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The photoelectron resonance capture ionization (PERCI) of cysteine (Cys) and small gas-phase neutral peptides that contain the Cys residue (Cys-Gly, g-Glu-Cys, and glutathione (g-Glu-Cys-Gly)) is reported. At an ionization energy less than 1eV two types of dissociative electron attachment ionization were observed for Cys: hydrogen atom loss, resulting in formation of the ion [Cys-H]-, and dissociation of the CH2-SH bond, resulting in formation of the ion [SH]-. The presence of these ions suggests that both the p*(-CO2H) and *(C-S) orbitals can act as low energy electrophores on Cys. This ionization trend was observed for the dipeptides Cys-Gly and g-Glu-Cys as well as glutathione, with evidence that dissociation of the CH2-SH bond in these peptides can also result in ions of the form [M-SH...

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The addition of titanium to eutectic braze compositions causes these alloys to readily wet and bond to A1N ceramics. Electron microscopic characterizations of the metal-ceramic interfaces reveal the presence of TiN, along with other Ti- and Al-containing phases. The formation of such interfacial reaction products is an additional thermodynamic driving force for the creation of useful metal-ceramic bonds. 12 refs., 4 figs., 1 tab.

Science.gov (United States)

The purpose of this study was to evaluate the resin-dentin interfacial morphology and shear bond strength of several new and experimental dentin bonding systems classified as single-bottle/total etch, multi-step/total etch, and self-etching. Class 1 and 5 cavities were prepared from freshly extracted permanent molars and restored with composite resin. Each bonded sample was cross sectioned and one-half was completely demineralized and deproteinized, while the other half was polished along the cut surface to permit measurement of the thickness of resin-infiltrated dentin layer (RIDL) within intertubular dentin (iRIDL) and around the peritubular walls (pRIDL) of resin tags by SEM. Shear bond strength was measured for all the systems 2 minutes after photocuring. SEM showed iRIDL and resin tags of different morphology depending on material and dentin location. The iRIDL was thinner in superficial dentin and ...

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Research activity during the 1991--1992 funding period has been concerned with the following topics relevant to carbon monoxide activation. (1) Exploratory studies of water gas shift catalysts heterogenized on polystyrene based polymers. (2) Mechanistic investigation of the nucleophilic activation of CO in metal carbonyl clusters. (3) Application of fast reaction techniques to prepare and to investigate reactive organometallic intermediates relevant to the activation of hydrocarbons toward carbonylation and to the formation of carbon-carbon bonds via the migratory insertion of CO into metal alkyl bonds.

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Applying the thermochemical selectivity criterion of Hadnett et al. It is shown that the selectivity of the furan formation is not limited by a too low strength of the C-H bonds in furan when compared with the C-H bond dissociation energy in the educt molecule butadiene. In the oxidation of butadiene on a CsH{sub 2}PMo{sub 12}O{sub 40} catalyst a maximum yield of 22 mol% furan has been obtained. To improve this comparatively low furan yield oxidation activity of the catalyst must be lowered to prevent the consecutive reaction to maleic anhydride. (orig.)

International Nuclear Information System (INIS)

Layer-by-layer formation for #pi#-conjugated azomethine multilayers bonded on substrates was investigated. The multilayers were synthesized using ethanol (EtOH) and dichloromethane (DCM) as reaction solvents. The multilayer characteristics were analyzed using UV-vis absorption spectroscopy, ellipsometric thickness, and atomic force microscopy. The absorption spectra and ellipsometric thicknesses of multilayers formed using EtOH and DCM were compared. The results indicate that EtOH is more suitable than DCM for such layer-by-layer formation. In addition, bandgaps estimated from the absorption edge of multilayers were investigated. The results indicate that the bandgap decreases as the number of benzene rings contained in the molecular chain of the multilayer increases. Also, a multilayer with four benzene rings bonded on a substrate had a bandgap close to that of a polymer with a similar chemical ...

British Library Electronic Table of Contents (United Kingdom)

Abstract The Jebel Ressas Pb-Zn deposits in North-Eastern Tunisia occur mainly as open-space fillings (lodes, tectonic breccia cements) in bioclastic limestones of the Upper Jurassic Ressas Formation and along the contact of this formation with Triassic rocks. The galena-sphalerite association and their alteration products (cerussite, hemimorphite, hydrozincite) are set within a calcite gangue. The Triassic rocks exhibit enrichments in trace metals, namely Pb, Co and Cd enrichment in clays and Pb, Zn, Cd, Co and Cr enrichment in carbonates, suggesting that the Triassic rocks have interacted with the ore-bearing fluids associated with the Jebel Ressas Pb-Zn deposits. The 18O content of calcite associated with the Pb-Zn mineralization suggests that it is likely to have precipitated from a fl...

International Nuclear Information System (INIS)

Sorption of oxidized and reduced forms of molybdosilicic, molybdophosphoric and molybdovanadophosphoric acids by polyurethane foam based on ethers and esters is studied. On the basis of sorption dependence on solution pH, polyurethane foam type and spectral characteristics of sorbates the suggestion has been made that in the polyurethane foam phase there are two main types of sorbent-sorbate interaction: electrostatic (ion-ion) and with hydrogen bond formation: and it is impossible to determine the contribution of every interaction

International Nuclear Information System (INIS)

The high resolution absorption, luminescence and excitation spectra of the orthorhombic potassium lanthanum praseodymium ternary chloride, K_2La_1_-_xPr_xCl_5, (0.02 #<=# x #<=# 0.15) single crystals were recorded at 4, 77 and 293 K with different excitation sources. The experimental 4f"2 energy level scheme of the Pr"3"+ ion in K_2LaCl_5 derived from the absorption and emission spectra consisted of 86 (out of 91) Stark components. This energy level scheme was simulated by using a phenomenological crystal field (cf) model which included eight free ion and nine cf parameters according to the C_2_v symmetry. Despite the approximate C_2_v point symmetry instead of the real C_s one, the simulation yielded a very satisfactory rms deviation of 17 cm"-"1 between the experimental and calculated energy level schemes. The results, especially the weak cf strength, are discussed taking into account the bonding characteristics in K_2LaCl_5.

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In this Letter, we present Quantum Mechanics/Molecular Mechanics (QM/MM) calculations on molecules containing a 2-deoxycytidine-3prime-monophosphate moiety (3prime-dCMPH). In particular, we examine the effect that including neighbouring nucleotides at the Molecular Mechanic (MM) level has on the calculated electron affinities and on the energetic barriers of the C3prime-O3prime bond cleavage. Our results demonstrate that the surrounding nucleotides relocate the excess electron from the p* orbital of the base to a diffuse phosphate-centred orbital, leading to the formation of a dipole-bound anion state. Both the electron affinities and the activation energy of C3prime-O3prime bond cleavage are strongly increased.

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Short communication.

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One salt and two Cu(II) complexes (H2hsm)(ox), 1, [Cu(hsm)(ox)], 2, and [Cu(hsm)(ox)H2O], 3, have been synthesized and X-ray characterized (hsm is histamine and ox2? is the oxalate dianion). Starting from the prochiral tetracoordinated complex 2, pentacoordinated complex 3 crystallizes as a racemic mixture of the enantiomeric ? and ? isomers, in space group P21/c. In all cases, the side chain of the hsm group is gauche, allowing the formation of strong hydrogen bonds in the salt 1, and to chelate the metal center in complexes 2 and 3. The combination hsm/ox seems to favor the formation of 2D supramolecular structures (planes or wavy planes), through efficient networks of N?H???O hydrogen bonds. Cell parameters: 1, P21/c, a?=?6.260 (2) ?, b?=?11.500 (4) ?, c?=?12.525 (4) ?, ??=?104.047 (17)...

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We have undertaken a program which measures the photoelectron spectra of negative-ion beams. This experiment has afforded us direct information about these ions and the corresponding neutral radicals. Several ions and numerous radicals are believed to be crucial intermediates in combustion processes and flame chemistry. We have fabricated a spectrometer which directly measures electron affinities (EA). Knowledge of the EA and gas-phase acidity of a radical has enabled us to deduce several radical heats of formation and bond strengths.

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In this, the last of a series of three papers, we discuss a method of forming iron phosphate ceramics by a reduction process. We report the formation of iron oxide ceramics by reducing hematite with iron in a phosphoric acid solution. The reaction results in a rapid-setting ceramic (at room temperature) with a compressive strength of 3700 psi and a density of 1.7 g/cm{sup 3}. Although the exact mineral form of the binder is difficult to determine because it is mostly amorphous and hence is not amenable to X-ray diffraction analyses, this material is expected to consist of iron hydrophosphates. The reduction process is very useful in recycling several industrial wastes that are rich in hematite, including iron mine tailings, red mud (a caustic waste from the alumina industry), and machining swarfs. Formation of ceramics with red mud and swarfs is also discussed.

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Oxide catalysis plays a central role in hydrocarbon processing and improvements in catalytic activity or selectivity are of great technological importance because these improvements will translate directly into more efficient utilization of hydrocarbon supplies and lower energy consumption in separation processes. An understanding of the relationships between surface structure and catalytic properties is needed to describe and improve oxide catalysts. Our approach has been to prepare supported oxides that have a specific structure and oxidation state and then employ these structures in reaction studies. Our current research program is focused on studying the fundamental relationships between structure and reactivity for two important reactions that are present in many oxide-catalyzed processes, partial oxidation and carbon-carbon bond formation. Oxide catalysis can be a complex process with both metal cation and oxygen anions participating in ...

Science.gov (United States)

... more than expected in developing a unique bond strength measurement protocol that is important for a wide range of bond strength measurements. ...

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Having recently discovered that polynuclear heteroaromatic nitrogen compounds can be selectively reduced only at the nitrogen containing ring, we have now turned our attention towards the cleavage of the carbon nitrogen bonds in this reduced ring. Highlights for this reporting period are: (1) Studies with the 50% nickel oxide catalyst clearly show that 1,2,3,4-tetrahydroquinoline(THQ) provides approximately 20% more liquid product that does quinoline. Thus a first step selective hydrogenation to 1,2,3,4-THQ would enhance the overall HDN reaction to provide a more substantial conversion to substituted benzene and aniline derivatives. (2) The dramatic effect of the nitrogen atom is to inhibit aromatic ring hydrogenation and, to some extent, carbon-carbon bond hydrogenolysis reactivity. This is shown with proplybenzene as the substrate, where only methane gas is produced in the HDN reaction with the 50% nickel oxide catalyst. (3) The HDN reaction ...

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The paper gives results of a study to identify active sites and surface functional groups that may contribute to the absorption of elemental mercury (Hg) by relatively inexpensive calcium (Ca)-based sorbents. The study investigated the formation of chlorine (Cl) sites in CA-based sorbents as well as their role and reactivity in the absorption of Hg. HCl-exposed calcium sulfate dihydrate (gypsum) exhibited a superior Hg sorption capability. Crystalline water molecules on the surface of the gypsum were confirmed to contribute indirectly to Hg uptake. These surface molecules may have absorbed HC1 through hydrogen bond formation between an oxygen atom of a crystalline water molecule and a hydrogen atom of an HCl molecule. Two adjacent, physically absorbed HCl molecules could then trap an Hg molecule through formation of a mercuric-chloride-like molecule. Significant correlations between Cl and Hg uptake by ...

International Nuclear Information System (INIS)

In this study, a range of joining technologies has been investigated for creating attachments between refractory metal and Ni-based superalloys. Refractory materials of interest include Mo-47%Re, T-111, and Ta-10%W. The Ni-based superalloys include Hastelloy X and MarM 247. During joining with conventional processes, these materials have potential for a range of solidification and intermetallic formation-related defects. For this study, three non-conventional joining technologies were evaluated. These included inertia welding, electro-spark deposition (ESD) welding, and magnetic pulse welding (MPW). The developed inertia welding practice closely paralleled that typically used for the refractory metals alloys. Metallographic investigations showed that forging during inertia welding occurred predominantly on the refractory metal side. It was also noted that at least some degree of forging on the Ni-based superalloy side of the joint was necessary to achieve ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Thermomechanical behavior of membranes based on blends of poly(vinyl alcohol) (PVA) with different weight percentage (wt %) of glycerol has been studied. Solid-state PVA/Glycerol polymer membranes were prepared by a solution casting method. The films were studied for thermal characteristics by differential scanning calorimetry (DSC) and thermogravimetric analysis and for the mechanical properties including hardness and modulus by nanoindentation method. The dispersion of glycerol within the polymer matrix was examined using scanning electron microscopy. Fourier transform infrared spectroscopy was used to confirm the formation of hydrogen bonding between the plasticizer and PVA in their blends and also to provide information on compatibility and physical interactions between the gl...

British Library Electronic Table of Contents (United Kingdom)

Porous ?-SiAlON ceramics are synthesized by reaction bonded method using hollow alumina spheres (HASs) as both sintering aids and pore-forming agents. Both micropores and macropores, which are constructured by SiAlON grains with different morphologies, are formed in the final SiAlON samples. The micropores are three-dimentional, and are built by equiaxial grains. While the hollow macropores, which have the similar morphology to hollow alumina sphere, are packed by elongated grains. In the sintering process, the solid dissolution process takes place, giving rise to the different alumina concentration of liquid phase, and thus resulting in the formation of two kinds of grains, the equiaxial grain and the elongated grain.

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The kinetic rate constants for the cracking, isomerization, and disproportionation of n-heptane over a CrHNaY (32% chromium exchanged) zeolite catalyst at 400, 450, and 470/sup 0/C have been calculated. The interaction of n-heptane with a model Lewis acid such as BF/sub 3/ and progress along the reaction coordinate have been studied by means of molecular orbital calculations. From the kinetic results, i.e., activation energies and frequency factors, and the theoretical calculations, it can be concluded that the controlling step in these reactions is not the formation of the carbonium ion, but the subsequent transformation of this carbonium ion. In addition, the theoretical calculations show that the attack of a Lewis acid is more likely to occur on a carbon atom than on a C-H bond.

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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 ...

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The increasing use of quantum-chemical methods in catalysis has underscored the importance of developing and improving semiempirical approximations oriented toward calculations of the total energy and geometry, offering a means for examining intermolecular interactions. In this article a general approach is proposed, using weighting factors for certain regions of distances, i.e., introducing different parametrization into the various regions. A scheme designated MINDO/3-HB is presented as an extension of the MINDO/3 scheme to the region of hydrogen bonds and ..pi..-complexes of olefins with Broensted acid centers (BACs). Examples of cluster calculations are given for the adsorption of ammonia, pyridine, ethylene, and ethanol on the BACs of zeolites. In the example of the process of zeolite synthesis, the possibilities of the cluster approach are discussed for calculations related to the formation of catalysts.

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A method for detecting electrons emitted as secondary particles by photon incidence to a specimen, as well as a method of using the photons emitted by electron incidence as detecting particles are explained. Pd-Si(100)2{times}1 system is adopted for a case study of using photo-electron spectroscopy where synchrotron emitted light in soft X-ray region is used as the incident light. Pd atoms are deposited little by little on clean Si surface to investigate the electron structure of the surface, and the interface electron structure after bonded formation of Pd(thin film)-Si(substrate) is estimated. Radiation soft X-ray spectroscopy is employed to observe the real state of the bonded interface of Pd(thin film)-Si(substrate) prepared by depositing Pd film in a short period of time. In the case of radiation soft X-ray spectroscopy with electron beam excitation, bonded system of thin film and substrate can be ...

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Novel complexes of the type (Pt(DACH)(N-R-iminodiacetate)), wherein DACH represents (R,S)- and (R,R)-1,2 diaminocyclohexane and R represents /minus/Me, /minus/EtOH, and /minus/CH/sub 2/Ph groups, have been prepared, purified, and characterized by spectroscopic techniques (/sup 1/H, /sup 13/C, and /sup 195/Pt NMR;MS(FAB);IR) and by the measurement of selected physical properties (pH, pK/sub a/, conductivity, and molecular weights). The data are consistent with the formation of two diastereomeric complexes in unequal proportions in which the N-R-iminodiacetate ligand appears to be bonded as a pseudofacial tridentate chelate. One are of the ligand forms a stable five-membered-ring O,N-chelate while the other arm appears to be involved in ion-pair formation (zwitterion-like) involving the carboxylate anion and the formally positive Pt(II) central metal atom. It has been demonstrated indirectly that an active impurity was ...

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Combustion scientists are primarily concerned with the fuels most often burned as energy sources (coal, petroleum products, and natural gas), with the goal of learning to burn them as efficiently, intensely, and cleanly as possible. Discovering those slight rearrangements of chemical bonds that together account for the net chemical transformation is the key to understanding how combustion proceeds. Once these reactions have been defined, the chemist can determine the rate coefficient of each reaction as a function of temperature and assemble the information into flame models. The computer programs that use these models to predict experimental results combine two sets of equations describing (1) the diffusive and reactive rates of change in concentration of all the molecules in the flame and (2) the flow of the reacting gases. Although the details of hydrocarbon-flame models are still disputed, many of their general features are clear and the basic reactions ...

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Two manufacturing processes have been developed for fabricating PLZT bonded lens assemblies (BLA's) for the USAF EEU-2/P Thermal/Flash Protective Goggle. One process utilizes thin Sylgard spacers which remain in the BLA to establish bond thickness between...

Science.gov (United States)

...2010-10-01 false Who must post a geothermal bond? 3214.10 Section 3214...MINERALS MANAGEMENT (3000) GEOTHERMAL RESOURCE LEASING Personal and... § 3214.10 Who must post a geothermal bond? (a) The lessee...

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There are many factors affecting diffusion bonding in order to obtain high quality joining. Therefore, in the beginning, we constructed diffusion bonding model based on void growth mechanism to predict bonding pressures and times. In addition, in order to compare theoretical values with experimental values, diffusion bonding tests were carried out by using commercial AZ31 magnesium alloy sheets with different grain sizes, 16 and 130 {mu}m. The present AZ31 alloys were successfully diffusion bonded at several conditions, and the bonding strength was more than 0.8 of each parent materials. The experimental bonding conditions in high quality joining, times and pressures, were good agreed with prediction analysis. (orig.)

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... content of the environment) are significant factors affecting the useful service life of adhesive bonded plastic composite sandwich panels at 650 F ...

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An essential issue in gallium (Ga)-stabilized fcc-phase plutonium ({delta}-Pu) is the formation of helium (He) voids and bubbles emanating from the radiolytic decay of the Pu. The rate of formation of He voids and bubbles is related to the He-defect formation energies and their associated migration barriers. The size and shape distributions of the bubbles are coupled to these critical migration processes. The values of the defect formation energies, internal pressure, and migration barriers can be estimated from atomistic calculations. Complicating this picture is the destruction of He-filled voids and bubbles by subsequent radiolytic decay events. The present study concerns the construction of the necessary potential energy surfaces for the Pu-He and He-He interactions within the modified embedded atom method (MEAM). Once fully tested, the potentials will be used to estimate the He-defect ...

International Nuclear Information System (INIS)

The fission gas xenon bonded in bubbles, in pore, and in the lattice of mixed carbide fuels is measured by electron-probe microanalysis. Radial xenon distribution and release curves are determined and are calibrated by gas chromatography of the bonded fission gas and by burnup analysis in the respective pin sections of the irradiation experiments FR2 6A and 6C, Mol 11/K 2, and DFR 330/1. The results are correlated to the microstructure of the fuel, bonding medium, temperature, and burnup. (Auth.).

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Cationic five-coordinate [Pt(3-R{sup 1}-4-R{sup 2}-C{sub 6}H{sub 3})(MeCN) (6-Me-py-2-CH=NPh)(C{sub 2}H{sub 4})]{sup +} complexes (R{sup 1}, R{sup 2} = H, Me, OMe) undergo an unexpected rearrangement at 0{degrees}C in chloroform solution, affording, after treatment with aqueous LiCl, the neutral four-coordinate species [Pt(2-Et-4-R{sup 1}-5-R{sup 2}-C{sub 6}H{sub 2})Cl(6-Me-py-1-CH=NPh)]. Pt-C{sub aryl} bond breaking and making is involved in the whole process, resulting in a 1,2-shift of the platinum atom to an adjacent position of the benzene ring. The same compound is obtained, together with products deriving from a typical insertion, when an equimolar amount of ethylene is added to a chloroform solution of [Pt(3-R{sub 1}-4-R{sup 2}-C{sub 6}H{sub 3})(MeCN)(6-Me-py-2-CH=NPh)]{sup +} at 0{degrees}C. When higher ethylene/Pt ratios are used, only five-coordinate [Pt(3-R{sup 1}-4-R{sup 2}-C{sub 6}H{sub 3}CH{sub 2}CH{sub ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Series of typical -type and pseudo--type halogen-bonded complexes BClY and BBrY and hydrogen-bonded complex BHY (B = C2H4, C2H2, and C3H6; Y = F, Cl, and Br) have been investigated using the MP2/aug-cc-pVDZ method. A striking parallelism was found in the geometries, vibrational frequencies, binding energies, and topological properties between BXY and BHY (X = Cl and Br). It has been found that the lengths of the weak bond d(X)/d(H), the frequencies of the weak bond (X)/(H), the frequency shifts (XY)/(HY), the electron densities at the bond critical point of the weak bonds c(X)/c(H), and the electron density changes c(XY)/c(HY) could be used as measures of the strengths of typical -type and pseudo--type halogen/hydrogen bonds. The typical -type and pseudo--type halogen bond and hyd...

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Basic research of the structure and electronic properties of a-Si:H is reported with particular emphasis on the role of defects. The main findings are as follows: (1) low defect density material can be deposited at a high rate using SiH/sub 4/ diluted in He or Ne. Using Ar or Kr results in a high defect density and columnar material; (2) an electrical bias during deposition modifies the band gap, hydrogen concentration and structure; (3) the clustering of hydrogen in the regions between the columns is confirmed; (4) hydrogen diffusion is observed by NMR; (5) the oxidation of an a-Si:H surface results in approx. 3 x 10/sup 11/ cm/sup -2/ dangling bonds at the interface; (6) auger recombination of photoexcited carriers is a significant non-radiative mechanism at low temperatures; (7) non-radiative recombination by diffusion and capture at dangling bonds is observed at temperatures above 50 to 100/sup 0/K; (8) the defect density in doped and ...

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The diminishing clean oil reserve is driving the search for new or improved ways to reduce the level of NSO-containing species found in high abundance in heavy crude oils. Hydrotreatment is the currently preferred technique to remove those polar species. Unfortunately, nitrogen-containing compounds cause coke formation on the surface of the hydrotreatment catalyst, leading to partial or complete deactivation. Here, positive- and negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) identify those nitrogen compounds that resist hydrotreatment. ESI preferentially ionizes polar (e.g., heteroatom-containing) species: basic molecules are detected as positive ions and acidic/neutral molecules as negative ions. FT-ICR MS resolves thousands of species in a single mass spectrum, allowing for unambiguous determination of elemental composition, C{sub c}H{sub h}N{sub n}O{sub o}S{sub s}, for identification of compound ...

International Nuclear Information System (INIS)

FT-IR spectra of the products obtained in each step of the tetramethyltin (TMT)/3-wt.% Re_2O_7/Al_2O_3-SiO_2 and TMT/Al_2O_3-SiO_2 system preparation are presented and discussed. The obtained spectra show that TMT reacts with alumina-silica hydroxyl groups already at room temperature, yielding surface methyltin compounds; NH_4ReO_4 reacts with alumina-silica surface at temperatures up to 423 K, yielding rhenium surface species and ammonia, which is strongly bonded by acidic sites of the Broensted kind. FT-IR spectrum of the system (TMT)/3-wt.% Re_2O_7/Al_2O_3-SiO_2 indicated the absence of surface methyl tin compounds observed on the surface system TMT/Al_2O_3-SiO_2 , and the presence of physically adsorbed TMT; after 5 h of evacuation of the TMT/3-wt.% Re_2O_7/Al_2O_3-SiO_2 system, the FT-IR spectrum indicated the presence of only a single band at 2977 cm"-"1, which may be assigned to the C-H bond stretching of the methyl group in the surface ...

Science.gov (United States)

In this study, considering that Hg(2+) in wet flue gas desulfurization (FGD) systems can easily be reduced and then released into atmosphere, causing secondary pollution, the researches about Hg(2+) reduction and Hg(0) re-emission mechanism were carried out. The effects of several experimental parameters on the reduction were studied, including initial pH, temperature, and concentrations of Cl(-) and S(IV). Our experimental results indicated that Cl(-) had a restraining effect on the Hg(2+) reduction and Hg(0) re-emission, after 24h reaction, only 20.5% of Hg(2+) was reduced with 100mM Cl(-) in simulated desulfurization solution. Cl(-) can slow Hg(2+) reduction and Hg(0) re-emissions dramatically through changing reaction mechanism, with formation of new intermediate: ClHgSO(3)(-), which can decompose to Hg(0), but much more slowly than Hg(SO(3))(2)(2-) or HgSO(3). Simulating the conditions of the practical application (initial pH 5, T=50 degrees ...

British Library Electronic Table of Contents (United Kingdom)

In this research, new thin freestanding films of poly(methyl methacrylate) (PMMA)/50% epoxidised natural rubber (ENR 50) were doped with lithium triflate, LiCF3SO3 salt was prepared by a solvent casting method. The incorporation of ENR 50 is found to increase the conductivity of PMMA/LiCF3SO3 by two orders of magnitude at room temperature. The highest conductivity achieved was 5.09x10-5Scm-1 at room temperature when 60% of LiCF3SO3 salt was introduced into the PMMA blend containing 10% ENR 50. The formation of excessive hydrogen bonds and interchain crosslinking limit the performance of the blend at higher concentrations of ENR 50. The ionic conduction mechanisms in PMMA/ENR 50/LiCF3SO3 electrolytes obey the Arrhenius rule in which the ion transport in these materials is thermally assisted...

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Molecular dynamics simulations have been used to study the differences between two DNA and RNA 14-mer quadruplexes of analogous sequences. Their structures present a completely different fold: DNA forms a bimolecular quadruplex containing antiparallel strands and diagonal loops; RNA forms an intrastrand parallel quadruplex containing a G-tetrad and an hexad, which dimerizes by hexad stacking. We used a multiscale computational approach combining classical Molecular dynamics simulations and density functional theory calculations to elucidate the difference in stability of the 2-folds and their ability in coordinating cations. The presence of 2'-OH groups in the RNA promotes the formation of a large number of intramolecular hydrogen bonds that account for the difference in fold and stability of the two 14-mers. We observe that the adenines in the RNA quadruplex play a key role in conserving the geometry of the hexad. We predict the cation ...

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We have investigated the structures formed by oligonucleotides composed of two or four repeats of the telomeric sequences from Oxytricha and Tetrahymena. The Oxytricha four-repeat molecule (d(T4G4)4 = Oxy-4) forms structures with increased electrophoretic mobility in nondenaturing gels containing Na+, K+, or Cs+, but not in gels containing Li+ or no added salt. Formation of the folded structure results in protection of a set of dG's from methylation by dimethyl sulfate. Efficient UV-induced cross-links are observed in Oxy-4 and the related sequence from Tetrahymena (d(T2G4)4 = Tet-4), and join thymidine residues in different repeats. Models proposed to account for these data involve G-quartets, hydrogen-bonded structures formed from four guanosine residues in a square-planar array. We propose that the G-quartet structure must be dealt with in vivo by the telomere replication machinery.

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Pd/sub 2/Si layers produced by evaporation or sputtering onto silicon substrates were examined by high resolution electron microscopy, microdiffraction, X-ray, energy loss and Auger spectroscopy. The Si-Pd/sub 2/Si interfaces produced by evaporation were in all cases rougher and more polycrystalline than those produced by sputtering. X-ray microanalysis showed the predictable variation in palladium distribution across the interface but quantification did not produce the expected palladium-to-silicon ratios, primarily because of probe broadening and X-ray-induced fluorescence. Energy loss spectra showed plasmon energy shifts and changes in Si L edge shape due to bond formation with palladium. Auger data provided evidence for a small amount of oxygen at the Si-Pd/sub 2/Si interface. Electrical measurements of the ideality factor for Schottky barriers made from the materials produced higher values for the rougher evaporation-formed interfaces ...

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The effect of electron and ion beam irradiation on the Sisub(LVV) Auger spectra of SiO/sub 2/, Si/sub 3/N/sub 4/ and Si-oxynitride films was measured by the relative intensity of the 92 eV signal, characteristic for the formation of 'free' silicon during irradiation. While in Si-oxynitride the beam effects were almost negligible, some damage was found in Si/sub 3/N/sub 4/, but SiO/sub 2/ appeared to be extremely sensitive for electron and ion beam irradiation. By low energy electron loss spectroscopy of ion bombarded SiO/sub 2/ and Si/sub 3/N/sub 4/ films new electron states due to broken Si-O and Si-N bonds could be determined within the band gap of the insulators. The measured energy losses were interpreted by means of electron energy level schemes of the amorphous films.

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Physico-chemical characterizations performed on samples of 100Cr6 steel implanted both with boron and nitrogen revealed the formation of boron nitride along with the following new phases: Fe{sub 1-x}(B, N), Fe{sub 2-x}(B, N) and Fe{sub 3-x}(B, N). A thorough analysis of boron NITRIDE (5BN) indicates that a low ion current density (3 {mu}A.cm{sup -2}) in the case of the boron plus nitrogen sequence favours the formation of sp{sup 2} bonds (hexagonal-BN) while a higher ion current density (6{mu}A.cm{sup -2}) promotes sp{sup 3} bonds (cubic-BN) in the opposite sequence. Tribological tests carried out on these samples revealed that nitrogen and boron implantations do not lead to any significant improvement of friction and wear at variance with the results obtained by others authors. However, on a set samples accidentally contaminated with carbon during implantation, we noticed a considerable improvement of ...

Science.gov (United States)

We report on the effect of potato maltodextrins with variable dextrose equivalent (Paselli SA-2, SA-6 and SA-10) on the surface behavior at the air-water interface of the mixture: legumin+small-molecule surfactant. Distinct in nature small-molecule surfactants (model: sodium salt of capric acid, Na-caprate; and commercially important: a citric acid ester of monoglyceride, CITREM) have been under our consideration. The role of the structure of both of the maltodextrins and the small-molecule surfactants in the effect studied has been elucidated by measurements in a bulk aqueous medium of the enthalpy of their interaction from mixing calorimetry, value of weight average molecular weight of the maltodextrins and the thermodynamics of the pair maltodextrin-solvent and maltodextrin-protein interactions from laser static light scattering. The combined data of mixing calorimetry and light scattering suggest some complex formation between the small-molecule surfactants and ...

International Nuclear Information System (INIS)

A wide variety of thin film coatings, deposited by different techniques and with potential applications in various important areas, have been characterised by the Phase Modulated Spectroscopic Ellipsometer, installed recently in the Spectroscopy Division, B.A.R.C. The Phase Modulated technique provides a faster and more accurate data acquisition process than the conventional ellipsometry. The measured Ellipsometry spectra are fitted with theoretical spectra generated assuming an appropriate model regarding the sample. The fittings have been done objectively by minimising the squared difference (#chi#"2) between the measured and calculated values of the ellipsometric parameters and thus accurate information have been derived regarding the thickness and optical constants (viz, the refractive index and extinction coefficient) of the different layers, the surface roughness and the inhomogeneities present in the layers. Measurements have been done on (i) ion-implanted Si-wafers to ...

Science.gov (United States)

... without the problem of purple plague. The Au-Ni-In evaporated ... surface and bonding degradation (purple plague) St step-stress ...

CERN Document Server

If (S,h) is an open book with disconnected binding then we can form a new open book (S',h') by capping off one of the boundary components of S with a disk. We define a U-equivariant map on Heegaard Floer homology which sends c^+(S',h') to c^+(S,h), and we discuss various applications. In particular, we compute the 3-dimensional invariant associated to any contact structure with non-vanishing contact invariant which is compatible with a genus one open book with periodic monodromy.

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.

Energy Technology Data Exchange (ETDEWEB)

This thesis deals with the special electronic properties of the transition-metal aluminides. Following quasicrystals and their approximants it is shown that even materials with small elementary cells exhibit the same surprising effects. So among the transition-metal aluminides also semi-metallic and semiconducting compounds exist, although if they consist of classic-metallic components like Fe, Al, or Cr. These properties are furthermore coupled with a deep pseusogap respectively gap in the density of states and strongly covalent bonds. Bonds are described in this thesis by two eseential properties. First by the bond charge and second by the energetic effect of the bond. It results that in the caes of semiconducting transition-metal aluminides both a saturation of certain bonds and a bond-antibond alteration in the Fermi level is present. By the analysis of the ...

International Nuclear Information System (INIS)

The changes in microstructure of a specially prepared boron nitride (BN) film as a function of film depth were studied by high resolution transmission electron microscopy (HRTEM) and other materials analysis tools. These changes were then correlated to the changes in processing parameters during film growth. The analyzed film was fabricated by the four-step ion-assisted deposition procedure known to be effective in film-stress engineering for the formation and retention of a thick cubic BN (cBN) layer with a three-step buffer-layer deposition. In this deposition, the energy of the ions assisting cBN formation was increased stepwise from 200 to 280, and then to 360 eV [S.F. Wong, C. W. Ong, G.K.H. Pang, K.Z. Baba-Kishi, W. M. Lau, J. Vac. Sci. Technol. A 22 (2004) 676]. The nominal thickness of the cBN layer was 650 nm and that for each of the three buffer layers was about 160 nm. Both the HRTEM and electron diffraction results confirmed that ...

British Library Electronic Table of Contents (United Kingdom)

Ultrasonic gold and aluminum wire wedge bonding are widely used for electrical and signal interconnections of the integrated circuit chip packages. In this paper, based on the metallurgical theories and thermal aging test methods, the long-term thermal reliabilities of gold and aluminum wire wedge bonding on aluminum and Au/Ni/Cu pads, were investigated, respectively. At 200degreeC, the Au/Al bond interfaces evolved little when the storage time was less than 48h; with the aging time increasing, the interfacial intermetallic compounds (IMC) grew up from the pad (vertical growth); the primary compounds were Au5Al2 near the bond toe and heel, and Au2Al at the periphery. Then, the thickness of IMC was unchanged, and extended horizontally (lateral growth), Au5Al2 transformed into more stable Au...

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No abstract prepared.

International Nuclear Information System (INIS)

The model compounds, 8-methoxypsoralen-CH_2O(CH_2)_n-adenine (MOPCH_2OC_nAd, n=2,3,5,6,8, and 10) in which 5 position of 8-methoxypsoralen (8-MOP) is linked by various lengths of polymethylene bridge to N"9 of adenine. UV absorption spectra are identical with the sum of MOPCH_2OC3 and adenine absorption spectra. Solvent effect on the UV absorption and fluorescence emission spectra indicate that the lowest excited singlet state is the (#pi##->##pi#"*) state. The spectral characteristics of the fluorescence of MOPCH_2OC_nAd are strongly dependent upon the nature of the solvents. The fluorescence emission spectra in aprotic solvents are broad and structrueless due to the excimer formation through the folded conformation accelerated by hydrophobic #pi#-#pi# stacking interaction. Increasing polarity of the protic solvents leads to higher population of unfolded conformation stabilized through favorable solvation and H-bonding, and consequently to ...

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The objective of this project is to develop a pellet formulation which is capable of achieving low sulfur partial pressures and a high capacity for sulfur, loaded from a hot fuel gas and which is readily regenerable. Furthermore the pellet must be strong for potential use in a fluidized bed and regenerable over many cycles of loading and regeneration. Regeneration should be in air or oxygen-depleted air to produce a high-concentration sulfur dioxide. Fixed-bed tests were conducted with several formulations of manganese sesquioxide and titania, and alumina They were subject to a simplified fuel gas of the oxygen-blown Shell type spiked with a 30,000ppmv concentration of H{sub 2}S. Pellet crush strengths for 4 and 2mm diameter pellets was typically 12 lbs per pellet and 4 lbs per pellet, respectively. For the most favorable of the formulations tested and under the criteria of break-through at less than 100ppmv H2S and loading temperatures of 500{degrees}C and an empty-bed space velocity ...

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In order to obtain knowledge about formation and growth of condensed ring structure in a coalification process, discussions were given on product skeleton structure by using hydrogenation and hydrocracking of heated cellulose. In underwater heating of cellulose, reaction of dehydration has occurred at 200{degree}C or lower, that of decarbonation at 250{degree}C or higher, and that of demethanizing at 300{degree}C, resulting in production of a dark-brown coal-like substance. The substance has lower H/C value and higher O/C value than coal. As the underwater heating temperature rises, the hydrogenation reactivity of the heated substance decreases, and so does the ratio of conversion into toluene solubles. These phenomena are related to strength of cross-linking bond between unit skeleton structures. A substance heated at an underwater heating temperature of 200{degree}C turns toluene-soluble almost completely even during the hydrogenation ...

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Acidic constituents in crude oil are associated with the formation of stable emulsions during production and present a challenge for efficient oil recovery and processing. Acid molecules, including naphthenic acids and acidic sulfur in crude oil cause corrosion in refineries and pipelines. Naphthenic acids are also significant because of their surface activity and marginal water solubility, so that they may leach to wastewaters and cause adverse environmental effects. Acidic components of oil are not limited to carboxylic acids but also molecules that contain sulfur and nitrogen. As such, an improved understanding of the chemistry and physics of petroleum at the molecular level is needed in order to understand the range of problems associated with acidic oil components and to design better solutions. The applications of negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) for speciation of acidic oil ...

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With its 527 217 m{sup 3} of low and medium activity wastes put in storage between 1969 and 1994, the C.S.M.( center of storage of Manche) is and remains to this day a necessary element to understand the problems posed by the eternal storage of nuclear materials and the limits of the notion of reversibility. There are therefore teachings to be drawn. We cannot repeat past mistakes in particular with high activity wastes which we wish to bury deep underground. This report is based on the analysis of the existing bibliography, of the internal A.N.D.R.A. documents which we released to the public, of the lessons drawn from our participation in the official concerting and work groups, and finally of the data obtained after inquiries were done in the region in the framework of R.I.V.I.E;R.E. (citizens network of radioecological surveillance, information and evaluation). In spite of all efforts produced, many questions remain unanswered regarding this site so it is ...

International Nuclear Information System (INIS)

The principle of conservation and transferability of chemical bonds explains the recent discovery by extended x-ray absorption fine-structure measurements of two unequal anion-cation bond lengths R/sub A/C and R/sub B/C in A/sub x/B/sub 1-x/C zinc-blende semiconductor alloys despite the close adherence of the lattice constant to the average value (Vegard rule). This bond alternation, manifested as a structural distortion to a local chalcopyrite coordination around the anions, explains also most of the observed optical bowing in semiconductor alloys.

Science.gov (United States)

Lecture notes (pdf) on Ceramics is part of a physics course on the properties of matter from the University of Auckland, Department of Chemical and Materials Engineering. The following topics are covered: types of chemical bonding, degree of ionic character, structure of ceramics and crystallography, interstitial sites in different crystal structures, silicate structures, glasses, glass transition temperature, glass viscosity, thermal and mechanical properties of ceramics and glasses, fracture properties of ceramics and processing of ceramic materials. Keywords: ionic bonds; covalent bonds; coordination numbers; thermal shock; grain growth; sintering; green body

Science.gov (United States)

A silicon solar cell assembly comprising a large, thin silicon solar cell bonded to a metal mount for use when there exists a mismatch in the thermal expansivities of the device and the mount.

UK PubMed Central (United Kingdom)

Aesthetic dentistry continues to evolve through innovations in bonding agents, restorative materials, and conservative preparation techniques. The use of direct composite restoration in posterior teeth...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Introduction The objective of this study was to investigate the in-vitro fluoride release from a glass ionomer orthodontic bonding system (Fuji I, GC Corporation, Tokyo, Japan) over a 2-month period and the in-vivo enamel fluoride uptake after 6 months. Methods Ten metal brackets were bonded with either glass ionomer or composite resin (Transbond XT, 3M Unitek, Monrovia, Calif; Light Cure), which served as controls, to recently extracted molars. The bonded teeth, cut at the level of their roots, were stored in distilled water that was renewed after every fluoride measurement at 1, 3, 7, 30, and 60 days. The in-vitro fluoride release was measured by using a fluoride ion-selective electrode, connected to an ion analyzer. Fifteen pairs of premolars were bonded with metal brackets with either ...

Science.gov (United States)

... Kingdom Atomic Energy Authority, .... G. .. aphit. J..int. Report No. AERE R/M 165 (April, 1958). (2) Slaughter, G. M., Metallurgy ...

Energy Technology Data Exchange (ETDEWEB)

Predictions of the combination of our recent model for the formation of planetary nebulae (due to a diverging pulsational instability) together with nuclear-burning shell flashing, with regard to formation of multiple shells, are explored and discussed.

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This paper describes a feasibility demonstration of a thermal scanning NDE system for thermal spray coatings. Non-bonds were detected between several types of coatings and their substrates. Aluminum anti-skid coatings having very rough surfaces were included. A technique for producing known non-bond areas for calibrating and demonstrating NDE methods was developed.

Science.gov (United States)

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.

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Substantial changes in the radial distribution function of amorphous Si films have been observed in neutron-diffraction studies. The spectra indicate changes in short-range order associated with an approx.11% modification in the bond-angle distribution width. The results allow the first direct comparison of structural and vibrational Raman probes of variations in local order in thin-film amorphous solids. Good agreement is obtained between the measured bond-angle variation and that based on Raman estimates.

International Nuclear Information System (INIS)

Four inorganic hydrogen-bonded crystals with second-order nonlinear properties have been discovered: K_4LiH_3(SO_4)_4, Na_2SeO_4#centre dot#H_2SeO_3#centre dot#H_2O, Cs_1_,_5Li_1_,_5H(SO_4)_2 and NH_4HSeO_4. (author)

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The results of Independent Energy's Financial Rankings survey for 1992 as well as the second half of 1992 showed increased activity in almost every category. In stronger showing was evident in all categories except corporate finance and revenue bonds. The total amount of project finance equity and debt, corporate finance and revenue bonds reported in 1992 was nearly $16 billion - up 45% from what was reported in 1991.

International Nuclear Information System (INIS)

The Ni(H_2O)_6 ion is located at an inversion center. Six octahedral water molecules surround the Ni"I"I ion and form hydrogen bonds with the sulfate groups. Each ammonium group binds to the sulfate groups through hydrogen bonds. (orig.).

Science.gov (United States)

Based on our cryogenic FT-IR spectroscopic studies of hydrogen bonds in cholic acid, the two-dimensional FT-IR spectroscopy was applied to enhance our understanding of the hydrogen bonds. Fine spectral structures were revealed by asynchronous 2D FT-IR spectra. The co-relationship among various bands was discussed according to the synchronous 2D FT-IR spectra. .

International Nuclear Information System (INIS)

Nuclear fuel cycle information in some countries that develop, supply or use nuclear energy is presented. Data about Argentina, Australia, Belgium, Netherlands, Italy, Denmarmark, Norway, Sweden, Switzerland, Finland, Spain and India are included. The information is presented in a tree-like graphic way. (C.S.A.).

British Library Electronic Table of Contents (United Kingdom)

ObjectivesThe aim of this study was to evaluate the relationship between micro-tensile bond strength (mTBS) and ultimate tensile strength (UTS) of resin composite restorations in cavities filled by a bulk or incremental technique using the micro-tensile test.MethodsClass I cavities (4mm long, 3mm wide, 3mm deep) were prepared into dentine of sixteen human molars. All cavities were bonded with Clearfil SE Bond and restored with AP-X composite with either a bulk or incremental technique. After storage in water for 24h, the teeth were vertically sectioned to yield two slabs. Each slab was sectioned into three sticks. Sticks of one slab were trimmed into an hourglass of 0.7mm2 area at resin-dentine interface for bond strength measurement while the other sticks were trimmed at the centre of the...

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Short communication

Science.gov (United States)

Methods of acidizing a subterranean well formation, acidizing compositions, and sequestering additives for preventing the precipitation of metal compounds in the formation are described. Use of the methods and chemicals described should lead to improved formation permeability as compared to use of previous methods and chemicals. 12 claims.

Energy Technology Data Exchange (ETDEWEB)

To improve adherent properties of electrogalvanized steel (EGS) to polymeric topcoats, the surfaces of EGS were modified by polyelectrolyte-modified zinc phosphating solution. The electrochemical reaction between phosphating solution and EGS led to the complete coverage with fully grown hopeite crystals after only 5 sec treatment, thereby improving adhesion to topcoating and providing protection of EGS against corrosion. To evaluate the ability of polyphenylene sulfide (PPS) polyaryl thermoplastic coatings to protect zinc phosphate (Zn{center_dot}Ph)treated steels from corrosion in a wet, harsh environment ( 1.0 wt % H{sub 2}SO{sub 4}, 3.0 wt % NaCl and 96.0 wt % water at temperatures from 25{degrees} to 200{degree}C), we exposed them in an autoclave to attempt heating-cooling cyclic fatigue tests (1 cycle = 12 hr at 200{degrees}C + 12 hr at 25{degrees}C) up to 90 times. The major chemical reaction at the interface between the PPS and Zn in the Zn-Ph layer during cycling led to the ...

British Library Electronic Table of Contents (United Kingdom)

Statement of problem The use of titanium has increased for metal ceramic restorations, as well as for use in titanium implants, with developments in CAD/CAM technology. Some surface treatments of titanium have been introduced to enhance the titanium bond strength to low-fusing porcelains; however, a more reliable, easily used dental laboratory method has not been established. Purpose The purpose of this study was to compare the effect of laser etching as a titanium surface treatment with 3 other surface treatments (machining, airborne-particle abrasion, and acid etching), evaluating their ability to enhance the bond strength between a titanium substrate and porcelain. Material and methods A total of 64 specimen rods of commercially pure titanium (ASTM grade 2, 20 mm in length and 5.7 mm in...

British Library Electronic Table of Contents (United Kingdom)

On ships, tankers and similar vessels structural defects such as cracks and corrosion damage are typically repaired by welding. However, welding is unwanted hotwork on floating offshore units (FOUs) such as floating, production, storage and offloading (FPSO) and floating, storage and offloading (FSO) vessels because it requires shutdown of parts of the vessel thus resulting in expensive production delays. Bonded fibre composite material patch repairs can be used as an alternative to overcome the hazards of hotwork associated with welding. The patches are bonded over the defect and the integrity of the original structure is hence restored. The patch repair technology can also be utilised to provide upgrades, such as life extensions and higher design requirements. A recommended practice (RP)...

Energy Technology Data Exchange (ETDEWEB)

Low power rf measurements, S11, of electro-discharge machined (EDM) diffusion bonded mm-wave traveling wave rf cavities were not in satisfactory agreement with electromagnetic simulations. During subsequent mechanical inspection, the cell-to-cell iris were found to be distorted. This led to a series of systematic experiments to study the mechanical properties of oxygen free high conductivity Copper (OFHC) and Glidcop AL-15. Results of these studies which include cell-to-cell iris distortion, EDM machining accuracies, surface quality, and the results of different bonding techniques are presented. The results of our mechanical studies are used to develop a set of mechanical design constraints for a second series of constant impedance W-Band structures that also used wire EDM and high temperature bonding for their manufacture.

International Nuclear Information System (INIS)

Electron charge distributions are presented for Nb_3Ge, Nb_3Al, and two other hypothetical A-15 structures. Results indicate that the bonding in these materials is mainly metallic in character with some covalentlike bonding between Nb-chain atoms. We find significant coupling between neighboring chains and also between chain atoms and atoms at the cubic site. Comparison is made with various theoretical models. Investigation of the charge character of states near E/sub F/ suggests further developments in current theories on the structural transformation of A-15 compounds. The effect of chain dimerization on electronic states and charge distribution of Nb_3Ge is also investigated.

Science.gov (United States)

Electron charge distributions are presented for Nb/sub 3/Ge, Nb/sub 3/Al, and two other hypothetical A-15 structures. Results indicate that the bonding in these materials is mainly metallic in character with some covalentlike bonding between Nb-chain atoms. We find significant coupling between neighboring chains and also between chain atoms and atoms at the cubic site. Comparison is made with various theoretical models. Investigation of the charge character of states near E/sub F/ suggests further developments in current theories on the structural transformation of A-15 compounds. The effect of chain dimerization on electronic states and charge distribution of Nb/sub 3/Ge is also investigated.

UK PubMed Central (United Kingdom)

Unlike most mammalian species, the prairie vole is highly affiliative, forms enduring social bonds between mates, and displays biparental behavior. Over two decades of research in this species...Full Text Available

Science.gov (United States)

... 2-37 2.3.1.5.4 Imperfect Bonding of Die ..... 2-37 2.3.1.5.5 "Purple Plague" .... 2-37 2.3.1.5.6 Tool Damage ..... 2-37 ...

UK PubMed Central (United Kingdom)

The detailing of the intermolecular interactions in dense solid oxygen is essential for an understanding of the rich polymorphism and remarkable properties of this element at high pressure. Synchrotron...Full Text Available

UK PubMed Central (United Kingdom)

The mechanism by which mechanical force regulates the kinetics of a chemical reaction is unknown. Here, we use single-molecule force–clamp spectroscopy and protein engineering to study the effect...Full Text Available

UK PubMed Central (United Kingdom)

Human Factor VIII/von Willebrand factor, purified by calcium citrate-cellulose chromatography and 4% agarose gel filtration was subjected to sodium dodecyl sulfate gel electrophoresis on gels containing...Full Text Available

UK PubMed Central (United Kingdom)

The adhesive proteins secreted by marine mussels form a natural glue that cures rapidly to form strong and durable bonds in aqueous environments. These mussel adhesive proteins contain an unusual...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The pozzolanic behaviour of compound-activated red mud-coal gangue has been investigated through TG, DTA, XRD, FTIR and {sup 27}Al MAS NMR. From viewpoint of reaction kinetics, it is found that the pozzolanic reaction mechanism of the compound-activated red mud-coal gangue-lime system is clearly consistent with diffusion control up to 14 days, and the reaction rate constant calculated from Jander equation decreases with the increase of CaO addition in the system. The hydration products formed in the red mud coal gangue-lime systems at ambient temperature are essentially aluminous C-S-H and Ca{sub 3}Al{sub 2}O{sub 6} center dot xH{sub 2}O. From TG analysis results, it is thought that the high amount of Ca(OH){sub 2} in the pastes of studied system is not conducive to the continual increase of non-evaporable water content of the hydration products. Of particular interest. {sup 27}Al MAS NMR proved to be an effective technique to obtain valuable information of Al(4) ...

Science.gov (United States)

The results of an investigation into the behavior of adhesively bonded doubler splices of two composite material sandwich panels are presented. The splices are studied from three approaches: analytical; numerical (finite elements); and experimental. Several parameters that characterize the splice are developed to determine their influence upon joint strength. These parameters are: doubler overlap length; core stiffness; laminate bending stiffness; the size of the gap between the spliced sandwich panels; and room and elevated temperatures. Similarities and contrasts between these splices and the physically similar single and double lap joints are discussed. The results of this investigation suggest several possible approaches to improving the strength of the sandwich splices.

Energy Technology Data Exchange (ETDEWEB)

A billet of low-density carbon-bonded carbon fiber (CBCF) composite is machined into a desired attenuator or load element shape (usually tapering). The CBCF composite is used as a free-standing load element or, preferably, brazed to the copper, brass or aluminum components of coaxial transmission lines or microwave waveguides. A novel braze method was developed for the brazing step. The resulting attenuator and/or load devices are robust, relatively inexpensive, more easily fabricated, and have improved performance over conventional graded-coating loads.

British Library Electronic Table of Contents (United Kingdom)

The review covers the development within the field of cleavable surfactants since 2003. Cleavable surfactants are amphiphiles in which a weak linkage has been deliberately inserted, normally, but not always, between the hydrophobic tail and the polar headgroup. Alkali labile linkages that have been used for the purpose include normal ester bonds, betaine esters, and carbonates. Ketals and ortho esters are example of bonds that are susceptible to acid hydrolysis. Several investigations deal with cationic ester-containing surfactants, both monomeric and dimeric species, the latter being gemini surfactants. Ester, amide and carbonate containing surfactants have been investigated with respect to enzyme catalyzed hydrolysis. The main incentive for the development of novel cleavable surfactants ...

International Nuclear Information System (INIS)

A new potential function based on spectroscopic results for diatomic molecules is presented and applied to the hydrogen bonding systems. The potential energy of interaction is supposed to have electrostatic, polarization, dispersion, repulsion and effective charge-transfer contributions. Estimates of the effective charge-transfer quantity have been made based on the average charge of the proton donor and the acceptor atoms. For dimers such as water, methanol, acetic acid and formic acid, the vibrational stretching frequencies and dimerization energies are calculated and discussed in connection with Badger-Bauer rule. (author).

Science.gov (United States)

C C*R C" dC*9 4hC2 CX2VCTF CK/XCL` CCNA C?Q C.:FC C?v As1)Ax^IA} AyU$ =FA%WNA AfgJA Aw;ZAzg AyA!A A=!nA> CA!n/A* ? ...

British Library Electronic Table of Contents (United Kingdom)

An approach to the calculation of the quantity of heat consumed in the process of coal formation is presented. The variability of this parameter in a coalification series is analyzed using coals from the Kuznetsk and Tunguska Basins as an example.

UK PubMed Central (United Kingdom)

The formation of the nicotinamide adenine dinucleotide phosphate-dependent formate dehydrogenase in Clostridium thermoaceticum is stimulated by the presence of molybdate and selenite...Full Text Available

Science.gov (United States)

International Patenting Trends in Advanced Materials: Ceramics (June 18, 1999) This report is the ... manufacturing, biotechnology, and advanced materials. Hypertext Format Portable Document Format ...

Energy Technology Data Exchange (ETDEWEB)

The ERICAM model (Environmental Risk Internalization through Capital Markets) includes the capital markets as a source contributing to the coverage of risks due to nuclear activites, thus enhancing the effectiveness and functions of the nuclear liability law. The model proposed will allow higher amounts for compensation and will increase financial security, flow of information, and efficient use of resources. The implementation of the model can be achieved on the financing side by issuing Nuke bonds, linking accident-specific options to government bonds. This will essentially increase the risk coverage compared to present means, and will be a pin-pointed addition to the existing layer system. There are three institutions proposed to act as mediators in the implementation of the model: A government authority to supervise the trade in Nuke bonds. Risk-bearing associations in oder to enhance the model`s efficiency, and to ...

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We have demonstrated in this work (1) that methane is readily activated at mild conditions (100[degree]C, 1 torr) over a relatively noble metal, Pd. This was observed using a stepped and kinked Pd(679) crystal (1), and other crystal faces are now being investigated to establish whether the cracking of the C-H bond of methane on Pd is structure sensitive or structure insensitive. Oxygen chemisorption is extremely structure sensitive: weakly bonded, highly reactive oxygen overlayers form on Pd(100) surface (2), while strongly bonded, moderately reactive oxygen overlayers form on Pd(111) and Pd(679). Reaction of the weakly bonded oxygen with surface carbide gives rise to CO[sub 2] over clean Pd(100) but to CO over halogen-doped Pd(100) (3--5). The effect of halogens is primarily ensemble-controlling, or oxygen-supply restricting, but long range influence of surface Cl on the strength of the Pd-O ...

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Anisotropic Nd{endash}Fe{endash}B magnet powders can be produced by the hydrogenationdecomposition-desorption-recombination (HDDR) process from Nd{endash}Fe@ xnB{endash}Co{endash}M ({ital M}=Ga, Zr, Nb, Hf, and Ta) alloys. The present status of those HDDR powders and the bonded magnets made from them are reviewed with regards to the powder particle size dependence of their magnetic properties, their magnetic thermal stability, and their magnetization behavior. The results of a mechanistic study on the recombination step are also presented. The magnetic properties of the anisotropic HDDR powder depend relatively little on the powder particle size. Bonded magnets with a density of {approximately}6.20 g/cm{sup 3} and a BH{sub max} of 18.5{endash}20.5 MGOe can be produced from anisotropic HDDR powders with particle sizes of below 300 {mu}m diam. The temperature coefficient of the intrinsic coercive force {sub {ital iH}}{sub {ital c}}, of the ...

KoreaScience (Korea)

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Science.gov (United States)

Neutrino processes role in star evolution and onset of supernovae explosion

KoreaScience (Korea)

Full Text Available

International Nuclear Information System (INIS)

Cyclic strength of #alpha#+#beta#-titanium alloy BT3-1 is studied under load frequencies of 33 and 300 Hz. The increase in the cyclic strength with growing frequency is caused by formation of FCC interphase layers of titanium hydrides. Their formation is one of possible ways of raising the fatigue strength of titanium alloys. Peculiarities of FCC interlayer formation in #alpha#+#beta# phases under loading frequency variation are revealed.

International Nuclear Information System (INIS)

... 1343-3563 v. 57(1) SPECIFIC NUCLEAR REACTORS AND ASSOCIATED

International Nuclear Information System (INIS)

Published in summary form only.

Energy Technology Data Exchange (ETDEWEB)

Chlorination of water can lead to the formation of chloropicrin. The numerous potential precursors (of various reactivities) observed during this study, confirm this hypothesis. Combination of ozonation and chlorination can also lead to the formation of this compound, dangerous to health; however, the conditions of the formation and particularly the impact of a nitration reaction in the gas phase are still not clearly defined.

Science.gov (United States)

ice could be responsible for the formation of martian gullies. Tomorrow's picture: whirlpool ...

International Nuclear Information System (INIS)

Three new rare earth metal-rich compounds, Gd_6MTe_2 (M=Co, Ni) and Er_6RuTe_2, were synthesized in direct reactions between the R, R_3M, and R_2Te_3 (R=Gd, Er, M=Co, Ni, Ru). These materials all adopt the same Zr_6CoAl_2 structure type with space group P6-bar 2m (No. 189, Z=1). Single crystal structures of Gd_6CoTe_2 and Er_6RuTe_2 were determined and lattice parameters are a=b=8.3799(5), c=3.9801(4) A, and a=b=8.1473(5) A, c=3.9962(4) A, respectively. Gd_6NiTe_2 was characterized by X-ray powder diffraction; lattice parameters are a=b=8.412(2), c=3.9577(9) A. Metal-metal bonding correlations were analyzed using the empirical Pauling bond order concept.

Energy Technology Data Exchange (ETDEWEB)

Urea-formaldehyde resin bonded particle board, medium density fiberboard and plywood paneling are used as flooring, wall paneling, for cabinet work and in furniture, and are present in almost every office, home and public building. If large quantities of these products are used in poorly ventilated spaces, high manufacturing quality control is necessary to avoid problems of latent formaldehyde release. Indoor air formaldehyde concentrations depend on the nature of the product, the product surface to air volume (loading) factor, temperature, humidity, age and product emission rates. Standard test methods are now available for measuring product emission rates that make it possible to predict the performance of UF-bonded pressed wood materials if use conditions and environmental parameters are known. Recent modifications in adhesive and board manufacturing parameters have made it possible to reduce formaldehyde emission significantly, and ...

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To improve the surface properties of magnesium alloy, a lining process using shot peening was carried out. The lining of magnesium alloy with metals such as titanium and nickel is useful in heightening the corrosion and wear properties for the components. In the shot peening experiment, the foil set on the magnesium workpiece is pelted with many shots at a high velocity. The foil is bonded to the surface of the workpiece due to plastic deformation induced by the collision of the shots. A pure aluminum foil is inserted between the hard foil and magnesium workpiece to assist the bonding. To heighten the bondability, the foil and workpiece are heated and the flow stresses of the metals are reduced. In this experiment, a centrifugal shot peening machine with an electrical heater was employed. The workpieces were commercially magnesium alloys AZ31B and AZ91D, and the foils were commercially pure aluminum, pure titanium and pure nickel. The effects ...

International Nuclear Information System (INIS)

A family of sealant materials has been developed for use in the solid oxide fuel cell (SOFC) and in other applications in the temperature range of 800 endash 1000 degree C. These materials are based on glasses and glass-ceramics in the SrO endash La_2O_3 endash Al_2O_3 endash B_2O_3 endash SiO_2 system. The coefficients of thermal expansion (CTE) for these materials are in the range of 8 endash 13x10"-"6/degree C, a good match with those of the SOFC components. These sealant materials bond well with the ceramics of the SOFC and, more importantly, form bonds that can be thermally cycled without failure. At the fuel cell operating temperature, the sealants have viscosities in the range of 10"4-10"6 Pa-s, which allow them to tolerate a CTE mismatch of about 20% among the bonded substrates. The gas tightness of a sample seal was demonstrated in a simple zirconia-based oxygen concentration cell. copyright 1996 Materials Research ...

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A carbon-bonded carbon fiber (CBCF) insulation developed for a radioisotope heat source is made from chopped rayon fiber about 10 ..mu..m in diameter and 250 ..mu..m long, which is carbonized and bonded with phenolic resin particles. The CBCF is an excellent lightweight insulating material with a nominal density of 0.2 Mg/m/sup 3/ and a thermal conductivity of 0.24 W/(m-K) in vacuum at 2000/sup 0/C. Several attributes that make CBCF particularly suitable for the heat source application have been identified. These include light weight, low thermal conductivity, chemical compatibility, and high-temperature capabilities. The mechanical strength of CBCF insulation is satisfactory for the application. The basic fabrication technique was refined to eliminate undesirable large pores and cracks often present in materials fabricated by earlier techniques. Also, processing was scaled up to increase the fabrication rate by a factor of 10. The specific ...

Energy Technology Data Exchange (ETDEWEB)

Components of various forest and agricultural residue biomass-including the polyphenolic compounds-were converted into aqueous solution and/or suspension by extraction and digestion. Some biomass components reacted vigorously under alkaline catalysis with formaldehyde and initially showed a high degree of exothermic reaction; however, other components did not react as vigorously under these conditions, indicating that different biomass materials require different methods to obtain optimum reactivity for the copolymerization with phenol. Our primary goal is to develop adhesives capable of producing acceptable bond quality, as determined by the wood products industries` standards, under a reasonable range of gluing conditions. Copolymer resins of phenol, formaldehyde, and biomass components were synthesized and evaluated for gluability of bonding exterior grade structural replaced with chemicals derived from peanut hulls, pecan shell flour, pecan ...

International Nuclear Information System (INIS)

Comprehensive investigation has been made into the application of the polymerization hardening by radiation, particularly electron beam, to the composites of polymers and other materials. The report is divided into four parts, namely 1) characteristics and problems of the reaction of curing by radiation polymerization, 2) improvement of the bonding capability of high molecular weight materials, 3) bonding by radiation, and 4) composites made by the impregnation and polymerization hardening of monomers. The first part includes the effects of dose rate, temperature rise during the hardening, the peculiarity of electron beam irradiation at high dose rate, reaction environment and additive effects. Main conclusions are as follows: caution must be taken to the amount of residual double bonds because they affect the quality of hardened polymers; the polymerization hardening reaction at high dose rate cannot be analogized by that ...

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The Coalspur Formation is a continental succession of interbedded mudstone, siltstone and fine grained sandstone with subordinate coarser grained sandstone layers and channel lag deposits. Chert-pebble conglomerate (the Entrance conglomerate) occurs at the base of the formation, and coal beds interbedded with coaly shale and numerous thin bentonites occur in the upper part of the formation. An economically significant amount of high-quality thermal coal occurs within the upper, Paleocene part of the formation named the Coalspur coal zone. Coal from this zone, also known as the Coal Valley coal zone is being exploited in the Coal Valley Mine. 17 refs., 4 figs.

Science.gov (United States)

Elastically deforming thin glass (thickness = 0.13 to 0.80 mm) provides an alternate method of forming a curved glass reflector which can eliminate some of the disadvantages of thicker glass. A concept is described where silvered thin glass is bonded to a steel backing to form a laminate with a reflectance greater than 93%. Subsequent bending of the flat reflector laminate to a concentrating profile produces compressive stresses throughout the glass if the laminate is properly designed. These compressive stresses enhance fracture resistance and the lamination provides protection for the silver. The design of the laminate is outlined for 0.25 and 0.51 mm thickness glass and fabrication procedures are discussed. Thermal/humidity cycling, hail impact, bond strength measurements and reflectance results are presented which demonstrate the performance capabilities of this reflector laminate concept.

British Library Electronic Table of Contents (United Kingdom)

Nanomaterials are increasingly being used to modify adhesives used in aerospace and materials applications. Improvements in thermal and mechanical properties have been found by incorporation of small amounts of nanosize materials in to such adhesives. However, the introduction of nanomaterials to adhesives used in civil engineering applications is still a new approach which needs to be explored, especially in retrofitting of structures. This paper presents part of an ongoing research to address the effect of adding nanomaterials to modify a thermosetting adhesive used for bonding carbon fibre reinforced polymer (CFRP) composites to concrete members. Vapour grown carbon fiber (VGCF) was chosen to modify the adhesive. Different concentrations of carbon nanofibres PR-24 XT-LHT were adopted fo...

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In recent years sufficient new spectra of actinides in their numerous valence states have been measured to encourage a broader scale analysis effort than was attempted in the past. Theoretical modelling in terms of effective operators has also undergone development. Well established electronic structure parameters for the trivalent actinides are being used as a basis for estimating parameters in other valence states and relationships to atomic spectra are being extended. Recent contributions to our understanding of the spectra of 4+ actinides have been particularly revealing and supportive of a developing general effort to progress beyond a preoccupation with modelling structure to consideration of the much broader area of structure-bonding relationships. We summarize here both the developments in modelling electronic structure and the interpretation of apparent trends in bonding. 60 refs., 9 figs., 1 tab.

British Library Electronic Table of Contents (United Kingdom)

A cyclic hexapeptide, annomuricatin A (the molecular formula: C27H38N6O7), was isolated from the seeds of Annona muricata. The types and sequence of the amino acids were confirmed by X-ray diffraction analysis. The stereochemistry of the title cyclopeptide was clarified by X-ray crystallographic study. The backbone contains two b-turns, one is type I b-turn and the other is type II, which are stabilized by two transannular 41 backbone hydrogen bonds between Ala and Phe. There are intermolecular hydrogen bonds between the cyclopeptide and the solvent molecules which maintained the steady spatial arrangement in crystal.

International Nuclear Information System (INIS)

A steadily increasing part of comminution is nowadays carried out by tube ball mills. Our investigations are a first step to a possible tuning of material distribution with mechanical stress characteristic of the grinding media charge, that is essential for a high efficiency of grinding. A BOND mill filled with porcelain balls as grinding media and labelled corundum (Au-198) as grinding material was used to measure the distribution of material over the cross-section. The evaluation was made by linear interpolation between all combinations of adjacent measuring points to calculate all coordinates with equal intensity for each selected level of activity. Two plottings showing the dependence of material distribution on the rotating speed are presented. (author).

International Nuclear Information System (INIS)

Beta-SiAlON powders have been synthesized using natural clay containing kaolin and quartz by carbothermal reduction and nitridation (CRN), then beta-SiAlON bonded corundum multiphase materials have been sintered using the as prepared powders. The results indicated that both the holding time and sintering temperature are relatively significant in accordance with optimal analysis by orthogonal method. Reaction process can be briefly interpreted by means of X-ray Diffraction and Difference Temperature Analysis as well as phase diagram principle. Bending strength and bulk density were measured in SiAlON in situ bonded corundum materials with doped various sintering agents. Furthermore, the relevant mechanical properties and microstructure were discussed in detail.

International Nuclear Information System (INIS)

In the frame of the Primary Wall Module prototype manufacturing for ITER, a consistent R and D phase was conducted in order to identify the industrial allowable tolerances and manufacturing problems which would occur when joining pieces by HIPping process during the PW module manufacturing. The purpose of this development was to give as industrial as possible manufacturing routes for joining together large Stainless Steel or DS-Copper pieces with Stainless Steel tubes and for bonding Beryllium tiles onto a curved component surface. The study concerned surface preparations, allowable gaps and joint geometry, Beryllium tile geometry, Titanium interlayer thickness, etc. This R and D phase also allowed the development and validation of different ultrasonic inspection tools needed for plate-plate, tube-plate, edge to edge plate bonding.

British Library Electronic Table of Contents (United Kingdom)

Ceramic coatings with high emission were fabricated on Ti6Al4V alloy by microarc oxidation (MAO) with additive FeSO4 into the electrolyte. The microstructure, chemical composition and chemical state of the coatings were determined by SEM, XRD, EDS and XPS, respectively. The bonding strength between the coating and substrate was studied by tensile strength test, together with the thermal shock resistance of the coating. The results showed that Fe content in the coating layer significantly affect its thermal emissivity. The relative content of Fe in the coatings surface increased at first and then decreased with increasing the concentration of FeSO4 in electrolytes, so does the emissivity of the coatings. The bonding strength became weaker with increasing the concentration of FeSO4. In addit...

Energy Technology Data Exchange (ETDEWEB)

The coherent flucton model is applied to the description of some basic nuclear properties, such as: ground state energies, bond energies, nucleon momentum spectra, and nuclear density distributions. It is shown that the momentum distributions of the nucleons coincide with the Fermi distribution for small momenta and exhibit a well pronounced high energy ''tail'', thus providing inclusive reactions of pi-meson generations in kinematically forbidden areas at nucleon-nucleon collisions. Analytical expressions for the bond energy and nuclear density distribution are derived. An agreement with the experimentally obtained data is achieved. The model features are discussed referring to the processes, characterized mainly by the geometric and dynamic properties of the nuclei, as well as by nuclear density distribution. In particular, ion-ion scattering processes at high energy are considered.

British Library Electronic Table of Contents (United Kingdom)

Many high-strain-rate compression measurements (2000 per second) using a specially designed split Hopkinson pressure bar (SHPB) for the plastic-bonded explosive PBX9501 have been reported in the literature, but there is a sparsity of data for a United Kingdom polymer-bonded explosives (PBX) known as EDC37. Both EDC37 and PBX9501 are cyclotetramethylenetetranitramine-based (HMX-based) PBXs with high filler contents. The binder systems for the PBXs are very different: EDC37 consists of a nitroplasticized nitrocellulose and PBX9501 a nitroplasticized ESTANE. PBX9501 exhibits nearly invariant fracture strains of ?1.5?pct as a function of temperature at high strain rates, whereas EDC37 fails at ?2 to 2.5?pct. The maximum compressive strengths for both PBXs were measured at 150?Mpa at ?55??C, bu...

British Library Electronic Table of Contents (United Kingdom)

Abstract Electronic structures of two representative zigzag and armchair models of aluminum phosphide nanotube (AlPNT) were investigated by density functional theory calculations. The structures were optimized and the bond lengths, tip diameters, band gaps, and dipole moments were calculated. Moreover, the quadrupole coupling constants (CQ) were calculated for the Al-27 atoms of the optimized structures. The same values of AlP bond lengths were calculated for both models. The larger value of band gap of armchair model than the zigzag model indicated the stronger dielectric property for the former model. The values of CQ(27Al) were the largest for the Al atoms placed at the tips of both zigzag and armchair AlPNT than other Al atoms, which could reveal dominant role of the Al atoms placed at...

International Nuclear Information System (INIS)

The effects of the heating rate from 0.6 up to 50"oC.s"-"1 on the thermoluminescence of #alpha#-Al_2O_3:C are very intensive. The material rapidly loses its high sensitivity as the heating rate increases. The peak shape characteristics, peak maximum and full width at half maximum agree only qualitatively with those theoretically predicted. The trapping parameters calculated by the curve fitting method, the peak shape method, the variable heating rate method and the initial rise method, were found to decrease as the heating rate increases. The validity of the results are discussed in the framework of the kinetic models. (author).

International Nuclear Information System (INIS)

The authors make two points. Firstly, they emphasise that while the correlation suggested by the B.C.S. formula, Tsub(c) = 1.14 thetasub(D) exp[-1/n(Esub(F))V], between Tsub(c) and the density of states at the Fermi energy, N(Esub(F)), appears to coincide with the empirical trends, this agreement is purely fortuitous. Such a correlation is due to the influence of N(Esub(F)) on the phonon frequencies, which in turn determine the strength of the electron-phonon coupling. Secondly, they point out that their analysis, which was developed for transition metals, is directly applicable to the A-15 compounds leading to results in agreement with the work of Fradin et al. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

Red mud is a waste generated by the aluminum industry, and its disposal is a major problem for this industry. Very rich in iron, it can be used as cheap pigment for colored concrete. The red coloration can be enhanced by calcination in the range of 600 to 800 C. Such operation also transforms the aluminum hydroxides (goethite and boehmite) and clays minerals into pozzolanic admixtures that are able to consume the calcium hydroxide produced by cement hydration. Thus, it is possible to develop a new admixture for concrete: a pozzolanic pigment. The pozzolanic properties of calcined red mud were investigated by monitoring lime consumption of different mixtures of OPC and red mud. The main products of hydration were C-S-H and mono-carboaluminate (C{sub 4}A{bar C}H{sub 11}). A uniform and durable colored concrete was obtained using white cement interground with 11% of burnt red mud.

International Nuclear Information System (INIS)

A spectrophotometric study has been made of the complex formation of vanadium (3) with arsenazo(1), arsenazo(3) and some monosubstituted derivatives of chromotropic acid and sulphanylamides. In acid medium vanadium (3) reacts with each of these reagents to produce a 1:1 complex. Optimum conditions of the complex formation was found. The effect of H"+ on the complex formation of vanadium (3) with chromotropic acid derivatives was established. It was found by the graphical method that the formation of the complex is accompanied by the elimination of one proton. Patterns were found of the influence of the nature of substituents in the organic compound on the ionization constants of acid groups and stability of complexes. Molar extinction coefficients, equilibrium constants of the formation reactions and instability constants for the complexes were calculated. The structure of complexes ...

Energy Technology Data Exchange (ETDEWEB)

To help confirm correct functioning of an epithermal neutron sonde, we measured tightly bonded water content of selected Nevada Test Site (NTS) drill holes. Tuff and alluvium samples were dried overnight at 105/sup 0/C. The samples were then heated for 45 min in a split tube furnace at 700/sup 0/C. The water that came off due to this heating was collected and the amount recorded. The error in this procedure is +- 0.59 wt %. Total water can be calculated for samples from analyses of free and tightly bonded water contents. The maximum error in this calculation is equivalent to the error in determining the more tightly bonded water. Average total water content values have been assigned to geologic units. These values, in weight fraction, are alluvium 0.14 +- .05 and tuff 0.19 +- .04. Further division of the tuff gives values of Rainier Mesa 0.15 +- .01, Paintbrush 0.18 +- .03, Tunnel Beds 0.20 +- .04, and Grouse Canyon 0.29 +- ...

Energy Technology Data Exchange (ETDEWEB)

This book presents papers on internal combustion engines. Topics considered include the influence of partial suppression of heat rejection on performance and emissions, duothermic combustion, turbochargers made of sintered silicon nitrides, heat flux, low heat rejection engines, exhaust energy recovery, combustion chamber insulation, computerized simulation, heat transfer, friction, hoop stress effects, and bonding ceramics and metals.

Energy Technology Data Exchange (ETDEWEB)

This study focuses on a series of Pt{sup II}(L-L{prime})(dppm){sup n+} complexes, where dppm is bis(diphenylphosphino)methane and L-L{prime} are C(caret)C{prime} (n = 0), C(caret)N (n = 1), and N(caret)N{prime} (n = 2) aromatic ligands. Structural characteristics are reported. Structural features indicate that the Pt-C bond distance is shorter than the Pt-N bond distance in symmetrical complexes and that the Pt-P bond distance trans to N is shorter than the Pt-P bond trans to C. This is consistent with the {sup 31}P NMR spectra where the chemical shift of the P trans to C is {approximately}10 ppm less than found for P trans to N. The energy maxima of the metal-to-ligand charge-transfer band for the complexes containing various L-L{prime} ligands occur in the near-UV region of the spectrum and fall into the energy series bpy > bph > phen > 2-phpy > 2-ptpy > 2-phq ...

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We have measured the oxygen positions in LaNiO{sub 3} films to elucidate the coupling between epitaxial strain and oxygen octahedral rotations. The oxygen positions are determined by comparing the measured and calculated intensities of half-order Bragg peaks, arising from the octahedral rotations. Combining ab initio density-functional calculations with these experimental results, we show how strain systematically modifies both bond angles and lengths in this functional perovskite oxide.

International Nuclear Information System (INIS)

The existence of a narrow peak of electron state density in A-15 is explained by a strong electron-phonon interaction that brings about the polaron narrowing of zone. In the supposition of weak and intermediate bond, the analytical expression for the critical transition temperature is found that corre lates Tsub(c) with phonon spectrum. The model permits to explain Tsub(c) correlation with the number of electrons per atom, temperature direction of resistance, value and temperature dependence of magnetic susceptibility and electron tehrmal capacity.

UK PubMed Central (United Kingdom)

During protein synthesis, aminoacyl-tRNA (aa-tRNA) and release factors 1 and 2 (RF1 and RF2) have to bind at the catalytic center of the ribosome on the 50S subunit where they take part in peptide bond...Full Text Available

International Nuclear Information System (INIS)

Our studies on K#beta#/K#alpha# X-ray intensity ratios of some of the technologically important 3d-transition metal compounds have been reviewed. Comparison of the experimental results with single-configuration Dirac-Fock calculations provided important information on the valence states of the transition metals in various compounds, which can be helpful in understanding the nature of bonding in the compounds. (author)

Energy Technology Data Exchange (ETDEWEB)

The method of double microwave--radio-frequency resonance has been used to obtain spectra of the 2/sub 11/reverse arrow2/sub 12/ and 3/sub 21/reverse arrow3/sub 22/ transitions in HCOOD, DCOOH, and HCOOH molecules. The constants of the quadrupole bond of the deuterons have been determined, magnetic interactions being taken into acocunt. A comparison with results of previous studies is given.

CERN Document Server

We show that usage of elementary submodels is a simple but powerful method to prove theorems, or to simplify proofs in infinite combinatorics. First we introduce all the necessary concepts of logic, then we prove classical theorems using elementary submodels. We also present a new proof of Nash-Williams's theorem on cycle-decomposition of graphs, and finally we obtain some new decomposition theorems by eliminating GCH from some proofs concerning bond-faithful decompositions of graphs.

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.

International Nuclear Information System (INIS)

This report seeks to address the role of hydrogen bonding with Bronsted acids and bases in proton-coupled electron transfer (PCET) as it pertains to concerted or stepwise pathways of quinone (Q) and hydroquinone (QH_2) electrochemistry. This study was performed using a series of techniques that included cyclic voltammetry (CV), digital simulations, computational chemistry and "1H NMR. Hydrogen bonding was inferred by a decrease in diffusion coefficient (D) values measured using a pulsed gradient echo- (PGE-) "1H NMR technique. Changes of 40.8% and 37.9% in D values were only noted after the addition of two equivalents of acetate to 1,4-hydroquinone (1,4-QH_2) and catechol (1,2-QH_2), respectively. In contrast, the D values for the addition of selected amines (pyridine, N,N-diisopropylethylamine and triethylamine) changed only 3.2% on average. Quantum mechanical calculations were conducted to determine the pK_a of all quinoid species to serve as ...

Energy Technology Data Exchange (ETDEWEB)

In order to watch the environment of the construction site of dismantling of the former pipe of releases in sea of Cogema-La Hague, the special and permanent commission of Information near the establishment Cogema of La Hague (C.S.P.I.) asked the association for the radiation monitoring in the West (A.C.R.O.) to realize a specific campaign of measures, on the basis of a protocol accepted by the C.S.P.I.. During the three years of the building work, two significant increases of the concentration in {sup 137}Cs in the marine flora with at most, 9.3 Bq/kg dry, are noticed so be it ten times the concentration that could be measured before the building work begins. We note a net improvement of the situation after the works. The {sup 137}Cs tends finally to disappear. For the sedimentary masses and the sands of beaches, it is outlined no increase of the contamination in {sup 137}Cs (during the works and in posteriori) which translates in a ...

UK PubMed Central (United Kingdom)

Peri-prosthetic infections are notoriously difficult to treat as the biomaterial implant is ideal for bacterial adhesion and biofilm formation, resulting in decreased antibiotic sensitivity....Full Text Available

UK PubMed Central (United Kingdom)

In an earlier report, we used differential cloning to identify genes that might be critical in controlling arterial neointima formation (Giachelli, C., N. Bae, D. Lombardi, M. Majesky, and S. Schwartz....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The present invention relates to a method of acidizing a subterranean formation or well bore employing an acidic solution containing a corrosion inhibitor composition comprising an inhibiting effective amount of an acetylenic alcohol, a quaternary ammonium compound, an aromatic hydrocarbon and an antimony compound.

UK PubMed Central (United Kingdom)

External application of auxin and cytokinin is required for the formation of flower buds on thin-layer tissue explants of Nicotiana tabacum cv Samsun. Interaction between both plant...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

An analysis is made of the manner in which the process of primordial black-hole formation and the subsequent accretion of gas depend on the equation of state. On the assumption that the process is spherically symmetric, the problem is solved numerically.

UK PubMed Central (United Kingdom)

Explants from flower stalks of Nicotiana tabacum L. were cultured on different cytokinins to induce flower bud formation. All cytokinins tested except zeatin and zeatin-riboside induced...Full Text Available

International Nuclear Information System (INIS)

... thermal power plants thermal reactors water cooled reactors WATER

Science.gov (United States)

... This pinhole process may be similar to the formation of an oxide layer in aluminum electrolytic capacitors immersed in a borax solution. ...

KoreaScience (Korea)

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International Nuclear Information System (INIS)

We have investigated the formation and coarsening of Ga droplets on focused-ion-beam (FIB) irradiated GaAs surfaces. To separately examine formation and coarsening, Ga droplets were fabricated by Ga"+ FIB irradiation of GaAs substrates with and without pre-patterned holes. We determined the droplet growth rate and size distribution as a function of FIB energy following irradiation. The data suggest a droplet formation mechanism that involves Ga precipitation from a Ga-rich layer, followed by droplet coarsening via a combination of diffusion and Ostwald ripening or coalescence via droplet migration (dynamic coalescence).

International Nuclear Information System (INIS)

Formation of basis type texture at rolling of Ti + 6.0% Al + 1.5% V + 1.0% Mo system alloy with initial prismatic texture is investigated by means of X-ray techniques. Variations of mechanical features in titanium alloy sheets depending on temperature-deformation conditions of rolling are investigated. Main conditions for formation of the intensive basis textute in the investigated alloy sheets which provides for isotropic properties in sheet plane and for increased ductility are determined.

Energy Technology Data Exchange (ETDEWEB)

This book of proceedings reports on 7 papers on combustion chemistry and formation of pollutants presented during the workshop organized by the `Combustion and Flames` section of the French society of thermal engineers. The chemistry of combustion is analyzed in various situations such as: turbojet engines, spark ignition engines, industrial burners, gas turbines etc... Numerical simulation is used to understand the physico-chemical processes involved in combustion, to describe the kinetics of oxidation, combustion and flame propagation, and to predict the formation of pollutants. (J.S.)

International Nuclear Information System (INIS)

The analysis of plasma density oscillations and ExB rotation of U-3M torsatron plasma was performed by UHR correlation reflectometry during the transport barrier formation. The connections between these characteristics and the phenomenon of inner and edge transport barrier formation were determined experimentally at the different values of HF power and plasma density.

Science.gov (United States)

The Multiple Address Processing Unit (MAPU) of the AN/TGC-26 tape relay center was originally designed to process ACP 127 message format. With the advent of JANAP 128 as a standardized message format a pressing need was felt for a MAPU modification to all...

Energy Technology Data Exchange (ETDEWEB)

The results of a time-resolved study of the avalanche and streamer formation phases leading to breakdown in atmospheric nitrogen and dry air. Results of experiments and two-dimensional simulations are presented. It is shown what processes are responsible for the formation of a streamer. The trends of externally measured quantities correspond with those predicted by our model. 3 figs., 5 refs.

Science.gov (United States)

(B204) The meeting will bring together observers and theorists in a highly interactive format, to further connect the local and cosmological star formation communities. Forward looking talks, aimed at the other communities, will survey terminology, achievements, problems and aspirations. Discussion will focus on the definition of the key questions, how the different communities can help each other, and preparations for the incorporation of realistic star formation into cosmological simulations.

International Nuclear Information System (INIS)

The results of real-time neutron diffraction measurements during the superconducting phase formation process in the Bi(Pb)-Sr-Ca-Cu-O system are reported. A Sr-Ca-Cu-O type precursor, with the same stoichiometry as the 2223 phase, was used as starting material, and the temperature range favorable to the formation of the 2223 phase was investigated. The diffraction patterns were processed by a multiphase Rietveld refinement. The formation and decomposition of the 2201 and 2212 phases were directly observed. Experimental evidence on the existence of a partially melted phase in the range 855-860 degrees C, involved in the formation of the 2223 phase, is discussed. 14 refs., 9 figs., 1 tab.

International Nuclear Information System (INIS)

The redistribution of implanted As and Sb following metal-silicide formation of Pt, Pd, and Ni has been studied. The phases of the silicides used were PtSi, Pd_2Si, and NiSi. Investigations with Rutherford backscattering analysis showed that after the formation of the silicides, the Sb was always found in the silicide layer near the surface of the samples, whereas PtSi and Pd_2Si caused a partial rejection of As for implanted doses of 2 x 10"1"5 cm"-"2 and higher. No rejection of As was found after the formation of NiSi. The results are discussed in terms of solid solubilities and impurity-metal compound formation. The data presented has implications in the fabrication of Ohmic contacts and the adjustments of the heights of Schottky barriers on silicon.

British Library Electronic Table of Contents (United Kingdom)

Summary: The KEGG PATHWAY database provides a widely used service for metabolic and nonmetabolic pathways. It contains manually drawn pathway maps with information about the genes, reactions and relations contained therein. To store these pathways, KEGG uses KGML, a proprietary XML-format. Parsers and translators are needed to process the pathway maps for usage in other applications and algorithms. We have developed KEGGtranslator, an easy-to-use stand-alone application that can visualize and convert KGML formatted XML-files into multiple output formats. Unlike other translators, KEGGtranslator supports a plethora of output formats, is able to augment the information in translated documents (e.g. MIRIAM annotations) beyond the scope of the KGML document, and amends missing components to fr...

CERN Document Server

Several complex organic molecules are routinely detected in high abundances towards hot cores and hot corinos. For many of them, their paths of formation in space are uncertain, as gas phase reactions alone seem to be insufficient. In this paper, we investigate a possible solid-phase route of formation for methyl formate (HCOOCH3). We use a chemical model updated with recent results from an experiment where simulated grain surfaces were irradiated with 200 keV protons at 16 K, to simulate the effects of cosmic ray irradiation on grain surfaces. We find that this model may be sufficient to reproduce the observed methyl formate in dark clouds, but not that found in hot cores and corinos.

International Nuclear Information System (INIS)

Applying the theory of depositional system, the depositional facies and depositional systems of the Zhiluo Formation in Dongsheng area are systematically analysed, and the authors proposed that sediments of the Zhiluo Formation are of fluvial facies, and streams of the Zhiluo time experienced three evolution stages, namely: the early braided stream, the middle low sinuosity meandering stream and the late high sinuosity meandering stream. Based on features of paleoclimatic evolution, the Zhiluo Formation is divided into two lithological members. The lower lithological member consists of sediments of braided and low sinuosity meandering streams under humid-ward paleoclimatic conditions forming grey sedimentary formation. The upper member is composed of sediments of meandering streams under arid-hot paleoclimatic conditions representing complex-colored (mainly red) sedimentary ...

International Nuclear Information System (INIS)

A variety of special regulations exist in Costa Rica for registration and transport of hazardous substances; these set the requirements for entry into the country and the security of transport units. However, the regulations mentioned no specific rules for storing hazardous substances. Tax deposits have been the initial place where are stored the substances that enter the country.The creation of basic rules that would be regulating the storage of hazardous substances has taken place through the analysis of regulations and national and international laws governing hazardous substances. The regulatory domain that currently exists will be established with a field research in fiscal deposits in the metropolitan area. The storage and security measures that have been used by the personnel handling the substances will be identified to be putting the reality with that the hazardous substances have been handled in tax deposits. A rule base for the storage of hazardous substances in tax deposits ...

Energy Technology Data Exchange (ETDEWEB)

Solid recycling of AZ31 Mg alloy with vapor deposition coating layer of high purity Mg was evaluated. In the open die forging experiments, two AZ31 Mg alloy specimens with the pure Mg layer were sufficiently bonded by forging at 673 K. Furthermore, the Al and Zn of the AZ31 substrate diffused up to the center of the pure Mg layer. By the theoretical analysis, it is suggested that the grain boundary diffusion enhanced by grain refinement due to hot forging contributes to the solid state bonding of the specimens. Also, the solid recycled specimen was fabricated from the AZ31 Mg substrate with pure Mg layer by hot extrusion at 673 K. The solid recycled specimen showed almost the same tensile properties as the virgin extruded specimen. This is probably related not only to the grain boundary diffusion but also severe plastic deformation by hot extrusion. (orig.)

British Library Electronic Table of Contents (United Kingdom)

New palladium(II) and platinum(II) complexes of saccharinate (sac), trans-[Pd(py)"2(sac)"2] (1), cis-[Pt(py)"2(sac)"2] (2), trans-[Pd(3-acpy)"2(sac)"2] (3) and cis-[Pt(3-acpy)"2(sac)"2] (4) (py=pyridine and 3-acpy=3-acetylpyridine) have been synthesized. Elemental analysis, UV-Vis, IR, NMR and TG/DTA characterizations have been carried out. The structures of 1-4 were determined by X-ray diffraction. The palladium(II) and platinum(II) ions are coordinated by two N-bonded sac ligands, and two nitrogen atoms of py or 3-acpy, forming a distorted square-planar geometry. The palladium(II) complexes (1 and 3) are trans isomers, while the platinum(II) complexes (2 and 4) are cis isomers. The mononuclear species in the solid state are connected by weak intermolecular C-H...O hydrogen bonds, C-H...@...

International Nuclear Information System (INIS)

Monte-Carlo simulations of 2-MeV #alpha#-particle channeling in Si_1_-_xSn_x alloys with 0#<=#x#<=#1 have been performed. The simulations are compared with measured channeling-angular scans for strained Si_0_._9_5Sn_0_._0_5 layers grown by molecular beam epitaxy (MBE). Agreement between simulated and measured angular scans can only be achieved if we assume a deviation of the crystal structure from the ideal one. This deviation can be attributed to a mosaic structure in the films and to an atomic-scale distortion of the crystal lattice due to an expected difference in the bond lengths between the Si-Si, Si-Sn and Sn-Sn atoms (such a difference in bond lengths has been observed in the epitaxial Si_1_-_xGe_x system). The contributions from both of these imperfections are estimated and discussed.

Energy Technology Data Exchange (ETDEWEB)

Private transfers of capital from the Organization of Petroleum Exporting Countries (OPEC) to developing countries are intended to complement private transfers from the Organization of Economic Cooperation and Development (OECD) by tapping the emerging capital markets in the Middle East. Developing countries will be able to diversify their borrowing and gain additional financing. The long-term investment of oil-producing countries will benefit and the pressures on the banking institutions to recycle funds will lessen. Middle East capital markets include international loans and international bonds. The history of the Kuwaiti dinar (KD) bond market, with its advantages for both investors and borrowers, illustrates the successful development of a capital market. Financial intermediation needs to be improved, however, if the Middle East is to become efficient enough to compete with the Euromarkets. Efficiency will require different measures and ...

Energy Technology Data Exchange (ETDEWEB)

The oxidation conditions were investigated for obtaining a higher productivity in the production of high strength carbon fiber from polyacrylonitrile (PAN). The effect of incorporation of 2 % comonomer such as methyl acrylate (MA), acrylate containing carboxylate (SA), acrylamide (AAm), and hydroxyethyl acrylate (HEA) on the oxidation conditions was also investigated. The measurement of DSC and bonded oxygen content revealed that the most effective comonomer for promoting the cyclization of nitril group and the bonding of oxygen was found to be SA, and the second best was AAm. The measurement of tensile strength of carbon fiber showed that the copolymer of SA, HEA, and MA gave a high strength fiber. It took a long time to oxidize the carbon fiber when it was oxidized at a temperature on which double layer structure was not formed. To shorten the production time, a method of combining the upper limit oxidation in which the double layer structure ...

Energy Technology Data Exchange (ETDEWEB)

The computer aided coal structure construction system is proposed, and a computational construction example is presented. The coal structure construction engine of this system fabricates molecular structure by connecting fragments sequentially inputted through a user interface. The best structure candidate is determined using construction knowledge and partial energy evaluation every addition of one fragment, and this process is subsequently repeated. The structure evaluation engine analyzes the 3-D conformation candidate by molecular dynamics, and evaluates the conformation by determining the energy value of an optimum structure. As an example, this system was applied to construction of coal molecular structure based on the actual data of partial structure composed of 26 structures from 2l kinds of aromatic cluster structures, 27 bonds from 2 kinds of bridged bonds, and 16 groups from 2 kinds of terminal substitutional groups. As a result, ...

Science.gov (United States)

New methodologies for fabrication of multilevel packaging, particularly for RF signal analysis, are investigated. A new method for ``gluing'' silicon wafers together with a Self Assembled Monolayers (SAMs) based nanoglue are discussed, as are methods to enable its use with nonconforming wafers. Results of bond strength measurements as a function of temperature and process will be presented. Surface area bonded is characterized by infrared (IR) imaging. We will also present a method of inducing self-alignment between whole silicon wafers with micrometer precision. This represents a qualitative departure from alignment of millimeter-sized object as has been previously demonstrated. Self-alignment is induced by creating hydrophilic and hydrophobic regions on the wafers and using capillary forces of water in these regions to force the wafers to align with little to no outside influence. Results are characterized by IR imaging. Physical ideas that ...

Science.gov (United States)

The purpose of this study was to assess the agreement between rectal temperature and infrared emission detection (IRED). The specificity and sensitivity, the positive predictive value and the negative predictive value were calculated. It was a prospective, observational and unblinded study. Thermoscan-pro-1 was used to collect pairs of data in 41 patients, all hospitalised on an acute geriatric ward during a 4-month period. 41% of the patients were febrile. The 'bias' between rectal and tympanic measurement (left ear) was -0.64 degree C (d) and the standard deviation 0.58 degree C (s). The '95% Confidence Interval' for the bias was -0.82 degree C and -0.46 degree C. The '95% limits of agreement' between the rectal measurement and the tympanic measurement (left ear) was -1.78 degrees C and 0.50 degree C. Regression analysis taught us that bias was increasing with increasing temperature. If we take into account one measurement with the IRED ear ...

International Nuclear Information System (INIS)

Ga"+ focused ion beam (FIB) patterning was used to structure highly oriented pyrolytic graphite surfaces with square, periodic arrays of amorphous carbon defects (mesh sizes: 300 nm-2 #mu#m). Controlled oxygen etching of these arrays leads to matrices of uniform, orientationally aligned, nm-sized, hexagonal holes. The properties of the resulting hole assembly (hole depths and lateral hole dimensions) have been investigated by means of atomic force microscopy, scanning electron microscopy and FIB sectioning. The hole dimensions and uniformity both depend on the FIB parameters and etching conditions. Etching temperatures from 500 to 700 deg. C were applied. Initial etch rates of up to 10"6 C s"-"1 per individual hole were observed when using oxygen pressures of 200 mbar. For an etch temperature of 590 deg. C the rate of etching of individual holes was found to depend measurably on the inter-hole separation. This confirms that the associated ...

Energy Technology Data Exchange (ETDEWEB)

The study had three objectives: to collect information that explain the impact of the Aube storage center (C.S.A.) on environment and allow to evaluate the consequences for man, secondly, to build a referential for any future inquiry or follow-up, thirdly, to allow to the local commission of information to elaborate an information towards the side residents and local actors that take into account their questions. Trees, waters, sediments, soils, grass, products of gardens and vineyards were the object of sampling, their dosimetry is given in this report. Other dosimetry measures were made along the nuclear site and the results are equally in this report. (N.C.)

Science.gov (United States)

Research continued on the synthesis of model compounds for coal liquefaction research. This report covers the actual laboratory investigation performed during the reporting period in order to attain the stated objective of the project, viz, the synthesis of a model compound containing tetrahydronaphthalene, naphthalene and phenyl moieties linked by methylene, ethylene and ether bonds. The overall synthetic approach aimed at obtaining the end product has been broken down into three major steps that involve the synthesis of three key reactive intermediates. These are: (1) 3,5-dimethyl-5-bromobenzyl chloride, (2) 1-chloromethylene-2-hydroxytetralin and (3) 2-chloromethylene-1-hydroxynaphthalene.

Energy Technology Data Exchange (ETDEWEB)

A high pressure waterjet has been used to study the surface roughening of superalloys as preparation for thermal spraying. Designed experiments for Mar-M 509 and Rene 80 were carried out for the effects of jet pressure and mass of water delivered per unit area. Comparisons were made of several superalloys in terms of erosion, surface roughness and topology. The mechanism of jet erosion of Rene 80 was studied in relation to its metallurgical microstructure. An MCrAlY coating by shrouded plasma spray was made over a waterjet prepared surface with excellent bonding and having an ideally clean interface.

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)

Using the slow electrons spectrometer one can get information on the surface structure, its element composition, chemical bonds, adsorption phenomena, electron state density and surface oscillation. We have developed the methods and created the apparatus that makes it possible to investigate the electron backscattering by solid surface. We have studied the electron scattering by the polycrystalline and monocrystalline. GaAs surface in the energy range of 0 to 9 eV. The FWHM of electron energy distribution function was 70 meV. (author).

Energy Technology Data Exchange (ETDEWEB)

Thin films of La{sub 0.6}Ca{sub 0.4}CoO{sub 3} perovskite were deposited on nickel plates by thermal decomposition of the metal nitrates. The electrochemical activity of the films for oxygen evolution in KOH solutions (0.1-1 M) was investigated. The reaction order with respect to OH{sup -} ion was found to be around 0.7. The results correlate fairly well with a mechanism in which breaking of the intermediate metal-peroxide bond at the Co ion is the rate-determining step. (author) 4 figs., 4 refs.

Energy Technology Data Exchange (ETDEWEB)

To expand the information base on molecular accessibility in solvent swelled coal, Argonne Premium Coal Samples (APCS) were swelled in polar, basic solvents before and after moisture loss and upon air oxidation. So far studies have been reported on the changes in pore size distribution as a function of temperature when polar basic swelling solvents are used. Additional studies employing EPR spin probe techniques performed on the breaking up of the hydrogen bonding between bedding planes were later confirmed by magnetic resonance imaging at Argonne National Lab and the University of Illinois.

British Library Electronic Table of Contents (United Kingdom)

Metalloid cluster compounds of group 14 of the general formulae EnRm with n > m (E = Si, Ge, Sn, Pb; R = ligand), where naked as well as ligand bound tetrel atoms are present, represent a novel class of cluster compounds in group 14 chemistry and can be seen as intermediates on the way to the elemental state. Therefore, interesting properties are expected for these compounds, which might complement results from nanotechnology. In this article, first results for germanium are discussed, together with novel build-up reactions on the way to novel materials based on metalloid cluster compounds. GRAPHICAL ABSTRACT[image omitted

International Nuclear Information System (INIS)

Free Electron Laser (FEL) with wide wavelength tunability has been developed and used for various applications. We report the structural-changes in P-ion-implanted diamond when we can achieve resonant excitation of the vibrations of specific bonds in the lattice of target (P-C) by using FEL. The change of property was analyzed by SIMS and Raman spectroscopy. After 5.8 #mu#m-FEL irradiation, we observed the crystallization of amorphous structure which was induced by P-ion-implantation. These results indicated the FEL annealing of diamond at room temperature. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

International Nuclear Information System (INIS)

The effect of a mineralizer, magnesium silicate, on the nitridation of compacts consisting of silicon, clay, silica and silicon carbide was examined in terms of their reaction depth, density, porosity, phase composition and microstructure. It was found that addition of mineralizer slowed down the nitridation significantly. The kinetic process of isothermal nitridation in the presence of magnesium silicate obeys a parabolic rate law. Otherwise it obeys a linear rate law. The results suggest that nitrogen transportation is the limiting step during nitridation when mineralizer is added. The mechanism of nitridation is discussed in terms of phase composition and microstructure. Copyright (2000) The Australian Ceramic Society

Energy Technology Data Exchange (ETDEWEB)

Molar enthalpies of sublimation of 1,2,4-, 1,2,3-, and 1,3,5-tri-hydroxy-benzene, were obtained from the temperature dependence of the vapor pressure measured by the transpiration method. The molar enthalpies of fusion and molar heat capacities of these compounds were measured by DSC. The measured data sets of vaporization, sublimation and fusion enthalpies were checked for internal consistency. Strength of the inter- and intra-molecular hydrogen bonding in di- and tri-hydroxy-benzenes have been assessed.

Environmental Research Database

ObjectivesObjectives Not AvailableDescriptionTo determine the effects of water penetration on the burst strength of filament wound composite pipes which have been damaged by impact and then subjected to long term pressurisation with sea water. ~%~ To monitor and characterise the damage and effects of sea water penetration using ultrasonic NDT. To determine the burst strength of bonded composite pipe joints with and without defects and to see whether the defects can be detected using ultrasonic NDT. [continued...

Energy Technology Data Exchange (ETDEWEB)

The General-Purpose Heat Source (GPHS), an improved radioisotope heat source, employs a unique thermal insulation material, carbon-bonded carbon fiber (CBCF), to protect the fuel capsule and to help achieve the highest possible specific power. The CBCF insulation is made from chopped rayon fiber about 10 ..mu..m in diameter and 250 ..mu..m long, which is carbonized and bonded with phenolic resin particles. The CBCF shapes, both tubes and plates, are formed in a multiple molding facility by vacuum molding a water slurry of the carbonized chopped-rayon fiber (54 wt %) and phenolic resin (46 wt %). The molded shapes are subsequently dried and cured. Final carbonization of the resin is at 1600/sup 0/C. Machining to close tolerances (+-0.08 mm) is accomplished by conventional tooling and fixturing. The resulting material is an excellent lightweight insulation with a nominal density of 0.2 Mg/m/sup 3/ and a thermal conductivity of 0.24 W(m.K) in ...

Energy Technology Data Exchange (ETDEWEB)

The thesis deals with methods of describing the reservoir rock in central oil and gas fields on the Norwegian continental shelf. Methods of enhancing the level of recovery are dealt with. Following topics are given: Sand body dimensions and infill sequences of stable, humid-climate delta plain channels; minipermeameter-based study of permeability trends in channel sand bodies; significance of tidal cyclicity for modelling of reservoir heterogeneities in the lower Jurassic Tilje Formation, mid-Norwegian shelf; geometry and facies of large-scale flow units in fluvial-dominated fan-delta-front sequences; quantified fluvial architecture in ephemeral stream deposits of the Esplugafreda Formation (Palaeocene), Tremp-Graus Basin, northern Spain; the Safari project - collection and storage of field analogue data for quantitative reservoir modelling; sedimentary architecture of field analogues for reservoir information (SAFARI): a case study of the ...