtuality and QCD vacuum condensates

    International Nuclear Information System (INIS)

    Zhou Lijuan; Ma Weixing

    2004-01-01

    Based on the Dyson-Schwinger equations (DSEs) in the 'rainbow' approximation, the authors investigate the quark virtuality in the vacuum state and quantum-chromodynamics (QCD) vacuum condensates. In particular, authors calculate the local quark vacuum condensate and quark-gluon mixed condensates, and then the virtuality of quark. The calculated quark virtualities are λ u,d 2 =0.7 GeV 2 for u, d quarks, and λ s 2 =1.6 GeV 2 for s quark. The theoretical predictions are consistent with empirical values used in QCD sum rules, and also fit to lattice QCD predictions

  10. Open string decoupling and tachyon condensation

    International Nuclear Information System (INIS)

    Chalmers, G.

    2001-01-01

    The amplitudes in perturbative open string theory are examined as functions of the tachyon condensate parameter. The boundary state formalism demonstrates the decoupling of the open string modes at the non-perturbative minima of the tachyon potential via a degeneration of open world-sheets and identifies an independence of the coupling constants g s and g YM at general values of the tachyon condensate. The closed sector is generated at the quantum level; it is also generated at the classical level through the condensation of the propagating open string modes on the D-brane degrees of freedom.

  11. Preoperational test report, primary ventilation condensate system

    Energy Technology Data Exchange (ETDEWEB)

    Clifton, F.T.

    1997-01-29

    Preoperational test report for Primary Ventilation Condensate System, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides a collection point for condensate generated by the W-030 primary vent offgas cooling system serving tanks AYIOI, AY102, AZIOI, AZI02. The system is located inside a shielded ventilation equipment cell and consists of a condensate seal pot, sampling features, a drain line to existing Catch Tank 241-AZ-151, and a cell sump jet pump. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  12. The Dynamics of Aerosols in Condensational Scrubbers

    DEFF Research Database (Denmark)

    Johannessen, Jens Tue; Christensen, Jan A.; Simonsen, Ole

    1997-01-01

    A mathematical model for the simulation of the dynamics of aerosol change in condensational scrubbers and scrubbing condensers is proposed. The model is applicable for packed column gas/liquid contact when plug flow can be assumed. The model is compared with experimental data for particle removal...... in a pilot plant condensational scrubber. The model can satisfactorily predict particle growth and particle deposition by diffusional, convective and inertial mechanisms for a wide range of conditions. The parameters of principal importance for the model precision are identified and a procedure...

  13. Model of a chromomagnetic condensate in QCD

    International Nuclear Information System (INIS)

    Vladimirsky, V.V.

    1996-01-01

    The simplest form of the effective Lagrangian of a gluon field leads to a deep degeneracy of a magnetic condensate that arises when the stability of the standard perturbative vacuum is violated by quantum effects. The inclusion of terms in the effective Lagrangian that conserve color and Lorentz invariance enables the possible types of Abelian and non-Abelian condensate fields to be classified. The degeneracy is partially removed. One of the four types of the condensate permits the emergence of closed vortex lines that correspond to cyclic permutations of colors upon circumventions around stringlike singularities

  14. Unfolding Reactions.

    Science.gov (United States)

    Streitberger, H. Eric

    1997-01-01

    Describes how students use paper-strip molecules in hands-on activities to show the synthesis of larger organic molecules from smaller molecules. Focuses initially on condensation molecules involving the functional groups in alcohol and carboxylic acids. (DDR)

  15. Holography, Gravity and Condensed Matter

    Energy Technology Data Exchange (ETDEWEB)

    Hartnoll, Sean [Stanford Univ., CA (United States). Dept. of Physics

    2017-12-20

    Over the five years of funding from this grant, I produced 26 publications. These include a book-long monograph on "Holographic Quantum Matter" that is currently in press with MIT press. The remainder were mostly published in Physical Review Letters, the Journal of High Energy Physics, Nature Physics, Classical and Quantum Gravity and Physical Review B. Over this period, the field of holography applied to condensed matter physics developed from a promising theoretical approach to a mature conceptual and practical edifice, whose ideas were realized in experiments. My own work played a central role in this development. In particular, in the final year of this grant, I co-authored two experimental papers in which ideas that I had developed in earlier years were shown to usefully describe transport in strongly correlated materials — these papers were published in Science and in the Proceedings of the National Academy of Sciences (obviously my contribution to these papers was theoretical). My theoretical work in this period developed several new directions of research that have proven to be influential. These include (i) The construction of highly inhomogeneous black hole event horizons, realizing disordered fixed points and describing new regimes of classical gravity, (ii) The conjecture of a bound on diffusivities that could underpin transport in strongly interacting media — an idea which may be proven in the near future and has turned out to be intimately connected to studies of quantum chaos in black holes and strongly correlated media, (iii) The characterization of new forms of hydrodynamic transport, e.g. with phase-disordered order parameters. These studies pertain to key open questions in our understanding of how non-quasiparticle, intrinsically strongly interacting systems can behave. In addition to the interface between holography and strongly interacting condensed matter systems, I made several advances on understanding the role of entanglement in quantum

  16. The Usefulness of Clinical and Laboratory Parameters for Predicting Severity of Dehydration in Children with Acute Gastroenteritis

    Science.gov (United States)

    Hoxha, Teuta Faik; Azemi, Mehmedali; Avdiu, Muharrem; Ismaili-jaha, Vlora; Grajqevci, Violeta; Petrela, Ela

    2014-01-01

    ABSTRACT Background: An accurate assessment of the degree of dehydration in infants and children is important for proper decision-making and treatment. This emphasizes the need for laboratory tests to improve the accuracy of clinical assessment of dehydration. The aim of this study was to assess the relationship between clinical and laboratory parameters in the assessment of dehydration. Methods: We evaluated prospectively 200 children aged 1 month to 5 years who presented with diarrhea, vomiting or both. Dehydration assessment was done following a known clinical scheme. Results: We enrolled in the study 200 children (57.5% were male). The mean age was 15.62±9.03 months, with more than half those studied being under 24 months old. Overall, 46.5% (93) had mild dehydration, 34% (68) had moderate dehydration, 5.5% (11) had severe dehydration whereas, 14% (28) had no dehydration. Patients historical clinical variables in all dehydration groups did not differ significantly regarding age, sex, fever, frequency of vomiting, duration of diarrhea and vomiting, while there was a trend toward severe dehydration in children with more frequent diarrhea (p=0.004). Serum urea and creatinine cannot discriminate between mild and moderate dehydration but they showed a good specificity for severe dehydration of 99% and 100% respectively. Serum bicarbonates and base excess decreased significantly with a degree of dehydration and can discriminate between all dehydration groups (P<0.001). Conclusion: Blood gases were useful to diagnose the degree of dehydration status among children presenting with acute gastroenteritis. Serum urea and creatinine were the most specific tests for severe dehydration diagnosis. Historical clinical patterns apart from frequency of diarrhea did not correlate with dehydration status. Further studies are needed to validate our results. PMID:25568559

  17. Efficient, Long-Life Biocidal Condenser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Environmental control systems for manned lunar and planetary bases will require condensing heat exchangers to control humidity. Condensing surfaces must be...

  18. Stroke from systemic vascular disorders in Saudi children: The devastating role of hypernatremic dehydration

    International Nuclear Information System (INIS)

    Salih, Mustafa A.; Al-Jarallah, Ahmed A.; Zahraa, Jihad N.; Alorainy, Ibrahim A.; Hassan, Hamdy H.

    2006-01-01

    Systemic vascular disorders, leading to childhood stroke, include volume depletion or systemic hypotension and hypernatremic dehydration. We describe 3 cases of stroke following systemic vascular disorders. These were diagnosed during a prospective and retrospective study on childhood stroke, which included 104 patients. Post-gastroenteritis hypernatremic dehydration is an important, potentially preventable, cause of stroke in Saudi children. (author)

  19. Rates of Hospitalization for Dehydration Following Hurricane Sandy in New Jersey.

    Science.gov (United States)

    Swerdel, Joel N; Rhoads, George G; Cosgrove, Nora M; Kostis, John B

    2016-04-01

    Hurricane Sandy, one of the most destructive natural disasters in New Jersey history, made landfall on October 29, 2012. Prolonged loss of electrical power and extensive infrastructure damage restricted access for many to food and water. We examined the rate of dehydration in New Jersey residents after Hurricane Sandy. We obtained data from 2008 to 2012 from the Myocardial Infarction Data Acquisition System (MIDAS), a repository of in-patient records from nonfederal New Jersey hospitals (N=517,355). Patients with dehydration had ICD-9-CM discharge diagnosis codes for dehydration, volume depletion, and/or hypovolemia. We used log-linear modeling to estimate the change in in-patient hospitalizations for dehydration comparing 2 weeks after Sandy with the same period in the previous 4 years (2008-2011). In-patient hospitalizations for dehydration were 66% higher after Sandy than in 2008-2011 (rate ratio [RR]: 1.66; 95% confidence interval [CI]: 1.50, 1.84). Hospitalizations for dehydration in patients over 65 years of age increased by nearly 80% after Sandy compared with 2008-2011 (RR: 1.79; 95% CI: 1.58, 2.02). Sandy was associated with a marked increase in hospitalizations for dehydration. Reducing the rate of dehydration following extreme weather events is an important public health concern that needs to be addressed, especially in those over 65 years of age.

  20. Preoperative dehydration increases risk of postoperative acute renal failure in colon and rectal surgery.

    Science.gov (United States)

    Moghadamyeghaneh, Zhobin; Phelan, Michael J; Carmichael, Joseph C; Mills, Steven D; Pigazzi, Alessio; Nguyen, Ninh T; Stamos, Michael J

    2014-12-01

    There is limited data regarding the effects of preoperative dehydration on postoperative renal function. We sought to identify associations between hydration status before operation and postoperative acute renal failure (ARF) in patients undergoing colorectal resection. The NSQIP database was used to examine the data of patients undergoing colorectal resection from 2005 to 2011. We used preoperative blood urea nitrogen (BUN)/creatinine ratio >20 as a marker of relative dehydration. Multivariate analysis using logistic regression was performed to quantify the association of BUN/Cr ratio with ARF. We sampled 27,860 patients who underwent colorectal resection. Patients with dehydration had higher risk of ARF compared to patients with BUN/Cr Dehydration was associated with an increase in mortality of the affected patients (AOR, 2.19; P dehydrated patients. Open colorectal procedures (AOR, 2.67; P = 0.01) and total colectomy procedure (AOR, 1.62; P Dehydration before operation is a common condition in colorectal surgery (incidence of 27.7 %). Preoperative dehydration is associated with increased rates of postoperative ARF, MI, and cardiac arrest. Hydrotherapy of patients with dehydration may decrease postoperative complications in colorectal surgery.

  1. Photo initiated thermal cyclo dehydration of polyamide acid with catalytic addition

    International Nuclear Information System (INIS)

    Toirov, A.; Shukronaev, S.P.; Yusupov, I.Kh.

    1992-01-01

    This article is devoted to photo initiated thermal cyclo dehydration of polyamide acid with catalytic addition. Thereby, authors investigated some properties of photo initiated cyclo dehydration process of polyamide acid obtained from dianhydride of pyromellitic acid and 4.4-diaminodiphenyl ether with three-phenyl phosphate.

  2. HIGH PERMEABILITY MEMBRANES FOR THE DEHYDRATION OF LOW WATER CONTENT ETHANOL BY PERVAPORATION

    Science.gov (United States)

    Energy efficient dehydration of low water content ethanol is a challenge for the sustainable production of fuel-grade ethanol. Pervaporative membrane dehydration using a recently developed hydrophilic polymer membrane formulation consisting of a cross-linked mixture of poly(allyl...

  3. Quality of frozen fruit bars manufactured through infrared pre-dehydration

    Science.gov (United States)

    In this study, frozen restructured whole apple and strawberry bars were manufactured by partial dehydration, using infrared (IR) heating, followed by restructuring and freezing. The objective of this investigation was to determine the effect of IR partial dehydration on the quality of restructured f...

  4. Dehydration of 2-Methyl-1-Cyclohexanol: New Findings from a Popular Undergraduate Laboratory Experiment

    Science.gov (United States)

    Friesen, J. Brent; Schretzman, Robert

    2011-01-01

    The mineral acid-catalyzed dehydration of 2-methyl-1-cyclohexanol has been a popular laboratory exercise in second-year organic chemistry for several decades. The dehydration experiment is often performed by organic chemistry students to illustrate Zaitsev's rule. However, sensitive analytical techniques reveal that the results do not entirely…

  5. Neonatal dehydrering (tørstefeber) hos nyfødte børn

    DEFF Research Database (Denmark)

    Zachariassen, Gitte; Juvonen, Pekka

    2002-01-01

    The aim was to identify characteristics in infants suffering from dehydration caused by breast-feeding malnutrition over a period of 21 months in South Denmark.......The aim was to identify characteristics in infants suffering from dehydration caused by breast-feeding malnutrition over a period of 21 months in South Denmark....

  6. Efficacy of home-style dehydrators for reducing Salmonella on whole-muscle chicken.

    Science.gov (United States)

    Weber, M J D; Boyle, E A E; Getty, K J K; Harper, N M; Weber, C G; Roenbaugh, T L

    2011-07-01

    Home-style dehydrators commonly used by consumers have limited relative humidity (RH) and temperature control. To evaluate the effect of dehydrator load on temperature and RH and subsequent reduction of Salmonella on whole-muscle chicken, chicken breasts were rolled and cut into samples (1 to 2 mm thick, 6 by 6 cm(2)) and inoculated with a five-strain Salmonella cocktail. The samples were allowed to air dry for 15 min and then were loaded into home-style three-tray (3T) or five-tray (5T) dehydrators, with 12 chicken pieces per tray. No difference (P > 0.05) was observed in RH or temperature between the 3T and 5T dehydrators. Peak RH was 38% and gradually deceased to 8.5% after 6 h of drying. Temperatures peaked at 57 °C after 6 h of drying. Dehydrator load had no effect (P > 0.05) on lethality for Salmonella. A reduction of 3.3 ± 0.2 log CFU/cm(2) was observed after 6 h of drying. However, sample location affected Salmonella reduction (P dehydrator type. When chicken was dried in home-style dehydrators, increasing the dehydrator load did not increase RH or achieve greater Salmonella lethality. Tray location had a significant impact on Salmonella lethality. Adequate reduction of Salmonella on chicken was not achieved when chamber temperatures were below 57 °C with limited RH throughout drying. Copyright ©, International Association for Food Protection

  7. Ultrasound accelerated Claisen Schmidt condensation: A green route to chalcones

    Science.gov (United States)

    Calvino, V.; Picallo, M.; López-Peinado, A. J.; Martín-Aranda, R. M.; Durán-Valle, C. J.

    2006-06-01

    Chalcones have been synthesized under sonochemical irradiation by Claisen-Schmidt condensation between benzaldehyde and acetophenone. Two basic activated carbons (Na and Cs-Norit) have been used as catalysts. The effect of the ultrasound activation has been studied. A substantial enhancing effect in the yield was observed when the carbon catalyst was activated under ultrasonic waves. This "green" method (combination of alkaline-doped carbon catalyst and ultrasound waves) has been applied to the synthesis of several chalcones with antibacterial properties achieving, in all cases, excellent activities and selectivities. A comparative study under non-sonic activation has showed that the yields are lower in silent conditions, indicating that the sonication exerts a positive effect on the activity of the catalyst. Cs-doped carbon is presented as the optimum catalyst, giving excellent activity for this type of condensation. Cs-Norit carbon catalyst can compete with the traditional NaOH/EtOH when the reaction is carried out under ultrasounds. The role of solvent in this reaction was studied with ethanol. High conversion was obtained in absence of solvent. The carbons were characterized by thermal analysis, nitrogen adsorption and X-ray photoelectron spectroscopy.

  8. Low Energy Nuclear Reactions?

    CERN Multimedia

    CERN. Geneva; Faccini, R.

    2014-01-01

    After an introduction to the controversial problem of Low Energy Nuclear Reactions (LENR) catalyzed by neutrons on metallic hydride surfaces we present the results of an experiment, made in collaboration with ENEA Labs in Frascati, to search neutrons from plasma discharges in electrolytic cells. The negative outcome of our experiment goes in the direction of ruling out those theoretical models expecting LENR to occur in condensed matter systems under specific conditions. Our criticism on the theoretical foundations of such models will also be presented.

  9. Nautilus Centripetal Capillary Condenser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A Nautilus Centripetal Capillary Condenser (NCCC) is proposed for the microgravity compatible removal of water from a saturated air stream. Successful development of...

  10. High temperature Bose-Einstein condensation

    Directory of Open Access Journals (Sweden)

    Begun Viktor

    2016-01-01

    Full Text Available The indications of a possible pion condensation at the LHC are summarized. The condensation is predicted by the non-equilibrium hadronization model for 2.76 TeV Pb+Pb collisions at the LHC. The model solves the proton/pion puzzle and reproduces the low pT enhancement of the pion spectra, as well as the spectra of protons and antiprotons, charged kaons, K0S, K*(8920 and ϕ(1020. The obtained parameters allow to estimate the amount of pion condensate on the level of 5% from the total number of pions at the LHC. The condensate is located at pT < 250 MeV.

  11. Kaon condensation in dense stellar matter

    International Nuclear Information System (INIS)

    Lee, Chang-Hwan; Rho, M.; Washington Univ., Seattle, WA

    1995-03-01

    This article combines two talks given by the authors and is based on Works done in collaboration with G.E. Brown and D.P. Min on kaon condensation in dense baryonic medium treated in chiral perturbation theory using heavy-baryon formalism. It contains, in addition to what was recently published, astrophysical backgrounds for kaon condensation discussed by Brown and Bethe, a discussion on a renormalization-group analysis to meson condensation worked out together with H.K. Lee and S.J. Sin, and the recent results of K.M. Westerberg in the bound-state approach to the Skyrme model. Negatively charged kaons are predicted to condense at a critical density 2 approx-lt ρ/ρo approx-lt 4, in the range to allow the intriguing new phenomena predicted by Brown and Bethe to take place in compact star matter

  12. Fundamentals of evaporation and condensation phenomena

    International Nuclear Information System (INIS)

    Munir, Z.A.

    1979-01-01

    Fundamental relationships governing evaporation and condensation processes are reviewed. The terrace-ledge-kink (TLK) model is discussed in terms of atomic steps comprising growth and evaporation of crystals. Recent results in the field are described

  13. Accretion of Ghost Condensate by Black Holes

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, A

    2004-06-02

    The intent of this letter is to point out that the accretion of a ghost condensate by black holes could be extremely efficient. We analyze steady-state spherically symmetric flows of the ghost fluid in the gravitational field of a Schwarzschild black hole and calculate the accretion rate. Unlike minimally coupled scalar field or quintessence, the accretion rate is set not by the cosmological energy density of the field, but by the energy scale of the ghost condensate theory. If hydrodynamical flow is established, it could be as high as tenth of a solar mass per second for 10MeV-scale ghost condensate accreting onto a stellar-sized black hole, which puts serious constraints on the parameters of the ghost condensate model.

  14. Recent developments in Bose-Einstein condensation

    Energy Technology Data Exchange (ETDEWEB)

    Kalman, G.

    1997-09-22

    This paper contains viewgraphs on developments on Bose-Einstein condensation. Some topics covered are: strongly coupled coulomb systems; standard response functions of the first and second kind; dynamical mean field theory; quasi localized charge approximation; and the main equations.

  15. Study of Trehalose Addition on Aroma Retention in Dehydrated Strawberry Puree

    Directory of Open Access Journals (Sweden)

    Draženka Komes

    2003-01-01

    Full Text Available In order to improve the quality of dehydrated fruit products, the influence of the addition of two sugars (sucrose and trehalose on the retention of aroma components during dehydration of strawberry puree was investigated. Manual headspace solid-phase microextraction (SPME, containing polydimethylsiloxane coated fibre (100 μm coupled with gas chromatography (GC-FID and GC-MS was used for the analysis of the aroma of strawberry puree dehydrated by using freeze drying and foam-mat drying. The analytes identified included esters, carbonyl compounds, terpenoids, several alcohols and acids. The results obtained in this study give further insight into the mechanisms concerning the application of trehalose as flavouring additive, due to its ability to retain and preserve the fruit volatiles responsible for the characteristic flavour of fresh fruits during dehydration processes. The best retention of aroma components in dehydrated strawberry puree was obtained by trehalose addition when combined with freeze drying.

  16. Separate and combined influences of dehydration and hyperthermia on cardiovascular responses to exercise.

    Science.gov (United States)

    González-Alonso, J

    1998-06-01

    During endurance exercise in the heat athletes lose 1-21/h of fluid due to thermoregulatory sweating. The ensuing dehydration is accompanied by higher and faster increases in core temperature, which per se can cause fatigue. The main cardiovascular consequences of combined dehydration and hyperthermia [1 degree C higher core temperature and 3-4 kg (4%) body weight loss] are the significant reductions in cardiac output (3 l/min), muscle blood flow, skin blood flow and blood pressure. Separately, however, hyperthermia (i.e., 39.3 C) and dehydration do not significantly reduce cardiac output or blood pressure. In conclusion, the superimposition of dehydration on hyperthermia during exercise in the heat causes greater alterations in cardiovascular function that make the dehydrated athlete much less able to cope with hyperthermia.

  17. Methods to increase the rate of mass transfer during osmotic dehydration of foods.

    Science.gov (United States)

    Chwastek, Anna

    2014-01-01

    Traditional methods of food preservation such as freezing, freeze drying (lyophilization), vacuum drying, convection drying are often supplemented by new technologies that enable obtaining of high quality products. Osmotic dehydration is more and more often used during processing of fruits and vegetables. This method allows maintaining good organoleptic and functional properties in the finished product. Obtaining the desired degree of dehydration or saturation of the material with an osmoactive substance often requires  elongation of time or use of high temperatures. In recent years much attention was devoted to techniques aimed at increasing the mass transfer between the dehydrated material and the hypertonic solution. The work reviews the literature focused on methods of streamlining the process of osmotic dehydration which include the use of: ultrasound, high hydrostatic pressure, vacuum osmotic dehydration and pulsed electric field.

  18. Research on terahertz properties of rat brain tissue sections during dehydration

    Science.gov (United States)

    Cui, Gangqiang; Liang, Jianfeng; Zhao, Hongwei; Zhao, Xianghui; Chang, Chao

    2018-01-01

    Biological tissue sections are always kept in a system purged with dry nitrogen for the measurement of terahertz spectrum. However, the injected nitrogen will cause dehydration of tissue sections, which will affect the accuracy of spectrum measurement. In this paper, terahertz time-domain spectrometer is used to measure the terahertz spectra of rat brain tissue sections during dehydration. The changes of terahertz properties, including terahertz transmittance, refractive index and extinction coefficient during dehydration are also analyzed. The amplitudes of terahertz time-domain spectra increase gradually during the dehydration process. Besides, the terahertz properties show obvious changes during the dehydration process. All the results indicate that the injected dry nitrogen has a significant effect on the terahertz spectra and properties of tissue sections. This study contributes to further research and application of terahertz technology in biomedical field.

  19. Conditions for maximum isolation of stable condensate during separation in gas-condensate systems

    Energy Technology Data Exchange (ETDEWEB)

    Trivus, N.A.; Belkina, N.A.

    1969-02-01

    A thermodynamic analysis is made of the gas-liquid separation process in order to determine the relationship between conditions of maximum stable condensate separation and physico-chemical nature and composition of condensate. The analysis was made by considering the multicomponent gas-condensate fluid produced from Zyrya field as a ternary system, composed of methane, an intermediate component (propane and butane) and a heavy residue, C/sub 6+/. Composition of 5 ternary systems was calculated for a wide variation in separator conditions. At each separator pressure there is maximum condensate production at a certain temperature. This occurs because solubility of condensate components changes with temperature. Results of all calculations are shown graphically. The graphs show conditions of maximum stable condensate separation.

  20. Effects of Pretreatments in Convective Dehydration of Rosehip (Rosa eglanteria

    Directory of Open Access Journals (Sweden)

    Alejandra Mabellini

    2012-04-01

    Full Text Available The aim of this work was to experimentally determine drying curves for thin layer and bed drying of rosehip fruits, with and without pretreatments, to reduce processing times as a function of drying air operating variables, to propose dehydration kinetics of fruits and to determine its kinetic parameters for further use within drying simulation software. Fruits were pre-treated both chemically and mechanically, which included dipping the fruits in NaOH and ethyl oleate solutions; and cutting or perforating the fruit cuticle, respectively. Simulation models were then adopted to fit the kinetics drying data considering fruit volume shrinkage. These simple models minimized the calculation time during the simulation of deep-bed driers. Results show that pre-treatments reduced processing times up to 57%, and evaluated models satisfactorily predicted the drying of rosehip fruit. Effective mass diffusion coefficients were up to 4-fold greater when fruit was submitted to mechanical pretreatments.