Science.gov (United States)

Hydrogen molecule adsorption on the (0001) surface of double hexagonal closed packed americium has been studied in detail within the framework of density functional theory. Weak molecular hydrogen adsorptions were observed. The most stable configuration corresponded to a Hor2 approach molecular adsorption at the one-fold top site where the molecule's approach is perpendicular to a lattice vector. Adsorption energies and adsorption geometries for different adsorption sites will be discussed. The change in work functions, magnetic moments, partial charges inside muffin-tins, difference charge density distributions and density of states for the bare Am slab and the Am slab after adsorption of the hydrogen molecule will be discussed. Reaction barrier for the dissociation of hydrogen molecule will be presented. The ...

Czech Academy of Sciences Repository

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The dissociation of methylal is investigated using mass spectrometry, combined with a pyrolytic radical source and femtosecond pump probe experiments. Based on preliminary results two reaction paths of methylal dissociation are proposed and discussed. (author) 4 fig., 3 refs.

International Nuclear Information System (INIS)

The production of molecularly imprinted polymers (MIPs) for the recognition of C-terminal cholecystokinin pentapeptide (CCK-5) in the presence of metal ion is reported. The MIPs were produced under the same molar ratio of template to monomers (acrylamide, N,N'-methylene bisacrylamide) in the presence or absence of nitrilotriacetic acid-nickel (Ni-NTA) complex. Scanning electron microscopy images of MIPs were obtained in an attempt to correlate the adsorption characteristics with polymer's morphology. Subsequently Ni2+ was removed and substituted by other divalent ions such as Mg2+, Fe2+, Zn2+, Co2+ and Cu2+. It was found that polymers containing the metal ion complex with the order Fe-NTA, Ni-NTA and Cu-NTA presented lower dissociation constant values than the rest thus exhibiting stronger guest binding activity. The percentage of theoretical maximum binding sites Bmax was almost the same for these ions, indicating that the ion-template ...

Science.gov (United States)

Batch interaction experiments were performed under aerobic conditions to characterize the adsorption behavior and valence speciation of CoEDTA complexes (equimolar at 10 -5 mol/L) in a series of Pliocene subsurface sediments containing various amounts of Fe and Mn oxides. The experiments were performed in 0.003 mol/L Ca(ClO 4 ) 2 with a solids concentration of 500 g/L at variable pH (4-9) and at the natural pH of the sediments (pH = 8.3). Three of these subaerial sediments (Ringold 1, 2, 3) contained significant quantities of extractable Fe and Mn, while the fourth (Ringold 4) was virtually devoid of sesquioxide precipitates. Microscopic and mineralogic analyses of the most heavily encrusted material (Ringold 2) showed that the oxides existed as intergrain cements and contained crystalline goethite and rancieite/todorokite. Adsorption on a synthetic analog sorbent (0.6 mass % ferrihydrite-coated sand) over a range in pH showed that, while ...

Energy Technology Data Exchange (ETDEWEB)

Using adsorption data, the authors get formulas for the calculation of fractal dimensions: log[A{sub CO{sub 2}(DP)}/A{sub N{sub 2}(BET)}] = {minus}5.3984(2 {minus} D{sub 1})/2 and log[A{sub CO{sub 2}(BET)}/A{sub N{sub 2}(BET)}] = {minus}4.9569(2 {minus} D{sub 2})/2. The fractal dimensions (D) of 27 coals and 2 cokes have been obtained. The D of coals decreased with the increase of f{sub a} and reached a maximum at H/C equal to 0.66 (or C{sub daf} about 86%). The fractal dimension is relative to ash and volatiles of coal: D = 2.2237 + 0.6249 V{sub daf} + 0.8863 A{sub d}. The relationship between D of coal coke and its conversions (X) obeys the following equation: D = a exp({minus}bX) + c.

Energy Technology Data Exchange (ETDEWEB)

The partial oxidation of 1,3-butadiene has been investigated over VMoO catalysts synthesized by sol-gel techniques. Surface areas were 9-14 m{sup 2}/g, and compositions were within the solid solution regime, i.e. below 15.0 mol % MoO{sub 3}/(MoO{sub 3} + V{sub 2}O{sub 5}). Laser Raman Spectroscopy and XRD data indicated that solid solutions were formed, and pre- and post-reaction XPS data indicated that catalyst surfaces contained some V{sup +4} and were further reduced in 1,3-butadiene oxidation. A reaction pathway for 1,3-butadiene partial oxidation to maleic anhydride was shown to involve intermediates such as 3,4-epoxy-1-butene, crotonaldehyde, furan, and 2-butene-1,4-dial. The addition of water to the reaction stream substantially increased catalyst activity and improved selectivity to crotonaldehyde and furan at specific reaction temperatures. At higher water addition concentrations, furan selectivity increased from 12% to over 25%. The catalytic effects of water addition were ...

International Nuclear Information System (INIS)

The RKR potential energy curves are constructed for the ground states of diatomic hafnium oxide and thorium oxide. Using Lippincott and Hulburt-Hirschfelder potential function the dissociation energies are estimated by curve fitting method. The H-H potential function was found to give a better fit in both cases. The dissociation energies of hafnium oxide and thorium oxide are estimated as 9.04 #+-# 0.02 eV and 10.34 #+-# 0.01 eV respectively. (author).

International Nuclear Information System (INIS)

Short communication.

Energy Technology Data Exchange (ETDEWEB)

Schemata for modelling combustion processes do not yet include reaction rates for oxygenated fuels like methylal (DMM) which is considered as an additive or replacement for diesel due to its low sooting propensity. Density functional theory (DFT) studies of the possible reaction pathways for different dissociation steps of methylal are presented. Cleavage of a hydrogen bond to the methoxy group or the central carbon atom were simulated at the BLYP/6-311++G{sup **} level of theory. The results are compared to the experiment when dissociating and/or ionising DMM with femtosecond pulses. (author) 1 fig., 1 tab., 1 ref.

International Nuclear Information System (INIS)

The primary purpose of this short paper is to present a brief report on what we believe is state-of-the-art regarding the measurements of the dissociative recombination coefficient for the important interstellar ion H_3"+ at and near to thermal energies. However, theory has consistently indicated that dissociative recombination of H_3"+ should be inefficient at low energies. We do not try to present a detailed historical development of this topic here, but we rather refer the reader to our very recent papers and those of others. (author).

CERN Document Server

We calculate the quarkonium dissociation rate in the P and CP-odd domains (bubbles) that were possibly created in heavy-ion collisions. In the presence of the magnetic field produced by the valence quarks of colliding ions, parity-odd domains generate electric field. Quarkonium dissociation is the result of quantum tunneling of quark or antiquark through the potential barrier in this electric field. The strength of the electric field in the quarkonium comoving frame depends on the quarkonium velocity with respect to the background magnetic field. We investigate momentum, electric field strength and azimuthal dependence of the dissociation rate. Azimuthal distribution of quarkonia surviving in the electromagnetic field is strongly anisotropic; the form of anisotropy depends on the relation between the electric and magnetic fields and quarkonium momentum. These features can be used to explore the properties of the ...

Energy Technology Data Exchange (ETDEWEB)

Measurements of hydrogen adsorption capacity by activated charcoal has been made at a pressure minus than 10/sup -4/ Pa and at 18 K.

International Nuclear Information System (INIS)

The true potential energy curve for the x "1#SIGMA#"+ state of BeO has been calculated using the RKRV method. The dissociation energy of the ground state has been estimated to be 5.15 +- 0.05 eV by the curve-fitting method using the three-parameter potential energy function of Lippincott with an RKRV potential energy curve. (author).

International Nuclear Information System (INIS)

Isotopically selective IR multiphoton dissociation of molecules (SF_6, CF_3I) in a pulsed gas-dynamic flow interacting with a solid surface was studied for the first time. A noticeable (severalfold) increase in the yield of products (compared to excitation of molecules in an unperturbed flow) without a substantial decrease in the selectivity of the process was observed. Possible reasons for the effect are discussed. (laser applications and other topics in quantum electronics)

Science.gov (United States)

The thermodynamic characteristics of adsorption of proline and its hydroxy derivatives on the surface of graphitized thermal carbon black (GTCB) were calculated. The arrangement of hydroxyl groups in the amino acid molecule was shown to influence their adsorption on GTCB. The influence of internal rotation angles in proline and its hydroxy derivative molecules on their adsorption on GTCB was studied.

KoreaScience (Korea)

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British Library Electronic Table of Contents (United Kingdom)

The CO2 adsorption capacity of the low-cost solid sorbents of waste tire char (TC) and chicken waste char (CW) was compared with commercial active carbon (AC) and 5?? zeolite (ZA) using thermogravimetric analysis (TG), pressurized TG, and differential scanning calorimetry (DSC). The sorbents were degassed in a TG up to 150??C to release all gases on the surface of the sample, then cooled down to the designed temperature for adsorption. TG results indicated that the CO2 adsorption capacity of TC was higher than that of CW, but lower than those of AC and ZA. The maximum adsorption rate of TC at 50??C was 0.61% min?1, lower than that of AC, but higher than that of CW, 0.44% min?1. The maximum adsorption rate of ZA at 50??C was 3.1% min?1. When the pressure was over 4?bar, the adsorption rate ...

Science.gov (United States)

The thermodynamic characteristics of adsorption of iodobenzene, 2-iodothiophene, and 1- and 2-iodoadamantanes on the surface of graphitized thermal carbon black were determined experimentally. The influence of the special features of the molecular structure of the adsorbates on the thermodynamic characteristics of adsorption was studied. The atom-atom approximation of the semiempirical molecular-statistical theory of adsorption was used to calculate the thermodynamic characteristics of adsorption of the adsorbates using the newly determined potential function parameters of pair intermolecular interaction (?( r)) of I with C atoms of the basal graphite face. For the example of isostructural monohalogenated benzenes, thiophenes, and adamantanes, a comparative analysis of the contributions of the F, Cl, Br, and I atoms to the thermodynamic characteristics of adsorption was performed ...

International Nuclear Information System (INIS)

Temporal developments of the photoluminescence (PL) intensity at temperatures of 7, 100, and 294 K are analyzed using the rate equations including the exciton dissociation and association terms for an Al_0_._5_3In_0_._4_7P/Ga_0_._5_2In_0_._4_8P/Al_0_._5_3In_0_._4_7P-quantum well structure. At 7 K, the nonexponential time dependence of the PL intensity is caused by the exciton dissociation process. At 7 and 100 K, PL intensity is dominated by the exciton recombination even if the exciton density is smaller than the dissociated carrier density. The thermally excited background carriers affect the recombination processes at 100 and 294 K. At 294 K, the rise part of the PL intensity is dominated by the exciton recombination, though the dissociated carrier density dominates. [copyright] 2001 American Institute of Physics.

British Library Electronic Table of Contents (United Kingdom)

The thermodynamic characteristics of adsorption of iodobenzene, 2-iodothiophene, and 1- and 2-iodoadamantanes on the surface of graphitized thermal carbon black were determined experimentally. The influence of the special features of the molecular structure of the adsorbates on the thermodynamic characteristics of adsorption was studied. The atom-atom approximation of the semiempirical molecular-statistical theory of adsorption was used to calculate the thermodynamic characteristics of adsorption of the adsorbates using the newly determined potential function parameters of pair intermolecular interaction (?(r)) of I with C atoms of the basal graphite face. For the example of isostructural monohalogenated benzenes, thiophenes, and adamantanes, a comparative analysis of the contributions of ...

Energy Technology Data Exchange (ETDEWEB)

The characteristic rich shifting of the maximum adiabatic flame temperature from the stoichiometric value for mixtures of hydrocarbon and air is demonstrated to be caused by product dissociation and hence reduced amount of heat release. Since the extent of dissociation is greater on the lean side as a result of the stoichiometry of dissociated products, the peaking occurs on the rich side. The specific heat per unit mass of the mixture is shown to increase monotonically with increasing fuel concentration, and as such tends to shift the peak toward the lean side. It is further shown that this is the cause for the lean shifting of the adiabatic flame temperature of oxidizer-enriched mixtures of N{sub m}H{sub n} and F{sub 2} and of NH{sub 3} and O{sub 2}, with various amounts of inert dilution, even though their maximum heat release still peaks on the rich side. (author)

British Library Electronic Table of Contents (United Kingdom)

The removal of color from aquatic systems caused by presence of synthetic dyes is extremely important from the environmental viewpoint because most of these dyes are toxic, mutagenic and carcinogenic. In this present study, the yellow passion fruit (Passiflora edulis Sims. f. flavicarpa Degener) peel a powdered solid waste, was tested as an alternative low-cost adsorbent for the removal of a basic dye, methylene blue (MB), from aqueous solutions. Adsorption of MB onto this natural adsorbent was studied by batch adsorption isotherms at room temperature. The effects of shaking time and pH on adsorption capacity were studied. An alkaline pH was favorable for the adsorption of MB. The contact time required to obtain the maximum adsorption was 56h at 25degreeC. Yellow passion fruit peel may be ...

Energy Technology Data Exchange (ETDEWEB)

Adsorption by activated red mud (ARM) is investigated as a possible alternative to the conventional methods of Cr(VI) removal from aqueous synthetic solutions and industrial effluents. Adsorption characteristics suggest the heterogenous nature of the adsorbent surface sites with respect to the energy of adsorption. Various factors such as pH, contact time, Cr(VI) concentration, amount of adsorbent, and temperature are taken into account, and promising results are obtained. The applicability of the Langmuir as well as Freundlich adsorption isotherms for the present system is tested. The loading factor (i.e., milligrams Cr(VI) adsorbed per gram of ARM) increased with initial Cr(VI) concentration, whereas a negative trend was observed with increasing temperature. The influence of the addition of anions on the adsorption of Cr(VI) depends on the relative affinity of the anions for the ...

UK PubMed Central (United Kingdom)

BackgroundChromatin insulators or boundary elements are a class of functional elements in the eukaryotic genome. They regulate gene transcription by interfering with promoter-enhancer...Full Text Available

UK PubMed Central (United Kingdom)

The widespread use of tobacco and alcohol among adolescents might be related to the ability of nicotine and ethanol to facilitate social interactions. To investigate the neurobehavioral mechanisms...Full Text Available

UK PubMed Central (United Kingdom)

To confirm that Mycobacterium tuberculosis chaperonin 10 (Cpn10) is secreted outside the live bacillus, infected macrophages were examined by electron microscopy. This revealed that...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A process for the recovery of nitrilotriacetic acid values from solutions containing polyvalent metal complexes of nitrilotriacetic and the decomposition products thereof is described, the process being characterized by the addition to such solutions of sufficient strong acid to dissociate the complex under conditions to precipitate the nitrilotriacetic acid.

UK PubMed Central (United Kingdom)

The hepatic uptake rate for certain albumin-bound drugs and metabolites correlates poorly with their equilibrium unbound concentration in the plasma, suggesting that binding equilibrium may not always...Full Text Available

UK PubMed Central (United Kingdom)

A rhabdomyosarcoma in a WAG/Rij rat with capacity for colony growth after tumour excision and enzymatic dissociation has been used to study response to high and low LET radiation. End points are tumor...Full Text Available

UK PubMed Central (United Kingdom)

Transthyretin aggregation-associated proteotoxicity appears to cause several human amyloid diseases. Rate-limiting tetramer dissociation and monomer misfolding of transthyretin (TTR) occur before...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Adsorptive removal of Pb(II) ions from aqueous solution onto a non-activated charcoal (CC) of oak wood origin was studied in comparison with an activated carbon of coal origin. The adsorption capacity for Pb(II) of the non-activated charcoal increased significantly with deceasing particle diameter, whereas the activated carbon (AC) exhibited approximately constant capacity for Pb(II) adsorption as a function of particle size. Adsorption to the ashes prepared from the non-activated charcoal and the activated carbon was also investigated to examine the role of mineral ash. Although the ash from the activated carbon did not show any Pb(II) adsorption, the ash from the charcoal was very effective for Pb(II) adsorption. Furthermore, Pb(II) was hardly adsorbed when the ash was removed from the non-activated charcoal by acid treatment. Based on the results, the ...

Science.gov (United States)

Some vapor-dominated geothermal reservoirs and low-permeability gas reservoirs exhibit anomalous behavior that may be caused by surface adsorption. For example, geothermal reservoirs in the Larderello area of Italy and reservoirs in the Geysers Geothermal...

International Nuclear Information System (INIS)

On the basis of the analytic continuations of semisimple Lie algebras discovered recently by us we construct manifestly quasiconformal infinite-dimensional algebras AC(so(4, 1)) and PAC(so(3, 2)) extending the conformal algebras in three-dimensional euclidean and Minkowski space-time like the Virasoro algebra extends so(2, 1). Their higher spin generalizations are also constructed. A counterpart of the central extension for D > 2 and possible appplications in exactly solvable conformal quantum field models in D > 2 are discussed. (orig.).

Energy Technology Data Exchange (ETDEWEB)

It is reported about the adsorptive stripping voltammetric determination of uranium, antimony, tin, vanadium and molybdenum using chloranilic acid as complex forming reagent. The determination limits are in the l{sup 1}-range. (orig.) [Deutsch] Es wird ueber die Bestimmung von Uran, Antimon, Zinn, Vanadium und Molybdaen durch Adsorptions-Stripping-Voltammetrie mit Chloranilsaeure als Komplexbildner berichtet. Die Bestimmungsgrenzen liegen im ng l{sup -1} Bereich. (orig.)

International Nuclear Information System (INIS)

The adsorption properties of four samples of the #alpha#-modification of boron nitride (#alpha#-BN) were investigated by the gas-chromatographic method. According to the electron microscopy data, the #alpha#-BN particles possess the shape of thin plates. An #alpha#-BN sample prepared from magnesium polyboride, is the most uniform adsorbent. For a series of n-alkanes, benzene, and alkyl benzenes, by testing the #alpha#-BN samples one has obtained the retained volumes (Henry constants) and the values of the differential adsorption heat, which are close to those of the surface zero filling. These thermodynamic characteristics of adsorption have shown that the #alpha#-BN, line the graphitized thermal carbon black, is not a specific adsorbent.

British Library Electronic Table of Contents (United Kingdom)

The adsorption of benzyl alcohol and 1-phenylethanol on graphitized thermal carbon black at 300 K is investigated. Thermodynamic characteristics of the adsorption of conformers stable in the gas phase and in the adsorbed state are determined by a molecular statistics method. The geometry of the molecules is optimized using the MP2 and B3LYP methods with a 6-311++G(d,p) basis set. Using the PBE0/6-31G(d) method, it is established that, in the adsorption of benzyl alcohol, two types of interactions, CH?O and OH??GTCB, occur. It is shown that, in 1-phenylethanol, intramolecular interactions are maintained.

British Library Electronic Table of Contents (United Kingdom)

The thermodynamic characteristics of adsorption of sulfur-containing amino acids and their derivatives on the surface of graphitized thermal carbon black were calculated by the molecular statistical method. The parameters of the atom-atom potential function of intermolecular interaction between the S atom in amino acids and the graphite C atom were determined. It was shown that an intramolecular H-bond influenced the adsorption of amino acids on the surface of graphitized thermal carbon black.

Energy Technology Data Exchange (ETDEWEB)

This study was aimed to test and select hydrophobic activated charcoal, manufactured in Romania, used as adsorbents of solvents which partly compose diluters employed in car industry. With regard to the diluters, three of the seven types of activated charcoal studied (Sorbent 1, R - Cafs and AD3) showed the greatest capacity of adsorption, when determined under dynamic and static conditions. (authors) 8 refs.

British Library Electronic Table of Contents (United Kingdom)

Henry constants for the adsorption of o- and p-phenylenediamines on the surface of graphitized thermal carbon black within the temperature range 433?479 K were calculated by the molecular statistical method. The parameters of the atom-atom potential function of intermolecular interaction between the nitrogen atom in aniline and isomeric phenylenediamines and the carbon atom of the basal face of graphite were determined. It was shown that an intramolecular H bond influenced the geometry and adsorption properties of o-phenylenediamine.

Energy Technology Data Exchange (ETDEWEB)

The adsorption equilibria of Kr, Xe and N{sub 2}, which are constituents of the off-gas from nuclear reprocessing processes, on representative adsorbents (Molecular Sieve 5A (MS5A) and activated charcoal) were studied. Adsorption experiments were conducted in the temperature range of 77 to 323 K using a packed bed column. The adsorption isotherms for the activated charcoal adsorbent were successfully correlated by the vacancy solution model. The adsorption isotherms for the MS5A adsorbent were properly correlated by the Langmuir model and the vacancy solution model. The adsorption experiments for the binary component systems (Kr-Xe, Kr-N{sub 2} systems) were also performed, and the results suggest that the coexistence of Xe greatly inhibits the adsorption of Kr. The coexistence of large amounts of N{sub 2} was also found to inhibit the ...

British Library Electronic Table of Contents (United Kingdom)

The comprehensive theoretical and experimental study of the adsorption of water and methanol molecules on active sites (carboxyl and phenol hydroxyl groups) on the graphitized thermal carbon black is performed. It is shown that microclusters formed upon the adsorption of these molecules on such sites are characterized by the cyclic structure comprising 4?5 molecules similar to that whose existence was revealed previously in liquid water and on the surface of silver iodide. The analysis of the studied adsorption clusters demonstrated that the formation of such cycles is governed primarily by the hydrogen bonding; however, a definite role is played also by energy effects associated with the changes in the state of molecular motion during adsorption. It is shown that the generalized Langmuir ...

British Library Electronic Table of Contents (United Kingdom)

Biomass fly ash was treated with alkaline solution to enhance its adsorption capacity of Reactive Black 5 dye. The results revealed that the alkaline concentration, solution to fly ash ratio, treatment temperature and treatment time had a positive effect on the dye adsorption capacity of the treated fly ash (TFA), due to dissolving SiO2 and increasing the proportion of unburned carbon. In addition, the dye adsorption behavior of the TFA in aqueous solution was investigated. The effects of various experimental parameters (initial pH, initial dye concentration and contact time) were determined spectrophotometrically. The dye adsorption capacity of the TFA was maximized at an alkaline pH (8.2-10.4). The adsorption capacity of dye by the TFA increased with increasing initial dye concentration....

Energy Technology Data Exchange (ETDEWEB)

Although sulfur is present in many forms in kerosene, mercaptans are most objectionable due to their obnoxious odour and corrosive action. In this study, removal of one of the mercaptans has been reported, using red mud as an unconventional adsorbent. Red mud is a waste product from aluminium producing industries and has been used as an adsorbent for the removal of sulfur compounds as well as for other purposes. Adsorption studies described in this paper indicate that low concentration and high temperature favour the removal of 1-butanethiol from kerosene oil by adsorption on red mud. A first order mechanism has been proposed to describe the adsorption in the present system. Equilibrium data at different temperatures fit well in the Langmuir isotherm equation. Thermodynamic parameters for the present system indicate the feasibility of removal of 1-butanethiol from kerosene oil by adsorption on red mud. ...

Energy Technology Data Exchange (ETDEWEB)

Experiments were carried out to learn methanol sorption characteristics of heat-treated coal. When Taiheiyo coal is heat-treated at 125{degree}C, performed with a first methanol adsorption at 25{degree}C, and then desorption at 25{degree}C, a site with strong interaction with methanol and a site with relatively weak interaction are generated in test samples. A small amount of methanol remains in both sites. Then, when the methanol is desorbed at as low temperature as 70{degree}C, the methanol in the site with strong interaction remains as it has existed therein, but the methanol in the site with relatively weak interaction desorbs partially, hence the adsorption amount in a second adsorption at 25{degree}C increases. However, when desorption is performed at as high temperature as 125{degree}C, the methanol in the site with strong interaction also desorbs, resulting in increased adsorption heat in the ...

UK PubMed Central (United Kingdom)

Prostaglandin (PG) D2 has been shown to be transformed by human 11-ketoreductase to 9 alpha,11 beta-PGF2, a biologically active metabolite that is produced in vivo. During the course of developing a...Full Text Available

International Nuclear Information System (INIS)

The RESF is utilized for storage of spent fuel under emergency conditions as well as for testing of FM heads. It receives cooling supply from the PHT Pressurizing pumps and after removal of decay heat from the spent fuel it goes to the D2O Storage Tank. The geometry of the RESF system is such that it can not sustain the thermosyphon loop during SBO, due to high frictional forces. To achieve the sustained thermosyphon, modifications in the design were suggested viz., removal of the steam trap and the relief valve above it and replacement by a solenoid valve (SV-16). In the event of SBO, SV-16 will open on 'RESF channel temperature high' signal and connect to FT D2O tank. The tank, being at atmospheric pressure and at lower elevation, will provide higher cooling flow rate through the RESF channel. D2O is periodically removed from the FT ...

Energy Technology Data Exchange (ETDEWEB)

Rotationally resolved spectra of kinetic energy releases epsilon-c in predissociations of H/sub 2/, after dissociative charge exchange of H/sub 2/ /sup +/ with Cs atoms, are obtained. The experiments are performed with natural and with pure parahydrogen. The predissociations with epsilon-c<1.9 eV constitute less than 5% of the total amount of dissociations to HXchemically bondH at a beam energy of 5 keV. All strong rotational peaks observed could be attributed to n = 3 Rydberg states which predissociate to H(1s)+H(2l). Vibrational-rotational series are observed of the d /sup 3/Pi/sub u//sup +/, D /sup 1/Pi/sub u//sup +/, and J /sup 1/..delta../sub g//sup +/ states. Predissociation by barrier tunneling is reported of v = 4 levels of the h /sup 3/..sigma../sub g//sup +/ state and of v = 4 and 5 levels of the i /sup 3/Pi/sub g/ state. Selectivity of the charge-exchange process for different n = 3 states, or even for different parity states, is ...

Energy Technology Data Exchange (ETDEWEB)

Removal of sulfonamide (SAs) and tetracycline (TAs) classes of antibiotic compound from deionized water and DOC water by powdered activated carbon (PAC) adsorption was evaluated in this study. According to the study results, TAs were more easily adsorbed than SAs although TAs were more hydrophilic than SAs. The phenolic compounds in TAs might be responsible for their high adsorption. Complex formation of TAs with metal and metal oxide on the surface of activated carbon might also contribute to higher adsorption. The hydrophobic effect was important for removal of SAs. More hydrophobic SAs were removed more easily. The carbon type was not important for adsorption of SAs and TAs. Coal based carbon and coconut based carbon showed similar removal efficiencies for these antibiotics. Dissolved organic materials interfered with adsorption of SAs and TAs. Organic interference was more ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes statistical methods used to evaluate data for toluene (at several typical operating temperatures and humidity levels) and to determine which measure of humidity (relative or absolute) is more important in determining carbon adsorption efficiency. The water content of a solvent-laden stream is critical for its control via carbon adsorption, especially at relative humidities about 50-70%. (Relative humidity is the percent of saturation: absolute humidity is the total water content.)

British Library Electronic Table of Contents (United Kingdom)

Isosteric heats and adsorption isotherms of methane on nanometer active carbon were measured at supercritical temperature (273-373 K) and pressure from 0 to 10 MPa. The measured data agreed well with Dubinin-Astakhov (DA) model at lower pressure but failed when pressure exceeded a special range. General Freundlich (GF) equation was used to modify the DA equation at high pressure and thus formed a combined bisection model GFDA. The adsorption mechanism of methane on nanometer active carbon was raised according to GFDA model and the heterogeneous energy distribution of the adsorbent was analyzed.

International Nuclear Information System (INIS)

A numerical and experimental investigation is carried out in a solar thermochemical reactor for the thermal dissociation of ZnO at 2000 K using concentrated solar energy. The reactor consists of a cavity-receiver lined with ZnO particles and directly exposed to high-flux irradiation. A transient heat transfer model is formulated to link the rate of radiation, convection, and conduction heat transfer to the reaction kinetics. The radiosity and Monte Carlo methods are applied to obtain the distribution of net radiative fluxes at the internal surfaces of the reactor cavity and at the surface of the ZnO bed. Validation is accomplished in terms of the calculated and measured transient temperature profiles and chemical reaction rates.

International Nuclear Information System (INIS)

A time-of-flight mass spectrometer has been constructed to measure the energy spectra of particles scattered by 10"0 with primary energies between 200 eV and 15 keV. The energy resolution #DELTA#E/E of the system is between 0.1 and 0.4%. Energy spectra of scattered molecules and their dissociation products are shown for 570 eV H_2"+ and 4430 eV N_2"+ as projectiles. Electron capture into unbound states of the neutral molecule, with perhaps some contribution from mutual scattering within the molecule, appears to explain the observed dissociation product energy spectra peak widths. (orig.).

International Nuclear Information System (INIS)

A kind of polymer-metal complex gel electrolyte is successfully prepared and is used in dye-sensitized solar cells. Raman and X-ray photoelectron spectroscopy confirm the structure of this complex and is found that the metal ion reacts with nitrogen in the polymer. This novel electrolyte shows apparent diffusion coefficient of iodide of 8.37 x 10-7 cm2 s-1 and the energy conversion efficiency of 6.10% when the amount of ZnI2 is 0.04 M. By studying the dissociation active energy of the inorganic salt in electrolytes, we find that the metal salts can dissociate more easily after reacting with polymer and as a result can provide extra free iodide ion. The cell maintains ca. 93% of its initial efficiency after 20 d without further sealing, which shows good long-time stability.

International Nuclear Information System (INIS)

Electron simulated desorption of anions from CFCl_3 and CF_2Cl_2 condensed on an Au substrate is studied in the energy range 0-15 eV. The negative fragments are recorded mass spectro metrically as the function of the incident electron energy. Below 10 eV we observe anion desorption via pronounced resonance profiles which are characteristic for dissociative electron attachment (DA) while the continuous rise of the signal at higher energies accounts for dipolar dissociation (DD) and processes involving secondary electrons from the metallic substrate. For both compounds F"- and Cl"- are the only fragment anions we could observe. (author).

Energy Technology Data Exchange (ETDEWEB)

The authors present results of grazing incidence X-ray diffraction studies concerning the effect of pH (and thus, of headgroup dissociation) on Langmuir monolayers of fatty acids, in the absence of any divalent cations in the aqueous subphase. An increase in pH transforms the distorted-hexagonal S phase first to the partially disordered Rotator-I phase with less distortion, and then to the completely disordered Rotator-II phase with an undistorted hexagonal structure. The S-Rotator-I and Rotator-I-Rotator-II transitions are pushed to lower temperatures with increase in pH. The fact that the effects of pH increase are almost identical to the effects of increasing temperature indicates the important role of headgroup-headgroup interactions in these monolayer phases.

Energy Technology Data Exchange (ETDEWEB)

The proton and deuteron spectra following resonant multiphoton ionization of H{sub 2} and HD at 193 nm through the {ital E},{ital F} state have been studied at power densities of 10{sup 10} W/cm{sup 2}. Our results show that the intermediate state induces competition between 3(2+1)-photon ionization, dissociation, and dissociative ionization channels. We find that the competition depends on the specific vibrational and rotational levels excited in the intermediate state. At the same time, the mere presence of this bound intermediate state renders these three-photon fragmentation channels so efficient that higher-order fragmentation processes, such as Coulomb explosions requiring many more photons, are not observed.

Energy Technology Data Exchange (ETDEWEB)

This paper presents the isothermal characteristics of methanol onto two specimens of activated carbons namely Maxsorb III and Tsurumi activated charcoal. Dubinin Raduskevich (D-R) equation is used to correlate the adsorption isotherms and to form the pressure-temperature-concentration diagram for both of the assorted pairs. Experimental results show that the maximum adsorption capacity of Maxsorb III/methanol pair is 1.76 times that of activated charcoal/methanol pair. Employing a time-independent mathematical model, the performance of adsorption cooling cycle using Maxsorb III/methanol and activated charcoal/methanol pairs has been studied and compared with that of three other types of carbon based adsorbent/methanol pairs. Theoretical calculations show the superiority of Maxsorb III/methanol pair for both of air-conditioning and ice-making applications. (author)

International Nuclear Information System (INIS)

... adsorption aqueous solutions astatine complexes astatine ions enthalpy organic

Energy Technology Data Exchange (ETDEWEB)

The economic feasibility of using granular activated carbon (GAC) to remove organic contaminants from industrial and municipal wastewater is contingent upon its reuse during multiple adsorption-regeneration cycles. The most common process for the regeneration of GAC is the thermal method. Drawbacks associated with thermal regeneration include a 5--10% loss of carbon due to oxidation and attrition, a decrease in adsorption capacity, and high energy costs. The purpose of this study was to investigate the regeneration of GAC using hydrothermal technology. Phenol contaminated and non-contaminated GAC samples were regenerated using supercritical water (411 deg C and 26.2 MPa) with dissolved oxygen concentrations of 0 mg/L, 5 mg/L, and 100 mg/L. For comparative purposes, GAC was regenerated using subcritical water (300 deg C and 12.4 MPa) with a dissolved oxygen concentration of 5 mg/L. Regenerated GAC samples were evaluated in terms of ...

British Library Electronic Table of Contents (United Kingdom)

The thermodynamic characteristics of adsorption (TCA) on the basal face of graphite have been calculated in terms of the semiempirical molecular statistical theory of adsorption for molecules of O-, S-, and Se-containing heteroadamantanes of different structure and isostructural cyclohexane derivatives. The influence of the nature, number, and position of heteroatoms in the adamantane framework on the TCA values was studied in detail, which made it possible to predict the retention of the compounds considered on the surface of graphitized thermal carbon black under the conditions of equilibrium gas adsorption chromatography. The introduction of each subsequent heteroatom into a polyheteroadamantane molecule makes a non-additive contribution to the TCA values. The contributions of various f...

British Library Electronic Table of Contents (United Kingdom)

The thermodynamic characteristics of adsorption (the Henry constant, the heat and entropy of adsorption) of amino acids associates with acetic, trifluoroacetic, nonafluoropentanoic acids and formamide with different values of hydrogen bond lengths and various conformations on a graphitized thermal carbon black (GTCB) were calculated. The experimental results, as the Henry constant, lnK1, and the differences in the molar Gibbs energies, d(DG), obtained by a high performance liquid chromatography (HPLC) on a carbon sorbent Hypercarb, were compared with the values of thermodynamic characteristics of adsorption of the amino acids on the GTCB surface calculated by a molecular-statistical method. A satisfactory correlation was observed between the experimental and calculated values with a coeffi...

UK PubMed Central (United Kingdom)

Substances cross the blood-brain barrier (BBB) by a variety of mechanisms. These include transmembrane diffusion, saturable transporters, adsorptive endocytosis, and the extracellular pathways. Here,...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Immobilized eggshell with a polymer mixture of alginate and polyvinyl alcohol was applied as a biocomposite adsorbent (ESC) for the adsorption of C.I. Remazol Reactive Red 198 from aqueous solution. ESC was characterized using XRD, TGA, FTIR and SEM. The Red dye adsorption onto the ESC was investigated in a batch system with respect to initial dye concentration, pH, contact time, agitation speed, solution temperature and biocomposite dosage. The prepared biocomposite exhibits high efficiency for red dye adsorption and the equilibrium states could be achieved in 3h for the different studied initial dye concentrations. The equilibrium isotherm study indicated that sorption data were analyzed and fitted well by both Langmuir and Temkin models compared to Freundlich model. The maximum monolaye...

International Nuclear Information System (INIS)

The total amount of uranium dissolved in seawater at a uniform concentration of 3 mg U/m3 in the world's oceans is 4.5 billion tons. An adsorption method using polymeric adsorbents capable of specifically recovering uranium from seawater is reported to be economically feasible. A uranium-specific nonwoven fabric was used as the adsorbent packed in an adsorption cage 16 m2 in cross-sectional area and 16 cm in height. We submerged three adsorption cages in the Pacific Ocean at a depth of 20 m at 7 km offshore of Japan. The three adsorption cages consisted of stacks of 52 000 sheets of the uranium-specific non-woven fabric with a total mass of 350 kg. The total amount of uranium recovered by the nonwoven fabric was >1 kg in terms of yellow cake during a total submersion time of 240 days in the ocean.

International Nuclear Information System (INIS)

Russian (Jan 1978). USSR Chorna, IM Beshta, EI Kvitkovskij, LN L'vovskij

CERN Document Server

We consider two-dimensional large N gauge theory with D adjoint scalars on a torus, which is obtained from a D+2 dimensional pure Yang-Mills theory on T^{D+2} with D small radii. The two dimensional model has various phases characterized by the holonomy of the gauge field around non-contractible cycles of the 2-torus. We determine the phase boundaries and derive the order of the phase transitions using a method developed in an earlier work (hep-th/0910.4526), which is nonperturbative in the 'tHooft coupling and uses a 1/D expansion. We embed our phase diagram in the more extensive phase structure of the D+2 dimensional Yang-Mills theory and match with the picture of a cascade of phase transitions found earlier in lattice calculations (hep-lat/0710.0098). We also propose a dual gravity system based on a Scherk-Schwarz compactification of a ...

Energy Technology Data Exchange (ETDEWEB)

In this letter we present a derivation, from the D0-brane picture, of the background monopole field and in general of the full dynamics of the Yang-Mills theory on the dielectric D2-brane of Myers. To do this we study the large N limit of the fuzzy sphere relevant to the dielectric solution. In contrast to the usual interpretation where the commutative D2-brane picture arises directly from the large N limit of the D0-brane picture, we find that a residual non-commutativity must be preserved in order to make the connection by means of the Seiberg-Witten map.

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Classical molecular dynamics simulations are carried out to investigate the salvation shell exchange kinetics of potassium ion in bulk water, chloroform, and carbon tetrachloride. The reactive flux method is used to compute the dissociation rates. The influence of the solvent on the reaction rates and kinetic properties of this exchange process will be discussed. Comparison will be also be made to the prediction of the Grote-Hynes theory.

International Nuclear Information System (INIS)

The process of infrared multiple photon dissociation (IRMPD) of molecules is of great fundamental importance and has practical significance, such as isotope separation etc. Unfortunately, a clear insight into the process has been hindered by the bewildering array of important variables affecting MPD. The dissociation probability #gamma#(#phi#) i.e. the yield has been found to be a sensitive function of laser fluence #phi# along with numerous other parameters like laser frequency, gas pressure etc. We have shown that in single frequency IRMPD an accurate quantitative characterization of the dissociation probability can be adequately expressed by a 'power law' model with two fitting parameters namely critical fluence, #phi#c and multi photon order, m. This model was exploited in analysing our MPD results on various systems. However, the small isotope shift encountered in heavy elements and the sticking phenomenon observed in ...

Energy Technology Data Exchange (ETDEWEB)

During this report period our research efforts have concentrated on studies of the dissociation reactions of model peptides and other biologically important molecules. In addition, a considerable amount of research effort has been directed toward improving the apparatus used for laser-ion beam photodissociation. The instrumental improvements include some changes on the original apparatus, but most of this effort involved designing a second generation laser-ion beam photodissociation instrument.

UK PubMed Central (United Kingdom)

The values of the second dissociation constant pK₂ and related thermodynamic quantities of the ampholyte 3-(N-morpholino)-2-hydroxypropanesulfonic acid (MOPSO) have...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

The thermodynamic characteristics of adsorption on the surface of graphitized thermal carbon black at 300 K were determined by the molecular statistical method for three phenylalklylamines. The influence of the intramolecular H-bond on the conformation of the molecules compared with structurally related n-alkyl-benzenes was considered. It was shown that the conformations of the molecules could influence chromatographic retention. Conformational isomers stabilized by intramolecular H-bonds were found to retain their structure in adsorption on graphitized thermal carbon black.

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This is the first time that the adsorption of binary mixtures of polycyclic aromatic hydrocarbons (PAHs) has been studied. This study was carried out at laboratory scale in an experimental apparatus specially designed for this aim: with gas-phase fluorescence, a new detection procedure was used. Experimental conditions, mainly in terms of temperature (150C) and contaminant concentration (approximately 1 ppmv), close to the ones observed in energy generation systems, were applied. The PAH adsorption process interpretation was carried out by recording the experimentally obtained breakthrough curves. After the detection parameter optimization, the influence of adsorbate characteristics in the hot gas cleaning of PAH was studied. In this system, the adsorption of 10 binary mixtures of five PAH (naphthalene (Np), fluorene (Fu), phenanthrene (Phe), fluoranthene (Fl), and pyrene (Py)) on an activated carbon was investigated. It ...

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The authors identify a need for a device which can remotely measure methane in coal mines. Similar techniques which have been used to measure atmospheric pollutants are discussed. These techniques include adsorption, Raman scattering and fluorescence. While differential adsorption and Raman scattering techniques have potential there are a number of problems to be resolved before they could be applied effectively. It is felt that an area which may provide suitable technology sometime in the future is in the field of laser sources. 6 refs., 4 tabs.

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Adsorption isotherms for phenol and o-cresol on activated charcoal at neutral pH and several dissolved oxygen concentrations were conducted at 23{degree}C. Significant improvements in capacities were observed with increasing dissolved oxygen concentrations for the two adsorbates. These statistically-significant additional capacities were not due to biological activities but merely due to surface chemical reactions. The improvement in capacity was directly related to the amount of oxygen per unit mass of GAC.

British Library Electronic Table of Contents (United Kingdom)

The interaction between gravity convection and Marangoni convection in a horizontal rectangular channel filled with a liquid containing a surfactant and a drop of another liquid is numerically investigated. For large Schmidt numbers the occurring oscillatory regime of solutal convection is analyzed. In the model with a surface phase the effect of the adsorption and desorption processes on the convective flow structure is determined. The corresponding initial and boundary value problem is solved using a difference method.

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Red mud is generated as a by-product in the production of Al(OH){sub 3}/Al{sub 2}O{sub 3} from bauxite ore. In this study the pellet-type adsorbents have been made from the red mud, and their adsorption capacities of heavy metal ions have been tested. The pellet-type adsorbents were synthesized to utilize the excellent adsorption capacity of the powder-type adsorbent for industrial application. The pellet-type adsorbents were prepared by mixing several kinds of additives with the red mud. It is found that the pellet-type adsorbent, made by sintering a mixture of red mud (96.0 wt%), polypropylene (2.5 wt%), fly ash (0.5 wt%), and sodium meta-silicate (1.0 wt%) at 1200 deg.C for 30 minutes, has the highest adsorption capacity. In this work, the two kinds of pellet-type adsorbents (bead-type, crushed-type) were prepared. The crushed-type adsorbent was found to show a better adsorption/desorption ...

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This study deals with the adsorption and desorption of lead (c <= 10/sup -8/ - 10/sup -3/ M), labelled with /sup 212/Pb or /sup 210/Pb, on glass in relation to pH and composition of the solution, concentration of lead and time. The prevailing mechanism of the adsorption in the pH range from 3 to 8 is the ion exchange of Pb/sup 2 +/ and PbOH/sup +/ ions in electric double layer on the surface of glass. At the higher pH values lead (c <= 10/sup -8/ - 10/sup -6/ M) is adsorbed mainly by physical adsorption or chemisorption of its hydrolyzed forms. A rather high adsorption capacity of glass, exceeding 3.10/sup -9/ M/cm/sup 2/, has been found in neutral solutions for the cationic forms of lead. The adsorbed lead can be easily desorbed with the solution of 1 M nitric acid.

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The behaviour of hydrogen adsorption on palladium has been investigated by a.c. impedance measurements in 0.1 M NaOH solution of pH 13 at 298 K. The electrode impedance has been measured by superimposing an a.c. voltage of 5 mV amplitude ranging between 10{sup -1} and 10{sup 4} Hz on a d.c. potential range from -0.76 to 0.44 V (standard hydrogen electrode (SHE)). The equivalent circuit representing the hydrogen adsorption reaction is proposed from the analysis of the frequency dependence of electrode admittance. The capacitance, arising from the adsorbed hydrogen, has been determined as a function of applied potential by complex non-linear least-squares curve fitting method based on the proposed equivalent circuit. As the cathodic applied potential increased from -0.36 to -0.76 V (SHE), the adsorption capacitance considerably increased owing to the enhanced coverage of hydrogen adsorbed on the palladium surface. In the ...

Science.gov (United States)

In this paper, the effects of surface mediation on the adsorption isotherm and isosteric heat of adsorption on a graphite surface were investigated, as the surface mediation is known to affect the intermolecular interaction of adsorbed molecules close to the surface. Kim and Steele (Phys. Rev. B 45 (11) (1992) 6226-6233) and others have assumed that the surface mediation is confined only to the first layer. This will be tested in this paper with a combined experimental and Grand Canonical Monte Carlo (GCMC) simulation of adsorption of argon on graphitized thermal carbon black (GTCB) over a range of temperatures (77-95.25K). By matching the simulation results against the experimental data, we have found that the surface mediation is extended up to the fourth layer, rather than only the first as suggested by Kim and Steele, and the extent of this mediation is reduced with distance from the surface. This reinforces the ...

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As an important radioisotope in nuclear industry and other fields, americium-241 is one of the most serious contamination concerns duo to its high toxicity and long half-life. In this experiment, the biosorption of {sup 241}Am from solution by Candida sp., and the effects of various experimental conditions on the adsorption were investigated. The preliminary results showed that the adsorption of {sup 241}Am by Candida sp. was efficient. {sup 241}Am could be removed by Candida sp. of 0.82 g/L (dry weight) from {sup 241}Am solutions of 5.6-111 MBq/L (44.3-877.2 {mu}g/L)(C{sub 0}), with maximum adsorption rate (R) of 98% and maximum adsorption capacities (W) of 63.5 MBq/g biomass (dry weight) (501.8 {mu}g/g). The biosorption equilibrium was achieved within 4 hour and the optimum pH was pH = 2. No significant differences on {sup 241}Am adsorption were observed at 10 C-45 C, or in ...

British Library Electronic Table of Contents (United Kingdom)

The thermodynamic characteristics of sorption of the isomeric tricyclo[5.2.1.02.6]decane (tetrahydrodicyclopentadiene, TDCPD) molecules were for the first time determined experimentally and by molecular statistical methods under the conditions of gas-adsorption chromatography on graphitized thermal carbon black and gas-liquid chromatography on stationary liquid phases of different polarities (Apiezon L and Carbowax 20M). The effects of the chemical nature of sorbents on the retention of the TDCPD isomers are considered. A procedure for calculating the thermodynamic characteristics of adsorption of molecules with a complex structure is suggested within the framework of the atom-atom approximation of the semiempirical molecular statistical theory of adsorption for the example of isostructura...

British Library Electronic Table of Contents (United Kingdom)

Two polymeric biosorbents were prepared from cotton stalk (CS) and wheat straw (WS) by the epichlorohydrin-diethylenetriamine-trimethylamine method. Amine-crosslinked cotton stalk (AC-CS) and wheat stalk (AC-WS) were used for the adsorption of phosphate, and their physicochemical properties as well as biosorption properties for phosphate were discussed intensively. Results indicated that the contents of holocellulose in CS and WS corresponded to the distinct phosphate adsorption capacities between AC-CS and AC-WS. Zeta potential and Raman spectra analysis illustrated the electrostatic attraction between phosphate ions and biosorbents. The adsorption of phosphate was not strongly pH dependent when the pH was about 4.0-9.0. The Langmuir isotherm provided the better fit and the maximum adsorp...

Energy Technology Data Exchange (ETDEWEB)

Anion-exchange chromatography of element 105, dubnium (Db), produced in the {sup 248}Cm({sup 19}F, 5n){sup 262}Db reaction is investigated together with the homologues Nb and Ta, and the pseudo-homologue Pa in 13.9 M hydrofluoric acid (HF) solution. The distribution coefficient (K{sub d}) of Db on an anion-exchange resin is successfully determined by running cycles of 1702 chromatographic column separations. The result clearly indicates that the adsorption of Db on the resin is significantly different from that of the homologues and that the adsorption of anionic fluoro complexes of these elements decreases in the sequence of Ta{approx}Nb>Db{>=}Pa. (orig.)

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Five corrosion probes were received from West Valley Nuclear Services for evaluation in simulated tank 8D-2 3rd-stage sludge wash slurry. The same waste slurry simulated was also used in a series of ongoing corrosion studies assessing the effects of in-tank sludge washing on the integrity of tank 8D-2. Two of the corrosion probes were installed in the coupon corrosion test vessels operating at {approximately}150{degrees}F to compare performance of the probes with that observed by coupon tests conducted in the same vessels. Corrosion rate data calculated from electrical resistance measurements of the corrosion probes were evaluated for this study using two slightly different approaches. One approach uses the total length of exposure of the probe to give a ``time-averaged`` value of the corrosion rate. The other approach uses a shorter period of time (relative to the length of the test) in the calculation ...

International Nuclear Information System (INIS)

In order to evaluate the integrated performance of RELAP5/MOD3/CANDU"+ for CANDU operational transient analysis, we assesed the code to the D_2O leakage event occurred at Wolsung-I, 600 MW(e) CANDU reactor, on Oct. 20, '94. D_2O leakage event was initiated by stuck opening of liquid relief valve No.4 in primary coolant pressure and level control system. Assessment calculation was performed for the plant transients up to 1000 seconds after the initiating event. Calculation results are compared with those measured in primary heat transport system, pressure and inventory control system and boiler secondary system. Comparison with the plant trip log shows that the RELAP5/CANDU"+ is able to simulate the plant transients properly, from which we can conclude that the RELAP5/CANDU"+ is validated for application to CANDU operational transient analysis. CANDU specific models used in the assessment are fuel bundle ...

International Nuclear Information System (INIS)

An attempt to classify experimental data and to present new approach for the problem of cumulative production of particles and high-transverse momentum particles (#pi#"#+-#, k"#+-#, p, p-bar, d) on Li"6, Be, Mg, Si, "5"4","5"6","5"8Fe, "5"8","6"1","6"4Ni, Cu, "6"4Zn, "1"1"2","1"1"8","1"2"4Sn, "1"4"4","1"5"4Sm, "1"8"2","1"8"6W, U nuclei is made in the review. Particle cumulative production, quark-parton structure function, A dependence of particle production on nuclei and in nuclear collisions and A dependence of inclusive cross sections of particle cumulative production are discussed. Reactions with dissociation on nucleons of deuteron, helium and compound nuclei are considered. Possibility of unified description of different processes is discussed in terms of nucleus flucton model. 35 refs.; 22 figs.

International Nuclear Information System (INIS)

The present investigation compares the suitability of two radiolabeling techniques for hemoglobin. "1"2"5I labeling of hemoglobin with Iodogen as iodinating agent caused major changes in the chromatographic behaviour and an accelerated plasma clearance of the labeled hemoglobin in rats. A recently developed two-step procedure for "9"9"mTc labeling gave better results. The label had only minimal influence on the chromatographic behaviour of hemoglobin. In vivo, no free label occurred in the circulation and no transfer of the label to other plasma proteins took place. The plasma clearance of "9"9"mTc-labeled hemoglobin in rats was slowed. However, this could be explained entirely by diminishing glomerular filtration, probably by inhibition of the dissociation of the hemoglobin molecule into dimers. The plasma clearance of hemoglobin modified by intramolecular cross-linking, which prevents dissociation of the molecule into dimers and thus ...

Energy Technology Data Exchange (ETDEWEB)

The chemical interaction of a Si{sub 3}N{sub 4} ceramic with pristine and oxidised 100Cr6 steel was studied by means of static interaction couple experiments between 500 and 1200 C. Si{sub 3}N{sub 4} was not chemically stable in contact with oxidised steel at elevated temperatures, and reacts with the formation of N{sub 2}, SiO{sub 2} and/or Fe{sub 2}SiO{sub 4} at temperatures at and above 1000 C. At 700 and 500 C, Si diffusion into the oxide layer indicated the dissociation of the Si{sub 3}N{sub 4} ceramic. Si{sub 3}N{sub 4} also dissociated in contact with pristine steel. In the temperature region between 700 and 1100 C, the Si dissolves and diffuses into the steel whereas a nitrogen pressure is built-up in the voids of the metal-ceramic interface, limiting the degree of interaction. Above 1100 C, the nitrogen dissolves and diffuses into the steel as well, enhancing the reactivity and resulting in the formation of a strong metal-ceramic ...

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By isomorphous replacement of silicon by phosphorus the authors have synthesized crystalline aluminosilicophosphates with structures of the zeolites type A and faujasite. They determine the adsorption capacity of specimens treated at 575-1275/sup 0/K. They show that the thermal stability and acid resistance of aluminosilicophosphates depend on the quantity of phosphorus in their structure.

British Library Electronic Table of Contents (United Kingdom)

We carried out theoretical analyses based on ab initio calculations incorporates in which free energy of the vapor phase is incorporated in order to determine the initial growth kinetics of c-GaN on GaN(001)-(4x1). The feasibility of the theoretical approach had been confirmed by calculations of Ga adsorption-desorption transition temperature and transition beam equivalent pressures on the GaAs(001)-(4x2)b2 surface in our previous work [Y. Kangawa, T. Ito, A. Taguchi, K. Shiraishi, T. Ohachi, Surf. Sci. 493 (2001) 178]. The results of calculations suggest that no Ga adsorption occurs on the initial surface under typical growth conditions but that a Ga adsorption site appears after N adsorption on GaN(001)-(4x1). That is, in the initial growth stage of c-GaN on GaN(001)-(4x1), a N-adsorbed ...

UK PubMed Central (United Kingdom)

Amorphous silicates having small particles with a large surface area were found to have high nonspecific adsorption capacity. Investigations with Escherichia coli T4 bacteriophage have...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Soil vapor extraction (SVE) is a widely accepted in-place treatment technology that uses forced air to remove contaminant vapors from zones of permeable vapor flow, thereby enhancing the volatilization of contaminants from the subsurface. The resulting off-gases are contaminated with volatiles and semi-volatiles and have to treated by catalytic or thermal destruction systems, activated carbon adsorbers, or bioreactors. Of these, activated carbon adsorption is the most commonly used technology. From the theoretical foundation of SVE and carbon adsorption, two nomographs were developed for remedial investigation, feasibility studies, planning, operation, and preliminary design purposes. An advantage of such nomographs is that they graphically indicate the sensitivity of the remediation process to different design parameters and critical ranges within a given parameter. In effect, nomographs can help to foster an intuitive understanding of the SVE ...

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A solar-powered adsorption air-conditioning system was designed and installed in the green building of Shanghai Research Institute of Building Science. The system contained 150 m{sup 2} solar collectors and two adsorption chillers with nominal refrigeration capacity of 8.5 kW. Based on performance characteristics of the adsorption chiller, the operation mode of the solar-powered air-conditioning system was optimized by maintaining a phase shift of 540 s between the two adsorption chillers. Thereafter, the whole system realized stable operation by the balance of heat consumption and refrigeration output. From June to August of 2005, the solar-powered air-conditioning system continuously ran between 9:00 and 17:00. The operation performance of the system under representative working condition showed that the average refrigeration output of the solar-powered air-conditioning system was 15.3 kW during an 8 ...

International Nuclear Information System (INIS)

The acid corrosion inhibition process of mild steel in 1 M HCl by 1-butyl-3-methylimidazolium chlorides (BMIC) and 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM]HSO_4) has been investigated using electrochemical impedance, potentiodynamic polarization and weight loss measurements. Potentiodynamic polarization studies indicate the studied inhibitors are mixed type inhibitors. For both inhibitors, the inhibition efficiency increased with increase in the concentration of the inhibitor and the effectiveness of the two inhibitors are in the order [BMIM]HSO_4 > BMIC. The adsorption of the inhibitors on mild steel surface obeyed the Langmuir's adsorption isotherm. The effect of temperature on the corrosion behavior in the presence of 5 x 10"-"3 M of inhibitors was studied in the temperature range of 303-333 K. The associated activation energy of corrosion and other thermodynamic parameters such as enthalpy of activation (#DELTA#H), entropy of ...

International Nuclear Information System (INIS)

Japanese (Jul 1976). Japan Kametani, Katsuaki Tomura, Kayoko . National

Energy Technology Data Exchange (ETDEWEB)

The biosorption of {sup 241}Am from solution by a fungus--Rhizopus Arrihizus (R. arrihizus), and the effect of experimental conditions on the adsorption were investigated. The preliminary results showed that the biosorption of {sup 241}Am by R. arrihizus is very efficient. An average of more than 99% of the total {sup 241}Am was removed by R. arrihizus of 1.3 g/l (dry weight) from {sup 241}Am solutions of 5.6-111 MBq/l (44.3-877.2 {mu}g/l) (C{sub 0}), with adsorption capacities (W) of 4.2-79.4 MBq/g biomass (dry weight) (33.2-627.5 {mu}g/g). The biosorption equilibrium was achieved within 1 h and the optimum pH ranged from 1 to 3. No significant differences in {sup 241}Am biosorption were observed at 10-45 deg. C, or in solutions containing Au{sup 3+} or Ag{sup +}, even 2000 times above {sup 241}Am concentration. The relationship between concentrations and adsorption capacities of {sup 241}Am indicated that the {sup 241}Am ...

International Nuclear Information System (INIS)

Interfacial tension at the aqueous solution of di-2-ethylhexylphosphoric acid or its copper salts/water solutions has been measured by the drop volume method.

Energy Technology Data Exchange (ETDEWEB)

We have studied the impact of overexpression of an intracellular signaling protein, integrin-linked kinase (ILK), on the survival and function of encapsulated islet tissue used for the treatment of type 1 diabetes. The dimensions of the encapsulated tissue can impact the stresses placed on the tissue and ILK overexpression shows the ability to extend function of dissociated cells as well as intact islets. These results suggest that lost cell-extracellular matrix interactions in cell encapsulation systems can lead to decreased insulin secretion and ILK signaling is a target to overcome this phenomenon. (communication)

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Gas hydrates have impacted the oil and gas industry since 1934, when they were first found to plug pipelines. Today we know that in deep oceans and in permafrost, very substantial gas reserves are present in hydrated form. Concerns are being raised about in situ dissociation for both energy and greenhouse implications upon methane release. In Japan work is underway to consider the storage of carbon dioxide, concentrated in clathrates. This talk will deal with some basic questions. Why should we be interested in gas hydrates? What are gas hydrates? How do gas hydrates form? How might hydrates impact on the energy/environmental picture?

CERN Document Server

We consider non-relativistic systems in quantum mechanics interacting through the Coulomb potential, and discuss the existence of bound states which are stable against spontaneous dissociation into smaller atoms or ions. We review the studies that have been made of specific mass configurations and also the properties of the domain of stability in the space of masses or inverse masses. These rigorous results are supplemented by numerical investigations using accurate variational methods. A section is devoted to systems of three arbitrary charges and another to molecules in a world with two space-dimensions.

International Nuclear Information System (INIS)

A few industry-derived and conventional building materials have above acceptable radioactivity. An examination of some materials presently used, or with a potential for use, has shown that in phosphogypsum, fly ash, zircon kyanite tailings, red mud and brickmaking clay, the radium equivalent activities of the finer fractions (<53 #mu#) are higher than those of the larger fractions. Consequently, the radioactivity of these materials could be reduced by dry-sieving and discarding the fines. In blast furnace slag and dissociated zircon, no such reduction would occur since the radioactivity is evenly distributed in all sized fractions.

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Passage of neon gas through activated charcoal is planned to be the primary method of removing impurities from the liquid neon scintillator in the CLEAN experiment. In order to quantify this technique, the breakout curves for hydrogen, nitrogen, argon and krypton impurities in neon-saturated activated charcoal were measured. Adsorption coefficients and the number of theoretical stages were measured for hydrogen in the temperature range between 300 and 80 K, nitrogen between 300 and 200 K, and argon between 300 and 190 K. The adsorption coefficient for krypton was measured at 300 K.

International Nuclear Information System (INIS)

The method of programmed thermodesorption has been used to study the forms of hydrogen adsorption in ZrNiHsub(x) hydride. It is shown that high concentration of the hydrogen, which extracted from hydride in the temperature range of 240-260 deg C results in appearance of ''reverse'' peak. Charge of hydride adsorption properties during its oxidation-reduction treatment is studied. Comparison with spectra of hydrogen thermodesorption from the surface of Ni/ZrO_2 deposited catalyst and zirconium oxide is carried out.

Science.gov (United States)

The total area ( s m) of Voronoi-Dirichlet polyhedron faces corresponding to all intermolecular contacts of one molecule in the structure of crystals and the total volume of pyramids ( V m) built on such faces and containing the nuclei of atoms participating in intermolecular contacts in their vertices were determined for 19 unsaturated hydrocarbons. The differential molar heat of adsorption of the hydrocarbons on graphitized thermal carbon black was found to be linearly related to the s m or V m integral parameters of their Voronoi-Dirichlet polyhedra. Aromatic hydrocarbons on the one hand and saturated hydrocarbons, olefins, and acetylene on the other are characterized by different dependences because of the special shapes of their molecular Voronoi-Dirichlet polyhedra.

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SO/sub 2/ adsorption onto faujasite-type zeolites (Na-X, Na-Y) was investigated by combined UV and IR spectroscopy. Formation of chemisorbed HSO/sub 3//sup -/ species, indicated by a UV band around 215 nm and a low-frequency IR band at 1240 cm/sup -1/, was shown to depend significantly upon the presence of water. Differences in the behavior of Na-X and Na-Y were discussed in terms of different site populations.

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Photoemission-electron-microscopy (PEEM) is introduced as a tool for the characterization of organic electronic devices. PEEM-measurements are used for imaging as well as for spectroscopic analyses by illumination with light of a Hg-lamp (4.9 eV), a D2 lamp (7.3 eV), and with synchrotron radiation for resonant photoelectron spectroscopy. We determine the charge carrier concentration inside the channel region of the organic device and its lateral distribution. From resonant photoelectron spectroscopy (RPES) we deduce the electronic states which are accessible with the Hg and D2 illumination. Photoelectron-spectroscopy at selected areas ({mu}-PES) gives information on the absolute values of surface potentials in lateral resolution. We are able to perform these studies with applied voltages at the source- and drain-electrode.

International Nuclear Information System (INIS)

We have applied photofragment ion imaging to investigate the dissociation dynamics of low-lying, doubly excited states of molecular hydrogen. A doubly excited electronic state is one in which both of the hydrogen electrons reside in excited molecular orbitals. Two-step, two-color multiphoton excitation of H_2, first via 201.8 nm, two-photon excitation into the E, F "1#SIGMA#"+_g(v_E=0, J=1) state, followed by #approx#563 nm, 1+m (m=1, 2) excitation through the B double-prime "1#SIGMA#"+_u(v=0, J=0, 2), D "1#PI#_u(v=2, J=1, 2), and B' "1#SIGMA#"+_u(v=4, J=0, 2) states provides a ready means of populating several low-lying doubly excited states of H_2 at increasing internuclear separations. From these doubly excited repulsive states, both dissociation and autoionization processes are possible. Because the excitation energy remains relatively constant as each intermediate state is accessed, differences in the photodissociation dynamics via each ...

Energy Technology Data Exchange (ETDEWEB)

The receptor occupancy-biological effect relationship for muscarinic receptors in guinea pig ileal smooth muscle has been studied by comparison of radioligand binding and contractile response. Muscarinic receptors in homogenates of ileal smooth muscle were labeled with (/sub 3/H)-1-Quinuclidinyl benzilate. Treatment with propylbenzilylcholine mustard (PrBCM), to inactivate irreversibly muscarinic receptors, caused a large dose dependent rightward shift of the dose-response curve to three agonistic furtrethonium derivatives with a concomitant decrease in maximal response. Using those data, the fraction of receptors remaining unoccupied (q-values) and true affinity constants (-log K/sub A/-values) were calculated. Exposure to 20 or 60 nM PrBCM for 15 minutes resulted in a 39% and a 61% reduction in specific (/sup 3/H)-1-Quinuclidinyl benzilate binding sites respectively to be compared with a 62% and a 85% decrease expected from calculated q-values. K/sub A/-values for the methyl and ...

Science.gov (United States)

In this paper, we evaluate the performance of the 1- and 5-site models of methane on the description of adsorption on graphite surfaces and in graphitic slit pores. These models have been known to perform well in the description of the fluid-phase behavior and vapor-liquid equilibria. Their performance in adsorption is evaluated in this work for nonporous graphitized thermal carbon black, and simulation results are compared with the experimental data of Avgul and Kiselev (Chemistry and Physics of Carbon; Dekker: New York, 1970; Vol. 6, p 1). On this nonporous surface, it is found that these models perform as well on isotherms at various temperatures as they do on the experimental isosteric heat for adsorption on a graphite surface. They are then tested for their performance in predicting the adsorption isotherms in graphitic slit pores, in which we would like to explore the effect of confinement on the ...

Science.gov (United States)

In this paper we investigate the effects of surface mediation on the adsorption behavior of argon at different temperatures on homogeneous graphitized thermal carbon black and on heterogeneous nongraphitized carbon black surface. The grand canonical Monte Carlo (GCMC) simulation is used to study the adsorption, and its performance is tested against a number of experimental data on graphitized thermal carbon black (which is known to be highly homogeneous) that are available in the literature. The surface-mediation effect is shown to be essential in the correct description of the adsorption isotherm because without accounting for that effect the GCMC simulation results are always greater than the experimental data in the region where the monolayer is being completed. This is due to the overestimation of the fluid-fluid interaction between particles in the first layer close to the solid surface. It is the surface mediation ...

International Nuclear Information System (INIS)

The WBURN (2-D, 2-group, coarse mesh) code is developed to analyze the equilibrium core characteristics of CANDU-PHWR. The equilibrium characteristics of Wolsung reactor computed by using WBURN are compared with the values given in the Wolsung FSR. The changes of equilibrium core characteristics caused by the variation of design parameters for operating conditions are also investigated. The numerical results indicate that the average discharge irradiation in the Wolsung reactor can be increased up to about 5%. (Author).

International Nuclear Information System (INIS)

The temperature coefficient has been investigated on the Wolsung nuclear power reactor, in which fuel is natural uranium dioxide and moderator heavy water. The numerical computations are carried out in terms of changes of the effective neutron multiplication factor with respect to fuel, moderator, and coolant temperatures. Those results are compared with the computed values of temperature coefficient based on the LATREP computer code. (author).

International Nuclear Information System (INIS)

In developing new receptor-site specific brain imaging agents labeled with I-123 for single photon emission computed tomography (SPECT), an analog of raclopride, 3-["1"2"5I]-iodo-N-[(1-ethyl-2-pyrrolidinyl)-methyl]-2-hydroxy-6-me-thoxy benzamide (IBZM), was prepared using a method similar to that reported for raclopride and its derivatives. (author).

International Nuclear Information System (INIS)

Hydrology and hydrogeochemical are auxiliary techniques to valid conceptual hydrogeology an recharge models. Stable isotopes from water trace sources and path flow and Tritium indicates age. This paper is about the use of D 18, D2H y 3H to study the aquifer system on Bajo Cauca antioqueno.

International Nuclear Information System (INIS)

This paper describes a reactor design to facilitate a room-temperature nuclear fusion/fission reaction to generate heat without generating unwanted neutrons, gamma rays, tritium, or other radioactive products. The room-temperature fusion/fission reaction involves the sequential triggering of billions of single-molecule, "6LiD 'fusion energy pellets' distributed in lattices of a palladium ion accumulator that also acts as a catalyst to produce the molecules of "6LiD from a solution comprising D_2O, "6LiOD with D_2 gas bubbling through it. The D_2 gas is the source of the negative deuterium ions in the "6LiD molecules. The next step is to trigger a first nuclear fusion/fission reaction of some of the "6LiD molecules, according to the well-known nuclear reaction: "6Li + D #-># 2"4He + 22.4 MeV. The highly energetic alpha ...

Energy Technology Data Exchange (ETDEWEB)

Hexavalent Cr has been identified as one of the toxic metals commonly present in industrial effluents. Among the treatment techniques developed for removing Cr(VI) from waste waters, sorption is most commonly applied, due to its simplicity and efficiency. However, few adsorbents can be recycled and reused cost-effectively. In this study, the removal and recovery of Cr(VI) from water using Li/Al LDH was investigated. The removal of Cr(VI) by Li/Al LDH was evaluated in a batch mode. The results demonstrated that Cr(VI) adsorption onto Li/Al LDH occurs by replacing the Cl{sup -} that originally exists in the interlayer of the adsorbent. The degree of Cr(VI) adsorption observed for Li/Al LDH was relatively high and the process occurred rapidly; however, a portion of adsorbed Cr(VI) was gradually desorbed, due to the Li de-intercalation of Li/Al LDH. Lithium de-intercalation from Li/Al LDH with interlayer Cl{sup -} and interlayer Cr(VI) follows the ...

Science.gov (United States)

We model nongraphitized carbon black surfaces and investigate adsorption of argon on these surfaces by using the grand canonical Monte Carlo simulation. In this model, the nongraphitized surface is modeled as a stack of graphene layers with some carbon atoms of the top graphene layer being randomly removed. The percentage of the surface carbon atoms being removed and the effective size of the defect (created by the removal) are the key parameters to characterize the nongraphitized surface. The patterns of adsorption isotherm and isosteric heat are particularly studied, as a function of these surface parameters as well as pressure and temperature. It is shown that the adsorption isotherm shows a steplike behavior on a perfect graphite surface and becomes smoother on nongraphitized surfaces. Regarding the isosteric heat versus loading, we observe for the case of graphitized thermal carbon black the increase of heat in the ...

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The coal rank, coal distribution, and coalbed methane of four major coal zones in the Hinton and Grande Cache areas of Alberta were investigated. Coal rank in the study area ranges from subbituminous and high volatile C bituminous at surface for the Upper Cretaceous/Tertiary coal measures and semianthracite for the Lower Cretaceous Luscar Group in the Alberta Syncline. In the Rocky Mountain Foothills, maximum cumulative coal thicknesses occur in the Smoky River, Cadomin-Luscar, and Coal Valley coalfields. Cumulative coal thicknesses generally decrease east of the deformed belt; however, coal isopach maps indicate local cumulative coal thicknesses in excess of 25 m. A regional coalbed methane assessment for strata east of the deformed belt shows favorable coalbed methane adsorption capacities in Luscar Group coals. These coals occur, however, at depth levels [gt]2500 m. In contrast, Brazeau and Coalspur Formation coals occur at favorable depth levels ([lt] 1100 m) ...

Science.gov (United States)

In this paper, we studied vapor-liquid equilibria (VLE) and adsorption of ethylene on graphitized thermal carbon black and in slit pores whose walls are composed of graphene layers. Simple models of a one-center Lennard-Jones (LJ) potential and a two-center united atom (UA)-LJ potential are investigated to study the impact of the choice of potential models in the description of VLE and adsorption behavior. Here, we used a Monte Carlo simulation method with grand canonical Monte Carlo (GCMC) and Gibbs ensemble Monte Carlo ensembles. The one-center potential model cannot describe adequately the VLE over the practical range of temperature from the triple point to the critical point. On the other hand, the two-center potential model (Wick et al. J. Phys. Chem. B 2000, 104, 8008-8016) performs well in the description of VLE (saturated vapor and liquid densities and vapor pressure) over the wide range of temperature. This UA-LJ model is then used in ...

Science.gov (United States)

The thermodynamic characteristics of sorption of the isomeric tricyclo[5.2.1.02.6]decane (tetrahydrodicyclopentadiene, TDCPD) molecules were for the first time determined experimentally and by molecular statistical methods under the conditions of gas-adsorption chromatography on graphitized thermal carbon black and gas-liquid chromatography on stationary liquid phases of different polarities (Apiezon L and Carbowax 20M). The effects of the chemical nature of sorbents on the retention of the TDCPD isomers are considered. A procedure for calculating the thermodynamic characteristics of adsorption of molecules with a complex structure is suggested within the framework of the atom-atom approximation of the semiempirical molecular statistical theory of adsorption for the example of isostructural norbornane molecules. The procedure involves simultaneous variation of geometric parameters and refinement of the parameters that ...

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Porous carbon with high surface area and pore volume was prepared by a reverse replication process and its toluene equilibrium adsorption behavior was investigated. The preparation process of the porous carbon was composed of following sub-processes in series: synthesis and template preparation of silica gel, impregnation and polymerization of DVB monomer in silica template, carbonization of DVB polymer in a silica-polymer composite, and HF-assisted selective etching of silica in carbon-silica composite, The prepared porous carbon was nano porous and had ultrahigh specific surface area (2007 m{sup 2}/g) and large pore volume (3.07cm{sup 3}/g). The nanoporous carbon showed rapid toluene adsorption rate and good toluene adsorption capacity, compared with a commercial Y-type zeolite, In the present study, a reverse replication process to prepare nanoporous carbons will be introduced and its application potential as a gas ...

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The adsorption capacity of radionuclides onto suspended sediment was experimented on each of the coastal seawater sampled around the Kori and the Wolsung nuclear power plant. During the experiment the quantity and size fraction of suspended sediment were adjusted and the seawater and sediment chemistry is approximated to the expected field condition. Because the sorption capacity depends on the specific minerals, ocean chemistry and radionuclide involved, it is necessary to analyze sediment mineralogy. Clay mineral is dominant in seabed mineral and suspended sediment as the result of x-ray diffraction. Radionuclide sorbed to silty-clay mineral can be rather transported to ocean than scavenged to seabed because of low quantity and fine grained suspended sediment in the coast around the Kori and the Wolsung. The result of adsorption examinations shows that {sup 139}Ce and {sup 51}Cr and {sup 110m}Ag are strongly sorbed to suspended particle, ...

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This paper presents the performance analysis on a hybrid air-conditioning system according to the hybrid building energy system of the green building demonstration project in Shanghai, in which a 150 m{sup 2} solar collector is used to power two 10 kW adsorption chillers, a vapor compression heat pump is used to cool air in the evaporating end while the condensing heating at about 80{sup o}C is fully used to regenerate a liquid desiccant dehumidification system. In the hybrid system, the sensible cooling to the air is treated mainly by solar adsorption cooling and vapor compression cooling, whereas the latent heat is treated by the liquid desiccant dehumidification system with regeneration from the condensing heat of the heat pump. The results show that the performance of this system is 44.5% higher than conventional vapor compression system at a latent load of 30% and this improving can be achieved by 73.8% at a 42% latent load. The optimal ...

British Library Electronic Table of Contents (United Kingdom)

Porous phosphate heterostructures (PPH), functionalized with different ratios of aminopropyl and mercaptopropyl groups, labelled as Nx=5,25,50-PPH and Sx=5,25,50-PPH, respectively, were tested as adsorbents for Ni(II) and Hg(II) found in industrial sewage from electroplating processes and button battery recycling. X-ray diffraction was used to study the structures. The specific surface area of the pristine material (PPH) was 620m^2g^-^1, whereas the specific surface areas of the modified mercaptopropyl (S5-PPH) and aminopropyl (N5-PPH) were 472 and 223m^2g^-^1, respectively. The adsorption data were fitted to a Langmuir isotherm model. The S5-PPH material was saturated by 120mmol Hg(II) per 100g of material, whereas for Ni(II) adsorption, N25-PPH material displayed the highest adsorption w...

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The biosorption of copper(II) ions from aqueous solution by Tectona grandis L.f. was studied in a batch adsorption system as a function of pH, metal ion concentration, adsorbent concentration and adsorbent size. The biosorption capacities and rates of copper(II) ions onto T. grandis L.f. were evaluated. The Langmuir, Freundlich, Redlich-Peterson and Temkin adsorption models were applied to describe the isotherms and isotherm constants. Biosorption isothermal data could be well interpreted by the Langmuir model with maximum adsorption capacity of 15.43 mg/g of copper(II) ion on T. grandis L.f. leaves powder. The kinetic experimental data properly correlated with the second-order kinetic model. Various thermodynamic parameters such as {delta}G{sup o}, {delta}H{sup o}, and {delta}S{sup o} were calculated indicating that this system was a spontaneous and exothermic process.

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Desorption behavior of pyrene, phenanthrene and naphthalene from fullerene, single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) was examined. Available adsorption space of carbon nanotubes (CNTs) was found to be the cylindrical external surface, neither the inner cavities nor inter-wall spaces due to impurities in the CNTs and restricted spaces (0.335 nm) of the MWCNTs, respectively. Desorption hysteresis was observed for fullerene but not for CNTs. Deformation-rearrangement was proposed to explain the hysteresis of polycyclic aromatic hydrocarbons (PAHs) for fullerene, due to the formation of closed interstitial spaces in spherical fullerene aggregates. However, long, cylindrical carbon nanotubes could not form such closed interstitial spaces in their aggregates due to their length, thus showing no significant hysteresis. High adsorption capacity and reversible adsorption of PAHs on CNTs ...

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One option in establishing advanced technology for disposing of high-level radioactive waste (HLW) is to remove TRU elements from HLW and then transform them into short-lived radionuclides. Tertiary pyridine-type anion exchange resin was investigated as a separation medium for spent fuel reprocessing using a HCl solution. Distribution coefficients of typical elements, along with uranium, were measured in the pyridine resin--HCl solution system, where HCl concentration was varied from 1 to 9 M. The results reveal: elements of the alkali metal, alkaline earth and lanthanide groups are not adsorbed, the adsorption patterns of the transition metals differ according to HCl concentration, and uranium is adsorbed in the high HCl concentration region. Furthermore, the present report describes the experimental results obtained for the adsorption behaviour of uranium, americium, curium and various lanthanide elements on tertiary pyridine-type anion ...

Science.gov (United States)

This study investigated the feasibility of using a new adsorbent prepared from coconut coir pith, CP (a coir industry-based lignocellulosic residue), for the removal of uranium [U(VI)] from aqueous solutions. The adsorbent (PGCP-COOH) having a carboxylate functional group at the chain end was synthesized by grafting poly(hydroxyethylmethacrylate) onto CP using potassium peroxydisulphate-sodium thiosulphite as a redox initiator and in the presence of N,N'-methylenebisacrylamide as a crosslinking agent. IR spectroscopy results confirm the graft copolymer formation and carboxylate functionalization. XRD studies confirm the decrease of crystallinity in PGCP-COOH compared to CP, and it favors the protrusion of the functional group into the aqueous medium. The thermal stability of the samples was studied using thermogravimetry (TG). Surface charge density of the samples as a function of pH was determined using potentiometric titration. The ability of PGCP-COOH to remove U(VI) from aqueous ...

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Metals for potential use in the dissociator and the synthesizer reactors of a distributed solar receiver thermochemical transport loop utilizing SO/sub 3//SO/sub 2//O/sub 2/ molecular chemistry were tested in SO/sub 2//O/sub 2/ mixtures at 500/sup 0/C and 900/sup 0/C, respectively, for times of up to four weeks. They included titanium, aluminum and nickel, and iron-base, nickel-base and cobalt-base superalloys. Weight gain measurements determine the oxidation/sulfidation kinetics. Electron microprobe analysis identifies any possible penetration of oxygen and sulfur into the metal and the formation of internal oxides and sulfides. The most promising candidates as a result of these tests are the cobalt-base superalloys.

British Library Electronic Table of Contents (United Kingdom)

Photoelectron resonance capture ionization aerosol mass spectrometry (PERCI-AMS) has been applied to the analysis of proxies for marine aerosols with and without ozone; proxies used were mixed oleic acid-amino acid particles. The mechanism of ion formation for serine (104 m/z), glutamic acid (146 m/z), and phenylalanine (164 m/z) was dissociative electron attachment. This corresponds to loss of the hydrogen atom only, allowing for straightforward identification of the free amino acids. No ozonolysis products for the free amino acids were observed, even at high concentrations of ozone (500 ppm for 19 s). The direct detection of a novel gas-phase hydrated anion, [serine + H2O-H]-, is described. These preliminary results suggest that PERCI-AMS may provide an effective, simple and direct onlin...

International Nuclear Information System (INIS)

Formation kinetics and composition of products of interaction of binary and ternary tungsten-molybdenum-rhenium alloys containing 30#+-#3 at.% (27-47 weight %) Re with products of thermal dissociation of ammonia and nitrogen-oxygeneous mixtures are studied. Mo-45% Re-10%W ternary alloy occupies intermediate position between W-27%Re and Mo-47%Re binary alloys, while its corrosion resistance and corrosion nature are close to those of W-Re and mechanical features - to those of Mo-Re alloy. It is explained by the fact, that the variation of W and Mo ration occurs in thin surface layer of ternary alloys in contrast to the initial state and the enrichment of near-the-surface layer with tungsten occurs under hot and cold deformation, at aging in the air, and during oxidation-reduction treatment. 4 refs.; 7 figs.

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Gamma-aminobutyric acid type A receptor-associated protein (GABARAP) belongs to a family of small ubiquitin-like adaptor proteins implicated in intracellular vesicle trafficking and autophagy. We have used diffusion-ordered nuclear magnetic resonance spectroscopy to study the temperature and concentration dependence of the diffusion properties of GABARAP. Our data suggest the presence of distinct conformational states and provide support for self-association of GABARAP molecules. Assuming a monomer-dimer equilibrium, a temperature-dependent dissociation constant could be derived. Based on a temperature series of {sup 1}H{sup 15}N heteronuclear single quantum coherence nuclear magnetic resonance spectra, we propose residues potentially involved in GABARAP self-interaction. The possible biological significance of these observations is discussed with respect to alternative scenarios of oligomerization.

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The equilibrium composition and temperature resulting from the combustion of hydrocarbon fuels in combination with hydrogen have been analytically evaluated. Rich, lean and stoichiometric mixtures have been considered for this purpose. The flame temperature data obtained from computer calculations has been fitted with an equation expressed in terms of calorific value, C/H ratio, air-fuel ratio and heat of dissociation of the fuel mixture. This equation can be used to calculate the flame temperature directly without resorting to the elaborate calculation of species concentration. The results obtained using the equation have been found to have an accuracy of 0.05 to 2.5% for different fuel combinations. (author).

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Treatment of coal or coconut shell activated carbons with either phosgene or chlorine at 180{degree}C followed by washing with methanol or water results in chlorinated carbons with very similar pore structures to their precursors. Water adsorption experiments show that the modified materials are relatively hydrophobic, presumably as a result of replacement of oxygen-containing surface groups by chlorine. Adsorption of the model hydrophobic vapour chloropicrin from humid air is usually better for the modified carbons which, unlike the controls, do not appear to be subject to degradation in performance on ageing in a humid atmosphere. The stability of the modified carbons is probably a consequence of the chlorination of those sites on the control carbons that are prone to ready oxidation or hydroxylation. 1 tab., 2 figs., 17 refs.

Energy Technology Data Exchange (ETDEWEB)

A fusion reactor (such as NET/ITER) which breeds its own tritium fuel requires tritium recovery, purification and separation from the other isotopes. Cyclic adsorption processes are strong candidates for several of the processes involved: amongst other advantages, they promise a low tritium inventory. A good adsorbent for such processes must have high adsorption capacity, high selectivity and very low tritium retention after each cycle. Pure zeolite powder is shown to have an excellent combination of these three properties. However, in practice problems can arise from tritium which is not removed by reactivation. In this paper we show that tritium retention in zeolites can be caused either by water retained in the zeolite structure, which can be removed by ore rigorous activation, or by water tapped on binders in commercial pellets. (orig.).

British Library Electronic Table of Contents (United Kingdom)

The effect of sodium gluconate anion (SG) on the corrosion and scale inhibition of ordinary steel in simulated cooling water has been studied using weight loss, polarisation curves, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM) techniques. SG was studied in concentration from 10-4M to 10-1M. Results obtained reveal that SG perform excellently as corrosion and scaling inhibitor for ordinary steel in simulated cooling water. An increase of SG concentration leads to the increase of the corrosion potential towards the positive direction. The inhibition efficiency was a low temperature dependence. The inhibitor mechanism was treated as an adsorption process according to Langmuir adsorption isotherm. The SEM/EDAX data show that was a corrosion and scale inhi...

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Pd-induced surface structures on Si(1 1 3) have been studied by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS). In the initial process of the Pd adsorption below 0.10 ML, Pd silicide (Pd{sub 2}Si) clusters are observed to form randomly on the surface. By increasing the Pd coverage to 0.10 ML, the clusters cover the entire surface, and an amorphous layer is formed. After annealing the Si(1 1 3)-Pd surface at 600 deg. C, various types of islands and chain protrusions appears. The agglomeration, coalescence and crystallization of these islands are observed by using high temperature (HT-) STM. It is also found by XPS that the islands correspond to Pd{sub 2}Si structure. On the basis of these results, evolution of Pd-induced structures at high temperatures is in detail discussed.

British Library Electronic Table of Contents (United Kingdom)

The key factors of enzymatic lysis of cells are the interaction between the enzyme and the cell - catalytic and non-catalytic adsorption of enzyme on cell surface. Here, the studies of lysis of intact Escherichia coli cells by chicken egg white lysozyme were performed. It was found that the ionic strength has a dual effect onto the system. On the one hand, the desorption constant of the enzyme increases with the increase of the solution ionic strength, which results in a better enzyme performance. On the other hand, due to the higher osmosis, the cell lysis rate decreases with the increasing of ionic strength of the system. It was found that pH 8.6 and 30mM NaCl are optimal conditions for lysis of E. coli cells by lysozyme.

Science.gov (United States)

A novel wastewater treatment technique has been investigated, for reactive dye removal, in batch kinetic systems. These experimental studies have indicated that charred dolomite has the potential to act as an adsorbent for the removal of Brilliant Red reactive dye from aqueous solution. The effect of initial dye concentration, adsorbent mass:liquid volume ratio, and agitation speed on dye removal have been determined with the experimental data mathematically described using empirical external mass transfer and intra-particle diffusion models. The experimental data show conformity with an adsorption process, with the removal rate heavily dependent on both external mass transfer and intra-particle diffusion. PMID:12691893

British Library Electronic Table of Contents (United Kingdom)

Palladium deposition on Pt(110) electrodes was studied. Differently from Pt(111) and Pt(100), first and further layers cannot be distinguished in this case only through the voltammetric behavior of hydrogen and anion adsorption. The potential of zero total charge (pztc) was determined as a function of the amount of deposited Pd using CO charge displacement experiments and voltammetric curves. The variation of the voltammetric charge due to hydrogen and anion adsorption has been followed during Pd deposition. The voltammetric charge between 0.06 and 0.4V first decreases to a minimum, then increases and finally becomes stable, suggesting that the surface is finally covered with a Pd multilayer. The pztc and CO oxidation charge show similar behavior. CO oxidation, NO reduction and Cu UPD were...

British Library Electronic Table of Contents (United Kingdom)

The acid corrosion inhibition process of mild steel in 1M HCl by 1-butyl-3-methylimidazolium chlorides (BMIC) and 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM]HSO4) has been investigated using electrochemical impedance, potentiodynamic polarization and weight loss measurements. Potentiodynamic polarization studies indicate the studied inhibitors are mixed type inhibitors. For both inhibitors, the inhibition efficiency increased with increase in the concentration of the inhibitor and the effectiveness of the two inhibitors are in the order [BMIM]HSO4>BMIC. The adsorption of the inhibitors on mild steel surface obeyed the Langmuirs adsorption isotherm. The effect of temperature on the corrosion behavior in the presence of 5x10-3M of inhibitors was studied in the temperature range of 3...

British Library Electronic Table of Contents (United Kingdom)

The adsorption of CO2 on a number of activated carbons, thermal carbon black, and oxide materials at 195 K was studied using static and dynamic techniques. The landing surface areas ?(CO2) ? 0.19 nm2 on thermal carbon black and the absolute values of sorption for P/P 0 < 0.4 were determined. The density of adsorbed CO2 in the micropore volume was estimated at ?(CO2) = 0.91 g/cm3. It was demonstrated that the previously found effect of a weakening of the sorption interaction of nitrogen molecules with thin-walled materials (which manifested itself in an analysis of sorption isotherms by a comparative method) was pronounced to a lesser degree for the sorption of CO2. At the same time, the presence of supermicropores in activated carbon samples resulted in overestimated values of surface area...

Energy Technology Data Exchange (ETDEWEB)

Mutations in the mouse formin (Fmn) gene, formerly known as the limb deformity (ld) gene, give rise to recessively inherited limb deformities and renal malformations or aplasia. The Fmn gene encodes many differentially processed transcripts that are expressed in both adult and embryonic tissues. To study the genomic organization of the Fmn locus, we have used Fmn probes to isolate and characterize genomic clones spanning 500 kb. Our analysis of these clones shows that the Fmn gene is composed of at least 24 exons and spans 400 kb. We have identified two novel exons that are expressed in the developing embryonic limb bud as well as adult tissues such as brain and kidney. We have also used a microsatellite polymorphism from within the Fmn gene to map it genetically to a 2.2-cM interval between D2Mit58 and D2Mit103. 36 refs., 6 figs., 1 tab.

International Nuclear Information System (INIS)

Targeted studies completed include the evaluation of tritiated N-0437, evaluation of "3"5S-cysteamine, evaluation of "1"8F-FDG and initiation of synthetic efforts towards the synthesis of iodinated N-0437 and pergolide analogs. The direction of the project has been changed due to several factors which include the decided lack of favorable experimental results, the excellence of results using muscarinic receptor ligands in pituitary, brain and heart and the contention of the DOE review panel that the original grant proposal was based on flawed assumptions together with their perceived lack of importance to pituitary imaging. In the final year of this grant, three studies will be completed. The first study is the continuation of synthetic efforts to prepare iodinated N-0437 and pergolide analogs for possible use as brain imaging agents. The second study is directed towards completion of biochemical evaluation of various muscarinic receptor analogs for heart, brain and (possible) ...

International Nuclear Information System (INIS)

Computer simulated small-angle neutron scattering curves of spherical poly disperse extruded unilamellar liposomes from saturated 1,2-diacylphosphatidylcholines in the aqueous phase are evaluated by using a multi shell model, which divides the lipid bilayer of liposomes into the polar head group region, and the nonpolar hydrocarbon region consisting of the chains of methylene groups and of the region of methyl groups. In the each of these regions, the coherent neutron scattering length density is supposed to by homogeneous. The evaluation is based on obtaining of radius of gyration from Kratky-Porod plot of small-angle neutron scattering data in the Guinier region of small scattering vector values. From radii of gyration obtained at several different molar fractions N_D_2_O/(N_D-2_O + N_H_2_O) in the aqueous phase (contrasts) and independent volumetric data, the lipid surface area A_L (or the bilayer ...

Energy Technology Data Exchange (ETDEWEB)

The main purpose of this study is to develop a thermal hydraulic auditing code for the CANDU reactor, modifying the model of existing PWR auditing tool , i.e. RELAP5/MOD3. This scope of project is a fourth step of the whole project, applying the RELAP5/MOD3/CANDU+ version for the real CANDU plant LOCA Analysis and D2O leakage incident. There are three main models under investigation, i.e. Moody critical flow model, flow regime model of horizontal CANDU bundle, and fuel element heatup model when the stratification occurs, especially when CANDU LOCA is tested. Also, for Wolsung unit 1 D2O leakage incident analysis, the plant behavior is predicted with the newly developed version for the first 1000 seconds after onset of the incident, with the main interest aiming for system pressure, level control system, and thermal hydraulic transient behavior of the secondary system. The model applied for this ...

International Nuclear Information System (INIS)

The "2"0 "2"1 "2"2Ne("6Li, d)"2"4 "2"5 "2"6Mg reactions have been studied at a bombarding energy of 32 MeV. Alpha particle spectroscopic strengths have been extracted for several low-lying levels by a finite-range distorted wave analysis. These are compared with theoretical predictions. The agreement is good both for relative strengths to different levels within a nucleus and for ground-state strengths relative to the "1"6O("6Li, d) result. Strengths calculated using eigenfunctions determined in large shell-model computations agree well with pure symmetry SU(3) predictions. The "2"1Ne("6Li, d) angular distributions for transitions to the ground-state band of "2"5Mg are characterized by the lower of the two L-transfers allowed for populating each level. For the 3"+(5.24 MeV) unnatural parity level in "2"4Mg, a two-step calculation gives a better account of the data than does a compound nuclear calculation. (Auth.).

International Nuclear Information System (INIS)

The "8"8Y decay has been studied with the aim to discover emission of monohromatic positrons (MP). The "8"8Sr(d,2N) reaction was used for production of "8"8Y (#beta#"+, Tsub(1/2)=106.6 days) nuclides. The prismatic beta spectrometer has been used to measure spectra of electrons and positrons. No MPs have been found. The resulting upper bound for their emission rate turned out to be lower than theoretically expected one.

Energy Technology Data Exchange (ETDEWEB)

A simple and rapid procedure was developed for the purification of cyclotron-produced {sup 203}Pb via the {sup 203}Tl(d,2n) {sup 203}Pb reaction. A Pb(II) selective ion-exchange resin, with commercial name Pb Resin from Eichrom Technologies, Inc., was used to purify {sup 203}Pb from the cyclotron-irradiated Tl target with excellent recovery of the enriched Tl target material. The purified {sup 203}Pb was used to radiolabel the monoclonal antibody Herceptin. The in vitro and in vivo properties of the {sup 203}Pb radioimmunoconjugate were evaluated.

International Nuclear Information System (INIS)

Problem areas in BWRs, PWRs and PHWRs, from the viewpoint of chemistry, and the problem of fission product release in nuclear reactors are discussed. These problem areas are : fuel performance, off-normal water chemistry due to condenser leaks, the transport and deposition of the activated corrosion and fission products, denting in steam generators (in the case of PWRs), ingress of air in the cover gas helium and consequent radiolysis of D_2O in the moderator circuit (in the case of PHWRs). (M.G.B.).

International Nuclear Information System (INIS)

Full text: In heavy-water-moderated power reactors, tritium is primarily produced by neutron capture in deuterium nuclei in the moderator and coolant. For CANDU 6 reactors, the estimated steady-state values are #approx# 3 TBq#centre dot#kg"-"1 D_2O in the moderator and #approx# 74 GBq#centre dot#kg"-"1 D_2O in the coolant. Tritium removal is one option available to reactor operators for use in their heavy water and tritium management strategies. The WTRF is designed to remove tritium from tritiated heavy water in each of the four CANDU units at the Wolsung Site, to immobilize the tritium and to store it on site. The detritiation process is based on three steps: the first one (front-end) involves the transfer of tritium from heavy water to deuterium gas; the second one (enrichment) concentrates the tritium in a cryogenic distillation system to produce essentially pure ...

Science.gov (United States)

The widespread use of tobacco and alcohol among adolescents might be related to the ability of nicotine and ethanol to facilitate social interactions. To investigate the neurobehavioral mechanisms underlying the prosocial effects of nicotine and ethanol, we focused on social play behavior, the most characteristic social activity in adolescent rats. Social play behavior is rewarding, and it is modulated through opioid, cannabinoid and dopaminergic neurotransmission, which are also involved in the reinforcing properties of nicotine and ethanol. We found that nicotine and ethanol increased social play, without affecting locomotion or social exploration. Their effects depended on the level of social activity of the partner, and were comparable in familiar and unfamiliar environments. At doses that increased social play, nicotine and ethanol had no anxiolytic effects in the elevated plus-maze. By contrast, the prototypical anxiolytic drug diazepam reduced social play at doses that reduced ...

International Nuclear Information System (INIS)

Asialoorosomucoid (ASOR) is internalized and degraded by HepG2 cells after binding to the asialoglycoprotein (ASGP) receptor, internalization through the coated pit/coated vesicle pathway, and trafficking to lysosomes. Primaquine, an 8-aminoquinoline antimalarial compound, inhibits ASOR degradation at concentrations greater than 0.2 mM by neutralizing intracellular acid compartments. This leads to alterations in surface receptor number, receptor-ligand dissociation, and receptor recycling. We have investigated the effects of primaquine on 125I-ASOR uptake and degradation as a function of primaquine concentration and duration of exposure. Concentrations below those required for neutralization of acidic compartments block 125I-ASOR degradation in HepG2 cells and lead to intracellular ligand accumulation. This effect is maximal at 80 microM primaquine. The intracellular 125I-ASOR is undegraded, dissociated from the ASGP receptor, and contained ...

Energy Technology Data Exchange (ETDEWEB)

The PbII binding characteristics of the previously reported PbII binding proteins of rat kidney cytosol were investigated further. Saturation and Scatchard analysis of /sup 203/Pb binding in whole cytosol and in 40% saturated ammonium sulfate precipitated fractions disclosed a class of relatively high-affinity sites with an apparent Kd of approximately 50 nM and binding capacities of approximately 41 and 9 pmol/mg of protein, respectively. Two /sup 203/Pb binding proteins with approximate molecular masses of 63K and 11.5K daltons and a high molecular weight component (greater than 200K) were isolated by Sepharose-6B column chromatography. The time course of association of /sup 203/Pb with cytosol and the 63K protein showed maximum binding at 18 hr which was stable up to 25 hr at 4 degrees C. The approximate half-time dissociation rate (T 1/2) of specifically bound /sup 203/Pb to the 63K protein was 100 min at 4 degrees C whereas the 11.5K protein showed little ...

Science.gov (United States)

Under different sintering temperatures(340 degrees C, 440 degrees C, 540 degrees C, 640 degrees C), four TiO2 particles were prepared. The crystal types of all four samples were found to possess anatase structures by XRD. It was obtained by N2 experimental adsorption at low temperature (77K) that their surface areas and average pore size were between 79 and 124 m2/g, 56.8 and 254.8 A respectively. The pore structure of TiO2 particles was characterized by scanning electron microscope (SEM). The tests of adsorption dynamics for FGD and the performance of SO2 removal were investigated in a fixed-bed system for different samples. The results show that SG540 sample which made at 540 degrees C sintering temperature had the most quality among the four samples. It can adsorb SO2 of 38.9 mg for one gram SG540 sample. Different operating conditions for SG540 such as adsorption temperature, SO2 concentration in flue gas and the ...

Energy Technology Data Exchange (ETDEWEB)

The equilibrium dynamic capacity of polymer materials based on 2,4,6-triamino-1,3,5-triazine has been determined. The possibility of their application as absorbents of sulfur dioxide from exhaust gases has been shown.

Energy Technology Data Exchange (ETDEWEB)

This paper advances hypotheses on the chemistry of the interaction of thorium and yttrium with organic-inorganic salts of molybdenum polyacids. On the basis of an analysis of the data of an adsorption experiment and the quantitative relationships that follow from the law of mass action, it is shown that thorium is absorbed by the solid phase by coprecipitation with the participation of complex formation, while the coprecipitation of yttrium with salts of polyacids is due to a reaction of ion exchange chemisorption.

Energy Technology Data Exchange (ETDEWEB)

Germanium coordination compounds (GCC) with oxiethilidendyphosphonic acid (Ge-Oedph) film structures electrophysical, optical, structural and adsorptive properties investigation results are represented. This structure concerns to a new perspective class of functional materials. The mechanism GCC films electric conductivity is investigated and explained. GCC possible application fields are specified.

International Nuclear Information System (INIS)

The structure of a fragment of the germanium complex compound (GCC) with oxyethylidenediphosphonic acid and the adsorption properties of GCC films with respect to the vapors of water and some other organic liquids have been studied. The electric conductivity of GCC films has been investigated, and its mechanism has been explained.

Energy Technology Data Exchange (ETDEWEB)

This paper investigates the spectral characteristics of three-dimensionally porous carbon dioxide indicators based on a porous silicate glass and phenolphthalein. The absorption spectra of the original solutions of phenolphthalein in alkaline and acid solutions are shown. The solutions were acidified by bubbling CO/sub 2/ through an alkaline phenolphthalein solution. The authors have succeeded in producing a reversible colorimetric adsorption indicator for carbon dioxide which after proper calibration enables the CO/sub 2/ content of an atmosphere to be estimated quantitatively.

Energy Technology Data Exchange (ETDEWEB)

Results are reported which were obtained when investigating the anodic behavior of titanium in sodium iodide solutions. It was concluded that in order to explain the special features in the anodic behavior and anionic anodic activity of titanium one must take into account, both a redistribution of the potential drop between the oxide and the Helmholtz layer and a potential-dependent variation of the catalytic and adsorption properties of the oxidized titanium anode.

Science.gov (United States)

The performance of intermolecular potential models on the adsorption of benzene on graphitized thermal carbon black at various temperatures is investigated. Two models contain only dispersive sites, whereas the other two models account explicitly for the dispersive and electrostatic sites. Using numerous data in the literature on benzene adsorption on graphitized thermal carbon black at various temperatures, we have found that the effect of surface mediation on interaction between adsorbed benzene molecules must be accounted for to describe correctly the adsorption isotherm as well as the isosteric heat. Among the two models with partial charges tested, the WSKS model of Wick et al. that has only six dispersive sites and three discrete partial charges is better than the very expensive all-atom model of Jorgensen and Severance. Adsorbed benzene molecules on graphitized thermal carbon black have a complex orientation with ...

Science.gov (United States)

The simulation of the temporal evolution of the various neutral gaseous species studied (O, O{sub 3}, H, OH, HO{sub 2}, H{sub 2}O{sub 2}, N, NO, NO{sub 2}, NO{sub 3}, N{sub 2}O, N{sub 2}O{sub 5}, HNO{sub 2}, and HNO{sub 3}) use corona effects. The physical conditions of the discharge were used. The reactions take place in dry or humid air, after the dissociation of O{sub 2}, N{sub 2}, and H{sub 2}O by an electronic pulse. When water vapor is present, there is a probability of production of H{sub 2}O{sub 2}, HNO{sub 2}, and HNO{sub 3} in air. Temperature and humidity have cumulative effects. With multiple pulses, the O{sub 3} maximal concentration is obtained for a limited number of pulses.

International Nuclear Information System (INIS)

In this paper the structural and functional changes of gamma irradiated bovine hemoglobin are presented. Aqueous solutions/1%/of HbO_2 were irradiated in air with doses ranging from 1 to 4 Mrad. Isoelectric focusing indicated change of the charge of irradiated hemoglobin. The isoelectric point of hemoglobin was displaced towards more acid values with increasing doses, up from 1 Mrad. Fingerprint analysis and peptide column chromatography of irradiated hemoglobin demonstrated disturbances increasing with the dose. These changes were confirmed by amino acid analysis which showed that Cys, Met, Trp, His, Pro and Tyr residues were destroyed or modified following irradiation. At doses exceeding 1 Mrad the irradiated solutions of hemoglobin showed a decrease of heme-heme interaction and an increase of affinity for oxygen. Differences observed in oxygen-dissociation curves seem to be correlated with the radiation induced destruction of amino acid residues which are ...

Energy Technology Data Exchange (ETDEWEB)

A system of equations describing transient enhanced diffusion of beryllium in InGaAs due to kick-out mechanism or due to formation, migration, and dissociation of the pairs ''beryllium atom-group III self-interstitial'' is proposed and analyzed. Simulation of coupled diffusion of beryllium atoms and self-interstitials in InGaAs during rapid thermal annealing was done for the case of dual implantation. For the experiment under consideration the first ion implantation of phosphorus atoms produced the region of extended defects that led to ''uphill'' diffusion of implanted Be in the defect region and in the vicinity of the surface. The suggested reason of ''uphill'' diffusion could be related to the nonuniform distribution of group III self-interstitials that was formed due to the absorption of point defects on the extended defects and on the surface of a ...

International Nuclear Information System (INIS)

Marker experiments for studying the mass transport through a palladium silicide layer on a crystalline substrate during thermal oxidation at 700 to 850 deg C have been reported recently. In this work argon gas embedded in amorphous silicon during sputtering was implemented as the inert marker and the oxidation of PdSi was processed above 900 deg C. At this high-temperature oxidation silicon-rich silicide PdSisub(y), with y exceeding 5, may be obtained. This can be anticipated by considering the Pd-Si phase diagram which shows the liquid phase may appear at an annealing temperature above 892 deg C. As a result, a non-stoichiometric and non-uniform silicide layer may develop at the sample surface. Marker analysis showed that both palladium and silicon dissociated at the Pdsub(x)Si/ SiO_2 interface and moved to the substrate with the silicon being the dominant diffuser. The Rutherford backscattering spectra (RBS) showing the oxide film and composition isothermally ...

CERN Document Server

We summarize results of recent studies of heavy quarkonia correlators and spectral functions at finite temperatures from lattice QCD and systematic T-matrix studies using QCD motivated finite-temperature potentials. We argue that heavy quarkonia dissociation shall occur in the temperature range $1.2 \\le T_d/T_c \\le 1.5$ by the interplay of both screening and absorption in the strongly correlated plasma medium. We discuss these effects on the quantum mechanical evolution of quarkonia states within a time-dependent harmonic oscillator model with complex oscillator strength and compare the results with data for $R_{\\rm AA}/R_{\\rm AA}^{\\rm CNM}$ from RHIC and SPS experiments. We speculate whether the suppression pattern of the rather precise NA60 data from In-In collisions may be related to the recently discovered X(3872) state. Theoretical support for this hypothesis comes from the cluster expansion of the plasma Hamiltonian for heavy quarkonia in a strongly ...

International Nuclear Information System (INIS)

ZrO_2/O'-sialon composites were obtained via reaction sintering of ZrSiO_4 and Si_3N_4 powders at about 1700 deg C. Y_2O_3 was effective in both stabilizing of zirconia and densifying the composites. However, it is not easy to select an optimum value of the single additive to balance these two requirements simultaneously. With low Y_2O_3 addition, some tetragonal zirconia grains in the sintered samples are transformable during mechanical grinding but the full densification of the material is then sacrificed. On the other hand, addition more Y_2O_3 to achieve complete densification results in the zirconia being stabilized into undesirable t' or cubic forms. Therefore no improved toughening effects have been achieved in the composites. Heat-treatment of the materials at 1400 deg C. results in the diffusion of yttria from the grain boundary phase to zirconia and the formation of the O'-cubic zirconia composite may still provide a useful refractory material. 11 refs., 5 tabs., 2 figs.

Energy Technology Data Exchange (ETDEWEB)

A versatile, high brightness, volume type, low power RF source, capable of producing positive ion beams with intensities as high as 1 mA from gaseous feed materials and microamperes of negative ion beams has been characterized. The source can also be operated as a plasma sputter negative ion source to generate up to 1 mA of a selected species. The performance of the source in the positive and negative volume modes of operation can be greatly enhanced by addition of a removable, water cooled filament assembly in place of the negative sputter probe. For examine, the material utilization efficiencies of gaseous feed species can be more than doubled, total current intensities increased up to 40%, molecular dissociation fractions increased by 20% and minimum operating pressures reduced by a factor of four when operated in the volume mode. These added electrons also favorably effect, as a consequence of lower pressures, the emittance apparently through a reduction of ...

Energy Technology Data Exchange (ETDEWEB)

A study was undertaken of the effect of monovalent cations (Li/sup +/, Na/sup +/, K/sup +/) on the dielectric constant (epsilon) of the water-lipid interface of unilamellar phosphatidylcholine (PC) vesicles, i.e., the ester carbonyl oxygen region of the PC molecules or the neighborhood of the oxygen atoms of the phosphorylcholine moiety. epsilon was determined by reacting the free radical 1,1-diphenyl-2-picrylhydrazyl with ..cap alpha..-tocopherol incorporated in the lipid vesicles. The results are consistent with a decrease of epsilon (LiCl: 35.5 to 29.5; NaCl: 34 to 29; KCl: 33 to 29) as the concentration of the salts in the solvent media increases from 0.025 to 0.5 M. These effects can be rationalized in terms of dielectric saturation at the water-lipid interface brought about by ion-induced local electric fields. In the unilamellar PC vesicles the effect of the ions on epsilon follows the sequence K/sup +/ > Na/sup +/ > Li/sup +/ which contrasts strikingly with what happens ...

International Nuclear Information System (INIS)

A new series of lithium ionic liquids were prepared by introducing of two electron-withdrawing trifluoroacetyl groups in borate salts containing two methoxy-oligo(ethylene oxide) groups in the structures. Successive substitution reactions of oligo-ethylene glycol monomethyl ether and trifluroacetic acid from LiBH_4 yielded the lithium salts, which were clear and colorless liquids at room temperature. The fundamental physicochemical properties, such as density, thermal property, viscosity, ionic conductivity, self-diffusion coefficients, and electrochemical stability, were measured. The lithium ionic liquids had self-dissociation ability and conducted ions even in the absence of organic solvents. New polymer electrolytes, named 'ion gels', were prepared by radical cross-linking reactions of a poly(ethylene oxide-co-propylene oxide)tri-acrylate macromonomer in the presence the lithium ionic liquid. An increase in the glass transition temperatures (T _g) of the ion ...

International Nuclear Information System (INIS)

The applicability of in situ, real-time RBS is demonstrated by characterizing the growth of thin Pd_2Si films on Si left angle 111 right angle substrates using isothermal as well as non-isothermal annealing. In contrast to the currently fashionable in situ ramped resistance technique, it is possible to extract the activation energy from a single run with a constant heating rate. The results, which are in excellent agreement with the literature, will be compared for isothermal annealing, fitting an appropriate model for the growth process to data from a single run and a Kissinger-like analysis with different ramp rates. In situ, real-time RBS was also used to study marker motion during CrSi_2 formation in the Si left angle 100 right angle /Pd_2Si/Cr system. It is possible to distinguish between the following mechanisms: (1) CrSi_2 formation via dissociation of the Pd_2Si at the Pd_2Si/Cr interface and subsequent reaction of Pd to form Pd_2Si at the Si/Pd_2Si ...

International Nuclear Information System (INIS)

Polycrystalline silicon films have been grown from Si_2H_6 by low-pressure chemical vapour deposition at 800 K and in situ laser annealing (LA) on amorphous silicon seed layers deposited on a metallic Ti/Pd/Ag multilayer. The crystalline volume fraction in the seed layer was controlled by thermal annealing. According to the metal-induced crystallization effect, the presence of the metal induces a lower-temperature crystallization of silicon in the seed layers. X-ray diffraction and scanning electron microscopy data show that the formation of palladium silicides in the seed layer drives the growth of wire-like columns which are found to change morphology depending on the seed layer microstructure and LA parameters. It is suggested that superficial palladium was found to affect also the growth rate by enhancing the Si_2H_6 dissociation.

CERN Document Server

Aims: The production of saturated organic molecules in hot cores and corinos is not well understood. The standard approach is to assume that, as temperatures heat up during star formation, methanol and other species evaporate from grain surfaces and undergo a warm gas-phase chemistry at 100 K or greater to produce species such as methyl formate, dimethyl ether, and others. But a series of laboratory results shows that protonated ions, typical precursors to final products in ion-molecule schemes, tend to fragment upon dissociative recombination with electrons rather than just ejecting a hydrogen atom. Moreover, the specific proposed reaction to produce protonated methyl formate is now known not to occur at all. Methods: We utilize a gas-grain chemical network to probe the chemistry of the relatively ignored stage of hot core evolution during which the protostar switches on and the temperature of the surrounding gas and dust rises from 10 K to over 100 K. During this ...

International Nuclear Information System (INIS)

An assay for the microsomal hydroxylation of lauric acid (LA), based on HPLC with flow-through radiochemical detection, has been developed. Conditions were optimized for resolution and quantitation of three microsomal metabolites of "1"4C-LA, one of which has not been reported previously as a metabolite of LA in mammalian microsomal incubations. These products, 12-(omega)-hydroxy-LA, 11-(omega-1)-hydroxy-LA, and a novel metabolite, 10-(omega-2)-hydroxy-LA, were isolated by HPLC and identified by gas chromatography/mass spectrometry. In the presence of NADPH, the formation of all three metabolites was linear with time and microsomal protein concentration. Hydrogen peroxide also supported the microsomal metabolism of LA, although the ratio of metabolites was substantially different than that produced by NADPH-supported microsomes. Several biochemical probes (metyrapone, #alpha#-naphthoflavone, 2-diethylaminoethyl-2,2-diphenylvalerate hydrochloride, and 10-undecynoic acid) were used to ...

Energy Technology Data Exchange (ETDEWEB)

In the search for new brain imaging agents for use with single photon emission computed tomography (SPECT), quantitative structure activity relationship (QSAR) analysis of the correlations between initial brain uptake and physicochemical parameters like lipophilicity, log P, molecular weight, log MW and log U/D (undissociated/dissociated), of the {sup 99m}Tc-DADT (diaminedithiol) complexes and {sup 99m}Tc-PAO (propyleneaminoxime) complexes have been analyzed. High correlations are found for both the {sup 99m}Tc-DADT complexes (r = 0.94) and for the {sup 99m}Tc-PAO complexes (r = 0.83) which are significant at 99.9 and 99.5 percentile level, respectively. These results will help the further design of better ligands for {sup 99m}Tc in brain imaging. (author).

Science.gov (United States)

Our research in the general area of acid catalysis involves the characterization of solid acidity and the corresponding assessment of catalytic performance of acidic materials. Acid characterization studies are required to provide essential information about the type of acid site (i.e., Lewis versus Bronsted), the strength of the sites, and the mobility of molecules adsorbed on the acid sites. An accurate measure of acid strength is given by the heat of adsorption of a basic probe molecule on the acid site. A thermodynamic representation of the mobility of adsorbed species on these sites is given by the entropy of adsorption. Important techniques used in these acid site characterization studies include microcalorimetry, thermogravimetric measurements, temperature programmed desorption, infrared spectroscopy and solid state nuclear magnetic resonance. The combination of these acid site characterization studies with reaction kinetics measurements ...

Energy Technology Data Exchange (ETDEWEB)

Biosorption has been developed as an effective and economic method to treat wastewater containing low concentrations of metal pollutants. In this study, a bacterium, Citrobacter freudii, was used as a biosorbent to adsorb uranium ions. The thermodynamics and kinetics of this adsorption, as well as its mechanism, were investigated. The results indicated that the biosorption rate could be better described by a pseudo 2nd-order model than a pseudo 1st-order model. The adsorption of U (VI) proceeded very rapidly in the first 30 min and subsequently slowed down continuously for a long period. The biosorption isotherm of uranium by C. freudii could be described well by the Langmuir or Freundlich isotherm, and the latter was better. The thermodynamics parameters, {delta}H{sup o}, {delta}G{sup o}, and {delta}S{sup o} were calculated according to the results of the experiment, which showed this biosorption as being endothermic and spontaneous. The ...

International Nuclear Information System (INIS)

In nuclear power plant Paks, Hungary, alkaline oxidative (NaOH, KMnO_4, H_2O) and acidic reductive (citric- and oxalic acid, water) liquids are using for the decontamination of primary circuit equipment (main liquid circulating pumps, steam generators, pipelines etc). The above mentioned decontamination liquids are containing "1"1"0"mAg, "9"5Nb, "5"4Mn, "5"8 Co, "6"0Co, "5"1 Cr, "1"2"4 Sb radioisotopes, summarized radioactivity is between 10"3-8x10"4 kBq/dm"3 liquid. The decontamination liquid can be cleaned with reactive adsorption (active carbon) and ion-exchange process at elevated temperature (333-368 K) in multilayered columns. After purification the summarized radioactivity for "5"4Mn, "6"0Co, and "1"1"0"mAg are in the outlet liquid below 1 kBq/dm"3. Decontamination factor DF#approx =#10"3-10"4, volumetric reduction factor VRF#approx =#50-500.

Energy Technology Data Exchange (ETDEWEB)

Geological clay formations are investigated for use as final underground deposit for heat producing nuclear waste. Special kinds of clay (e.g. bentonite) can also be used for the construction of geotechnical barriers. For the long time safety prognosis of the nuclear waste repositories the development of geochemical transport models is indispensable. The transport of aqueous solutions in clay is a complex process. The three-layer-minerals bentonite and illite swell by the adsorption of water, if the volume is restricted a high swelling pressure develops. The excellent barrier effect of natural clay formations and geotechnical clay barriers is based on the high swelling pressure and the high adsorption capacity for radionuclides and other pollutants. The two-layer-mineral kaolinite has no swelling capacity. In contrast to sandy layers a special geochemical transport potential exists in clay besides the well known matrix potential which ...

Energy Technology Data Exchange (ETDEWEB)

Results on the oxidative dehydrogenation of ethane on rare-earth oxide (REO) based catalysts (Na-P-Sm-O, Sm-Sr(Ca)-O, La-Sr-O and Nd-Sr-O) are described. Oxygen adsorption was found to be a key factor which determines the activity of this type of catalysts. Continuous flow experiments in the presence of catalysts which reveal strong oxygen adsorption showed that the reaction mixture is ignited resulting in an enhanced heat generation at the reactor inlet. The heat produced by the oxidative reactions was sufficient under the conditions chosen for the endothermic thermal pyrolysis which takes place preferentially in the gas phase. Ignition of the reaction mixture is an important catalyst function. Contrary to non-catalytic oxidative dehydrogenation, reaction temperatures above 700 C could be achieved without significant external heat input. Ethylene yields of up to 34-45% (S=66-73%) were obtained on REO-based catalysts under non-isothermal ...

Energy Technology Data Exchange (ETDEWEB)

In the past three years, we followed the work plan as we suggested in the proposal and made every efforts to fulfill the project objectives. Based on our large amount of creative and productive work, including both of experimental and theoretic aspects, we received important technical breakthrough on naphthenic acid removal process and obtained deep insight on catalytic decarboxylation chemistry. In detail, we established an integrated methodology to serve for all of the experimental and theoretical work. Our experimental investigation results in discovery of four type effective catalysts to the reaction of decarboxylation of model carboxylic acid compounds. The adsorption experiment revealed the effectiveness of several solid materials to naphthenic acid adsorption and acidity reduction of crude oil, which can be either natural minerals or synthesized materials. The test with crude oil also received promising results, which can be potentially ...

Energy Technology Data Exchange (ETDEWEB)

Hydrogenolysis of quinoline was carried out using red mud catalyst at 390{degree}C and 450{degree}C to study denitrogenation reaction in the first stage liquefaction of coal. Quinoline was decomposed to ammonia via 1-THQ or hydrogenated to 5-THQ. The reaction rate constants obtained at 390{degree}C were k{sub 1} = 1.83 {times} 10{sup {minus}6}, k{sub 2} = 1.16 {times} 10{sup {minus}7}, and k{sub 3} = 3.24 {times} 10{sup {minus}7} mol {center dot} dm{sup {minus}3} {center dot} min{sup {minus}1} {center dot} g {center dot} {sup {minus}1}. The rate constants for hydrogenation of quinoline were in the order of hexadecane > trans-decalin > 1-methylnaphthalene. Ratios of equilibrium adsorption constant between trans-decalin and quinoline and between 1-methylnaphthalene and quinoline were found to be 0.055 and 0.155 respectively. The equilibrium constant of phenol to red mud catalyst adsorption was calculated to be 3 times of that of quinoline, ...

Energy Technology Data Exchange (ETDEWEB)

A detailed study of adsorption of automobile exhaust hydrocarbons in Ag{sup +}-exchanged zeolites under cold-start conditions (room temperature and in the presence of water) was carried out with FT-IR spectroscopy, using toluene and propylene as probes. The results show that exchanged Ag{sup +} in zeolites is unique for trapping olefin and aromatic hydrocarbons due to its resistance to water adsorption. In contrast, exchanged Cu{sup 2+} in zeolites, which has good hydrocarbon trapping properties under dry conditions, does not trap hydrocarbons under wet conditions. Here, solvation of Cu{sup 2+} screens the interactions of the cation with adsorbed hydrocarbons. The results also show that, in addition to the nature of the cation, the structure of the zeolite also plays a role in hydrocarbon trapping. Aging at high temperatures, with water vapor (=10%) and SO{sub 2} (=15ppm), leads to a decrease of the trapping centers in the zeolites due to ...

International Nuclear Information System (INIS)

The nature of the electrolyte strongly influences the electrode kinetics of the oxygen evolution reaction (OER) and electrochemical ozone production (EOP) mainly by affecting the degree of coverage by the intermediates of both processes. The anomalous behaviour of the Tafel coefficient, b, as a function of temperature was attributed to surface adsorption of the electrolyte species, and the competition between them, as well as gas bubble adherence. Comparison of the current efficiencies of the EOP, PHI_E_O_P, determined for different temperatures and supporting electrolyte compositions, showed the presence of fluorinated anions increases PHI_E_O_P. The influence of the anion nature on PHI_E_O_P, when analysed in the light of the proposed electrode mechanism, reveals introduction into the electrolyte of anions having a high electronegativity changes the double layer structure resulting in an increase of surface concentration of the active centres leading to EOP. The ...

Science.gov (United States)

Two major modes of CO adsorption on SiO{sub 2}-supported Pd reflect different extents of back-donation, which is, at least in part, controlled by the local electron density at the adsorption site. The fraction of CO in the bridging mode (B) increases and that of the linear mode (L) decreases, with increasing size of the Pd particles, indicating high electron density at Pd atoms in terraces of close-packed crystal faces, in agreement with Smoluchowski's classical model. For samples reduced at 300{degree}C our data points and those of other authors are located on a common curve of B/L vs metal dispersion. Extensive reduction at 600{degree}C results in significantly lower B/L values, attributed to the incipient formation of a palladium silicide. Oxidation followed by reduction at 300{degree}C destroys the silicide, and the B/L value returns to the original curve.