Solid Phase Deposition Research Articles

Blocking Behavior of Organic Solid Phase in the Carbon Dioxide Multiphase and Multicomponent Displacement Process

Better dealing with carbon issues can support the management of current greenhouse gas emissions while achieving energy economic diversification and energy security. Carbon dioxide displacement has become the most acknowledged and practical method in enhanced oil recovery system. This is because of its oil sweep efficiency and ability to reduce the level of greenhouse gas emission. Nevertheless, it would lead to the organic solid phase deposition, which causes the changes of the wettability and the damages of wellbores and reservoirs. In this study, we used slim tube test and component test to research the dynamic characteristics of displacement process. In addition, the mechanism of porous media blockage was also investigated. Results show that when the displacement pressure closed to the minimum miscibility pressure, reservoir blockage in pore throat could happen. Component test characterizes that during near miscible displacement process, the components of oil sample varied obviously, the variation range of peak component carbon marks fluctuated strongly. Crude oil component differentiation could happen after carbon dioxide fully contacted with oil. Besides, the rapid extraction mechanism of aromatic hydrocarbons played a significant role in this process under such condition. The reason is that the solubility of saturated hydrocarbons to asphaltene and non-hydrocarbons is obviously weaker than aromatic hydrocarbons. Controlling the pressure is considered as an important link to prevent the occurrence of blocking in the carbon dioxide multiphase and multicomponent displacement process.

Amorphous Solid Phase Deposition of Ions and Phosphate within Eukaryotic Mitochondrial Matrices - Imaging and Characterization by CryoSTEM Tomography and Energy- Dispersive X-ray Spectroscopy

Amorphous Solid Phase Deposition of Ions and Phosphate within Eukaryotic Mitochondrial Matrices - Imaging and Characterization by CryoSTEM Tomography and Energy- Dispersive X-ray Spectroscopy

Influence of injection pressure and injection volume of CO2 on asphaltene deposition

ABSTRACTTo further improve the oil displacement effect by CO2 flooding, the trends and conditions of asphaltene deposition under different injection pressures and injection volumes of CO2 were studied by SDS solid phase deposition testing system, high temperature and high pressure microscope, and P-X phase diagram. When the mole fraction of CO2 in crude oil increases to a certain value, asphaltene deposition appears. The lower the pressure, the lower the mole fraction of CO2 in crude oil causing the asphaltene deposition there is. After the onset of asphaltene deposition, the degree of deposition increases with an increase in pressure. The amount of the deposited asphaltene under miscible displacement is the highest, under near-miscible displacement is the second highest, and under immiscible displacement is the lowest. When the dissolution of CO2 in crude oil reaches the saturation point, the asphaltene deposition becomes slow. Besides, it is feasible to prevent or reduce the asphaltene deposition by adjusting the thermodynamic parameters according to the phase behaviors of the CO2-crude oil system. The experimental results can provide theoretical basis for optimization design of the parameters of CO2 flooding.

Influence of peritectic transformation on the hardening, structure, and properties of steel castings

The influence of peritectic transformation on the deposition of solid phase over the cross section of pearlitic steel ingots with 0.2–0.4% C is studied. To prevent structural and chemical microheterogeneity, measures ensuring dense and uniform metal over the casting cross section are proposed.

Occurrence of Atrazine and Related Compounds in Sediments of Upper Great Lakes.

Surface grab and core sediment samples were collected from Lakes Michigan, Superior, and Huron from 2010 to 2012, and concentrations of herbicides atrazine, simazine, and alachlor, as well as desethylatrazine (DEA), were determined. Concentrations of atrazine in surface grabs ranged from 0.01 to 1.7 ng/g dry weight and are significantly higher in the southern basin of Lake Michigan (latitude <44°) than other parts of the three lakes. The highest concentration of alachlor was found in sediments of Saginaw Bay in Lake Huron. The inventory and net fluxes of these herbicides were found to decline exponentially from the south to the north. The concentration ratio of DEA to atrazine (DEA/ATZ) increased with latitude, suggesting degradation of atrazine to DEA during atmospheric transport. DEA/ATZ also increased with sediment depth in the sediment cores. Diffusion of deposited herbicides from the upper sediment into deeper sediments has occurred, on the basis of the observed patterns of concentrations in dated sediment cores. Concentrations of atrazine in pore water were estimated and were higher than those reported for the bulk waters, suggesting the occurrence of solid-phase deposition of atrazine through the water column and that contaminated sediments act as a source releasing atrazine to the overlying water.

Sputtered alumina as a novel stationary phase for micro machined gas chromatography columns

Silica and graphite sputtering have previously been reported as novel solid stationary phase deposition techniques for micro gas chromatography columns. As a conventional solid stationary phase in gas chromatography, compatible with sputtering yet so far unreported, alumina was evaluated in this study. Alumina sputtered semi-packed micro columns were fabricated (including an activation step) and proved able to separate a mixture of volatile alkanes (C1-C4 with isomers) in less than 1min. Kinetic and a thermodynamic evaluation led to calculation of 4,500 theoretical plates for ethane in 1.1m (HETPmin = 250μm) and a Gibbs free energy for propane of 30.2kJmol(-1), making this stationary phase's properties very close to those observed with silica-sputtered micro columns.

Direct laser printing of thin-film polyaniline devices

We report the fabrication of electrically functional polyaniline thin-film microdevices. Polyaniline films were printed in the solid phase by Laser-Induced Forward Transfer directly between Au electrodes on a Si/SiO2 substrate. To apply solid-phase deposition, aniline was in situ polymerized on quartz substrates. Laser deposition preserves the morphology of the films and delivers sharp features with controllable dimensions. The electrical characteristics of printed polyaniline present ohmic behavior, allowing for electroactive applications. Results on gas sensing of ammonia are presented.

Use of trivalent iron bacterial sulfuric acid solutions in hydrometallurgy

Differences are established for composition, physicochemical, rheological, and processing properties of trivalent iron bacteriological solutions from solutions without bacteria, governing predominantly the use of oxidation with bacteria in hydrometallurgical processes. Bacterial solutions have considerable oxidation-reduction potential, solubility of trivalent iron compounds, viscosity, and low surface tension. As a result of this, the oxidation rate for sulfides and solid phase deposition in bacterial solutions is higher than in solutions without bacteria.

The effect of post-treatments on the powder morphology of titanium dioxide (TiO2) powders synthesized for cold spray

In this study, a novel synthesis method of TiO2 powders that can be cold sprayed is presented. The synthesis technique is a simple hydrolysis method of titanyl sulfate (TiOSO4) in distilled water with a small addition of inorganic salt. At a relatively low hydrolysis temperature, pure anatase TiO2 can be obtained and post-synthesis treatments (annealing or hydrothermal treatment) do not alter this phase structure. The powder is agglomerated with fine nano primary particles, with different post-synthesis treatments leading to different TiO2 nanostructures. Annealing causes a significant growth of primary particles with the existence of internal pores within a particle. On the other hand, hydrothermal treatment produces a unique oriented agglomeration structure where the primary particles are agglomerated in one single crystal axes. It is believed that the synergistic effect of inorganic ion adsorption and post-treatments results in the observed nanostructures. After cold spraying, it is revealed that these TiO2 powders could be deposited via supersonic solid phase deposition (cold spray).

On the energetics of chemolithotrophy in nonequilibrium systems: case studies of geothermal springs in Yellowstone National Park

ABSTRACTChemolithotrophic micro‐organisms are important primary producers in high‐temperature geothermal environments and may catalyse a number of different energetically favourable redox reactions as a primary energy source. Analysis of geochemical constituents followed by chemical speciation and subsequent calculation of reaction free energies (ΔGrxn) is a useful tool for evaluating the thermodynamic favourability and potential energy available for microbial metabolism. The primary goal of this study was to examine relationships among geochemical gradients and microbial population distribution, and to evaluate the utility of energetic approaches for predicting microbial metabolism from free‐energy calculations, utilizing as examples, several geothermal habitats in Yellowstone National Park where thorough geochemical and phylogenetic analyses have been performed. Acidic (pH ∼ 3) and near‐neutral (pH ∼ 6–7) geothermal springs were chosen for their range in geochemical properties. Aqueous and solid phase samples obtained from the source pools and the outflow channels of each spring were characterized for all major chemical constituents using laboratory and field methods to accurately measure the concentrations of predominant oxidized and reduced species. Reaction free energies (ΔGrxn) for 33 oxidation–reduction reactions potentially important to chemolithotrophic micro‐organisms were calculated at relevant spring temperatures after calculating ion activities using an aqueous equilibrium model. Free‐energy values exhibit significant variation among sites for reactions with pH dependence. For example, free‐energy values for reactions involving Fe3+ are especially variable across sites due in large part to the pH dependence of Fe3+ activity, and exhibit changes of up to 40 kJ mol−1 electron from acidic to near neutral geothermal springs. Many of the detected 16S rRNA gene sequences represent organisms whose metabolisms are consistent with exergonic processes. However, sensitivity analyses demonstrated that reaction free energies do not generally represent the steep gradients in local geochemical conditions resulting from air–water gas exchange and solid phase deposition that are important in defining microbial habitats and 16S rRNA gene sequence distribution within geothermal outflow channels.

Growth of β-FeSi2 layers on Si (111) by solid phase and reactive deposition epitaxies

Iron silicides were grown on Si (111) substrates by Solid Phase Epitaxy (SPE) and Reactive Deposition Epitaxy (RDE) to identify the optimum conditions to obtain the semiconduting β-FeSi2 phase. The films were produced under different growth and annealing conditions and analyzed in situ and ex situ by X-ray Photoelectron Spectroscopy, and ex situ by Conversion Electron Mössbauer Spectroscopy. The use of these techniques allowed the investigation of different depth regions of the grown layer. Films of the ɛ-FeSi and β-FeSi2 phases were obtained as well as the mixtures Fe3Si+ɛ-FeSi and ɛ-FeSi+β-FeSi2. The sequence Fe3Si→ɛ-FeSi→β-FeSi2 was found upon annealing, where the phase transformation occurred due to the migration of silicon atoms from the substrate to the surface region of the grown layer. The best conditions for the phase transformation in SPE samples were met after annealing in the range 700 – 800 °C. For the RDE samples, the transition to the beta phase occurred between 600 and 700 °C, but pure β-FeSi2 was obtained only after two hours of annealing at 700 °C.

Recovery of fortified (2 ppb) EPA method 525.1 analytes from Chesapeake Bay water via solid phase deposition followed by supercritical fluid elution

AbstractApplication of solid phase deposition/supercitical fluid (SPD/SF) elution to real, brackish water samples, obtained from the Chesapeake Bay, has been investigated. The fortified (2ppb) brackish water samples contained suspended sediment, dissolved organic matter and salt. The sediment made post‐deposition drying of the SPE disk difficult and the residual water interfered with analyte recovery. Attempts to dry the disk included increasing the vacuum drying time, use of a higher percent of modifier, and desiccation. The best results were obtained by first drying the disk for 10 min under a stream of nitrogen, followed by overnight desiccation, and finally, SF elution. The SF method required a 3 step, 42 min extraction which reduced organic solvent use by 60% compared to traditional elution. All but five analytes met EPA criteria when fresh desiccant was used to dry the disk; four of the unacceptable recoveries were presumably due to plasticizer contamination.

直流磁場印加の下での溶融塩電析

The effect of a direct magnetic field on the solid phase deposition of aluminum has been studied by using the molten salt of 2AlCl3-NaCl with addition of 5 mass% MnCl2. In the weak magnetic field range natural convection predominates the mass transfer rate of deposition and in the strong magnetic field range electromagnetic force controls the mass transfer rate and increases the critical current density to keep the deposition surface bright and smooth. Based on the boundary layer theory taking account of the electromagnetic force the analytical expression of the mass transfer rate has been derived. The theoretical result predicts the critical current density is proportional to one third power of the magnetic flux density and is confirmed by the experimental results.

Sensitive enzyme-linked immunosorbent assay for detection of Clostridium botulinum neurotoxins A, B, and E using signal amplification via enzyme-linked coagulation assay.

A new immunoassay amplification method has been applied to the measurement of toxins A, B, and E from Clostridium botulinum. The technique is a modified enzyme-linked immunosorbent assay (ELISA) which relies on the detection of sandwich complexes on microtiter plates by a solid-phase coagulation assay known as ELCA, or enzyme-linked coagulation assay. In the method, a coagulation activating enzyme (RVV-XA) isolated from the venom of Russell's viper is conjugated to affinity-purified horse antibodies specific for toxin type A, B, or E. Plates are coated with affinity-purified antibodies, and standard captag (capture-tag) protocols using labeled antibody are employed to bind the toxin from solution. Complexes are detected by adding a modified plasma substrate which contains all the coagulation factors mixed with alkaline phosphatase-labeled fibrinogen and solid-phase fibrinogen; deposition of solid-phase, enzyme-labeled fibrin on the solid phase is then a reflection of formation of toxin-RVV-XA-antibody complexes on the solid phase. Because of the ability to detect RVV-XA by this coagulation assay at concentrations < 0.1 pg/ml, it was possible to measure C. botulinum toxins A, B, and E at mouse bioassay levels (< 10 pg/ml, or < 0.07 pM) for both purified neurotoxin and crude culture filtrates obtained from strains known to produce appropriate single toxins. ELISA-ELCA should be applicable to measurement of toxins in most of the materials (contaminated food, blood, and excreta) for which the comparably sensitive mouse bioassay is currently employed. This method has the potential of broad application to the measurement of low concentrations of any antigen for which appropriate immunochemical reagents are available, in a color test format.

Dealing with highly active wastes formed in nuclear-fuel regeneration

At present, highly active liquid wastes are concentrated by boiling down in standard evaporation units and sent for temporary storage in special stainless-steel holding tanks of volume ranging from a few tens to a few hundreds of cubic meters. The tanks are fittted with spiral cooling units, which maintain a temperature of no more than 50-60~ in the wastes throughout storage. The complex chemical composition of the wastes results in a set of radiation-chemical transformations, which may lead to the release of gaseous products and deposition of solid phase. Hazardous concentrations of hydrogen in the gas space of the tank are prevented by continuous blowing of air above the level of the liquid radioactive wastes, with subsequent purification of the air from aerosols in special filters. The pH values of the liquid wastes are continuously monitored and corrected here, in order to exclude the deposition of solid phase. With the aim of increased reliability and prevention of escape of the wastes into the environment, the tanks are fitted with double walls and special drip pans for collecting any leakage and returning it rapidly to the tank.

Intensification of heat-transfer processes in disperse system flow with solid phase deposition

The influence of the thickness of particle deposits and surface roughness on the heat-transfer and resistance coefficients is examined. It is shown that for high degrees of roughness resulting from the deposition of coarse particles, the efficiency decreases with increase in the thickness of the layer deposited, even at large Re numbers.

Heat and mass transfer in a gas‐transport reactor for multicomponent solid phase deposition

AbstractGas temperature distribution in an epitaxial horizontal flow reactor was measured by means of a thin thermoprobe and measurement error was calculated. For a turbulent gas flow, the thickness of an equilibrium layer was estimated, the results obtained being coincident with the boundary layer thickness determined from the relationships for gas temperature distribution in the reactor. The distribution pattern of the rates of mass‐transfer processes is discussed with reference to multicomponent solid phase deposition lengthwise the reactor. That the layer of nearly uniform composition can be deposited under turbulent flow conditions only is exemplified by the deposition of solid solutions of aluminium and gallium nitrides.

The Formation and Remineralization of Artificial White Spot Lesions: A Constant Composition Approach

Artificial white spot lesions have been prepared on bovine enamel surfaces by the controlled addition of lactate buffer containing methylhydroxydiphosphonate ions. The rates of remineralization have been measured using a constant composition method in solutions of calcium phosphate of low supersaturation. Deposition of new hydroxyapatite solid phase takes place exclusively within the white spot lesion at a rate appreciably slower than that of an acid-etched enamel surface, probably due to the presence of methylhydroxydiphosphonate located within the intact surface region of the lesion.