Solid Impurities Research Articles

Removal of Liquid and Solid Impurities from Uranyl Nitrate Hexahydrate Crystalline Particles in Crystal Purification Process

The purification behavior of uranyl nitrate hexahydrate (UNH) was investigated to evaluate the decontamination performance of liquid and solid impurities using a dissolver solution of mixed oxide (MOX) fuel in batch experiments. The UNH crystal recovered from the MOX fuel dissolver solution containing simulated fission products (FPs) was purified by a sweating and melt filtration process. Although the decontamination factors (DFs) of Pu, Cs, and Ba did not change in the sweating process, that of Eu increased with increases in temperature and time. These results indicate that liquid impurities such as Eu were effectively removed by the sweating method, but solid impurities such as Pu, Cs, and Ba were minimally affected in the batch experiments. On the other hand, the DF of Ba increased with 0.45 and 5.0 μ filters in the melt filtration process. Since Pu and Cs formed as Cs2Pu(NO3)6 in the course of U crystallization and was accompanied with the UNH crystal, these behaviors were similar to each other. Although the DFs of Pu and Cs did not change with the 5.0 μ filter, it increased approximately twofold with the 0.45 μ filter. The particle size of Cs2Pu(NO3)6 is relatively small and might pass through the 5.0 μ filter in the melt filtration process. The liquid impurities as Eu remained in the molten UNH crystal with some filters.

Purification of Aluminum Nitrate Nonahydrate by Melt Crystallization

The objective of our study is to investigate the effect of melt crystallization on inorganic hydrate for purification of crystals including impurity. Melt crystallization is widely applied in the chemical and food industry to purify organic crystals by separating impurities inside the crystals. The target crystals are mainly organic crystals; however, some inorganic crystals are considered for purification by melt crystallization, because of having lower melting point as hydrate crystals. Therefore, we prepared hydrate crystals including impurities and carried out melt crystallization to investigate the purification mechanism on inorganic crystals. Aluminum nitrate nonahydrate was selected as purification target and strontium nitrate was selected as liquid impurity. As solid impurity, we selected barium nitrate. In conclusion, liquid impurity in target crystals was removed by sweating and washing with melt. Moreover, it was considered that the purification mechanism differs depending on the state of the impurity, and melt crystallization is an effective tool for purification the inorganic hydrate crystals.

Long‐living nanobubbles of dissolved gas in aqueous solutions of salts and erythrocyte suspensions

Results of experiments combining laser modulation interference microscopy and Mueller matrix scatterometry show that macroscopic scatterers of light are present in liquids free of external solid impurities. Experimental data on distilled water and aqueous NaCl solutions of various concentrations as well as physiological saline solution are reported. The experimental data can be interpreted by using a model of micron-scale clusters composed of polydisperse air nanobubbles having effective radii of 70-100 nm. Their concentration increases with the growth of ionic content. We hypothesize that under certain conditions those clusters of nanobubbles can affect the erythrocyte structure.

Performance of Alloy 625 under Combustion Gas Environments: A Review

The nickel-based alloy 625 in the form of thermal sprayed coatings, as weld overlay, and as an alloyed material has been used extensively to minimize high temperature oxidation and hot corrosion in incinerators, supercritical water oxidation processes, biomass-fired plants, and other industries. Corrosion in these applications occurs due to the combination of gaseous species in the form of CO2, O2, SO2, and HCl; and solid impurities which form chlorides and sulphates of alkali and heavy metals (K, Na, Zn, Pb, Sn, etc) with low melting points. Even though alloy 625 has some shortcomings under certain conditions at high temperatures, the alloy from its beginning has had significant success, and its production has increased considerably worldwide. This paper will review some aspects for which alloy 625 is the material of choice and explain its unique features in many applications.

The effect of structural flaws on the properties of the sapphire shell of a discharge radiation source

This paper is devoted to consideration of the key mechanisms of structural flaw formation in single-crystal sapphire tubes grown according to the method of A. V. Stepanov. The effects of solid and gaseous impurities and blocks on the optical properties and mechanical strength of the sapphire used as a shell in discharge lamps is investigated. Methods for improving the quality of sapphire tubes are proposed.

Interdiffusion Studies in the Co- Mo System

Study of interdiffusion in the Co-Mo system is important to understand the performance of turbine blades in jet engine applications. Mo is added to superalloys to increase the solid solution strengthening and the creep resistance. In this study, the interdiffusion coefficient in the Co(Mo) solid solution and impurity diffusion coefficient of Mo in Co are determined. Further, the activation energy and pre-exponential factors are calculated, which provide an idea about the atomic mechanism of diffusion.

Toxicological Methods for Tracing Drug Abuse: Chromatographic, Spectroscopic and Biological Characterisation of Ecstasy Derivatives

Analysis often reveals variability in the composition of ecstasy pills from pure 3,4-methylenedioxymethamphetamine (MDMA) to mixtures of MDMA derivatives, amphetamine, and other unidentified substances. For a comprehensive toxicological analysis one needs to know all steps to MDMA synthesis which may originate impurities. The aim of this study was to synthesise and determine the chemical-physical and in vitro biological properties of a series of MDMA derivatives.3,4-methylendioxyphenyl-2-nitropropene (MDNP) was obtained by condensation of piperonal with an excess of nitroethane in the presence of ammonium acetate. MDNP was then reduced to methylenedioxyamphetamine (MDA) by LiAlH3. All compounds were analysed using HPLC and spectroscopic technique [Raman, nuclear magnetic resonance (NMR), or infrared (IR)] at all the steps of synthesis. In addition, we assessed the biological potentials of these compounds by measuring in vitro their (i) blood cell/whole blood partition coefficient, (ii) binding to plasmatic proteins (Fbp), and (iii) membrane adsorption. Chemical structure was determined with antibody fluorescence polarisation immunoassay (FPIA). This study showed the presence of solid impurities, particularly of a neurotoxic compound of Al3+ in the final products. FPIA identified the aminoethane group close to the substituted benzene ring, but did not detect the two major precursors of MDMA: MDNP and piperonal. Raman spectroscopy is an attractive alternative technique to characterise ecstasy pills and it can identify stereoisomeric forms such as cis-MDNP and trans-MDNP, which exhibit signals at 1650 cm-1 and 1300 cm-1, respectively.

Adsorption efficiency of coconut shell-based activated carbons on colour of molasses, oils, dissolved oxygen and related parameters from industrial effluent

The adsorption efficiency of FeCl3, CaCl2 and K2CO3-activated carbon for the 500μm particle size produced from previously carbonized coconut shell on some adsorbates obtained from an industrial effluent and wastewaters as well as the colour of molasses has been studied. The adsorbates include oil and grease, dissolved oxygen (DO); biochemical oxygen demand (BOD) and chemical oxygen demand (COD), dissolved and suspended solids as well as total solids present in an industrial effluent sample. A colour comparator was used to determine the colour of the molassess, volumetric analysis was used to determine oxygen and related parameters while oil and grease were determined by gravimetry. The results showed that the activated carbons used in this study are capable of reducing the level of colour present in molasses and amount of oil/grease from a textile effluent. Ninety two and 97.4% of molasses and oil/grease respectively can be adsorbed onto 500μm particle size of ZnCl2 – activated carbon at room temperature. Out of the four activated carbons, (FeCl3-Ac, CaCl2-Ac, ZnCl2-Ac and K2CO3-Ac,) the FeCl3-Ac is most effective in adsorbing the dissolved oxygen, chemical oxygen demand, biochemical oxygen demand, dissolved, suspended and total solid present in a sample of a textile effluent. The FeCl3-Ac is more effective in adsorbing the solid impurities than the oxygen demands but least effective in adsorbing dissolved oxygen. There is a high correlation coefficient between the oxygen parameters and solids present in the effluent. This shows that the greater the amount of solids in an effluent the more the amount of oxygen required for biochemical and chemical processes. ZnCl2-activated carbon most effectively adsorbed 92.2% colour of the molasses while the FeCl3-activated was most effective in adsorbing 94.3% of oil/grease, 46.2% of dissolved oxygen, 71.9% of BOD, 72.1% of COD and 96% each of dissolved solids (DS), suspended solids (SS) and total solids (TS). The coefficients of correlation found between each of DO, COD or BOD and DS, SS and TS adsorbed were 0.999, 0.907 and 0.763 respectively. Key words: Coconut shell, activated carbon, adsorption, oxygen demand, solids.

Topological close packed μ phase formation and the determination of diffusion parameters in the Co–Mo system

The study on the formation and growth of topological close packed (TCP) compounds is important to understand the performance of turbine blades in jet engine applications. These deleterious phases grow mainly by diffusion process in the superalloy substrate. Significant volume change was found because of growth of the μ phase in Co–Mo system. Growth kinetics of this phase and different diffusion parameters, like interdiffusion, intrinsic and tracer diffusion coefficients are calculated. Further the activation energy, which provides an idea about the mechanism, is determined. Moreover, the interdiffusion coefficient in Co(Mo) solid solution and impurity diffusion coefficient of Mo in Co are determined.

Determination of the microstructure of gas bubbles in highly purified water by measuring the elements of the laser radiation scattering matrix

Modulation interference microscopy and measurements of the elements of the light scattering matrix showed that doubly distilled water purified from solid impurities contains macroscopic scatterers in the form of micron clusters formed by polydisperse air bubbles with the effective radius 70–90 nm. The fractal dimension of clusters lies within 2.4–2.8 and their concentration is ∼106 cm-3.

Nanoscale structure of dissolved air bubbles in water as studied by measuring the elements of the scattering matrix

Results of experiments with laser modulation interference microscopy and the Mueller-matrix scatterometry show that macroscopic scatterers of light waves are present in doubly distilled water free of external solid impurities. The experimental data can be interpreted using a computational model of micron-scale clusters composed of polydisperse air bubbles having effective radii of 70-90 nm. The fractal dimension of such clusters was evaluated as 2.4-2.8 and their concentration appeared to be approximately 10(6) cm(-3).

Development of an Aqueous Palm Oil Extraction System

Continuous attempts have been made to re-examine the aqueous extraction of palm oil (through pit technology) and device a means of improving the technology particularly for the small-scale processors. A novel aqueous batch extraction system was developed and was subsequently evaluated for its performance in palm oil processing. The crude oil produced from the traditional pit technology and aqueous batch extraction system were compared and evaluated using a 23 factorial experimental design. The factors considered were fruit sterilization time, variety of fruit and processing technology. The crude oil produced at different factor levels was assessed for its solid impurities, moisture content and oil content. The result indicates that the crude oil yield from batch extraction system are higher with values of 30.4%, 30.9%, 42.0% and 43.2% compared with pit technology method with 26.8%, 27.7%, 38.6% and 39.6% respectively. The throughput of the batch extraction system (120kg of mash/ h) was found to be higher than pit technology that could take only 65kg of mash / h. Keywords: palm oil, aqueous-extraction, traditional-method, mechanical system, efficiencyDiscovery and Innovation Vol. 19 (3) 2007: pp. 202-207

Reply to comment by M. A. Kendrick and D. Phillips (2009) on “The Paleozoic metamorphic history of the Central Orogenic Belt of China from 40Ar/ 39Ar geochronology of eclogite garnet fluid inclusions” by Hua-Ning Qiu and J. R. Wijbrans (2008) [Earth Planet. Sci. Lett. 268 (2008) 501–514

The 40Ar/ 39Ar apparent ages found by Qiu and Wijbrans [Qiu, H.N. and Wijbrans, J.R., 2008. The Paleozoic metamorphic history of the Central Orogenic Belt of China from 40Ar/ 39Ar geochronology of eclogite garnet fluid inclusions. Earth Planet. Sci. Lett., 268, 501–514. doi: 10.1016/j.epsl.2008.01.042; Qiu, H.N. and Wijbrans, J.R., 2006. Paleozoic ages and excess 40Ar in garnets from the Bixiling eclogite in Dabieshan, China: new insights from 40Ar/ 39Ar dating by stepwise crushing. Geochim. Cosmochim. Acta, 70, 2354–2370. doi: 10.1016/j.gca.2005.11.030.] for crushing in vacuo experiments on Dabieshan eclogite garnets are best explained by a simple mixing model with radiogenic 40Ar ⁎ and air argon for the final plateau data, and excess 40Ar released in the initial crushing steps. More intricate models such as the hypothesized mixture of phengite, K-feldspar, amphibole and omphacite solid impurities by Kendrick [Kendrick, M.A., 2007. Comment on ‘Paleozoic ages and excess 40Ar in garnets from the Bixiling eclogite in Dabieshan, China: new insights from 40Ar/ 39Ar dating by stepwise crushing by Hua-Ning Qiu and J.R. Wijbrans’. Geochim. Cosmochim. Acta, 71, 6040–6045. doi: 10.1016/j.gca.2007.01.029.] and Kendrick and Phillips [Kendrick, M.A. and Phillips, D., 2009. Discussion of ‘The Paleozoic metamorphic history of the Central Orogenic Belt of China from 40Ar/ 39Ar geochronology of eclogite garnet fluid inclusions by Qiu Hua-Ning and Wijbrans J.R.’. Earth Planet. Sci. Lett.] cannot explain the consistently observed 40Ar/ 39Ar age plateaux and isochrons because mixing of more than two K-containing end members each with different ages, different initial 40Ar/ 36Ar ratios and different proportional argon release patterns cannot define an isochron and age plateau, and the solid inclusion mixing model fails to address the consistently observed correlation between the radiogenic signal and chlorine derived 38Ar.

Producing and quantifying enriched para-H2

The production of enriched para-H(2) is useful for many scientific applications, but the technology for producing and measuring para-H(2) is not yet widespread. In this note and in the accompanying auxiliary material, we describe the design, construction, and use of a versatile standalone converter that is capable of producing para-H(2) enrichments of up to > or = 99.99% at continuous flow rates of up to 0.4 SLM. We also discuss para-H(2) storage and back conversion rates, and improvements to three techniques (thermal conductance, NMR, and solid hydrogen impurity spectroscopy) used to quantify the para-H(2) enrichment.

Study of nanostructure of highly purified water by measuring scattering matrix elements of laser radiation

Experiments on modulation interference microscopy and measurement of light scattering matrix elements showed that double distilled water purified from solid impurities contains macroscopic scatterers of optical radiation. It follows from numerical calculation that these scatterers can be micrometer-scale clusters formed by polydisperse air bubbles with effective radii of 70 to 90 nm. The fractal dimension of such clusters is within 2.4–2.8 and their concentration is ∼ 106 cm−3.

Effect of Solid Solution Impurities on Dislocation Nucleation During Nanoindentation

Dislocation nucleation in solid solutions of face-centered-cubic metallic materials was studied using nanoindentation. The effects of solute impurities in the copper–nickel system on the formation of dislocations in a previously dislocation-free region were demonstrated to be minimal. The shear stress required to nucleate dislocations in copper is approximately 1.6 GPa, while in nickel a 3.9 GPa shear stress is required. Changes in shear stress for nucleation track closely with changes in elastic modulus showing the nucleation stress is approximately 1/30 to 1/20 of the shear modulus. The expected solid-solution strengthening is identified within the same experimental method, demonstrating unambiguously the fact that solid-solution impurities in this system will impact the propagation of dislocations during plastic deformation but not alter the homogeneous nucleation of dislocations in these materials.

Mathematical modeling and computer simulation of molten metal cleansing by the rotating impeller degasser: Part I. Fluid flow

The removal of dissolved hydrogen and solid impurity particles from molten alloys by rotary degassing is a widely used foundry practice. Rotary degassing involves purging a gas into the molten alloy through holes in a rotating impeller. Monatomic dissolved hydrogen either diffuses into these gas bubbles or it forms diatomic hydrogen gas at the bubbles’ surface; in any case, hydrogen is removed from the melt with the rising bubbles. Simultaneously, solid particles in the melt collide with one another due to turbulence created by the impeller rotation and the gas flow and form aggregates. These aggregates either settle to the furnace floor, or are captured by the rising gas bubbles and are also removed from the melt. A mathematical model has been developed to simulate the turbulent multiphase flow field that develops in the melt during rotary degassing. The mathematical model allows calculation of the mean turbulence dissipation energy and the distribution of gas bubbles in the melt. Both these quantities are input into other mathematical models that simulate the removal of dissolved hydrogen and impurity solid particles from the melt.

Interaction of Impurity (Li, Be, B and C) and Hydrogen Isotope Pellet Injection with Reactor-relevant Plasmas

Based on the two-dimensional kinetic ablation theory of the hydrogen pellet ablation developed by Kuteev [B.V. Kuteev, Nuclear Fusion, 35 (1995) 431], an algorithm of erosion speed and ablation rate calculations for Li, Be, and B impurity pellets in reactor-relevant plasma has been derived. Results show compatibilities of lithium pellet injection used in α-particle diagnostics are positive in comparison with other solid impurity pellets (e.g. Be, B and C). Using the 2-D Kuteev lentil model, including kinetic effects, we find that currently existing pellet injection techniques will not meet core-fueling requirements for ITER-FEAT. A pressure as high as 254 MPa must be applied to a pellet accelerator with a 200 cm-long single-stage pneumatic gun, in order to accelerate a pellet with a radius rp0 = 0.5 cm to a velocity of νp0, 24 × 105 cm/s penetrating 100 cm into the ITER plasma core. Comparisons of pellet velocity- and radius-dependent penetration depth between the Neutral Gas Shielding and the Kuteev's models are made. However, we find that the isotopic effects can lead to a 33% lower pellet speed for solid DT, compared to an identical H2 pellet penetrating the same length in ITER-FEAT plasma, and our calculations show that HFS injection will much improve core fueling efficiency.

Mathematical modeling and computer simulation of molten aluminum cleansing by the rotating impeller degasser: Part II. Removal of hydrogen gas and solid particles

Rotary degassing is widely used in the foundry industry for removing hydrogen gas and solid impurities from molten aluminum alloys. In this method, a specially designed impeller rotates inside the melt and gas is purged into the molten alloy through holes located at the bottom of the impeller. The purged gas forms bubbles that rise to the melt's surface. While rising, the bubbles pick up hydrogen gas and solid impurities from the melt and carry them to the surface where they are incorporated into the sludge layer. Removal of hydrogen from the melt is essentially a consequence of diffusion of the dissolved hydrogen from the melt into the rising gas bubbles, and removal of solid particles is a consequence of their clustering and settling, as well as their attachment to the rising gas bubbles. A mathematical model is developed to simulate the removal of hydrogen and unwanted solid particles from aluminum alloy melts. Hydrogen removal is modeled by applying conservation of mass to the melt and developing a hydrogen mass balance. Similarly, particle removal is modeled by applying a special particle population balance. This model is comprehensive as it allows simulation of the entire rotary degassing melt-cleansing process including the removal of unwanted particles and hydrogen gas.

環境負荷低減のための廃食用油利用システムの検討

Thermal recovery of used cooking oil yielded in a university campus was examined. The used oil was directly combusted for generating hot water. Because the oil obtained contains much amount of solid impurities and water, ultra sonic treatment was carried out for preparing fuel from the waste. Simple assessment on the CO2 emission resulted in the reduced emission, which could be emphasized by longer utilization. The limited oil amount yielded and also the discontinuous thermal demand in the university campus were the important factors for completing the utilizing system.