magnesium nitrate strontium: Topics by WorldWideScience.org

Entrained Solids, Strontium-Transuranic Precipitation, and Crossflow Filtration of AN102 Small C

Carrier-free "8"8Y radioisotope, which has the longest half life (T=106.6 d) of yttrium radioisotopes and is a #gamma#-ray emitter, was obtained by proton irradiation of strontium, followed by cooling for one month. Then, "8"8Y was purified by precipitating strontium as strontium nitrate and extracting yttrium with tri-n-butyl phosphate (TBP). The decontamination factor of strontium to yttrium was more than 4x10"3 and chemically pure yttrium radioisotope was obtained. (author) 6 refs.

3

Effect of different fuels on the strontium hexaferrite nanopowder synthesized by a surfactant-assisted sol-gel auto-combustion method

This work is the first active crossflow filter testing of the new strontium-permanganate process for Envelope C at the Savannah River Technology Center. Extreme filtration difficulties with the ferric hydroxide precipitation led to investigations of other chemistries with simulants. The current process includes the isotopic dilution by precipitation from inactive strontium nitrate addition. A permanganate strike to replace ferric reagents was found to provide practical filterability and good lanthanide or transuranic decontamination. That work had been supported with simulant and active beaker testing.

2000-09-27

4

British Library Electronic Table of Contents (United Kingdom)

In this research a sol-gel auto-combustion route has been proposed to synthesize strontium hexaferrite nanopowder, using metal nitrates, ammonia as pH adjusting agent, n-decyltrimethylammonium bromide as a cationic surfactant and different fuels such as citric acid, glycine, acetylacetone and oxalic acid. The formation temperature of strontium hexaferrite and its crystallite size in presence of different fuels were compared together. The results showed the lowest formation temperature as well as the smallest crystallite size in the presence of citric acid as 900degreeC and 37.3nm respectively.

2007-01-01

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Determination of some minor and trace elements in iron ores by ion exchange chromatography, spectrophotometry and atomic absorption spectrometry

A sample preparation for quantitative determination of magnesium in individual lymphocytes by electron probe X-ray microanalysis.

A method is described for determination of aluminium, cadmium, cobalt, chromium, copper, calcium, magnesium, sodium, potassium, manganese, nickel, lead, strontium, zinc, titanium and vanadium in iron ore. After dissolution, a 1 gram sample of iron ore is applied to a column of AGI-X8 anion exchange resin (chloride form), in 100 ml of 7M HCl. Aluminium, chromium, calcium, magnesium, sodium, potassium, manganese, nickel, lead, strontium, titanium and vanadium are eluted with 7M HCl; iron, copper and cobalt are eluted with 0.5M HCl; cadmium and zinc are eluted with 2M HNO_3. Iron is subsequently removed from copper and cobalt by a solvent extraction with methyl isobutyl ketone. The elements are determined in the eluates by atomic absorption spectrometry, except for titanium and vanadium, which are determined spectrophotometrically.

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We present a sample preparation method for measuring magnesium in individual whole lymphocytes by electron probe X-ray microanalysis. We use Burkitt's lymphoma cells in culture as the test sample and compare X-ray microanalysis of individual cells with atomic absorption analysis of pooled cell populations. We determine the magnesium peak-to-local continuum X-ray intensity ratio by electron probe X-ray microanalysis and calculate a mean cell magnesium concentration of 39 +/- 19 mmol/kg dry weight from analysis of 100 cells. We determine a mean cell magnesium concentration of 34 +/- 4 mmol/kg dry weight by atomic absorption analysis of pooled cells in three cell cultures. The mean cell magnesium concentrations determined by the two methods are not significantly different. We find a 10% coefficient of variation for both methods of analysis and a 30% coefficient of variation in ...

1986-01-01

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Phase diagrams

Testing of the SpinTek Rotary Microfilter Using Actual Waste

The description is presented of binary phase diagrams of titanium alloyed with the following elements: silver, aluminium, arsenic, gold, boron, barium, beryllium, bismuth, carbon, calcium, cadmium, cobalt, chromium, copper, iron, gallium, germanium, hydrogen, hafnium, indium, iridium, potassium, lithium, magnesium, manganese, molybdenum, nitrogen, sodium, niobium, nickel, oxygen, osmium, phosphorus, lead, palladium, platinum, plutonium, rhenium, lanthanium, cerium, preseodymium, neodymium, gadolinium, erbium, terbium, thulium, lutetium, rhodium, ruthenium, scandium, silicon, tin, strontium, tantalum, technetium, thorium, uranium, vanadium, tungsten, yttrium, ytterbium, zinc and zirconium.

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Strontium isotopic anomalies in the Allende meteorite

The Department of Energy selected caustic-side solvent extraction (CSSX) as the preferred cesium-removal technology for SRS high-level waste. In the pretreatment step of the CSSX flowsheet, the incoming salt solution, which contains entrained sludge, is contacted with MST to adsorb strontium and selected actinides. An alternative approach replaces MST with the addition of sodium permanganate, strontium nitrate, and hydrogen peroxide. The pretreatment operation then filters the resulting slurry to remove the sludge and MST or manganese oxide and strontium carbonate solids. The filtrate receives further treatment in the solvent extraction system. SRTC personnel coordinated tests using a SpinTek rotary microfilter at the vendor location in FY01. These tests demonstrated a significant improvement - 2.5 to 6 times increase - in performance relative to the conventional cross-flow filter units. Rotary ...

2004-02-13

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Investigation of new materials for SOFC applications; Untersuchungen zum Einsatz neuer Werkstoffe fuer SOFC-Anwendungen

Not Available

1978-07-01

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Thermodynamics of aqueous magnesium chloride, calcium chloride, and strontium chloride at elevated temperatures

Fuel cells based on solid oxides ('SOFC') are excellent alternative devices for power generation, when they are operated at high temperature, e.g. above 600 C. Having only fixed parts for the power generating part of the device is only one advantage of the fuel cell. Due to their unique design, these devices offer a maximum of efficiency for energy conversion compared to conventional power generating systems, which are mainly based on turbines. One aim of this thesis is the examination of alternative electrolyte and cathode materials for the SOFC applications at reduced temperatures, which means in the temperature range between 600 C and 750 C. For the first main task, several materials from the oxygen ion conducting electrolytes were selected. Different strontium and magnesium doped lanthanum gallate (LSGM) materials with additional transition metal doping were selected and prepared via two different preparation methods. The ...

2007-05-04

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Fractionation of isotopes of alkali metals and alkaline earth metals in ion exchange chromatography

Heat capacities and densities of aqueous MgCl/sub 2/, CaCl/sub 2/, and SrCl/sub 2/ from the accompanying paper are combined with literature data up to 473 K to yield temperature-dependent equations by using the ion-interaction model of Pitzer. These heat capacity equations have been integrated to yield the enthalpy and the Gibbs energy. The enthalpy parameters for 298 K are evaluated in separate calculations using published high-temperature osmotic data as well as heats of dilution, while the Gibbs energy parameters for 298 K are taken from the literature. The range of validity of the final equations is described.

1987-01-01

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A method for preventing cathodic deposition of molybdenum subchloride in LiCl-KCl molten salt

Fractionation of isotopes of the alkali metals and the alkaline earth metals in ion exchange chromatography of their chlorides was studied. The heavier isotopes of potassium and rubidium were found to be preferentially fractionated into the ion exchanger phase while the lighter isotopes of lithium, magnesium, calcium and strontium were enriched in the exchanger phase. This can be interpreted as a resultant of the relative significance of isotope effect upon dehydration and isotope effect accompanying the phase change of the hydrated metal ion. Found was no evidence of anomalous isotope effect attributable to the odd-even difference in mass number of isotopes. Based on the spectroscopic and solution chemical data (experimental and theoretical), the isotopic reduced partition function ratios of the hydrated alkaline metal ions and stretching force constants of metal ion-hydrating water bonds were estimated. (author).

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Chromatography of metal ions with a triazine chelating resin

Effects of ions of Group IA, IIA, IIIB, and VIIB elements on the cathodic deposition of a molybdenum were investigated in a KCl-LiCl (eutectic)-MoCl/sub 3/ molten salt at 773 K (500/degree/C). The results can be summarized as follows: The addition of potassium, rubidium, cesium, and barium cations and fluorine anions to the KCl-LiCl (eutectic)-MoCl/sub 3/ molten salt is effective in depressing the cathodic deposition of the molybdenum subchloride, which hinders the smooth, flat electrodeposition of molybdenum. The addition of lithium, sodium, magnesium, calcium, strontium, and aluminum cations and bromine and iodine anions promotes the undesirable cathodic deposition of the molybdenum subchloride.

1989-01-01

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Comparison of NH_4"+-N and NO_3"--N nutrition in hybrid and conventional rice at the late growth stage

The synthesis, characterization, and some analytical applications of a new triazine resin are described. Separation of group IB, IIB, VIB, and VIIB metal ions from group VIII metal ions is achieved by this PDT-4 resin. Calcium(II) and magnesium(II) are taken up at pH = 6, 0.1 M acetate and are eluted at pH = 6, 0.1 M sodium nitrate. Copper(II) is retained at pH = 6, 0.1 M acetate and pH = 1 hydrochloric acid and is eluted subsequently by 5 M perchloric acid. Molybdenum(VI) is sorbed selectively from 0.1 N sulfuric acid or hydrochloric acid and is eluted in a tight band by 0.1 N sodium hydroxide. Numerous rapid column chromatographic separations are reported using this new resin, including analysis of NBS standard samples.

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The difference of NH_4"+-N/NO_3"--N nutrition between hybrid and conventional rice varieties at the late growth stage was studied by using "1"5N-tracer technique. The results showed that the nitrate fertilizer utilization efficiency by the hybrid rice after anthesis was 7.8% higher than that by the ordinary rice variety, and the nitrate fertilizer recovery fraction by the former was 13.2% greater than that by the latter. The varietal difference in NO_3"--N uptake and utilization was almost twice as that in NH_4"+-N. It was also showed that "1"5N distribution in ear of the hybrid rice was about 20% greater than that of the conventional variety, but there were no obvious differences between NO_3"--N and NH_4"+-N. However, "1"5N distribution in the lower node leaves and root was found to be significant higher with NO_3"--N than that with NH_4"+-N in both rice varieties, particularly in the hybrid rice. Compared with NH_4"+-N, NO_3"--N top-dressing ...

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Chemistry of strontium

Measurement of crack growth rate of magnesium alloy AZ31

This paper describes stable strontium as composed of four stable isotopes ( Sr 88, Sr 87, Sr 86, and Sr 84), of which Sr 88 contributes more than 82% to its composition. Strontium exists in three crystalline, plymorphic forms; face-centered cubic alpha form, hexagonal beta form and body-centered cubic gamma form. Strontium occupies in many physicochemical aspects an intermediate position between calcium and barium, as does the solubility of strontium salts. As a result of its oxidation potential, strontium readily forms oxides, halides, and sulfide. The author proposes that the slight discrimination against strontium incorporation into bony tissues may be due to the difference in ionic potential (14%) between strontium and calcium. Ionic potential is an indicator of the strength of ionic bonds: strontium has a smaller ...

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Separation of magnesium from magnesium chloride and zirconium and/or hafnium subchlorides in the production of zirconium and/or hafnium sponge metal

No abstract prepared.

2005-07-01

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Studies of the behaviour of technical chemicals introduced into the subsoil under modelled conditions

This patent describes the producing of a refractory metal wherein a sponge refractory metal is produced as an intermediate product by the use of magnesium with the incidental production of magnesium chloride, and wherein residual magnesium is separated from the magnesium chloride and from refractory metal to a vacuum distillation step which fractionally distills the magnesium, the magnesium chloride, and the metal sub-chlorides; the steps of: recovering fractionally distilled vapors of magnesium chloride and metal sub-chlorides from a sponge refractory metal; separately condensing the vapors as separately recovered; and recycling the separately recovered magnesium at a purity of at least about 96%.

1990-09-21

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Numerical heat transfer studies of PCMs used in a box-type solar cooker

Because of the environmental hazard of organic solvents such as chlorinated or aromatic hydrocarbons, water soluble and biodegradable substitutes have come into use. It should be assessed how they affect soil and aquifer when spilled in leaks or accidents. This was simulated in a model system using methanol and percolation columns, one filled with material from the unsaturated subsurface and two with different materials from aquifers. The results reveal that a spill of the substitutes can also cause problems. In homogeneous soils and at long retention times until the substance reaches the aquifer, sorption and biological degradation are most likely to prevent contamination of the groundwater. When oxygen supply in the subsurface is insufficient, reducing conditions occur and sulphide is formed. The data show that much more methanol was eliminated than reflected by the consumption of electron acceptors. This indicates that sorption and anabolic turnover of the microorganisms play an ...

1993-04-01

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Effects of Soil Properties and Nitrogen Fertilization on Distribution of NO3-N in Soils of Eastern Poland

Theoretical investigations on the phase change materials (PCMs) used as the heat storage media for box-type solar cookers have been conducted in this study. The selected PCMs are magnesium nitrate hexahydrate, stearic acid, acetamide, acetanilide and erythritol. For a two-dimensional simulation model based on the enthalpy approach, calculations have been made for the melt fraction with conduction only. Different materials such as glass, stainless steel, tin, aluminum mixed, aluminum and copper are used as the heat exchanger container materials in the numerical calculations. The large value of thermal conductivity of heat exchanger container material did not make a significant contribution on the melt fraction except for at very low thermal conductivities. Based on the theoretical results, stearic acid and acetamide are found to be good compatibility with latent heat storage system. It is also found that the initial temperature of PCM does not ...

2008-05-15

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British Library Electronic Table of Contents (United Kingdom)

The effects of anthropogenic (nitrogen fertilization) and natural [soil texture, pH content of humus, ammonium nitrogen (N-NH4), and the available forms of phosphorus (P), potassium (K), magnesium (Mg)] factors on nitrate nitrogen (NO3-N) content and distribution were shown. The dependencies between these factors and the content of NO3-N in soil were estimated in three soil layers: 0-30 cm; 31-60 cm; 61-90 cm. The research was carried out in 2004-2006, and the soil samples were taken from 411 places throughout eastern Poland in two seasons: spring and autumn. The concentration of NO3-N significantly depended on the year of investigation, season of the year, and depth of sampling. Distribution of NO3-N in the soil profile indicates possibility of NO3 leaching during winter and early spring....

2011-01-01

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Induction and Repression of Nitrate Reductase in Neurospora crassa

Development of plasticity processing of magnesium alloys

Synthesis of wild-type Neurospora crassa assimilatory nitrate reductase is induced in the presence of nitrate ions and repressed in the presence of ammonium ions. Effects of several...Full Text Available

1978-02-01

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Phytochrome, Nitrate Movement, and Induction of Nitrate Reductase in Etiolated Pea Terminal Buds ¹

Recent developments on plastic forming technology of magnesium alloys are presented. Attempts have been undergoing with an aim at forming magnesium alloy parts at lower temperatures. It is believed that fine microstructure magnesium alloys usually have much higher plasticity at lower temperatures and even room temperatures. Extrusion is a method to form magnesium profile products and tube products, which is also one of the effective ways to make fine microstructure magnesium alloys. Superplasticity forming is another method to form high plasticity magnesium alloys. Hot forming of magnesium sheet parts is an important process to form magnesium products. Some developments related to above issues are discussed in the present paper. (orig.)

2003-07-01

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Differential Effect of Irradiance and Nutrient Nitrate on the Relationship of in Vivo and in Vitro Nitrate Reductase Assay in Chlorophyllous Tissues ¹

The role of phytochrome in the induction of nitrate reductase of etiolated field peas (Pisum arvense L.) was examined. Terminal bud nitrate concentration increased in darkness, and...Full Text Available

1975-06-01

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Blockage by acetylene of nitrous oxide reduction in Pseudomonas perfectomarinus.

Growth at increasing continuous irradiance (at high nutrient nitrate) and nutrient nitrate concentrations (at high continuous irradiance) furnished increases in the in vivo and in...Full Text Available

1977-04-01

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Reprocessing of research reactor spent nuclear fuel at the PA ''Mayak''

Suspensions of denitrifying cells of Pseudomonas perfectomarinus reduced nitrate and nitrate as expected to dinitrogen; but, in the presence of acetylene, nitrous oxide accumulated when nitrate or nitrate...Full Text Available

1976-04-01

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Reprocessing of research reactor spent nuclear fuel at the PA 'Mayak'

The first Russian reprocessing facility, known as RT-1 (located at PA-Mayak in Ural region) was started on the radiochemical plant base in 1977. Nowadays RT-1 is the sole operating reprocessing plant in Russia. The main features of RT-1 is its broad spectrum of reprocessing spent nuclear fuels (SNF). The following spent fuel types are reprocessed: -) SNF from PWR reactors (WWER-440) and FB reactor (BN-600); -) SNF of transport ship reactors; -) production reactors SNF; -) research reactor spent nuclear fuel. The world-known technological processes are used at RT-1, but there are the following distinctive features. First, the universality of the three technological lines which allows not only the reprocessing of various SNF kinds, but also to implement the combined reprocessing of some types of them. Secondly, extraction of neptunium during SNF reprocessing which is used to implement its separate storage and for radioisotope production. Thirdly, target enrichment of recycled uranium is ...

2007-03-11

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Fasting plasma magnesium concentrations and glucose disposal in diabetes.

The first Russian reprocessing facility, known as RT-1 (located at PA-Mayak in Ural region) was started on the radiochemical plant base in 1977. Nowadays RT-1 is the sole operating reprocessing plant in Russia. The main features of RT-1 is its broad spectrum of reprocessing spent nuclear fuels (SNF). The following spent fuel types are reprocessed: -) SNF from PWR reactors (WWER-440) and FB reactor (BN-600); -) SNF of transport ship reactors; -) production reactors SNF; -) research reactor spent nuclear fuel. The world-known technological processes are used at RT-1, but there are the following distinctive features. First, the universality of the three technological lines which allows not only the reprocessing of various SNF kinds, but also to implement the combined reprocessing of some types of them. Secondly, extraction of neptunium during SNF reprocessing which is used to implement its separate storage and for radioisotope production. Thirdly, target enrichment of recycled uranium is ...

2007-07-01

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Surface modification of magnesium base alloys by gas/plasma nitridation

Fasting plasma concentrations of magnesium were measured by neutron activation analysis in 30 non-diabetics and 87 diabetics (55 non-insulin-treated, 32 insulin treated). Plasma concentrations of magnesium...Full Text Available

1984-04-07

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Studies on Inhibition of Intestinal Absorption of Radioactive Strontium

Gas and plasma nitriding processes were executed in the magnesium with modification by titanium in search for an effective surface treatment method for magnesium alloys. Magnesium-nitrogen system has completely no solid solution or solubility, so that nitride should be only formed by eutectic reaction in the liquid phase. Hence, magnesium is difficult or nearly impossible to have its surface modified by nitriding. Addition of nitride forming element into magnesium enables us to lower the onset temperature of nitriding. Magnesium-titanium alloys with 1 to 5 wt% are yielded by the bulk mechanical alloying and, subjected to gas nitriding for various process conditions. Successful co-formation of Mg{sub 3}N{sub 2} as well as TiN becomes a proof to demonstrate the possibility of gas/plasma nitriding in the solid-state magnesium with aid of ...

2000-07-01

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Mean energies of photoneutron spectra for sup(67,70)Zn, sup(74,77)Se, sup(84,86,87,88)Sr, sup(181)Ta and sup(183)W isotopes

A method is reported which permits selective suppression of absorption of radioactive strontium from ingested food material, permitting the calcium to be available to the body. Studies were carried...Full Text Available

1964-08-08

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Strontium and uranium concentrations in aragonite precipitated by some modern corals

... reactions selenium 74 target selenium 77 target strontium 84 target strontium

1986-04-15

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Preparation of carrier-free yttrium-88 from strontium target by solvent extraction

... Oceanographic Institution, Mass. (USA) v. 8 p. 439-442. abundance

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Magnesium foam produced from bulk AZ31 magnesium alloy sheets

... carrier-free isotopes chemical preparation gamma spectra isotope production

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Effect of equal channel angular pressing on the deformation behaviour of magnesium alloy AZ31 under uniaxial compression

Using commercial AZ31 magnesium alloy sheets, we produced a foamable preform sheet containing titanium hydride (TiH{sub 2}) powder through diffusion-bonding and hot-rolling of four cycles. Heating the preform sheets in Ar atmosphere, we obtained closed-cell magnesium alloy foams with various porosities. The foamed specimen at 883 K showed the maximum porosities of 77%. (orig.)

2005-07-01

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I. Introduction

Wastenet

as a by-product during the purification of molten magnesium chloride prior to its electrolysis and during the

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Fatigue of magnesium alloys

No abstract prepared.

2006-07-01

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BC

Wastenet

as a by-product during the purification of molten magnesium chloride prior to its electrolysis and during the

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Some New Aspects of the in Vivo Assay for Nitrate Reductase in Wheat (Triticum aestivum L.) Leaves

Magnesium alloys show a high specific strength and are therefore increasingly used for light-weight constructions in transportation industry.{sup [1,2]} To predict the behaviour of the material under the influence of cyclic loading it is vital to understand the fatigue behaviour of magnesium alloys. Only when understood properly, it is possible to fully apply the potential weight reduction by using magnesium alloys. A very important aspect in fatigue of magnesium alloys is the influence of a corrosive media and elevated temperatures, of which both are relevant in automotive applications. These two factors tend to have deleterious effects on magnesium alloys and therefore also have to be considered in investigations on the fatigue behaviour of magnesium alloys. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

2004-05-01

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Reversible Inactivation of Nitrate Reductase by NADH and the Occurrence of Partially Inactive Enzyme in the Wheat Leaf 1

Experiments were carried out to clarify problems encountered in measuring metabolic and storage pool sizes of nitrate in wheat leaf sections with an in vivo nitrate reductase assay....Full Text Available

1980-01-01

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Pyridine Nucleotide Specificity of Barley Nitrate Reductase ¹

Nitrate reductase from wheat (Triticum aestivum L. cv Bindawarra) leaves is inactivated by pretreatment with NADH, in the absence of nitrate, a 50% loss of activity occurring in 30...Full Text Available

1983-03-01

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NasFED Proteins Mediate Assimilatory Nitrate and Nitrite Transport in Klebsiella oxytoca (pneumoniae) M5al

NADPH nitrate reductase activity in higher plants has been attributed to the presence of NAD(P)H bispecific nitrate reductases and to the presence of phosphatases capable of hydrolyzing NADPH to NADH....Full Text Available

1982-05-01

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Development of Nitrate Reductase Activity in Expanding Leaves of Nicotiana tabacum in Relation to the Concentration of Nitrate and Potassium

Klebsiella oxytoca can use nitrate and nitrite as sole nitrogen sources. The enzymes required for nitrate and nitrite assimilation are encoded by the nasFEDCBA operon....Full Text Available

1998-03-01

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Biochemical Characterization of Soybean Mutants Lacking Constitutive NADH:Nitrate Reductase ¹

Up to 80% of the total nitrate reductase activity (NRA) determined in vivo in different parts of vegetative tobacco plant (Nicotiana tabacum) was located in the leaves....Full Text Available

1988-05-01

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Vacuum distillation refining and recycling of magnesium alloys

Two nitrate reductase (NR) mutants were selected for low nitrate reductase (LNR) activity by in vivo NR microassays of M₂ seedlings derived from nitrosomethylurea-mutagenized...Full Text Available

1986-06-01

46

Forming characteristics of cast magnesium alloy sheets manufactured by roll strip casting process

Purification parameters of the vacuum distillation process for AM50A and AZ31B magnesium alloy were studied. The vacuum distillation tests were kept at 580 C to 620 C up to 10 h under a vacuum pressure of about 1 Pa. The purification ratio for AM50A magnesium alloy increases with increasing the purification time. The chemical compositions of materials deposited purifying at 580 C for AM50A magnesium alloy almost satisfy the values for pure magnesium specified by JIS standard specification. The chemical compositions of deposited materials at 600 C for AZ31B magnesium alloy satisfy the values specified by the standard specification except for Zn. (orig.)

2003-07-01

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Effects of rolling condition on warm deep drawability of magnesium alloy sheets produced by twin-roll strip casting

Plastic formability of cast magnesium alloy that were hot rolled after roll strip casting was investigated to ascertain the feasibility of semi-solid strip casting process of AZ31B magnesium alloy. Hot rolling and heat treatment conditions were changed to examine which conditions were appropriate for producing AZ31B wrought magnesium alloys after strip casting process. Microscopic observation of the crystals of the manufactured wrought magnesium alloys was performed. It has been found that a limiting drawing ratio of 2.7 was possible in a warm deep drawing test of the cast magnesium alloy sheets after being hot rolled. (orig.)

2004-07-01

48

Nucleon induced reaction cross-sections for strontium and cesium at energies 1 MeV to 10 GeV

Effects of rolling conditions on warm deep drawability of cast magnesium alloy that were hot rolled after roll strip casting were investigated to ascertain the feasibility of twin-roll strip casting process of AZ31B magnesium alloy. Hot rolling and heat treatment conditions were changed to examine which conditions were appropriate for producing AZ31B wrought magnesium alloys after strip casting process. Microscopic observation of the crystals of the manufactured wrought magnesium alloys was performed. It has been found that a limiting drawing ratio of 2.7 was possible in a warm deep drawing test of the cast magnesium alloy sheets after being hot rolled. (orig.)

2005-07-01

49

Simultaneous ultraviolet spectrophotometric determination of nitrate and nitrite in water

Nuclear reaction cross-sections for stable strontium and cesium isotopes, which were calculated by different approaches, are compared to available experimental data. Neutron and proton induced reaction cross-sections for the long-lived radionuclides [sup 90]Sr and [sup 137]Cs have been calculated in the energy range from 1 MeV to 10 GeV. Recommendations concerning cross-section calculations for strontium and cesium isotopes at intermediate and high energies are given. (orig.)

1993-06-01

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A rapid and accurate method for the direct simultaneous determination of nitrate and nitrite is proposed. The method is applied to the determination of nitrate and nitrite in rainwater and wastewater without preliminary separation. The determinations are performed by a CPA matrix method with ultraviolet spectrophotometric detection. The results obtained are in agreement with those obtained by conventional methods for the determination of nitrate and nitrite.

1991-02-01

51

Shale oil explosives

NO Generation from Inorganic Nitrate and Nitrite: Role in Physiology, Nutrition and Therapeutics

Ammonium nitrate shale oil explosives are provided which are effective, powerful, inexpensive, and safe. The explosives contain about 2% to 10% by weight shale oil and about 90% to 98% by weight ammonium nitrate. The shale oil can be whole shale oil or heavy shale oil containing from 0.1% to 65% by weight oil shale dust. The ammonium nitrate is preferably in the form of explosive grade ammonium nitrate prills.

1984-10-09

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Effect of Nitrite and Nitrate as the Source of OH Radical in the O3/UV Process with or without Benzene

Full Text Available

2009-08-01

53

Direct process for explosives

Full Text Available

2011-08-01

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Direct process for explosives

A direct process of making ethylenediamine dinitrate through the reaction of ethylenediamine and ammonium nitrate.

1982-01-01

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Degradation of leucine zipper-positive isoform of MYPT1 may contribute to development of nitrate tolerance.

A direct process of making ethylenediamine dinitrate through the reaction of ethylenediamine and ammonium nitrate is described.

1982-10-12

56

Reduction in blood pressure with a low sodium, high potassium, high magnesium salt in older subjects with mild to moderate hypertension.

PMID:19939965

2009-11-25

57

The effect of magnesium sulfate on postoperative pain in patients undergoing major abdominal surgery under remifentanil-based anesthesia

OBJECTIVE--To examine the effect of a reduced sodium and increased potassium and magnesium intake on blood pressure. DESIGN--Randomised double blind placebo controlled trial. SETTING--General population...Full Text Available

1994-08-13

58

Smoke Compositions Based on Phosphorus

Full Text Available

2008-09-01

59

Extraction of magnesium as the iodide by tributyl phosphate

... Both magnesium and aluminium phosphides are therefore potentially more efficient than either calcium or sodium phosphide. ...

1958-03-01

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Binary systems containing magnesium chloride, calcium chloride and thorium tetrafluoride

The extraction of magnesium by tributyl phosphate from KI solutions was investigated. With increasing KI and TBP concentrations, the extraction increased. The maximum extraction (82%) was attained at pH 4, and it did not decrease with a further pH increase. With decreasing pH, the extraction decreased because of HI extraction. The magnesium was extracted as the compound MgI/sub 2/ x 4TBP. Complexone III (at pH 3-4) does not affect the extraction of magnesium, which makes it possible to use it to mask other metals.

1987-08-20

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Revised minimum nitrite concentration for ESP

Russian (1972). USSR Desyatnik, VN Kurbatov, NN Raspopin, SP Trifonov,

1972-01-01

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Revised minimum nitrite concentration for ESP

Nitrite is to be used to inhibit pitting corrosion during Extended Sludge Processing (ESP) at the Savannah River Plant. The required nitrite concentrations are expressed as a function of the slurries' nitrate ion concentration and temperature. In the most dilute slurries, the nitrite inhibitor requirement is independent of the nitrate ion concentration and depends only on the temperature of the waste. The nitrate-independent concentration ensures that there is sufficient inhibitor, in sludge slurries whose nitrate has been depleted by radiolysis, to prevent pitting corrosion induced by other corrosive anions (e.g., sulfate and chloride). The threshold nitrate concentration at which the nitrite level is expressed as a function only of temperature is 0.02 M.

1992-10-26

63

The influence of process parameters on forged magnesium alloys

Nitrite is to be used to inhibit pitting corrosion during Extended Sludge Processing (ESP) at the Savannah River Plant. The required nitrite concentrations are expressed as a function of the slurries` nitrate ion concentration and temperature. In the most dilute slurries, the nitrite inhibitor requirement is independent of the nitrate ion concentration and depends only on the temperature of the waste. The nitrate-independent concentration ensures that there is sufficient inhibitor, in sludge slurries whose nitrate has been depleted by radiolysis, to prevent pitting corrosion induced by other corrosive anions (e.g., sulfate and chloride). The threshold nitrate concentration at which the nitrite level is expressed as a function only of temperature is 0.02 M.

1992-10-26

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Influence of rolling conditions on the microstructure and mechanical properties of magnesium sheet AZ31

Two extruded magnesium alloys, AZ31 and AZ61 were selected to evaluate the influence of process parameters on the material forgeability. The processing parameters considered for forging magnesium alloys were: compression load in the range 55 KN to 60 KN and forging temperature, in the range of ambient temperature to 300 C. Uniaxial compression tests were conducted to establish the strain-temperature relationship. The influences of process parameters on the microstructure were also evaluated. (orig.)

2003-07-01

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Double-electron-capture cross section for I/sup +/ in a magnesium-vapor target

Two aspects of the deformation behavior of magnesium sheets are the subject of this paper. First it will give a mechanical characterization of a commercial magnesium with a focus on the anisotropy and the possible microstructural causes of this behavior. The rolling process will be part of the second aspect. The aim is to show the influence of the parameters on the microstructure and texture and how this could affect the anisotropy in the rolled sheets. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

2003-12-01

66

Character of interaction of magnesium borates with water

Measurements of the double-electron-capture process in which a positive ion of iodine becomes a negative ion in a single collision with a magnesium atom are reported between 20 and 90 keV. The cross section is comparable to that for the rare gases and not as large as might be expected from a two-valence-electron atom. This process is probably insignificant in the production of negative ion beams using a magnesium-vapor target.

1987-06-15

67

Tensile properties and bending formability of drawn magnesium alloy pipes

The nature of interaction of some boromagnesium minerals with water is studied, the main stages of interaction are established. The methods of thermo-gravimetric, X-ray phase and chemical analyses are applied to state intermediate and final phases of magnesium borate interaction with water. ''Preobrazhenskite'' - ''inderite'' paragenesis is established. The notion ''magnesium borate solubility'' is shown to be senseless.

1986-11-01

68

Machinability of magnesium alloy in ultra-precision diamond cutting

Magnesium alloys are being increasingly utilized in a variety of fields as an alternative material to organic materials and aluminum alloys, owing to excellent properties. Those include low density, and excellent damping properties. When compared to organic materials, furthermore, Mg alloy excels at recyclability, heat radiation, and electromagnetic-shielding. Though most of magnesium alloy products are manufactured through die-casting and thixo-molding at present, the demand for the expanding of magnesium wrought alloy market is increasing. Taking full advantage of a drawing technique and applying it to the conventional extruded pipe, we have developed a new type of magnesium alloy pipe. The strength of the developed pipe is significantly higher than that of the conventional one, either extruded or die-casting. Some of the excellent properties were obtained from fundamental tests performed with the ...

2003-07-01

69

Strontium as modifier for AlSi and AlSiCu alloys

This paper deals with an experimental study of ultra-precision diamond cutting of magnesium alloy (AZ31). In order to investigate the machinability such as the cutting force and the surface integrity and understand the problems in a micro cutting, the experiments on the diamond cutting of magnesium alloy and pure aluminum with an ultra-precision turning machine has been carried out. The machinability of magnesium alloy was compared with that of pure aluminum and discussed. Consequently, both the thrust force component and the surface roughness obtained by cutting of magnesium alloy became larger than that of pure aluminum. It was also found that the inclusions or the defects in the work material caused to generate the scratches on the finished surface and influenced the integrity of mirror surface. (orig.)

2003-07-01

70

Semi-solid twin-roll casting process of magnesium alloy sheets

The optimum of strontium amount for good modification of AK7, AK9, AK11, AK52, AK104 alloys was determined on the base of the analysis of microstructural changes. The stability of the modifier was investigated on the way of successive remelting of billets. The influence of amount of modifier on the impact strength of the alloys was established. (author)

71

narI region of the Escherichia coli nitrate reductase (nar) operon contains two genes.

An experimental approach has been performed to ascertain the effectiveness of semi-solid strip casting using a horizontal twin roll caster. The demand for light-weight products with high strength has grown recently due to the rapid development of automobile and aircraft technology. One key to such development has been utilization of magnesium alloys, which can potentially reduce the total product weight. However, the problems of utilizing magnesium alloys are still mainly related to high manufacturing cost. One of the solutions to this problem is to develop magnesium casting-rolling technology in order to produce magnesium sheet products at competitive cost for commercial applications. In this experiment, magnesium alloy AZ31B was used to ascertain the effectiveness of semi-solid roll strip casting for producing magnesium alloy sheets. The temperature of the ...

2004-06-10

72

Tanana River Floodplain Dissolved Organic Nitrogen (DON) Budget, GPS coordinates for Tanana River Floodplain study plots

In previous studies it has been established that in Escherichia coli the three known subunits of anaerobic nitrate reductase are encoded by the narGHI operon. From the nucleotide sequence of the narI...Full Text Available

1988-04-01

73

Soybean Mutants Lacking Constitutive Nitrate Reductase Activity 1

Ammonium, Nitrate, and Amino Acid concentrations in .5M K2SO4 extracted T0 Tanana Floodplain soils Ammonium, Nitrate, and Amino Acid concentrations in . ... ...

74

Seasonal Patterns of Nitrate Reductase and Nitrogenase Activities in Phaseolus vulgaris L. ¹

The objectives of this study were to select and initially characterize mutants of soybean (Glycine max L. Merr. cv Williams) with decreased ability to reduce nitrate. Selection involved...Full Text Available

1983-06-01

75

Role of narK2X and narGHJI in Hypoxic Upregulation of Nitrate Reduction by Mycobacterium tuberculosis

The patterns of nitrate reductase activity (NRA) in the leaves (in vivo assay) and root nodule nitrogenase activity (C₂H₂ reduction) were investigated throughout...Full Text Available

1979-03-01

76

Rapid Modulation of Spinach Leaf Nitrate Reductase by Photosynthesis ¹

Mycobacterium tuberculosis is one of the strongest reducers of nitrate in the genus Mycobacterium. Under microaerobic conditions, whole cells exhibit upregulation of...Full Text Available

2003-12-01

77

Nodule and Leaf Nitrate Reductases and Nitrogen Fixation in Medicago sativa L. under Water Stress

Assimilatory nitrate reductase activity (NRA) in crude spinach leaf (Spinacia oleracea) extracts undergoes rapid changes following fluctuations in photosynthesis brought about by changes...Full Text Available

1991-06-01

78

Nitrogen metabolite repression of nitrate reductase in Neurospora crassa.

The effect of water stress on patterns of nitrate reductase activity in the leaves and nodules and on nitrogen fixation were investigated in Medicago sativa L. plants watered 1 week...Full Text Available

1982-02-01

79

Nitrogen fixation in nitrate reductase-deficient mutants of cultured rhizobia.

The effect of different nitrogen compounds on the induction of reduced nicotinamide adenine dinucleotide phosphate-nitrate reductase was examined in Neurospora crassa. Whereas in the wild-type strain...Full Text Available

1979-03-01

80

Nitric Oxide Emissions from Soybean Leaves during in Vivo Nitrate Reductase Assays ¹

Forty-eight mutants unable to reduce nitrate were isolated from "cowpea" Rhizobium sp. strain 32Hl and examined for nitrogenase activity in culture. All but two of the mutants had nitrogenase activity...Full Text Available

1977-02-01

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81

Nitrate Reductase Activity in Soybeans (Glycine max [L.] Merr.)

Recent work identified acetaldehyde oxime as the predominant product purged by inert gases from anaerobic in vivo nitrate reductase (NR) assays of soybean (Glycine max...Full Text Available

1987-09-01

82

Long-term effects of inhaled uranyl nitrate in rats

The optimum in vivo nitrate reductase (NR) assay medium for soybean (Glycine max [L.] Merr.) leaves was 50 mm KNO₃, 1% (v/v) 1- propanol, and 100...Full Text Available

1976-12-01

83

Light and Dark Controls of Nitrate Reduction in Wheat (Triticum aestivum L.) Protoplasts ¹

Rats were exposed to aerosols of "2"3"3U and "2"3"2U nitrate in a study of the long-term biological effects. Preliminary radiation dose estimates show lung > skeleton > kidney in each dose group.

1977-05-01

84

Involvement of a low-molecular-weight substance in in vitro activation of the molybdoenzyme respiratory nitrate reductase from a chlB mutant of Escherichia coli.

Protoplasts were isolated from the leaves of nitrate-cultured wheat (Triticum aestivum L. var. Frederick) seedlings. When incubated in the dark, protoplasts accumulated nitrite under...Full Text Available

1982-02-01

85

Insights into the Genome of Large Sulfur Bacteria Revealed by Analysis of Single Filaments

The soluble subcellular fraction of a chlB mutant contains an inactive precursor form of the molybdoenzyme nitrate reductase, which can be activated by the addition to the soluble fraction of protein...Full Text Available

1987-10-01

86

Impact of diffuse nitrate pollution sources on groundwater quality--some examples from Czechoslovakia.

Marine sediments are frequently covered by mats of the filamentous Beggiatoa and other large nitrate-storing bacteria that oxidize hydrogen sulfide using either oxygen or nitrate, which...Full Text Available

2007-09-01

87

Evolution of Nitrogen Oxide(s) during In Vivo Nitrate Reductase Assay of Soybean Leaves

In several regions of Czechoslovakia with intensive agricultural production, the correlation between the amount of nitrogen fertilizer applied and the nitrate content in groundwater has been recognized....Full Text Available

1989-11-01

88

Evidence for Iron-Dependent Nitrate Respiration in the Dissimilatory Iron-Reducing Bacterium Geobacter metallireducens

Studies were conducted to quantitate the evolution of nitrogen oxides (NO_(x)) from soybean [Glycine max (L.) Merr.] leaves during in vivo nitrate reductase...Full Text Available

1981-12-01

89

Evaluation of Direct Detection of Mycobacterium tuberculosis Rifampin Resistance by a Nitrate Reductase Assay Applied to Sputum Samples in Cotonou, Benin?

The dissimilatory iron-reducing bacterium Geobacter metallireducens was found to require iron at a concentration in excess of 50 μM for continuous cultivation on nitrate. Growth...Full Text Available

2001-08-01

90

Dependency of Nitrate Reduction on Soluble Carbohydrates in Primary Leaves of Barley under Aerobic Conditions 1

The aim of this study was to evaluate a nitrate reductase assay (NRA) performed on smear-positive sputa for the direct detection of rifampin resistance in Mycobacterium tuberculosis....Full Text Available

2007-07-01

91

Anaerobic Nitrate Respiration by Erwinia carotovora subsp. atroseptica during Potato Tuber Invasion

Nitrate reduction was studied as a function of carbohydrate concentration in detached primary leaves of barley (Hordeum vulgare L. cv Numar) seedlings under aerobic conditions in light...Full Text Available

1984-07-01

92

Acetaldehyde Oxime, A Product Formed during the In Vivo Nitrate Reductase Assay of Soybean Leaves 1

The in planta induction of anaerobic nitrate respiration by Erwinia carotovora subsp. atroseptica in relation to the in situ oxygen status in soft rotting potato tubers...Full Text Available

1993-11-01

93

Bioactivity and corrosion properties of novel coatings containing strontium by micro-arc oxidation

Evolution of nitrogen oxides (NO_(x), primarily as nitric oxide) from soybean (Glycine max [L.] Merr.) leaves during purged in vivo nitrate reductase assays...Full Text Available

1984-09-01

94

Nitrate Removal of a Cattail Wetland Cell Purifying Effluent from a Secondary-Level Treatment Plant During Its Initial Operating Stage

Research highlights: The dental implant of titanium could be modified by anodic oxidation. It was found that incorporation of strontium ions into the matrix increase the bone formation. In this study, we try to investigate the effect of corrosion property and bioactivity on coatings containing strontium by anodic oxidation. The results suggest that coatings containing strontium on titanium by anodic oxidation has the potential to show the stability and bioactivity in the clinical use. - Abstract: Pure titanium (Ti) and titanium alloys are considered as bio-inert materials in clinical use. Bioactivity is the ability to induce bone-like apatite on the material surface. The micro-arc oxidation (MAO) technique is an effective method for improving the surface properties of titanium. The aim of this study was to investigate the bioactivity and corrosion behavior of MAO coatings containing strontium, which is ...

2010-10-22

95

Application of the exergy method to environmental impact estimation: The ammonium nitrate production as a case study

Full Text Available

2004-12-01

96

Quantitative transfer of the molybdenum cofactor from xanthine oxidase and from sulphite oxidase to the deficient enzyme of the nit-1 mutant of Neurospora crassa to yield active nitrate reductase.

The exergy method is used to compare different production processes and various methods for emission abatement with respect to their overall environmental impact. Some ammonium nitrate production processes are studied as examples, because the pollutants (ammonia and ammonium nitrate), emitted from these processes into the air and/or into the water, are really a feedstock and a product from the production process. Therefore, the essential result of the waste flows treatment is the recycling of the pollutants (ammonia and ammonium nitrate) back into the production process, decreasing simultaneously the exergy input and cumulative exergy consumption. (author)

2010-08-15

97

Oxygen Inhibition of Nitrate Reductase Biosynthesis in Detached Corn Leaves via Inhibition of Total Soluble Protein Synthesis ¹

An assay method is described for measurement of absolute concentrations of the molybdenum cofactor, based on complementation of the defective nitrate reductase ('apo nitrate reductase') in extracts...Full Text Available

1984-04-15

98

Molecular recognition of nitrated fatty acids by PPAR[gamma

Detached first leaves of 3-day-old corn seedlings (Zea mays L. W64AxW183E) were incubated with nitrate in air or 100% O₂ in the light. Nitrate accumulation in the leaves...Full Text Available

1989-11-01

99

Elucidating novel pathways and regulation of nitrogen assimilation in alpha proteobacteria exemplified by the soil organism Paracoccus denitrificans

Peroxisome proliferator activated receptor-{gamma} (PPAR{gamma}) regulates metabolic homeostasis and adipocyte differentiation, and it is activated by oxidized and nitrated fatty acids. Here we report the crystal structure of the PPAR{gamma} ligand binding domain bound to nitrated linoleic acid, a potent endogenous ligand of PPAR{gamma}. Structural and functional studies of receptor-ligand interactions reveal the molecular basis of PPAR{gamma} discrimination of various naturally occurring fatty acid derivatives.

2010-03-08

100

Environmental Research Database

DescriptionThe importance of inorganic nitrate for the nutrition and growth of marine and freshwater autotrophic phytoplankton has long been recognised, in particularly because of the 'blooms' formed in nitrate and phosphate polluted water and their possible roles as carbon dioxide sinks. By contrast, the utilisation of nitrate by heterotrophic bacteria has historically received less attention. Up until now, the primary role of heterotrophic bacteria has classically been considered to be the decomposition [continued...

2010-01-31

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101

Deforestation and leaching of nitrogen as nitrates into underground water in intertropical zones: The example of Cote d'Ivoire (the Ivory Coast)

Plane-strain backward extrusion of AZ31 magnesium alloy

High nitrate contents (up to 200 mgl) has been observed in wells drilled into fractured aquifers lying beneath layers of weathered and decayed rock in the humid tropics where annual rainfall is over 1,000 mm and where there is no notable pollution. The source of the nitrates is linked mainly with localized deforestation by man.

102

Numerical Modeling of Magnesium Alloy Sheet Metal Forming at Elevated Temperature

Increase usage of magnesium components in the portable electronics industries has propelled considerable research interest on the development of magnesium forging. There have been some studies done in the area of sheet metal forming and forging of axis-symmetrical parts of magnesium alloys but there are very little work done on the plane strain backward extrusion of magnesium alloy. This paper deals with the analysis of plane strain extrusion of magnesium alloy, AZ31, using numerical modeling at different extrusion conditions of temperatures and friction coefficients. A commercially available finite element package, ANSYS/LSDYNA, was used in the finite element analysis. FE simulated results, material deformation, punch force and stress/strain distributions, were compared with actual experimental data. From the numerical analysis, a decrease in forging temperature from 300 C to 250 C ...

2003-07-01

103

Lining of magnesium alloys with foils using shot peening

The development of light-weight vehicle is in great demand for enhancement of fuel efficiency and dynamic performance. The vehicle weight can be reduced effectively by using lightweight materials such as magnesium alloys. However, the use of magnesium alloys in sheet forming processes is still limited because of their low formability at room temperature and the lack of understanding of the forming process of magnesium alloys at elevated temperatures. In this study, uniaxial tensile tests of the magnesium alloy AZ31B-O at various temperatures were performed to evaluate the mechanical properties of this alloy relevant for forming of magnesium sheets. To construct a FLD (forming limit diagram), a forming limit test were conducted at temperature of 100 and 200 deg. C. For the evaluation of the effects of the punch temperature on the formability of a rectangular cup drawing with AZ31B-O, ...

2007-05-17

104

Evaluation on the formability of magnesium alloy, AZ31

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 ...

2003-07-01

105

Recycler model magnet test on temperature compensation for strontium ferrite

Magnesium is known to have poor formability at room temperature, mainly attributed to its hexagonal lattice structure. This paper presents the findings generated from development of warm forming to produce thin-walled magnesium components. Finite element analysis was conducted to evaluate the formability of the material and the simulated results were compared to the tensile results and product formability. Tensile tests were used to verify the formability of the sheet metal at difference temperatures. The process parameters considered in the feasibility study were forming temperature, in the range of 28 C to 300 C and magnesium sheet (AZ31B-H24) thickness, in the range of 0.4 mm to 1 mm. Magnesium hand phone covers of a thickness down to 0.4 mm have been successfully produced. The feasible forming temperature was found to be between 200 C and 250 C. Metallographic examination shows evident of ...

2003-07-01

106

Physicochemical investigation of the behavior of elements in chloride melts in the presence of solid phases based on phosphates of polyvalent elements. II. Behavior of strontium and barium

The Recycler ring magnet will be made of Strontium ferrite permanent magnets. A strontium ferrite permanent magnet without compensation has a temperature coefficient of -0.2 % in dB/dT. To compensate this effect, we are utilizing 30 % Ni 70 % Fe alloy, a temperature compensation ferromagnetic material with a low Curie point. To search for optimum commercially available material and optimum condition, we made a couple of simple model magnets, and tested with several different compensating material. The test results are reported and its optimal conditions are shown. Several different configurations were tested including a possible 2 kG magnet configuration.

1995-10-01

107

Adsorption behavior of strontium on kaolinite and montmorillonite and their mixtures

The distribution of the alkaline earth elements strontium and barium between the solid phases of phosphates of transition elements of group 4 and chloride melts was studied. The distribution coefficients of strontium and barium were found at T = 700-800/sup 0/C. Phosphates of the type NaM/sub 2//sup (IV)/(PO/sub 4/)/sub 3/, where M/sub (IV)/ represents titanium, zirconium, and hafnium, were used as the solid phases. It was established that there is an enrichment of the precipitates with the distributed components. The distribution coefficient depends on the nature of the solid phase and the temperature. It was suggested that M/sup (II)/ x M/sub 4//sup (IV)/(PO/sub 4/)/sub 6/ is formed in processes of distribution, where M/sup (II)/ represents Sr, Ba.

1987-07-01

108

Damping measurements of the magnesium wrought alloys AZ31, AZ61 and AZ80 after indirect and hydrostatic extrusion

{sup 90}Sr, with a long half-life of 28.5 years, is the most dangerous strontium isotope. The adsorption behavior of radionuclides in the environment are closely related to the safe disposal of radioactive wastes. Since various types of minerals may exist in and around the repositories used for ultimate disposal of nuclear waste, the adsorption behavior of certain radionuclides onto and from these minerals and similar adsorbents should be studied in order to estimate the rates of transport of the nuclides in the event of water penetration into and through the repository. Information on the adsorption properties of the purified individual clay minerals may not be sufficient to predict the adsorption properties of a corresponding mixture, because these clay minerals may interact with each other and lead to modification of the adsorption properties of the mixture as compared to the pure minerals. The adsorption behavior of strontium on kaolinite ...

2004-07-01

109

Corrosion and protection of magnesium alloy AZ31D by a new conversion coating

Magnesium cast parts as well as indirectly and hydrostatically extruded profiles were used in order to investigate the influence of different microstructures on the damping behaviour of magnesium AZ-alloys. Especially, hydrostatic extrusion leads to a significant grain refinement in the extruded profile compared to indirect extrusion. Strain dependent damping measurements were carried out at room temperature using alloys AZ31, AZ61 and AZ80. Damping was determined as the logarithmic decrement of free bending beam vibrations. The results of these measurements after indirect and hydrostatic extrusion are shown and discussed. (orig.)

2005-07-01

110

A study on the grain refining effects of carbon inoculation by C{sub 2}Cl{sub 6} addition on AZ31 magnesium alloy

A chromium-free conversion coating for magnesium alloys were described. The conversion coating could be obtained when AZ31D magnesium alloy was immersed in a solution containing a manganese salt, phosphate and an inhibitor. Corrosion resistance of the chemical conversion coating was evaluated by anodizing polarization curve and salt immersion. XRD analysis showed that the conversion coating was mainly composed of Mn{sub 3}(PO{sub 4}){sub 2}. The morphology of the coating is observed by using SEM. The effect of electrolyte pH and concentration of inhibitor on coating growth are investigated. (orig.)

2003-07-01

111

Thermophysical Properties of Matter - The TPRC Data Series. ...

The effects of carbon inoculation by C{sub 2}Cl{sub 6} addition were investigated using commercial AZ31 magnesium alloy. The additions of C{sub 2}Cl{sub 6} to AZ31 magnesium alloy significantly reduce the grain size from 280 {mu}m to about 120 {mu}m and the tensile properties are also increased due to grain refinement. EPMA analysis shows that Al-C-O compounds are formed in the castings which are considered to function as nucleants. (orig.)

2003-07-01

112

The Effects of Magnesium on State 3 Respiration of Liver Mitochondria from Control and Cold-Acclimated Rats and Hamsters

... alloys--Lanthanum-- Magnesium--Magnasium &11oy8--Hagn*31Uft compounds--Manxganese--Manganes. alloys-- Mercury ...

2011-05-14

113

Temperature Dependent Constitutive Modeling for Magnesium Alloy Sheet

Increasing the Mg(2+) concentration results in a depression of succincoxidase-linked state 3

1978-01-01

114

Surface modification on magnesium alloys by coating with magnesium fluorides

Magnesium alloys have been increasingly used in automotive and electronic industries because of their excellent strength to weight ratio and EMI shielding properties. However, magnesium alloys have low formability at room temperature due to their unique mechanical behavior (twinning and untwining), prompting for forming at an elevated temperature. In this study, a temperature dependent constitutive model for magnesium alloy (AZ31B) sheet is developed. A hardening law based on non linear kinematic hardening model is used to consider Bauschinger effect properly. Material parameters are determined from a series of uni-axial cyclic experiments (T-C-T or C-T-C) with the temperature ranging 150-250 deg. C. The influence of temperature on the constitutive equation is introduced by the material parameters assumed to be functions of temperature. Fitting process of the assumed model to measured data is presented and the results are ...

2010-06-15

115

Pore formation during hybrid laser-tungsten inert gas arc welding of magnesium alloy AZ31B--mechanism and remedy

A new technique has been developed for improving corrosion resistance on magnesium alloys. Specimens of AZ31 magnesium alloy were dipped into molten salt of NaBF{sub 4} at 723 K for various times, and then cooled, rinsed with water, and dried in air. Corrosion resistance in the surface treated specimens was evaluated by salt immersion test using 1% NaCl solution as a time for occurring filiform corrosion. On an un-treated AZ31 alloy, the time for starting the filiform corrosion was about 1.2 ks, while on the surface treated specimen, the time was prolonged into about 1300 ks. Moreover, the surface treated specimen showed corrosion resistance in low pH solutions, such as 1% HNO{sub 3} and HCl solutions. (orig.)

2005-07-01

116

Pathogenesis of hypocalcemia in magnesium depletion

One of the major concerns during high speed welding of magnesium alloys is the presence of porosity in the weld metal that can deteriorate mechanical properties. This study seeks to analyze the presence method and quantity of pore during hybrid laser-tungsten inert gas arc (TIG) welding of magnesium alloy AZ31B by radiography, optical microscopy and electron probe microanalysis (EMPA). At the same time, it identifies both the mechanism of pore formation and a remedy for this problem. The experimental results indicate that lacking of shielding gas for laser beam is the dominant cause of macroporosity formation during the hybrid of laser-TIG welding of magnesium Alloys AZ31B plate, and hydrogen is not main cause to form large pores. A favorable weld without porosity can be obtained by appending lateral shielding gas for laser beam.

2005-01-15

117

Friction welding of AZ31 magnesium alloy

Hypocalcemia in the hypomagnesemic state in man is usually attributed to refractoriness of end-organs to the calcemic action of parathyroid hormone. We studied the responsiveness of end-organs to bovine...Full Text Available

1971-12-01

118

Direct strip casting of magnesium

In this paper, for an acceleration of utilization of magnesium alloy which is being interested in recent years, friction welding of AZ31 magnesium alloy was carried out, and the joint performance was discussed in relation to the deformation heat input in the upset stage and upset loss as a evaluation factor. Where, the deformation heat input in the upset stage is mechanical work represented by the product of upset speed and axial pressure. As a result, it was made clear that the friction welding of AZ31 magnesium alloy was easy in the atmosphere, and good welded joints without a non- adhesion area at the weld interface could de obtained. Moreover, the evaluation factors discussed were possible to evaluate to joint performance. (orig.)

2003-07-01

119

Design and microstructural analysis of magnesium alloys for dynamical applications

A new interest in magnesium alloys has arisen since light-weight constructions have become more and more attractive. Products that are currently available are mostly cast, forged, and extruded. A cost-effective production of sheet metals will render new perspectives in the design of light-weight constructions. The development of new casting technologies like thin slab casting or strip casting with an in-line rolling process is expected to result in a shorter processing time featuring a high potential of saving energy, time, and cost. Particular attention is paid to the casting process parameters such as casting speed and solidification speed. This article deals with some aspects of a magnesium-adapted single-belt caster. Results of casting experiments and material examination are shown as well as some advices given concerning safety and handling of liquid magnesium. (orig.)

2004-12-01

120

British Library Electronic Table of Contents (United Kingdom)

A microanalytical characterization of cast magnesium alloys of eutectic origin based on the Mg?Al?Ca ternary matrix system has been carried out in order to investigate the influence of alloying elements on their microstructure as well as microchemistry-processing-microstructural relations using structure-sensitive techniques of electron microscopy, mechanical spectroscopy (internal friction), X-ray diffractometry, and advanced microanalytical methods including electron probe compositional analysis. Following the data obtained here there is direct correlation of microstructure with creep properties of the new experimental magnesium alloys. The creep and heat-induced properties of the multicomponent magnesium alloys containing low range of inexpensive additions of titanium (0.07?0.2%) or str...

2011-01-01

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121

Corrosion resistance in magnesium alloys and deposition coated magnesium alloy

Compatibility of magnesium alloys with methanol-containing fuels

Corrosion behavior of deposition coated specimens prepared by the technique proposed by the authors is investigated in salt immersion tests, and also those of pure magnesium, 3N, 4N and 6N grades, and magnesium alloys, AZ31 and AZ91E, are investigated for comparison. Inhomogeneous corrosion occurs in AZ31 and AZ91E alloys when buffered solutions with pH values of 6.5 and 9.0 including 1% NaCl and a conventional 3% NaCl solution are used for immersion tests, while 6N-Mg shows homogeneous corrosion in such solutions. Corrosion behavior of the deposition coated specimen resembles that of 6N-Mg. Purification process included in the deposition coating technique provides homogeneity in microstructural and electrochemical terms, which results in improving corrosion resistance. (orig.)

2003-07-01

122

Catalyst for the manufacture of acrylonitrile and methacrylonitrile

Although magnesium is not attacked by hydrocarbons, it reacts vigorously with anhydrous methanol, raising concerns about the compatibility of the metal with methanol blend fuels. This paper describes the behavior of magnesium alloys in laboratory tests in static contact with methanol-containing fuels at 110/sup 0/F. Water in small concentrations (above 0.25% by weight of the methanol content) is shown to prevent the destructive attack of magnesium by these fuels. The required water content is well within the water tolerance of methanol-GTBA (gasoline grade tertiary-butyl alcohol) cosolvent fuel blends. Die cast AZ91HP shows greater resistance to methanol reaction than does AZ31B sheet.

1986-01-01

123

A new technique for surface modification in magnesium alloys by applying magnesium oxide coating

This patent describes a catalyst composition. It consists of the catalytic oxides of iron, bismuth, molybdenum and magnesium as essential components and optionally the oxides of cobalt, nickel, phosphorus and arsenic.

1989-09-05

124

A Subchronic Intravenous Toxicity Study of Magnesium Fructose-1,6-Diphosphate in Beagle Dogs

A new technique was proposed in order to improve poor corrosion resistance in magnesium. That is, magnesium hydroxide film was formed on the surface of 3 N-Mg by artificial corrosion in 1% MgCl{sub 2} solution for 3.6 ks, which followed by oxidation at 673 K for 3.6 ks in air. Corrosion resistance was evaluated by salt immersion tests in 1% NaCl solution under in situ laser microscopic observations. Bubble evolution, which occurred immediately at the beginning of the immersion test in the case of non-treated specimen, was suppressed by the process. And also, formation of filiform corrosion was suppressed for about 3.6 ks, which occurred at 180 s in the non-treated specimen. (orig.)

2003-07-01

125

British Library Electronic Table of Contents (United Kingdom)

Magnesium fructose-1,6-diphosphate is a novel agent of antimyocardial ischaemia. In the present study, the subchronic toxicity of magnesium fructose-1,6-diphosphate was investigated after 13-week repeated intravenous administration in beagle dogs. The animals received doses of 0, 75, 150 and 300 mg/kg/day (three males and three females for each dose). During the study period, clinical signs, mortality, body weights, food consumption, electrocardiogram, urinalysis, haematology, clinical biochemistry, macroscopic findings, organ weights and histopathology were examined. The administration of magnesium fructose-1,6-diphosphate resulted in increased incidence of clinical signs, including salivation and emesis. These effects were transient and were noted in almost all dogs given 300 mg/kg/day a...

2009-01-01

126

Degradation of leucine zipper-positive isoform of MYPT1 may contribute to development of nitrate tolerance

British Library Electronic Table of Contents (United Kingdom)

Aims A depressed cGMP-dependent protein kinase (PKG) activity is implicated in nitrate tolerance. The present study determines whether the leucine zipper-positive (LZ+) isoform of myosin phosphatase target subunit 1 (MYPT1), a key target protein for PKG actions, is involved in the development of nitrate tolerance. Methods and results Nitrate tolerance in in vitro preparations was obtained by a 24 h incubation with nitroglycerin (NTG). Nitrate tolerance in in vivo preparations was obtained by subcutaneous injection of mice with NTG, and the aortas were used. Protein levels of total MYPT1, MYPT1 (LZ+), PP1Cd, myosin light chain (MLC), and phosphorylated MLC were determined by Western blot analysis. Isometric vessel tension was determined by an organ chamber technique. Protein levels of MYPT1...

2010-01-01

127

Strontium-90 and cesium-137 in service water from June to December, 1981

Strontium isotope ratios and the origin of anorthosites

Service water, 100 l each, was collected at an intake of a water treatment plant and at a tap after water was left running for five minutes. The carriers of strontium and cesium were added to water immediately after sampling, and the sample was vigorously stirred and filtered. Then it was passed through a cation exchange column at a rate of 80 ml/min. Strontium and cesium were eluted with hydrochloric acid from the cation exchange column, and separated. After the radiochemical separation, the mounted precipitates were counted for activity using low background beta counters normally for 60 min. Net sample counting rates were corrected for counter efficiency, recovery, self absorption and decay to obtain the content of strontium-90 and cesium-137 radioactivity per sample aliquot. From the results, concentrations of these nuclides in the original sample were calculated. The maximum values obtained were 0.29 pCi/l of Sr-90 in ...

1981-12-01

128

Optical Feshbach Resonances in Alkaline Earth Atoms

Anorthosites are rocks consisting almost completely of calcic plagioclase, usually from andesine to labradorite. They are not widespread, and until recently were of no economic interest. However, with the advance of the new global tectonics, which has excited considerable interest in the structure and composition of upper-mantle rocks, interest in the anorthosites has grown. This has particularly been the case since the discovery of anorthosites on the moon, where they appear to be more widespread than on the earth. Data have recently been obtained on the strontium isotope compositions of anorthosite intrusions in the Dzhugdzhur-Stanovoy zone and in the rocks surrounding them, which have revealed some unexpected features. The paper describes the geological features of anorthosites, initial concepts on strontium isotope geochemistry, strontium isotope compositions of this region, and discusses some genetic consequences from ...

1986-01-01

129

Identification and validation of heavy metal and radionuclide hyperaccumulating terrestrial plant species. Quarterly technical progress report, March 20, 1995--June 20, 1995

Recent proposals have shown that a quantum degenerate gas of alkaline earth atoms can be used for a number of novel quantum computing and quantum simulation experiments. Strontium is a good candidate for such experiments because it can be controlled with high precision, as demonstrated in recent atomic clock experiments. Unfortunately, the small scattering length of strontium is not amenable to evaporative cooling techniques that are used to reach quantum degeneracy. Furthermore, increasing the scattering length of alkaline earths with a magnetic Feshbach resonance is not possible due to their spinless electronic ground state configuration. However, recent theoretical and experimental work suggests the possibility of changing scattering lengths in alkaline earths with laser light. Using this optical Feshbach resonance near strontium's narrow ^1S0->^3P1 intercombination transition might allow its scattering length to be ...

2009-10-01

130

Red muds are a new kind of sorbent for strontium

The biological accumulation of heavy metals and cesium, strontium, and uranium in plants is discussed. The role of nutrient deficiencies and foliar treatments of manganese and iron compounds is described.

1995-12-01

131

Migration of the long-lived radionuclides in soil-plant system under conditions of 30-km zone

Red mud is a kind of alumina production, characterized by high content of fine-dispersion Fe, Al and Ti oxyhydrates; it is studied from the viewpoint of its application as a sorbent for Sr. The red mud specific surface constitutes 23-25 m"2/g, the density is of 3.3-3.4 g/cm"3 and the melting temperature is 1350-1370 deg C. It is established that the maximum sorption capacity of the red mud for strontium equals 420 #+-# 24 mg-eq/100 g. The red mud high sorption properties make it possible to recommend it as a sorbent by constructing technogenic barriers at the radioactive wastes disposal sites

1996-04-01

132

Generator coordinate method for triaxial quadrupole collective dynamics in strontium isotopes

Field experiments were conducted in the 30-km zone of Gomel's region of the Byelorussia to study factors aecting a biological radionuclide accessibility. A contamination density by radiocesium equaled 2,7-9,9 MBk/m"2, strontium 90 - 0,3-0,5 MBk/m"2 in 1991. A sowing of oats barley, lupin was carried out. It was shown that radionuclide accumulation by agricultural plants was determined basically by biological peculiarities of plants in greater degree than by the contamination density. It was shown that strontium 90 migration from the soil was more intensive than that of radiocesium. 8 tabs.

1992-05-15

133

Fabrication of magnesium alloy (AZ31) sheet by extrusion

We discuss the algebraic structure of the generator coordinate method for triaxial quadrupole collective motion. The collective solutions are classified according to the representations of the permutation group of the intrinsic axes. Our method amounts to an approximate angular-momentum projection. We apply it to a study of the spherical-to-deformed-shape transition in light even strontium isotopes {sup 78-88}Sr. We find that triaxial configurations play a significant role in explaining the structure of the transitional isotopes {sup 80-82}Sr. (orig.).

1991-07-29

134

Deep drawing and impact extrusion of magnesium alloys at room temperature

In order to investigate the extrusion characteristics of magnesium alloy (AZ31), a computer simulation was attempted. Tensile properties of as-cast billet with different strain rates were incorporated into the simulation. The results showed a great change in distribution of stress and strain at near die region by the ram travel. It was found that the average grain size at longitudinal edge of the extruded sheet was smaller than that at center region, which might be attributed to recrystallization caused by severe plastic deformation. (orig.)

2004-07-01

135

A sample preparation for quantitative determination of magnesium in individual lymphocytes by electron probe X-ray microanalysis

Magnesium alloys and composites are potentially highly attractive materials for lightweight design in the automotive industry - if common forming technologies, i.e., deep drawing and cold extrusion, are applicable to them; so far, this is seldom the case. The authors have tested some candidate Mg alloys and discuss the results of their measurements in detail. The Figure shows a typical workpiece part obtained by a deep-drawing technique. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

2003-04-01

136

The forming process of magnesium alloy for Japanese home electric components

We present a sample preparation method for measuring magnesium in individual whole lymphocytes by electron probe X-ray microanalysis. We use Burkitt's lymphoma cells in culture as the test sample and compare X-ray microanalysis of individual cells with atomic absorption analysis of pooled cell populations. We determine the magnesium peak-to-local continuum X-ray intensity ratio by electron probe X-ray microanalysis and calculate a mean cell magnesium concentration of 39 +- 19 mmol/kg dry weight from analysis of 100 cells. We determine a mean cell magnesium concentration of 34 +- 4 mmol/kg dry weight by atomic absorption analysis of pooled cells in three cell cultures. The mean cell magnesium concentrations determined by the two methods are not significantly different. We find a 10% coefficient of variation for both methods of analysis and a 30% coefficient of variation in ...

1986-01-01

137

PVD-CrN coated magnesium alloy AZ91hp and steel 100Cr6 - investigation on the influence of the substrate material on coating properties; PVD-CrN Beschichtungen auf Magnesium AZ91hp und Stahl 100Cr6 - Untersuchung des Substrateinflusses auf die Schichteigenschaften

Magnesium alloys have replaced resins as a material for the components of electronic products such as cell phone and notebook personal computer mainly, because of their lightness and rigidity. Thin walls, a complicated shape, and high appearance quality are all needed in the external parts. Die-casting and injection molding are the main method of manufacturing magnesium alloy parts. The optimal cast conditions and mold design have been investigated in order that a few defects such as surface cracks and mold cavities in casting parts would be reduced. Instead of cast, plastic forming technologies such as warm drawing and hot forging have been developed to form thinner walls and less defects. Plastic formability of magnesium alloy in hot working is dependent on a grain size of material. The material with fine grains has advantage of being formed at high strain rate. The characteristics of forming processes of ...

2005-07-01

138

Fatigue properties of magnesium alloy under biaxial stress

PVD-chromium-nitride coated samples of substrates of the magnesium alloy AZ91hp and the roller and ball bearing steel 100Cr6 were investigated regarding structure, mechanical characteristics, adhesion and internal stresses. For the coatings the parameters layer thickness and substrate BIAS voltage were varied. Both substrate materials were coated in one lad. Results of the X-ray analysis of the internal stresses show significant differences between the coated magnesium and the coated steel substrates. In the case of the variation of the substrate BIAS voltage, for the coated steel a dependency of the internal stresses to coating parameters could be obtained. For the coated magnesium no dependency was recognizable. The coating structure was examined with scanning electron microscopy. Element depth profiles of the coated samples were performed with SIMS. (orig.)

2001-03-01

139

Electronic spectra of plutonium ions in nitric acid and in lithium nitrate solutions

Machines and structures, such as automobiles are usually subjected to biaxial or three-axial stresses instead of uniaxial stress. However, research on a fatigue failure under multi-axial stress has not been fully presented because such experiments are difficult. To solve this problem, we developed the servo biaxial fatigue-testing machine. In this research, we performed the biaxial fatigue tests of a magnesium alloy in order to clarify the effects from different heat treatments. Magnesium alloy is the lightest in weight among metal materials for structural use. The fatigue characteristics of a magnesium alloy are indispensable in order to create the design which ensures the reliability and the safety of the vehicles especially in long-distance run. The main conclusions are summarized as follows; (1) The mechanical property of magnesium alloy AZ31B falls by heat treatment at low temperature. (2) The ...

2004-07-01

140

Apparent molar volumes and apparent molar heat capacities of aqueous nickel(II) nitrate, copper(II) nitrate, and zinc(II) nitrate at temperatures from (278.15 to 393.15) K at the pressure 0.35 MPa

The absorption spectra of plutonium ions in nitric acid have been described. There is a characteristic change in the absorption spectra of Pu v in lithium nitrate solutions. In 2 M-lithium nitrate a new peak at 969 nm and high absorption at 1200 nm are noticed. A decrease in the absorption by about 20% and the appearance of a new shoulder at 1120 nm in 6 M-lithium nitrate are found. There is no change in the spectrum in 4 M-lithium nitrate. The absorption spectra of plutonium ions in the spectral range 200 - 400 nm are interesting. All plutonium ions have an intense band in the region 250 - 260 nm as well as a less intense and rather diffuse band at 320 - 330 nm in lithium nitrate solutions the sharp band at 250 - 260 nm has disappeared. This suggests that this band is very sensitive to the environmental field. The band is probably produced by 5 F"q#-># 5 f"q"-"1 6 d transition ...

1998-05-07

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

141

Solidification of problem wastes: Annual progress report, October 1985-September 1986

Apparent molar volumes V{sub phi} and apparent molar heat capacities C{sub p,phi} were determined for aqueous solutions of nickel(II) nitrate, copper(II) nitrate, and zinc(II) nitrate at molalities m=(0.01 to 0.5) mol {center_dot} kg{sup -1}, and at the pressure p=0.35 MPa. Solution densities obtained using a vibrating-tube densimeter at T=(278.15 to 368.15) K were used to calculate V{sub phi} values. Heat capacity measurements obtained with a twin fixed-cell, differential-output, power-compensating, temperature-scanning calorimeter at T=(278.15 to 393.15) K were used to calculate values of C{sub p,phi}. Our results were then fitted to functions of m and T and compared to literature values.

2004-05-01

142

The study of possibilities of selective recovery of palladium(II) from chloride and chloride-nitrate solutions by weakly basic anion exchangers

This report describes initial work on the development of solidification systems for sodium nitrate waste and compacted waste. Sodium nitrate waste has been solidified in three types of materials: polyethylene, polyester-styrene (PES), and latex cement. Evaluations of the properties of the waste form, such as the ANS 16.1 leaching test, water immersion test and compressive strength measurements were performed on the waste forms containing various amounts of sodium nitrate. 9 refs., 9 figs., 7 tabs.

1987-02-01

143

EVALUATION OF AMMONIUM NITRATE, ALUMINUM ...

... um. Water retention capacity is in the range from 40 to 46 %. Dowex

2009-06-14

144

Catalyst and method for reduction of nitrogen oxides

... 24 5 Exploding Bridgewire Test Vehicle.... . 0..... 25 ... 18 7 Results of Exploding Bridgewire TestLng of TP-41 and TP-41 Mixtures ..... ...

1964-05-14

145

Catalyst and method for reduction of nitrogen oxides

A Selective Catalytic Reduction (SCR) catalyst was prepared by slurry coating ZSM-5 zeolite onto a cordierite monolith, then subliming an iron salt onto the zeolite, calcining the monolith, and then dipping the monolith either into an aqueous solution of manganese nitrate and cerium nitrate and then calcining, or by similar treatment with separate solutions of manganese nitrate and cerium nitrate. The supported catalyst containing iron, manganese, and cerium showed 80 percent conversion at 113 degrees Celsius of a feed gas containing nitrogen oxides having 4 parts NO to one part NO.sub.2, about one equivalent ammonia, and excess oxygen; conversion improved to 94 percent at 147 degrees Celsius. N.sub.2O was not detected (detection limit: 0.6 percent N.sub.2O).

2008-08-19

146

Anodic protection of 304L stainless steel in highly concentrated solutions of nitrates and chromates

A Selective Catalytic Reduction (SCR) catalyst was prepared by slurry coating ZSM-5 zeolite onto a cordierite monolith, then subliming an iron salt onto the zeolite, calcining the monolith, and then dipping the monolith either into an aqueous solution of manganese nitrate and cerium nitrate and then calcining, or by similar treatment with separate solutions of manganese nitrate and cerium nitrate. The supported catalyst containing iron, manganese, and cerium showed 80 percent conversion at 113 degrees Celsius of a feed gas containing nitrogen oxides having 4 parts NO to one part NO.sub.2, about one equivalent ammonia, and excess oxygen; conversion improved to 94 percent at 147 degrees Celsius. N.sub.2O was not detected (detection limit: 0.6 percent N.sub.2O).

2008-05-27

147

DEVELOPMENT OF MONOSODIUM TITANATE (MST) PURCHASE SPECIFICATIONS

Jun 1978. p. 107-108. Israel Ben-Haim, M. Rabinovitz, E. IA--1348. Available

1978-06-01

148

Superplastic forming behaviors and microstructure characters of magnesium alloy sheet AZ31B

Savannah River National Laboratory (SRNL) evaluated the previous monosodium titanate (MST) purchase specifications for particle size and strontium decontamination factor. Based on the measured particle size and filtration performance characteristics of several MST samples with simulated waste solutions and various filter membranes we recommend changing the particle size specification as follows. The recommended specification varies with the size and manufacturer of the filter membrane as shown below. We recommend that future batches of MST received at SRS be tested for particle size and filtration performance. This will increase the available database and provide increased confidence that particle size parameters are an accurate prediction of filtration performance. Testing demonstrated the feasibility of a non-radiochemical method for evaluating strontium removal performance of MST samples. Using this analytical methodology we recommend that ...

2006-04-30

149

Microstructures and tensile properties of wrought magnesium alloys processed by ECAE

An experimental study on superplastic forming behaviors and microstructure characters of commercial magnesium alloy sheet AZ31B is presented in this paper. The main experimental results show that the commercial magnesium alloy AZ31B sheet has superplastic capability. For the received sheet without any pre-processing, the maximum elongation is 295%. The dynamic recrystallization and grain refinement can be found, In the case of temperature =# 350 deg. C. The superplastic behaviors can be improved by controlling the dynamic recrystallization and grain refinement. Some experimental results of free superplastic bulging are presented in this paper. The results show that influence of temperature on forming capability is much less than the influences of temperature on elongation. In addition, the maximum principle strain.

2004-06-10

150

Materials and processing designs for high-performance magnesium alloys

Magnesium alloys are ideal candidates to benefit from equal channel angular extrusion (ECAE) because of their poor forming characteristics due to a hcp structure. In this study, ECAE processing was applied to ZK31 and AZ31 magnesium alloys under various conditions. The grain size of as-ECAE specimens decreases with decreasing the processing temperature, however, the grain size decreases slightly with increasing number of repetitive processing. Both the tensile strength and 0.2% proof stress of as-ECAE specimens are high when processed at low temperature, but the elongation is high when processed at high temperature. Crystal orientation is different in the two alloys and it also varies according to the processing temperature for the two alloys. The difference of the crystal orientation influences the tensile properties, especially 0.2% proof stress. (orig.)

2003-07-01

151

Isothermal sheet formability and microstructure study of rolling processed magnesium alloy AZ31

Materials and processing designs for advanced magnesium alloys with fine microstructures and superior properties were established by the combination of the repeated plastic working and the Mg{sub 2}Si synthesis in solid-state. The grain size was less than 1 {mu}m via RPW process due to its severe plastic working on raw powder. The hot extruded magnesium alloys produced in industries showed high ultimate tensile strength, e.g. 420{proportional_to}450 MPa, when employing Mg-Zn-Al-Ca-RE (Rare Earth) alloy coarse powder, having 0.5{proportional_to}2 mm diameter, as input materials. (orig.)

2005-07-01

152

Hydrostatic extrusion of magnesium: process mechanics and performance

Applications of magnesium alloys are motivated mainly by their lightweight. However, manufacturing cost should also be evaluated when considering applying them. From this point of consideration, adoption of sheet forming processes, which previously have not been heavily researched, should be an option. This paper is intended to pioneer the study of the formability of magnesium alloy AZ31 out of rolled sheets at elevated temperatures. The rolled microstructures are examined and correlated with their formability. Post-forming conditions will also be investigated. The tool employed to perform the sheet forming experiments was a punchless die-setting which used pressurized gas to press the sheet into a female die cavity. This technique applied to Mg-alloy is unconventional and warrants attention for its potential utilization in the industry. (orig.)

2003-07-01

153

Fracture behavior under dynamic biaxial stress on magnesium alloy

Following the breakthrough for cast magnesium products, interest is now spreading to wrought applications - triggering a variety of technological questions. A major bottleneck in the manufacture of magnesium sections (profiles) by conventional hot extrusion is the low productivity, with extrusion speeds typically five to ten times lower than for comparable aluminium sections. This paper focuses on the use of hydrostatic extrusion as a means to overcome this problem. On the basis of an analytical model, it is clarified why and how process limits are affected by the process mechanics. Experimental work on the hydrostatic extrusion of the alloys M1A, ZM21 and AZ31 confirms that extrusion speed is indeed multiplied, whereas the resulting mechanical properties are similar to or better than those for conventional extrusions. (orig.)

2003-07-01

154

Anisotropic properties of magnesium sheet AZ31

We conduct the static and dynamic loading fracture experiments on magnesium alloy (AZ31B) under the equitable and inequitable biaxial stress. We process specimens as cross type with cracks. There are different kinds of cracks defined by their crack angles. By using a hydraulic high-speed biaxial experiment machine, we put the equitable and inequitable stresses on the specimen. We analyze results using the caustic method. The experiments reveal a few important results. There is negative correlation between the fracture toughness value and the plate thickness in the magnesium alloy sheet specimen. The fracture toughness value decrease in the case the crack has the angle different from the loading direction. The fracture toughness value decreases significantly under the inequitable biaxial stress. (orig.)

2004-07-01

155

310 nm irradiation of atmospherically relevant concentrated aqueous nitrate solutions: nitrite production and quantum yields.

Car weight corresponds directly to fuel consumption and driving performance. So in order to improve the fuel efficiency and performance of a car the weight has to be reduced. Magnesium as a light metal offers a wide range of weight saving opportunities, especially Magnesium wrought alloys with their improved mechanical properties have a high potential for structural applications. Mechanical properties in terms of their quality and anisotropy are dependent on the microstructure of the material and can be characterized by their degree of inhomogeneity, their grain size distribution and their crystallographic texture. Therefore the orientation distribution of grains, the grain size, its size distribution, the chemical composition (precipitates) itself influence the mechanical parameters and their anisotropy. In this presentation first results of mechanical anisotropy are given: differences in yield stress, r-values and their relation to the ...

2003-07-01

156

Influence of crystallization on the spectral features of nano-sized ferroelectric barium strontium titanate (Ba0.7Sr0.3Tio3) thin films

The heterogeneous processing of atmospheric aerosols by reaction with nitrogen oxides results in the formation of particulate and adsorbed nitrates. The water content of these hygroscopic nitrate aerosols and consequently the nitrate ion concentration depend on relative humidity, which can impact the physicochemical properties of these aerosols. This report focuses on the 310 nm photolysis of aqueous sodium and calcium nitrate solutions at pH 4 over a wide concentration range of nitrate ion concentrations representative of atmospheric aerosols. In particular, the quantum yield (phi) of nitrite formation was measured and found to significantly decrease at high concentrations of nitrate for Ca(NO(3))(2). In particular, phi for Ca(NO(3))(2) was found to have a maximum value of (7.8 +/- 0.1) x 10(-3) for nitrate ion solution concentrations near ...

2008-12-25

157

British Library Electronic Table of Contents (United Kingdom)

Ferroelectric barium strontium titanate (Ba0.7Sr0.3TiO3)(BST) thin films have been prepared from barium 2-ethylhexanoate [Ba[CH3(CH2)3CH(C2H5)CO2]2], strontium 2-ethylhexanoate [Sr[CH3(CH2)3CH(C2H5)CO2]2] and titanium(IV) isopropoxide [TiOCH(CH3)2]4 precursors using a modified sol-gel technique. The precursor except [TiOCH(CH3)2]4 were synthesized in the laboratory. Transparent and crack-free films were fabricated on pre-cleaned quartz substrates by spin coating. The structural and optical properties of films annealed at different temperatures have been investigated. The as-fired films were found to be amorphous that crystallized to the tetragonal phase after annealing at 550degreeC for 1h in air. The lattice constants "a" and "c" were found to be 3.974A and 3.990A, respectively. The grain...

2008-01-01

158

Batch test equilibration studies examining the removal of Cs, Sr, and Tc from supernatants from ORNL underground storage tanks by selected ion exchangers

Variable Frequency Microwave Synthesis of Silver Nanoparticles

Bench-scale batch equilibration tests have been conducted with supernatants from two underground tanks at the Melton Valley Storage Tank (MVST) Facility at Oak Ridge National Laboratory (ORNL) to determine the effectiveness of selected ion exchangers in removing cesium, strontium, and technetium. Seven sorbents were evaluated for cesium removal, nine for strontium removal, and four for technetium removal. The results indicate that granular potassium cobalt hexacyanoferrate was the most effective of the exchangers evaluated for removing cesium from the supernatants. The powdered forms of sodium titanate (NaTiO) and cystalline silicotitanate (CST) were superior in removing the strontium; however, for the sorbents of suitable particle size for column use, titanium monohydrogen phosphate (TiHP {phi}), sodium titanate/polyacrylonitrile (NaTiO-PAN), and titanium monohydrogen phosphate/polyacrylonitrile (TiP-PAN) gave the best ...

1995-06-01

159

The Conversion of Nitrite to Nitrogen Oxide(s) by the Constitutive NAD(P)H-Nitrate Reductase Enzyme from Soybean ¹

Synthesis of silver nanoparticles based on a polyol process and variable frequency microwave (VFM) was investigated. Comparing to a thermal method, the reaction by VFM radiation was much faster. The effects of silver nitrate concentration, poly(N-vinylpyrrolidone) (PVP) concentration, reaction time and reaction temperature were studied. It was found that the higher concentration of silver nitrate, longer reaction time and higher temperature increased the particle size while the higher concentration of PVP decreased the particle size.

2006-02-15

160

Rapid and Inexpensive Detection of Multidrug-Resistant Mycobacterium tuberculosis with the Nitrate Reductase Assay Using Liquid Medium and Direct Application to Sputum Samples?

A two-step purification protocol was used in an attempt to separate the constitutive NAD(P)H-nitrate reductase [NAD(P)H-NR, pH 6.5; EC 1.6.6.2] activity from the nitric oxide and nitrogen dioxide (NO_(x))...Full Text Available

1988-10-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

161

Open Reading Frame all0601 from Anabaena sp. Strain PCC 7120 Represents a Novel Gene, cnaT, Required for Expression of the Nitrate Assimilation nir Operon

For rapid and low-cost detection of multidrug-resistant (MDR) Mycobacterium tuberculosis, we applied the nitrate reductase assay (NRA) using a liquid medium directly to sputum samples....Full Text Available

2008-10-01

162

Isolation and Initial Characterization of Constitutive Nitrate Reductase-Deficient Mutants NR328 and NR345 of Soybean (Glycine max) ¹

Expression of the nitrate assimilation nir operon in the filamentous, heterocyst-forming cyanobacterium Anabaena sp. strain PCC 7120 requires the action of both the...Full Text Available

2003-09-01

163

In Vivo Determination of Parameters of Nitrate Utilization in Wheat (Triticum aestivum L.) Seedlings Grown with Low Concentration of Nitrate in the Nutrient Solution ¹

Two nitrate reductase deficient mutants of soybean (Glycine max [L.] Merr. cv Bragg) were isolated from approximately 10,000 M₂ seedlings, using a direct enzymic assay in...Full Text Available

1986-06-01

164

Six genotypes of winter wheat (Triticum aestivum L.) differing in grain protein concentration were grown on a nutrient solution containing low concentrations of NO₃⁻...Full Text Available

1981-12-01

165

Explosives for mining

Early disposition of inhaled uranyl nitrate ("2"3"2U and "2"3"3U) in rats

The explosive known under the name Saletrol (mixture of ammonium nitrate and hydrocarbon fuel or a mixture of ammonium nitrate, hydrocarbon fuel and aluminum powder) is characterized by the absence of physical stability during storage (the oily fluid flows from the upper layers of the explosive downward) and as a consequence of this, decrease in the required effectiveness of blasting and increased release of toxic gaseous blasting products. In order to eliminate this shortcoming, lightening clay is added to Saletrol in a quantity of 3-12% by weight of the total explosive mass.

1982-07-31

166

Uranyl nitrate ("2"3"3U) was retained mainly in lung, skeleton, pelt and kidney 60 days after inhalation exposure. The concentration in lung exceeded that in other tissues. Preliminary results with "2"3"2U indicate retention in lung similar to that of "2"3"3U, at total deposited mass levels of 0.1 #mu#g or less.

1977-05-01

167

Detonation of explosives

Assimilation of [¹⁵N]Nitrate and [¹⁵N]Nitrite in Leaves of Five Plant Species under Light and Dark Conditions 1

In recent years new, less-sensitive explosives have been developed together with new types of detonator. Four sections are covered: 1) Description of various developments achieved by the laboratories of Nobel Explosifs over the past 12 years; 2) Explanation of the limits of application of the various products; 3) Thoughts on the various detonator systems and their effectiveness; and 4) Advice and recommendations for the use of the new product range. The products in question are : dynamites, nitrates, oil nitrates, gels and slurry explosives. (17 refs.)

1983-04-01

168

Synthesis and photoluminescence properties of Sm3+-doped LaMgB5O10 and GdMgB5O10

Light dependency of nitrate and nitrite assimilation to reduced-N in leaves remains a controversial issue in the literature. With the objective of resolving this controversy, the light requirement for...Full Text Available

1983-02-01

169

Sol-gel coatings with phosphonate functionalities for surface modification of magnesium alloys

Luminescence and reflection spectra as well as luminescence kinetics of the 1 mol% Sm3+-doped crystalline lanthanum magnesium meta borate (LaMgB5O10) and gadolinium magnesium meta borate (GdMgB5O10) were analyzed. Materials were synthesized by conventional solid state route and showed bright orange-red emission under UV excitation. Emission spectra contain sharp and well resolved Sm3+4G5/2#->#6HJ transitions indicating a strong crystal-field effect. In case of gadolinium compound energy transfer between Gd3+ and Sm3+ was detected. The luminescent kinetics of the Sm3+ in analyzed powders is characterized by single exponential decay and experimental values vary in the range 2.2-2.4 ms. - Research highlights: ? Phosphorescence of samarium-doped lanthanide magnesium meta borates. ? Bright and well resolved orange-red emission of Sm3+ under UV excitation. ? Energy transfer from Gd3+ to Sm3+ in gadolinium ...

2011-07-01

170

Oxide growth on aluminium alloys in the presence of ammonium fluoborate

Hybrid organic-inorganic coatings with phosphonate functionalities have been synthesized and evaluated as prospective surface treatments for magnesium materials. These coatings have been processed via a sol-gel route by hydrolysis and condensation of a mixture of diethylphosphonatoethyltriethoxy-silane and tetraethoxy-silane with variable molar ratios. The coatings morphology and the surface chemistry at the coating/substrate interface have been characterized using scanning electron microscopy, X-ray photoelectron spectroscopy, "3"1P nuclear magnetic resonance spectroscopy, and time-of-flight secondary ion mass spectrometry. The corrosion protection performance of the coatings deposited on magnesium alloy AZ31B has been examined by a group of electrochemical techniques including potentiodynamic polarization and electrochemical impedance spectroscopy. In addition, a scanning Kelvin probe technique has been used to investigate interfacial ...

2006-08-30

171

INVESTIGATION OF GLASS-METAL COMPOSITE ...

The aim of this study as to determine the mechanisms involved in using ammonium fluoborate as a reducing atmosphere when preheating a high magnesium content aluminium alloy. Rutherford Backscattering (RBS) has been the major technique used in the analysis of samples, it revealed significant reduction in both the diffusion of magnesium to the surface and the calculated oxide thickness in the presence of NH{sub 4}BF{sub 4}. At temperatures above 500 deg C in air, SEM images revealed depressions and voids due to incipient melting at various stages, around the grain boundaries. Grain boundaries effectively acted as pipes aiding the diffusion of magnesium to the surface. These results have been verified through compositional analysis with both RBS and auger electron spectroscopy (AES). Results from NH{sub 4}BF{sub 4} atmosphere preheat conditions showed significant improvements. It was verified experimentally that above 500 deg ...

1996-12-31

172

Heterogeneous coupling of phenylethyne over Cu-Mg-Al mixed oxides. Influence of catalyst composition and calcination temperature on structural and catalytic properties

... having high fluidity. The SC-51A alloy contains 4.5 to 5.5% silicon, 1 to 1.5% coppers .4 to .6% magnesium, o35% sine, .8% iron, .5% manganes*, ...

1957-09-01

173

Flow microfluorometric and spectrophotofluorometric analysis of DNA staining in mammalian cells

The catalytic effects of copper-aluminium-magnesium oxides in the oxidative coupling of phenylethyne is described. The importance of surface properties as a redox site are discussed.

1997-07-01

174

Dietary Ammonium Chloride for the Acidification of Mouse Urine

The effects of various fixative agents, pH, ionic strength, stain concentration, and magnesium concentration on DNA staining with the antibiotics olivomycin, chromomycin A3, and mithramycin were examined with DNA in solution and in mammalian cells.

1977-01-01

175

Corrosion and histopathological studies on anode materials for implantable power sources. [In vivo corrosion studies on anode material

A novel therapeutic compound was found to induce bladder tumors in male rats. Given the location of the tumors and the increased amounts of calcium- and magnesium-containing solids found in the urine...Full Text Available

2009-03-01

176

A mechanistic understanding of the formability of magnesium: examining the role of temperature on the deformation mechanisms

The biocompatibility and corrosion resistance of various materials for use as sacrificial anodes in in vivo hybrid fuel cells were studied. Aluminium, zinc, and magnesium alloy AZ31B were studied, and the results are discussed.

1974-01-01

177

Production of plutonium, yttrium and strontium tracers for using in environmental research

The possibility of improving the cold formability of wrought magnesium alloys is considered in light of their good hot forming characteristics. Magnesium alloy AZ31B sheet is selected as a model system. Parameters affecting formability, such as strain hardening rate, strain rate sensitivity, and the degree of anisotropy are examined systematically by conducting tensile tests over a range of temperatures (room temperature to 250 C) and strain rates (1 x 10{sup -5} to 0.1 s{sup -1}). The plastic anisotropy and deformation texture evolution are examined in samples aligned with the sheet rolling and transverse directions. Polycrystal plasticity simulations using a viscoplastic self-consistent (VPSC) formulation are used to model the observed anisotropy and texture evolution. The adjustable parameters in the model are the relative critical resolved shear stresses of the dislocation mechanisms known to operate within magnesium. ...

2003-07-01

178

Optical and X-ray characterization of ferroelectric strontium-bismuth-tantalate (SBT) thin films

Summary of cyclotron production methods of "2"3"7Pu (45,2 d), "8"8Y (106,65 d) and "8"5Sr (64,84 d) tracers via nuclear reactions with protons and alphas on "2"3"5U, "8"8Sr and "8"5Rb targets in wide energy range is given. Chemical methods of separation and purification of the tracers from the irradiated uranium, strontium and rubidium targets are described. The tracers were used for determination of Pu (239-240), Sr-90 and Am-241 in the samples (soil, plants, underground waters) from Semipalatinsk Test Site. Obtained results are discussed.

2001-12-12

179

Assembly of a water-insoluble strontium metal-organic framework with luminescent properties

Metal-organic chemical vapor deposition (MOCVD) made layers of strontium-bismuth-tantalate (SBT) were characterized by spectroscopic ellipsometry (SE) using the Adachi model [S. Adachi, Phys. Rev. B 35 (1987) 7454-7463]. The evaluated optical parameters were correlated with the physical and chemical behavior examined by X-ray diffraction (XRD). As a result, it was possible to fit the measured spectra with the Adachi model in a wide range covering the region of the band gap. The Adachi model provides electronic layer parameters like the transition energy E 0 and broadening ?. Our investigations established a correlation between XRD-determined average grain size and the electronic layer parameters.

2006-10-31

180

British Library Electronic Table of Contents (United Kingdom)

A new strontium metal-organic framework, [Sr2(BTEC)(H2O)4] 2H2O (1) (H4BTEC=benzene-1,2,4,5-tetracarboxylic acid), has been successfully synthesized by mixing the starting reagents. The single-crystal structure analysis showed that compound 1 displayed three-dimensional structures containing inorganic motifs with two-dimensional layers pillar-connected through organic linkers and forming water-coordinated neutral framework. Further studies revealed that compound 1 was insoluble in water and that it emitted strong luminescence at approximately 437nm after dehydration.

2011-01-01

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181

The effect of temperature and flow stress for climb-controlled dislocation creep in magnesium alloy

Study of titanium-niobium alloys manufactured by magnesium thermic reduction of chlorides

Effect of strain rate, temperature and grain size in the climb-controlled dislocation creep region for AZ31 magnesium alloy was examined at lower temperature of {proportional_to}473 K. The flow stress was not affected by the difference in grain size. The strain rate sensitivity, m, was obtained 0.14 and 0.2 at low temperatures in high strain rate and at high temperature in low strain rate, respectively. It was found that the notion of effective diffusivity could express the dominant diffusion process during climb-controlled dislocation creep behavior uniquely. (orig.)

2003-07-01

182

Recrystallization during and following hot working of magnesium alloy AZ31

Chemical and phase homogeneity of titanium-niobium sponge, produced by a combined magnesium-thermic reduction of niobium pentachloride and titanium tetrachloride mixtures, is investigated. It is ascertained that a sponge consists of spherical shape particles and has a large number of pores. Particle sizes are reduced with niobium being substituted for titanium from 50-500 #mu#m for titanium sponge to 1-40 #mu#m for niobium one, which testifies to the bormation in a titanium-niobium sponge of an alloy and not a mechanical mixture. A number of solid solutions is detected by X-ray phase analysis. Lattice parameters are determined.

183

New coumarin-based sensor molecule for magnesium and calcium ions

The microstructures of magnesium AZ31 are examined following hot compression testing and annealing. The grain size, fraction dynamically recrystallized and, in a couple of cases, the crystallographic texture are reported. It was found that the progress of dynamic recrystallization is strongly sensitive to processing conditions but that the dynamically recrystallized grain size was less sensitive to stress than in other metals. It was also found that, for structures containing between 80 and 95% dynamic recrystallization, abnormal grain growth occurs during annealing. The crystallographic texture produced is also sensitive to the deformation conditions. (orig.)

2003-07-01

184

British Library Electronic Table of Contents (United Kingdom)

A new coumarin-based sensor molecule (L1) has been synthesized and this was found to bind calcium and magnesium ions more effectively as compared to other alkali/alkaline earth/lanthanide and certain transition metal ions. A significant enhancement in fluorescence intensity was observed on binding to Ca2+ and Mg2+ ions; while a minor quenching was observed for weakly bound Hg2+, Ni2+, Fe3+, and Co2+ ions. PET process, coupled with the ICT process, is proposed to explain the observed spectral response.

2009-01-01

185

Microstructure, texture and mechanical properties of the magnesium alloy AZ31 processed by ECAP

Hot workability, microstructural control and rate-controlling mechanisms in cast-homogenized AZ31 magnesium alloy

To investigate the influence of equal channel angular pressing on the microstructure and texture of the magnesium alloy AZ31, electron backscattering diffraction and well as neutron diffraction experiments were carried out. Through these experiments it was possible to trace the microstructure and texture evolution with strain accumulated with the increasing number of equal channel angular pressing passes. It was further demonstrated by subsequent compression tests that the microstructural changes produced by equal channel angular pressing have a beneficial effect on both the compressive strength and ductility of AZ31. (orig.)

2008-01-15

186

Effect of mineralizer on the nitridation of sialon-bonded silicon carbide products

Optimum conditions for microstructural control in industrial hot working of cast and homogenized AZ31 magnesium alloys are evaluated by using a processing map. The recommended window for bulk metal working of this alloy is the domain in the temperature range 300-450 C and strain rate range 1-10 s{sup -1}, and the optimum processing parameters are 400 C and 10 s{sup -1}, where grain-boundary self diffusion is the rate-controlling mechanism. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

2009-03-15

187

Diffusion bonding on superplastic-aluminum and -magnesium alloys

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

188

Use of Eu"3"+ as an oxygen environment probe in alkali-alkaline earth-lanthanide phosphates with the #beta#-K_2SO_4 structure

The superplastic characteristics and diffusion bonding behaviors were investigated in commercial 7475 aluminum alloy and AZ31 magnesium alloy sheets. In this study, the presently used materials behaved in a superplastic manner at {proportional_to} 773 K (7475Al) and {proportional_to} 523 K (AZ31). Then, by the theoretical relationship between pressure and time, these materials were successfully diffusion bonded at the superplastic temperatures. The bonding strength was more than 65 MPa. The experimental bonding conditions in high quality joining, times and pressures, were good agreed with prediction analysis. (orig.)

2004-07-01

189

Strengh functions of strontium 88 obtained from the analysis of the (#gamma#,n) reaction near the threshold

The use of europium as a local structural probe allows the various phases appearing in the NaCaPO_4-Na_3Eu(PO_4)_2 and NaSrPO_4-Na_3Eu(PO_4)_2 systems to be detected. The broadening of the europium emission lines in going from the calcium to the strontium phases illustrates the ease of displacement of the PO_4 groups. (Auth.).

1983-09-01

190

SOME RECENT DETERMINATIONS OF ATOMIC MASSES IN THE STRONTIUM-ZIRCONIUM REGION

The results of photoneutron spectra measurements for the reaction (#gamma#,n) on the Sr-88 nuclei near threshold are presented. The parameters of resonance levels, as well as radiative S_#gamma#"("1") and neutron S_n"("1") strength functions for transitions on the first excited level of Sr-87 were obtained. 2 refs.; 1 fig.; 1 tab.

1987-09-14

191

DEVELOPMENT OF PROTOTYPE TITANATE ION EXCHANGE LOADED MEMBRANES FOR STRONTIUM, CESIUM AND ACTINIDE DECONTAMINATION FROM AQUEOUS MEDIA

A large double-focusing mass spectrometer was used to obtain new values for the masses of Sr/sup 86/, Sr/sup 88/, and Zr/sup 90/. Mass differences calculated from these values are found to be in better agreement with nuclear transmutation information than were previous mass spectroscopically derived values. (auth)

1960-06-01

192

Immobilization of sodium nitrate waste with polymers: Topical report

We have successfully incorporated high surface area particles of titanate ion exchange materials (monosodium titanate and crystalline silicotitanate) with acceptable particle size distribution into porous and inert support membrane fibrils consisting of polytetrafluoroethylene (Teflon(reg_sign)), polyethylene and cellulose materials. The resulting membrane sheets, under laboratory conditions, were used to evaluate the removal of surrogate radioactive materials for cesium-137 and strontium-90 from high caustic nuclear waste simulants. These membrane supports met the nominal requirement for nonchemical interaction with the embedded ion exchange materials and were porous enough to allow sufficient liquid flow. Some of this 47-mm size stamped out prototype titanium impregnated ion exchange membrane discs was found to remove more than 96% of dissolved cesium-133 and strontium-88 from a caustic nuclear waste salt simulants. Since in traditional ion ...

2008-05-30

193

Immobilization of sodium nitrate waste with polymers: Topical report

This report describes the development of solidification systems for sodium nitrate waste. Sodium nitrate waste was solidified in the polymers polyethylene, polyester-styrene (PES), and water-extendible polyester-styrene (WEP). Evaluations were made of the properties of waste forms containing various amounts of sodium nitrate by leaching immersion in water, measuring compressive strengths and by the EPA Extraction Procedure. Results of the leaching test are presented as cumulative fraction leached (CFL), incremental leaching rate, and average leaching indices (LI). For waste forms containing 30 to 70 wt% sodium nitrate, the CFL ranged from 9.0 x 10"-"3 to 7.3 x 10"-"1 and the LI from 11 to 7.8. After ninety days immersion in water, the compressive strengths ranged from 720 psi to 2550 psi. The nitrate releases from these samples using the EPA Extraction Procedure were below 500 ppM. ...

2005-06-01

194

Shallow groundwater nitrogen and denitrification in a newly afforested, subirrigated riparian buffer

This report describes the development of solidification systems for sodium nitrate waste. Sodium nitrate waste was solidified in the polymers polyethylene, polyester-styrene (PES), and water-extendible polyester-styrene (WEP). Evaluations were made of the properties of waste forms containing various amounts of sodium nitrate by leaching immersion in water, measuring compressive strengths and by the EPA Extraction Procedure. Results of the leaching test are presented as cumulative fraction leached (CFL), incremental leaching rate, and average leaching indices (LI). For waste forms containing 30 to 70 wt% sodium nitrate, the CFL ranged from 9.0 x 10/sup -3/ to 7.3 x 10/sup -1/ and the LI from 11 to 7.8. After ninety days immersion in water, the compressive strengths ranged from 720 psi to 2550 psi. The nitrate releases from these samples using the EPA Extraction Procedure were below ...

1987-04-01

195

British Library Electronic Table of Contents (United Kingdom)

Summary 1. The EU -Nitrates Directive- (Directive 91/676/EEC) and the WFD (Water Framework Directive 2000/60/EEC) introduced a series of measures designed to reduce and prevent water pollution caused or induced by nitrates from agricultural sources. Therefore, there is an urgent requirement to control the nitrate concentration in freshwater. The objective of this paper was to verify the potential capacity of a specifically designed afforested riparian zone in removing the excess of nitrogen from river water. 2. A buffer zone was set with irrigation ditches, to produce a subsurface water flow carrying water from the study river through the buffer strip to drainage ditches. This experimental system enables the co-occurrence of two main processes: vegetation/microbial nitrogen uptake and deni...

2011-01-01

196

Nitrogen doping into titanium dioxide by the sol?gel method using nitric acid

British Library Electronic Table of Contents (United Kingdom)

N-doped TiO2 has been prepared by use of sol?gel systems containing titanium alkoxide, with nitric acid as the nitrogen source. The time needed for gelation of the systems was drastically reduced by ultrasonic irradiation. The peaks assigned to the nitrate and nitrous ions were observed by FT-IR measurement during the sol?gel reaction. The N-doping was confirmed by the observation of N?O peaks in the XPS spectrum of the sample heated at 400??C. The nitrate ion acted as an oxidizer of the ethanol solvent and titanium species. The TiO2 became doped with nitrogen oxide species as a result of reduction of nitrate ion incorporated into the dried gel samples. These results indicated that the added nitric acid was reduced during the sol?gel transition and heating process, and the resulting NO spe...

2011-01-01

197

Laser Raman microscopic studies of passive films formed on type 316LN stainless steels during pitting in chloride solution

Laser Raman microscopic studies of passive films formed on type 316LN stainless steels during pitting in chloride solution

The surface films formed on type 316LN stainless steels (SS) with different nitrogen contents, during potentiodynamic polarization in acidified 1 M NaCl solution, were characterized by Laser Raman Spectroscopy (LRS). LRS confirmed the presence of oxides and oxychlorides of iron and chromium, hydrated chlorides and nitrates in the film. Raman mapping showed increasing nitrate content in the film with increasing nitrogen content. The film on the uncorroded material showed the presence of chromium and molybdenum oxides. The improvement in pitting corrosion resistance of type 316LN SS with increasing nitrogen content was attributed to increased amount of nitrates in the passive film.

2010-06-15

198

Existing systems review of treatment media for the Bear Creek Valley treatability study, Oak Ridge Y-12 Plant, Oak Ridge, Tennessee

The surface films formed on type 316LN stainless steels (SS) with different nitrogen contents, during potentiodynamic polarization in acidified 1 M NaCl solution, were characterized by Laser Raman Spectroscopy (LRS). LRS confirmed the presence of oxides and oxychlorides of iron and chromium, hydrated chlorides and nitrates in the film. Raman mapping showed increasing nitrate content in the film with increasing nitrogen content. The film on the uncorroded material showed the presence of chromium and molybdenum oxides. The improvement in pitting corrosion resistance of type 316LN SS with increasing nitrogen content was attributed to increased amount of nitrates in the passive film.

2010-06-01

199

Comparison of sodium zirconium phosphate and Synroc matrices for immobilization of high-level waste

In situ treatment has been proposed as a remediation alternative for surface water and groundwater contaminated with uranium and nitrate as a result of former waste disposal practices in the S-3 Ponds. Interceptor trenches containing reactive media have been proposed to treat groundwater, and constructed wetlands and/or algal mats are potential alternatives for treating surface water. This report presents the results from testing of ten different reactive media, and combinations of media, that are candidates for use in the proposed interceptor trenches to remove uranium and nitrate from groundwater. It also presents the results of testing and evaluation of algal mats and wetlands for removing uranium and nitrate from surface water.

1998-01-01

200

Solidification of DOE problem wastes

The aims of the present work were to investigate possible compatibility between sodium zirconium phosphate (NZP) and Synroc titanate phases, to prepare NZP-based waste forms by hot-pressing rather than sintering, and to investigate the incorporation in NZP of (a) Cs/Sr as simulated heat-generating nuclides; (b) simulated actinides; and (c) simulated Purex waste. The NZP samples were prepared by methods similar to those used for Synroc. The precursor NZP phase was formed from tetrabutyl zirconate Zr(OC{sub 4}H{sub 9}){sub 4}, sodium nitrate, and 85% orthophosphoric acid. Simulated waste nitrate solutions were then mixed with the liquid precursor. After stir drying of the precursor, calcination was carried out at 700{degree}C to remove nitrates and organics.

1996-12-31

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201

Role of Respiratory Nitrate Reductase in Ability of Pseudomonas fluorescens YT101 To Colonize the Rhizosphere of Maize

Sodium nitrate waste has been successfully solidified in two types of polymeric materials: polyethylene, a thermoplastic material, and polyester styrene (PES), a thermosetting material. Waste form property evaluation tests such as ANS 16.1 leaching test and compressive strength measurements were performed on the waste forms containing various amounts of sodium nitrate. A single-screw extruder was employed for incorporating dry waste into polyethylene at its melt temperature of 120/sup 0/C to produce a homogenous mixture. Results of the leaching test for polyethylene waste forms containing 30, 50, 60 and 70 wt% sodium nitrate are presented as cumulative fraction leached and leaching indices ranging from 11 to 7.8. Two PES systems are discussed. The first is for solidification of dry salt wastes and the second is a water extendible system that is compatible with wet waste streams. Leaching data for PES and water extendible ...

1986-01-01

202

Reduction of Nitrate and Nitrite in Lambsquarters (Chenopodium album) Biotypes Resistant and Susceptible to Atrazine Toxicity ¹

Selection of the denitrifying community by plant roots (i.e., increase in the denitrifier/total heterotroph ratio in the rhizosphere) has been reported by several authors. However, very few studies...Full Text Available

2000-09-01

203

Rapid and Inexpensive Drug Susceptibility Testing of Mycobacterium tuberculosis with a Nitrate Reductase Assay

The nitrite-reducing activity of the normal susceptible biotype of lambsquarters (Chenopodium album L.) was strongly inhibited by atrazine in the assay medium, both in the case of the...Full Text Available

1980-05-01

204

Rapid Detection of Ofloxacin Resistance in Mycobacterium tuberculosis by Two Low-Cost Colorimetric Methods: Resazurin and Nitrate Reductase Assays

Multidrug-resistant tuberculosis is an increasing public health concern in many parts of the world, especially in low-income countries, where most cases occur. Traditional drug susceptibility testing...Full Text Available

2002-02-01

205

Physiological Adaptation of a Nitrate-Storing Beggiatoa sp. to Diel Cycling in a Phototrophic Hypersaline Mat?

We have evaluated the performance of two rapid, low-cost methods for the detection of ofloxacin (OFX) resistance with 95 Mycobacterium tuberculosis isolates from countries with high...Full Text Available

2005-04-01

206

Nitric Oxide and Nitrous Oxide Production by Soybean and Winged Bean during the in Vivo Nitrate Reductase Assay ¹

The aim of this study was to investigate the supposed vertical diel migration and the accompanying physiology of Beggiatoa bacteria from hypersaline microbial mats. We combined microsensor,...Full Text Available

2007-11-01

207

Nitrate Reduction by Roots of Soybean (Glycine max [L.] Merr.) Seedlings

This study was conducted to determine by gas chromatography (GC) and mass spectrometry (MS) the identity and the quantity of volatile N products produced during the helium-purged in vivo...Full Text Available

1986-11-01

208

Molybdoenzyme biosynthesis in Escherichia coli: in vitro activation of purified nitrate reductase from a chlB mutant.

Studies were conducted with 9 to 12 day-old soybean (Glycine max [L.] Merr. cv. Williams) seedlings to determine the contribution of roots to whole plant NO₃⁻...Full Text Available

1982-06-01

209

Interaction of tetravalent plutonium and zirconium with citric acid in nitric acid solutions

All molybdoenzyme activities are absent in chlB mutants because of their inability to synthesize molybdopterin guanine dinucleotide, which together with molybdate constitutes the molybdenum cofactor...Full Text Available

1992-12-01

210

Increase in Internode Length of Phaseolus lunatus L. Caused by Inoculation with a Nitrate Reductase-deficient Strain of Rhizobium sp. ¹

The interaction of Pu(IV) and Zr(IV) with citric acid in nitric acid solutions (C/sub HNO/sub 3// greater than 0.1 M) of lithium nitrate was studied by the distribution method in the interval of nitrate ion concentrations from 1 to 6 g-eq/liter. A 40 percent solution of TBP in decane was used as the extraction reagent. It was established that within the range of concentrations studied, complex compounds of plutonium and zirconium are formed: PuHCit/sup 2 +/ and ZrH/sub 2/Cit/sup 3 +/. The concentration equilibrium constants of the reactions of formation of these compounds retain a constant value at constant ionic strength and undergo substantial variation when the total concentration of the nitrate ion in solution is varied. The values of the effective equilibrium constants, calculated considering the change in the activity coefficient of the hydrogen ion, retain a constant value within a wide range of ...

1975-01-01

211

Identification of a new gene, molR, essential for utilization of molybdate by Escherichia coli.

Dramatic differences in the height of lima beans (Phaseolus lunatus L.) treated with two different Rhizobium strains were studied. Lima beans were grown in Perlite...Full Text Available

1981-01-01

212

Drug Susceptibility Testing of Mycobacterium tuberculosis by a Nitrate Reductase Assay Applied Directly on Microscopy-Positive Sputum Samples

A mutation in a new gene, molR, prevented the synthesis in Escherichia coli of molybdoenzymes, including the two formate dehydrogenase isoenzymes, nitrate reductase and trimethylamine-N-oxide reductase....Full Text Available

1990-04-01

213

Denitrification and Assimilatory Nitrate Reduction in Aquaspirillum magnetotacticum

Current methods for drug susceptibility testing of Mycobacterium tuberculosis are either costly or slow. As the prevalence of multidrug-resistant strains increases, the need for fast,...Full Text Available

2005-07-01

214

Crack tip oxidation of a superalloy in molten nitrate salt

Aquaspirillum magnetotacticum MS-1 grew microaerobically but not anaerobically with NO₃⁻ or NH₄⁺ as the sole nitrogen source. Nevertheless,...Full Text Available

1983-11-01

215

Biotransformation of Explosives by the Old Yellow Enzyme Family of Flavoproteins

Alloy 800 has been proposed for use in the receiver tube panel arrays of advanced solar central receiver (SCR) designs. In this application the alloy will be exposed to a molten mixture of sodium and potassium nitrate salts at temperatures ranging up to approximately 600/sup 0/C While these salts are routinely used in a variety of applications including metal heat treating and process heat transfer, common industrial experience has been limited to maximum temperatures of 400/sup 0/C - 450/sup 0/C. There is, therefore, considerable interest in the compatibility of these salts with containment alloys at the higher temperatures associated with SCR designs. Additionally, the containment alloy may be subject to thermally induced fatigue damage resulting from intermittent cloud cover and diurnal cycling. Previous work has found that slower near-threshold fatigue crack growth rates (FCGR) in Alloy 800 result when it is tested in molten nitrate salt at ...

1983-04-01

216

Ammonium and Nitrate Uptake by the Floating Plant Landoltia punctata

Several independent studies of bacterial degradation of nitrate ester explosives have demonstrated the involvement of flavin-dependent oxidoreductases related to the old yellow enzyme (OYE) of yeast....Full Text Available

2004-06-01

217

A Nitrate Reductase-less Variant Isolated from Suspension Cultures of Datura innoxia (Mill.) ¹

Background and AimsPlants from the family Lemnaceae are widely used in ecological engineering projects to purify wastewater and eutrophic water bodies. However, the biology of nutrient...Full Text Available

2007-02-01

218

Nuclear fuels and their use in atomic reactors: uranium

A comparative study has been carried out of the growth of two lines of Datura innoxia (Mill.) cells, designated DI-6 and NR1, their resistance to chlorate, and their ability to assimilate...Full Text Available

1980-10-01

219

Gastrointestinal absorption of transuranic elements by rats

The reactor fuel cycle based on uranium is described. The various stages in the cycle include mining of uranium ores followed by crushing and grinding, leaching and purification of leach liquor by ion exchange resin process or solvent extraction process, refining of uranium concentrate (yellow cake) by digesting with HNO_3 and then solvent extracting uranyl nitrate with TBP, conversion of uranyl nitrate to uranium hexafluoride, production of uranium metal, uranium enrichment, fabrication of reactor fuel elements and reprocessing of the spent fuel. Chemical reactions wherever they are involved are explained. (M.G.B.).

1978-01-01

220

Effect of lead nitrate on thyroid function on the Indian palm squirrel, Funambulus pennanti (Wroughton)

Absorption of ''organically bound'' "2"3"3U and "2"4"1Am from gastrointestinal tracts of adult rats was twice that of the inorganic nitrate form. There was no difference between transport of "2"3"2U and "2"3"3U by adult rats, but "2"3"2U absorption by newborn rats was four times that of "2"3"3U. Absorption of "2"3"8Pu nitrate through the gut of the newborn is relatively insensitive to dose but incorporation in the gut mucosa saturates at high dose levels. Absorption of "2"3"8Pu is greater at 4 hr of age than at 24 hr.

1977-05-01

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221

Temperature effects on wastewater nitrate removal in laboratory-scale constructed wetlands

Some of the known toxic effects of lead in mammals including man are, impaired heme synthesis, anemia, nepatopathy, nephropathy, behavioral disorders and neuropathy. However, very little is known about the effect of lead on endocrine physiology. Some data are available on lead induced impairment of thyroid function in occupationally exposed men and experimental rats. As lead nitrate is largely consumed through water and food, in this study the wild rodents Funambulus pennanti were administered lead through their drinking water and their thyroid structure, radioiodine 131-I percentage uptake and protein bound iodine (PBI) level were assessed.

1987-06-01

222

The phospholipid vesicles coating on metal chelated inorganic surfaces

Constructed wetlands may be used for removal of high nutrient loads in greenhouse wastewater prior to discharge into the environment. Temperature affects both the physical and biological activities in wetland systems. Since nitrification and denitrification are temperature-dependent processes, effluent nitrate concentrations will fluctuate due to changes in air and wetland temperature. In a cold climate, constructed wetlands can function in a temperature-controlled, greenhouse environment year-round. This work evaluates four temperature treatments on nitrate removal rates in five planted and five unplanted laboratory-scale wetlands. Wetlands were supplied with a nutrient solution similar to the fertigation runoff solution (100 PPM nitrate-N) used in greenhouse crop production. A first-order kinetic model was used to describe experimental nitrate depletion data and to predict nitrate ...

1999-02-01

223

Rapidly solidified AZ31 magnesium alloy ribbons used in rechargeable batteries

This work showed the formation of phospholipid vesicle coating on inorganic sericite surface with characterization by combining electron microscopy of FE-SEM, TEM, AFM, and qualitatively evaluated the coated phospholipid vesicle by XPS as a function of etching time. The possibility of phospholipid vesicle mobility on the surface was restrained by the chelation effect of magnesium cation. The stabilization properties of phospholipid vesicles on sericite surface were demonstrated by the various concentration of magnesium cation. The presence of magnesium was found to have a much more pronounced influence on the lipid deposition process. The Mg cation plays an important role for attaching the phospholipids with optimum concentration of 7 mM. Totally, the phospholipid vesicles coating on inorganic powder could be useful for bio-related fields such as cosmetics and drug delivery system as the key functional compounds. We hope ...

2007-09-01

224

Particle size effects on the desorption properties of nanostructured magnesium dihydride (MgH2) synthesized by controlled reactive mechanical milling (CRMM)

Better properties of magnesium make it a natural choice for use as an anode material in rechargeable batteries. However, the magnesium alloy thin sheets used in rechargeable batteries were produced by ingot casting and rolling. That technology was so complex and the cost was high. Rapidly solidification by melt spinning is an effect way to solve that problem. In this paper, the technology of rapidly solidified (RS) ribbons in Mg-3%Al-1%Zn-0.2%Mn alloy has been investigated using melt spinning technique. The effect of wheel speed on thickness and microhardness of the ribbons is presented. Microhardness is found to increase with the wheel speed. Rapidly solidification leads to small grains (1{proportional_to}2 {mu}m). The plasticity of the ribbons was well. The quantity of Mg{sub 17}Al{sub 12} decreases with the increase in wheel speed. When the wheel speed reaches 1600 rpm, no Mg{sub 17}Al{sub 12} phase precipitates. As the increase of the wheel ...

2005-07-01

225

Mushy state forming of magnesium alloy making use of resistance heating

In the present work the hydrogen desorption properties of nanostructured magnesium hydride (MgH2) synthesized by controlled reactive mechanical milling (CRMM) of elemental Mg powder under hydrogen are investigated. A profound effect of the particle size of synthesized MgH2 hydride on its hydrogen desorption characteristics measured by differential scanning calorimetery (DSC) has been found. All synthesized MgH2 powders are characterized by a double hydrogen desorption peak. Furthermore, below a certain threshold particle size the DSC desorption temperature of the peak doublet starts decreasing rapidly with decreasing of the mean hydride powder particle size (expressed as equivalent circle diameter-ECD). In contrast, the nanograin (crystallite) size of MgH2 does not seem to have apparent effect on the DSC desorption temperature. It is also observed that for powder particles smaller than some threshold value, X-ray diffraction shows the presence of two polymorphic ...

2006-11-09

226

In situ ellipsometric studies of formation kinetics of rare earth metal conversion coatings on magnesium alloy

Feasibility of mushy state forming of magnesium alloys making use of resistance heating was examined. Magnesium alloys, AZ31, AZ61 and AZ91, were taken up as experimental materials and cylindrical billets with a diameter of 15 mm and a height of 20 mm were used for both resistance heating and forming experiments. Input heat control was applied to the billet heating and insertion of thin discs of austenitic stainless steel with a low thermal conductivity between the billet and copper electrodes was attempted in order to improve the efficiency of the billet heating. Results were summarized as follows. (1) Resistance heating by input heat control was successful to heat the billets to their respective mushy state. (2) Insertion of the discs was very helpful in heating the billets and realized the heating in a couple of seconds. (3) The force applied to the electrodes to ensure the electrical contacts being too small, sparks occurred and welds arose ...

2003-07-01

227

Impact of elevated CO{sub 2} and nitrogen fertilization on foliar elemental composition in a short rotation poplar plantation

In situ spectroscopic ellipsometry was employed to investigate the initial regime of rare earth metal (REM) conversion coatings formation on AZ31 magnesium alloy. Three REM salts solutions, 0.05 mol.dm"-"3 Ce(NO_3)_3, La(NO)_3 and Sm(NO)_3 solutions, were used for REM conversion coatings preparation. By deconvoluting the ellipsometric data, the surface of the fresh well-polished AZ31 magnesium alloy was found to be covered with 15.80 nm thick native (hydr)oxide film; the refractive indices and the thickness of Ce, La and Sm conversion coatings were obtained. The formation kinetics of three REM coatings follows different exponential functions and the coatings exhibit different optical properties. La conversion coating has the largest n values and the lowest k values while Sm conversion coating is just opposite. Moreover, the pH variation of the bulk conversion solutions upon the coatings formation was recorded. It is confirmed that the reduction ...

2008-05-01

228

Evaluation of press formability in magnesium alloy

The experiment was carried out on a short rotation coppice culture of poplars (POP-EUROFACE, Central Italy), growing in a free air carbon dioxide enriched atmosphere (FACE). The specific objective of this work was to study whether elevated CO{sub 2} and fertilization (two CO{sub 2} treatments, elevated CO{sub 2} and control, two N fertilization treatments, fertilized and unfertilized), as well as the interaction between treatments caused an unbalanced nutritional status of leaves in three poplar species (P. x euramericana, P. nigra and P. alba). Finally, we discuss the ecological implications of a possible change in foliar nutrients concentration. CO{sub 2} enrichment reduced foliar nitrogen and increased the concentration of magnesium; whereas nitrogen fertilization had opposite effects on leaf nitrogen and magnesium concentrations. Moreover, the interaction between elevated CO{sub 2} and N fertilization amplified some element unbalances such ...

2007-06-15

229

The diffusion bonding and theoretical model including void growth mechanism in magnesium alloys

A press formability of magnesium alloy sheet cannot be evaluated by only general characteristics in tensile test; tensile strength, elongation n-value and r-value. For example, AZ31-alloy elongates about 20% in room temperature but breaks easily at shallow stage in deep drawing, which is caused by little local elongation (local necking). Crystallographic restriction of slip deformation in this alloy produces high strength, which almost equal to macroscopic fracture strength. In press forming, the bending under high tension requires a large deformability. A great difference in the deformability between AZ31 magnesium alloy and a strain hardened A1100 Aluminum (only 5% in elongation) is shown by static bending test with V-notch. In a rolled plate of AZ31, a crack is produced by stress concentration and propagates with reduced load at all testing temperature up to 453 K. In contrast, the point of notch in A1100 is dulled by local plastic ...

2003-07-01

230

Study on the interface of PVDF coatings and HF-treated AZ31 magnesium alloy: Determination of interfacial interactions and reactions with self-healing properties

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.)

2003-07-01

231

Sodium monocarboxylates as inhibitors of AZ31 alloy corrosion in a synthetic cooling water

Research highlights: ? Reports a high protection system for the alloy in corrosive environment. ? Describes an interfacial process with self-healing properties. ? Reports the influence of substrate pre-treatment in the coating performance. - Abstract: In this paper the interface of poly(vinylidene fluoride) coatings prepared by the dip coating method and HF-treated AZ31 magnesium alloy was evaluated. The best performance of this system in corrosion tests compared to ground, as-received and acetic acid cleaned substrates is related to an acid-base interaction at the interface and to interfacial reactions which resulted in a self-healing process. The protectiveness of the samples was investigated using impedance and immersion tests while the coating morphology and interface stability were investigated by scanning electron microscopy, X-ray photoelectron spectroscopy and adhesion tests.

2011-02-01

232

Microstructures of friction welded joints of AZ31 to AM60 magnesium alloys

This research investigated the inhibiting effects that sodium salts of linear monocarboxylic acids displayed towards the corrosion process of AZ31 Mg alloy in ASTM D 1387 saline solution (a synthetic industrial cooling water). The length of the aliphatic chain of the acids ranged between 7 and 15 carbon atoms. The inhibiting action of these salts can be related to the precipitation of an insoluble magnesium salt, which mainly affected the anodic reaction. The aliphatic chain length controlled the anion solubility and the reaction rate of magnesium carboxylate formation. For all the salts, an optimum concentration was experienced: 10{sup -2} M for sodium decanoate (caprate), 10{sup -3} M for sodium dodecanoate (laurate), 10{sup -4} M for sodium tetradecanoate (myristate); when this concentration was exceeded, a diminution (even a disappearance) in the inhibiting action was found. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

2009-03-15

233

Ion-radiation hardening of magnesium oxide crystals

AZ31 magnesium alloy was friction-welded to AM60 and the microstructures and the friction welding process were studied. The microstructures changed near the weld interface. The AZ31 was refined to a grain size of several {mu}m near the weld interface. The nucleation occurred in the shear bands that were introduced during the welding process. On the other hand, the eutectic structure was deformed and the lamellar structure which was composed of {alpha}-Mg and Mg{sub 17}Al{sub 12} was formed near the weld interface in AM60 alloy. In the friction process, the adhesion and peel off occurred alternately between AZ31 and AM60. Eventually, bonding was completed during upset process. (orig.)

2003-07-01

234

Internal strain and texture evolution during deformation twinning in magnesium

Consideration is given to the data, demonstrating the effect of ion radiation on strength characteristics of ionic crystals, presented by magnesium oxide. Crystals, prepared in the form of plates, were irradiated by Si"+, Fe"+, C"+ ions by the dose of 10"1"6-10"1"7 ion/cm"2 at room temperature in vacuum. The following characteristics were investigated: dislocation density, microhardness, crack resistance. Investigation of dislocation structure showed, that dislocation density in irradiated sample was 2-3 times higher, as compared to nonirradiated one. Sufficient increase of fracture viscosity of MgO crystals was revealed. It can be conditioned by occurrence of compression stresses in the surface layer, decelerating crack formation and propagation.

235

Initial grain size effect of dynamic recrystallization of magnesium alloy AZ31

The development of a twinned microstructure in hexagonal close-packed rolled magnesium compressed in the in-plane direction has been monitored in situ with neutron diffraction. The continuous conversion of the parent to daughter microstructure is tracked through the variation of diffraction peak intensities corresponding to each. Approximately 80% of the parent microstructure twins by 8% compression. Elastic lattice strain measurements indicate that the stress in the newly formed twins (daughters) is relaxed relative to the stress field in the surrounding matrix. However, since the daughters are in a plastically 'hard' deformation orientation, they quickly accumulate elastic strain as surrounding grains deform plastically. Polycrystal modeling of the deformation process provides insight about the crystallographic deformation mechanism involved.

2005-06-15

236

Grain refinement on AZ31 magnesium alloy by highly strained and annealed method

Dynamic development of new grain boundaries was studied in compression of a magnesium alloy AZ31 with initial grain sizes (D{sub 0}) of 22 {mu}m and 90 {mu}m at a temperature of 673 K. Kink bands are evolved near corrugated grain boundaries and in grain interiors at low strains accompanied with new fine grains. Kink bands are developed often perpendicular to the basal plane. The boundary misorientation of kink band as well as the volume fraction of new grains increases rapidly with increasing strain and approaches a saturation value in high strain. New fine grains are developed faster with decrease in the D{sub 0}. It is concluded that new grain evolution is controlled by a deformation-induced continuous reaction, i.e. continuous dynamic recrystallization (DRX). (orig.)

2003-07-01

237

Thermodynamics, lattice stability and defect structure of strontium silicides via first-principles calculations

Grain refinement in AZ31 magnesium alloy has been attempted by hot-rolling and annealing process. Specimens were solution heat treated at 673 K for 36 ks, then hot-rolled at 423-773 K with total reduction of 20-80% by multi pass process. The rolled specimens were annealed at 473-673 K for 3.6 ks. Grain sizes after the solution heat treatment were about 20 to 150 {mu}m. After hot-rolling at 573 K and annealing at 473 K, grain sizes decreased into about 5 to 10 {mu}m. Suppression of grain growth by pinning due to precipitates was observed by transmission electron microscopic observations. (orig.)

2004-07-01

238

Strength functions of primary transitions following thermal neutron capture in strontium

The thermodynamics of the Sr-Si system is of fundamental importance for the understanding of eutectic modification of Al-Si alloys. At the same time, strontium silicides have recently been found to have potential applications in electronic devices. Renewed research efforts have led to a re-evaluation of the phase equilibria in this system, resulting in the discovery of previously undetected stable intermetallic compounds. In this work, we investigate the finite temperature thermodynamic properties of the stable (and metastable) Sr-Si intermetallics. The vibrational properties of the intermetallic compounds are calculated within harmonic theory, with quasi-harmonic corrections to account for the effects of thermal expansion. The total free energies of the compounds are computed considering vibrational and electronic contributions, as well as weak anharmonic corrections. The ground state of the system is predicted and compared to previous experimental and ...

2009-09-18

239

Strength functions of primary transitions following thermal neutron capture in strontium

The primary E1, M1 and E2 ..gamma..-radiation in /sup 87,88,89/Sr observed after thermal neutron capture was compared with the predictions of single particle and giant resonance models. The nuclei feature a wide range of neutron binding energies between 6.3 and 11.1 MeV, which makes a 5.5 MeV spectrum of primary transition energies available for investigation. The (n, ..gamma..) reaction was used to estimate the parameters of the spin-flip M1 giant resonance in strontium. The total energy weighted M1 strength of this resonance exceeds the results of shell model and random phase approximation calculations for /sup 90/Zr by a factor of 3-4. The E1 strengths were found to agree with the established giant dipole resonance model. The few data on primary E2 transitions do not allow to differentiate between the giant quadrupole resonance and the single particle models.

1989-04-01

240

SELECTIVE REMOVAL OF STRONTIUM AND CESIUM FROM SIMULATED WASTE SOLUTION WITH TITANATE ION EXCHANGERS IN A FILTER CARTRIDGE CONFIGURATION

The primary E1, M1 and E2 #gamma#-radiation in "8"7","8"8","8"9Sr observed after thermal neutron capture was compared with the predictions of single particle and giant resonance models. The nuclei feature a wide range of neutron binding energies between 6.3 and 11.1 MeV, which makes a 5.5 MeV spectrum of primary transition energies available for investigation. The (n, #gamma#) reaction was used to estimate the parameters of the spin-flip M1 giant resonance in strontium. The total energy weighted M1 strength of this resonance exceeds the results of shell model and random phase approximation calculations for "9"0Zr by a factor of 3-4. The E1 strengths were found to agree with the established giant dipole resonance model. The few data on primary E2 transitions do not allow to differentiate between the giant quadrupole resonance and the single particle models. (orig.).

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241

Process development for remote-handled mixed-waste treatment

This report describes experimental results for the selective removal of strontium and cesium from simulated waste solutions using monosodium titanate (MST) and crystalline silicotitanate (CST)-laden filter cartridges. Four types of ion exchange cartridge media (CST and MST designed by both 3M and POROX{reg_sign}) were evaluated. In these proof-of-principle tests effective uptake of both Sr-85 and Cs-137 was observed. However, the experiments were not performed long enough to determine the saturation levels or breakthrough curve for each filter cartridge. POREX{reg_sign} MST cartridges, which by design were based on co-sintering of the active titanates with polyethylene particles, seem to perform as well as the 3M-designed MST cartridges (impregnated filter membrane design) in the uptake of strontium. At low salt simulant conditions (0.29 M Na{sup +}), the instantaneous decontamination factor (D{sub F}) for Sr-85 with the 3M-design MST cartridge ...

2011-05-26

242

Maintenance implementation plan for the B Plant/WESF. Revision 4

The Oak Ridge National Laboratory (ORNL) is developing a treatment process for remote-handled (RH) liquid transuranic mixed waste governed by the concept of minimizing the volume of waste requiring disposal. This task is to be accomplished by decontaminating the bulk components so the process effluent can be disposed with less risk and expense. Practical processes have been demonstrated on the laboratory scale for removing cesium 137 and strontium 90 isotopes from the waste, generating a concentrated waste volume, and rendering the bulk of the waste nearly radiation free for downstream processing. The process is projected to give decontamination factors of 10{sup 4} for cesium and 10{sup 3} for strontium. Because of the extent of decontamination, downstream processing will be contact handled. The transuranic, radioactive fraction of the mixed waste stream will be solidified using a thin-film evaporator and/or microwave solidification system. ...

1990-01-01

243

Experimental and theoretical isotope shifts of strontium levels subject to very strong configuration mixing

This Maintenance Implementation Plan (MIP) has been developed for maintenance functions associated with the B Plant/WESF (Waste Encapsulation Storage Facility) complex. The objective of this plan is to provide baseline information for establishing and identifying WHC conformance programs and policies applicable to implementation of DOE order 4330.4B guidelines. In addition, this maintenance plan identifies the actions necessary to develop a cost-effective and efficient maintenance program at B Plant/WESF. The B Plant WESF facility complex consists of three main facilities and several support structures located in the 200 East Area of the Hanford site. B Plant is a transition facility that is required to ensure safe storage and management of WESF (operating facility) cesium and strontium capsules. B Plant/WESF also contains substantial radiological inventory from previous campaigns. There are no production activities at B Plant, but several of its operating systems ...

1996-01-01

244

Effect of sintering optimization on the electrical properties of bulk BaxSr1-xTiO3 ceramics

The isotope shifts of the levels 5p/sup 2/ /sup 1/D/sub 2/, /sup 1/S/sub 0/ and 5sns /sup 1/S/sub 0/(n = 7,8) of strontium have been measured between the isotopes 84, 86, 87 and 88 in two-photon transitions from the ground state, using two lasers with different wavelengths. These levels occur below the beginning of the Rydberg series, and are known to exhibit very strong configuration mixing. Mass and field isotope shifts are calculated ab initio by means of the MCHF method for these levels and 5s4d /sup 1/D2, 5s6s /sup 1/S/sub 0/. The qualitative agreement between theory and experiment confirms the necessity of taking into account the mixing (up to 50%) with both the 5p/sup 2/ and 4d/sup 2/ perturbers in the wavefunction expansions.

1984-05-14

245

British Library Electronic Table of Contents (United Kingdom)

BaxSr1-xTiO3 (x=0.6, 0.75, 0.80, 0.85 and 0.9) compositions are prepared by solid-state reaction route using controlled heating and cooling. Density optimization by varying sintering temperature was achieved. X-ray diffraction (XRD) analysis shows the phase pure materials. The lattice constant decreases from 3.9868A (x=0.90) to 3.9449A (x=0.60) with increasing Sr2+; the tetragonal distortion also decreases. Dielectric constant show sharp peaks for samples having low strontium content (0.10, 0.15) and gets smeared out as the strontium content is increased (0.20, 0.25). For further higher Sr2+ composition (0.40), the dielectric peak could not be observed in the measured temperature range. The peak broadening in Sr2+ rich compositions indicates that diffused transitions and is attributed to t...

2008-01-01

246

Born-Oppenheimer breakdown effects and hyperfine structure in the rotational spectrum of strontium monosulfide, SrS

Adsorption/Membrane Filtration as a Contaminant Concentration and Separation Process for Mixed Wastes and Tank Wastes - Final Report

A newly constructed Fourier transform microwave spectrometer has been used to record the pure rotational spectra of four isotopomers of SrS ({sup 88}Sr{sup 32}S, {sup 87}Sr{sup 32}S, {sup 86}Sr{sup 32}S, and {sup 88}Sr{sup 34}S) between 6 and 26 GHz. The molecules were produced by reacting laser ablated strontium with carbonyl sulfide (0.1% in argon). Pure rotational transitions in the ground, first and second vibrational states have been observed. The data set has enabled a multi-isotopomer fit. Born-Oppenheimer breakdown terms for both atoms have been determined. The {sup 87}Sr nuclear quadrupole coupling constant in {sup 87}Sr{sup 32}S has been determined for the first time.

2007-12-06

247

A simple model for strontium breakthrough on zeolite columns

This project was conducted to evaluate novel approaches for removing radioactive strontium (Sr) and cesium (Cs) from the tank wastes. The bulk of the Sr removal research conducted as part of this project investigated adsorption of Sr onto a novel adsorbent known as iron-oxide-coated sand. The second major focus of the work was on the removal of cesium. Since the chemistries of strontium and cesium have little commonality, different materials (namely, cesium scavengers known as hexacyanoferrates, HCFs) were employed in these tests. This study bridged several scientific areas and yielded valuable knowledge for implementing new technological processes. The applicability of the results extends beyond the highly specialized application niches investigated experimentally to other issues of potential interest for EMSP programs (e.g., separation of chromium from a variety of wastes using IOCS, separation of Cs from neutral and acidic wastes with ...

1999-10-01

248

A novel photodiode made of hybrid organic/inorganic nanocomposite

The Process Waste Treatment Plant (PWTP) at the Oak Ridge National Laboratory is designed to remove radioactive contaminants, principally {sup 90}Sr, from process wastewater. Planned upgrades to the PWTP will use chabazite zeolite columns. Pilot-scale studies have shown that mass transfer zone lengths increase from 10 to about 30 cm as the superficial velocity increases from 5.5 to 22 cm/min. Calculations with a multicomponent equilibrium model showed that the distribution coefficient for strontium remains essentially constant over the process conditions, suggesting that a simple kinetic model (the Rosen long-bed solution) should adequately represent breakthrough behavior. Using a distribution coefficient of 4.87 L/g predicted by the equilibrium model, good agreement was found between experimental breakthrough curves and those calculated with the Rosen solution. This model allows prediction of bed depths and cycle times necessary to achieve the required ...

1995-04-01

249

Use of X-ray fluorescence analysis in the study of archeological samples

Novel hybrid organic/inorganic nanocomposites made of metal oxide and conjugated polymer nanocomposite and its application in bulk-heterojunction solar cells were studied. The composite was composed of different concentrations of strontium titanate (SrTiO_3) and polyaniline doped phosphoric acid. The optimum concentration of strontium titanate was found to be 0.2 v/v. An inorganic-organic photovoltaic device with a structure of Ag/Pani-H_3PO_4-SrTiO_3/Al has been fabricated. The ideality factor value of the diode was found to be 1.8. This n value of the diode implies a deviation from ideal junction behaviour. The barrier height #phi#_b value for the diode was found to be 0.56 eV. The Ag/Pani-H_3PO_4-SrTiO_3/Al diode shows a photovoltaic behaviour with a maximum open-circuit voltage V_o_c of 2.49 V, and short-circuit current I_s_c of 5.6 mA under light illumination #lambda# = 460 nm. The conversion efficiency was found to be 5.2%. It is ...

2009-08-07

250

Use of Eu/sup 3 +/ as an oxygen environment probe in alkali-alkaline earth-lanthanide phosphates with the. beta. -K/sub 2/SO/sub 4/ structure

Radionuclide X-ray fluorescence analysis (XFA) was used in the determination of the contents of metal residues in dosing plates for coin minting. XFA was also used for the determination of the strontium/calcium ratio in bone samples of different animals with the aim to obtain information on the food composition of these animals. It was found that bones of different animals can be distinguished based on the Sr/Ca ratio. No significant differences in the Sr/Ca ratio were observed in human bones of individuals from different social groups. (author). 1 fig., 5 tabs., 4 refs.

1988-09-26

251

The production of carrier-free lead-203

The use of europium as a local structural probe allows the various phases appearing in the NaCaPO/sub 4/-Na/sub 3/Eu(PO/sub 4/)/sub 2/ and NaSrPO/sub 4/-Na/sub 3/Eu(PO/sub 4/)/sub 2/ systems to be detected. The broadening of the europium emission lines in going from the calcium to the strontium phases illustrates the ease of displacement of the PO/sub 4/ groups.

1983-09-15

252

Study on the use of zirconium phosphate for radioactive waste treatment

The chemical separation of carrier-free "2"0"3Pb following deuterium bombardment of a "2"0"3Tl target is described. Coprecipitation from strontium sulphate was used to separate the "2"0"3Pb from a solution of the thallium target in sulphuric acid. The SrSO_4 precipitate was filtered, washed and dissolved in hydrochloric acid, from which "2"0"3Pb was again separated by precipitation on sodium chloride from a strongly acid solution. Advantages of the system are discussed and optimum conditions given. (U.K.).

253

Studies on radioactive liquid waste treatment by reverse osmosis

Zirconium phosphate was one of the earliest inorganic ion-exchange suggested for removing strontium and cesium from aqueous nuclear waste. This paper studied ionic exchange to remove Cs-137 and Sr-90 by using different cationic of zirconium phosphate. In this case the parameters studied were the effect of temperature and ion concentration to percent up take and distribution coefficients. It is also conducted the study on column experiments to determine the breakthrough curves for Cs-137 and Sr-90. The result showed the potential of use of zirconium phosphate in radioactive waste treatment. (author)

1998-12-01

254

Studies on radioactive liquid waste treatment by reverse osmosis

Reverse osmosis is a simple process and has relatively high decontamination factor compared to other processes used for the treatment of radioactive liquid waste. Furthermore the quantity of secondary waste of this process is small. In this study, test solution containing nine elements such as cesium, strontium, cobalt etc. in chloride forms are treated by reverse osmosis. Permeate rate decreases as the increase of osmotic pressure of feed solution and is expressed by linear equation. Decontamination factor of cations of univalency is more than ten, and about one tenth of that of bivalency. Decontamination factors of all the elements used in this experiment are approximately estimated using the solution-diffusion model.

1982-06-01

255

Production of carrier-free lead-203

Reverse osmosis is a simple process and has relatively high decontamination factor comparing to other processes used for the treatment of radioactive liquid waste. Furthermore the quantity of secondary waste of this process is small. In this study, test solution containing nine elements such as cesium, strontium, cobalt etc. in chloride forms are treated by reverse osmosis. Permeate rate decreases as the increase of osmotic pressure of feed solution and is expressed by linear equation. Decontamination factor of cations of univalency is more than ten, and about one tenth of that of bivalency. Decontamination factors of all the elements used in this experiment are approximately estimated using the solution-diffusion model. (author).

256

Polythermal study of the M(ClO_4)_2-H_2O systems, where M"2 = Mg"2"+, Ca"2"+, Sr"2"+, Ba"2"+

The chemical separation of carrier-free /sup 203/Pb following deuterium bombardment of a /sup 203/Tl target is described. Coprecipitation from strontium sulphate was used to separate the /sup 203/Pb from a solution of the thallium target in sulphuric acid. The SrSO/sub 4/ precipitate was filtered, washed and dissolved in hydrochloric acid, from which /sup 203/Pb was again separated by precipitation on sodium chloride from a strongly acid solution. Advantages of the system are discussed and optimum conditions given.

1982-07-01

257

New materials for SRS lasers

Crystallization points of aqueous solution of the systems M(ClO_4)_2-H_2O (M"2 = Mg"2"+, Ca"2"+, Sr"2"+, Ba"2"+), depending on the salt concentration, were identified by visual-polythermal method. Relying on model notions on the structure of the electrolyte solutions, specific features of strontium perchlorate solubility polytherm and concentration dependence of the relative dynamic viscosity of the salt aqueous solutions are discussed

2005-03-01

258

Dielectric behavior of Ba{sub 0.95}Sr{sub 0.05}TiO{sub 3} ceramics sintered by microwave

The problem of search for new materials for spectrally positioned laser sources, which is central for modern photonics, is discussed. The use of the stimulated Raman scattering effect in crystals offers a highly efficient way to the design of such sources. The recent results of investigations into this effect for a large number of various types of crystalline materials are presented. The most promising compounds, as regards the realisation of different laser operation modes, are considered, including calcium, strontium, barium and lead molybdates and tungstates. Several examples of functioning efficient lasers based on novel materials exhibiting the stimulated Raman light scattering effect are given.

2006-10-31

259

Structure and magnetic properties of nanostructural strontium ferrite prepared by mechanochemical treatment

Here we report detailed dielectric studies carried out on a Barium strontium titanate (BST) (95:5) composition. The material was synthesized by conventional ceramic method and microwave processing, and the later technique resulted in material with high density, improved microstructure and dielectric properties. The dielectric properties were studied as a function of frequency and temperature and well-defined ferroelectric behavior of first order transition was observed. It follows Curie-Weiss law above transition temperature (paraelectric region). Curie temperature is slightly higher for microwave sintered (MS) material.

2002-12-01

260

The separation and determination of trace elements in iron ore

Full text: It was recently-established for hexagonal barium ferrite-industrially important magnetically hard material that refinement of the crystallite dimensions into the nanoscale regime, typically #<=# 10 nm, leads after heat treatment at temperatures 800-1000 deg C to significant coercivity increase of up to 6.5 kOe (#approx#3-4 times) with saturation magnetisation values of 50-55 emu/g (#approx#95% of bulk at room temperature). High-energy mechanochemical processing has been applied to prepare nanostructural (nanocrystalline-amorphous) composites. High resolution electron microscopy studies reveal that the enhancement of the final magnetic properties was due to formation of magnetically noninteracting #approx#l,#mu#m Ba-ferrite particles with 5-10 nm amorphous surface layer - depending on annealing parameters. Similar situation was established also for ball milled strontium ferrite (SrFe_1_2O_1_9) powders where short annealing 4 h at 1000 deg C produced ...

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261

Magnesium Sensitizes Slow Vacuolar Channels to Physiological Cytosolic Calcium and Inhibits Fast Vacuolar Channels in Fava Bean Guard Cell Vacuoles1

The separation, concentration, and determination of trace elements in iron ores are described. After the sample has been dissolved, the iron is separated by liquid-liquid extraction with a liquid cation-exchanger, di-(2-ethylhexyl) phosphoric acid. The trace elements aluminium, cadmium, calcium, chromium, cobalt, copper, lead, magnesium, manganese, mercury, potassium, sodium, vanadium, and zinc are determined in the aqueous phase by atomic-absorption spectrophotometry.

2008-05-01

262

Enhanced corrosion resistance by sol-gel-based ZrO_2-CeO_2 coatings on magnesium alloys

Vacuolar ion channels in guard cells play important roles during stomatal movement and are regulated by many factors including Ca²⁺, calmodulin, protein kinases, and phosphatases....Full Text Available

1999-11-01

263

Dietary calcium and magnesium intakes and the risk of type 2 diabetes: the Shanghai Women's Health Study¹²³

The physical, chemical and mechanical properties of magnesium alloys make them attractive materials for automotive and aerospace applications. However, these materials are susceptible to corrosion and wear. This work discusses the potential of using sol-gel based coatings consisting of ZrO_2 and 15 wt.% of CeO_2. The CeO_2 component provides enhanced corrosion protection, while ZrO_2 impart corrosion as well as wear resistance. Coating deposition was performed by the dip coating technique on two magnesium alloy substrates with different surface finishes: AZ91D (as-casted, sand-blasted, and machined) and AZ31 (rolled and machined). All as-deposited coatings (xerogel coatings) were then subjected to 10 h annealing: a temperature of 180 C was applied to the AZ91D alloy and 140 C to the AZ31 alloy. Morphological and structural properties of the annealed coatings were investigated by scanning electron microscopy, atomic force microscopy and ...

2005-02-01

264

Development of zirconium alloys. Part II

Background: Diet plays a key role in the development of type 2 diabetes (T2D), but little is known about the contributions of specific nutrients in populations in which dietary patterns...Full Text Available

2009-04-01

265

Corrosion behaviors of Zn/Al-Mn alloy composite coatings deposited on magnesium alloy AZ31B (Mg-Al-Zn)

A number of alloys of zirconium have been investigated as part of a program aimed at improving the high-temperature tensile and creep strength of zirconium. These alloys include aluminum, beryllium, lead, magnesium, molybdenum, niobium, tantalum, tin, titanium, tungsten, vanadium, and zinc, binary and ternary alloys. The data indicate that aluminum, lead, molybdenum niobium, tin, titanium, tungsten, and vanadium can be used successfully to harden zirconium, and that aluminum, tin, titanium, and vanadium are particularly effective in maintaining the strength of zirconium at elevated temperatures.

1952-01-02

266

A comparison of nutrient dynamics in forest ecosystems along with the Warmth Index Gradient

After being pre-plated a zinc layer, an amorphous Al-Mn alloy coating was applied onto the surface of AZ31B magnesium alloy with a bath of molten salts. Then the corrosion performance of the coated magnesium alloy was examined in 3.5% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results showed that the single Zn layer was active in the test solution with a high corrosion rate while the Al-Mn alloy coating could effectively protect AZ31B magnesium alloy from corrosion in the solution. The high corrosion resistance of Al-Mn alloy coating was ascribed to an intact and stable passive film formed on the coating. The performances of the passive film on Al-Mn alloy were further investigated by Mott-Schottky curve and X-ray photoelectron spectroscopy (XPS) analysis. It was confirmed that the passive film exhibited n-type semiconducting behavior in 3.5% NaCl solution with a ...

2009-12-30

267

A Laser-Pointer-Based Spectrometer for Endpoint Detection of EDTA Titrations

Nutrient elements contained in litter fall flux, that of uptake flux and turnover rate had generally tended to increase with the increase in the Warmth Index, while the amount of nutrient in the A[sub 0] horizon and nutrient use efficiency did not. However, it is suggested that topographic and climatic aridity, and the amount of available and exchangeable phosphorus, calcium and magnesium greatly affect the nutrient dynamics in a each forest ecosystem as the Warmth Index increases. (J.P.N.).

1993-01-01

268

A Flow Stress Formulation of Magnesium Alloy at Elevated Temperature

A laser spectrometer for the ethylenediaminetetra-acetic acid (EDTA) titration of magnesium or calcium ions that is designed around a handheld laser pointer as the source and a photoresistor as the detector is developed. Findings show that the use of the spectrometer reduces the degree of uncertainty and error in one part of the EDTA titrations, however overall standard deviations depend on the skill of the student and their willingness to be careful and precise.

2004-12-01

269

Synthesis of Ln_0_._6Sr_0_._4Co_0_._8Fe_0_._2O_3_-_#delta# powders through glycine-nitrate combustion process

Dynamic recrystallization (DRX) is the main softening mechanism of magnesium alloy AZ31B in hot deformation. Theoretically, in the flow rule the atomic diffusibility and the driving force of dislocation migration are dependent on the temperature, and the dislocation density and the cumulation of grain boundary energy are dependent on the strain rate. The peak stress will appear when the flow driving force and resistance force reach a balance, after which the stress descending will take place due to recrystallization fraction. Since the DRX is a thermally activated process, the recrystallized volume fraction can be regarded as the function of strain through Avrami equation. Based on this idea, the paper proposes a new constitutive model characterizing dynamic recrystallization for magnesium alloy AZ31B. The model is described by a peak stress and a strain softening rate, in which the peak stress depends only on Zener-Hollomon parameter and is ...

2007-05-17

270

Study of Nitrate Stress in Desulfovibrio vulgaris Hildenborough Using iTRAQ Proteomics

Solid oxide fuel cell (SOFC) is a promising source of power generation in terms of conversion efficiency which is higher than the conventional one, as it is not limited by the Carnot efficiency. Theoretically, the SOFC have an efficiency of the order of 60-80 % but it is limited by the number of active side available for the reaction i.e. TPB (triple phase boundary) at the electrode-electrolyte interface which depends on the particle size of the materials employed during the fabrication of SOFC components (i.e. the method employed during the synthesis). Literally, there are several methods used in the syntheses of oxide materials such as conventional solid-state reaction, co-precipitation, hydrothermal rout, sol-gel and Glycine nitrate process (GNP) but among these GNP found to be effective over the other because of homogeneity, phase purity and smaller particle size of final product. In this work, the Nano-crystalline Ln_0_._6Sr_0_._4Co_0_._8Fe_0_._2O_3_-_#delta# ...

2010-12-01

271

Influence of temperature on strength of cemented surrogate nitrate salt waste

The response of Desulfovibrio vulgaris Hildenborough (DvH),a sulphate-reducing bacterium, to nitrate stress was examined usingquantitative proteomic analysis. DvH was stressed with 105 m M sodiumnitrate(NaNO3), a level that caused a 50 percent inhibition in growth.The protein profile of stressed cells was compared with that of cellsgrown in the absence of nitrate using the iTRAQ peptide labellingstrategy and tandem liquid chromatography separation coupled with massspectrometry (quadrupoletime-of-flight) detection. A total of 737 uniqueproteins were identified by two or more peptides, representing 22 percentof the total DvH proteome and spanning every functional category. Theresults indicate that this was a mild stress, as proteins involved incentral metabolism and the sulphate reduction pathway were unperturbed.Proteins involved in the nitrate reduction pathway increased. Increasesseen in transport systems for proline, ...

2006-10-12

272

Influence of temperature on strength of cemented surrogate nitrate salt waste

The Rocky Flats Plant (RFP) generates large volumes of a low level aqueous waste stream high in nitrate salts. The aqueous waste is concentrated by evaporation and then mixed with Portland cement prior to transport and disposal. Planned process upgrades include a new horizontal thin film evaporator. Temperature of brine at discharge end of the new evaporator will be near boiling point. Introduction of hot water to cement can degrade the monolithic waste form. However, the RFP salt waste contains high concentrations of compounds known to retard hydration. This paper discusses impact of introducing high temperature waste to cement. The study evaluated three waste compositions: (1) highest probable nitrate composition, (2) highest probable chloride composition, and (3) current composition. Results showed that compressive strength of final waste form increased with brine temperature, and waste forms from brine at the boiling point exhibited a near ...

1993-01-01

273

Biogeochemical cycling of N in tropical coastal zones: molecular microbial ecology of trace gas production.

The Rocky Flats Plant (RFP) generates large volumes of a low level aqueous waste stream high in nitrate salts. The aqueous waste is concentrated by evaporation and then mixed with Portland cement prior to transport and disposal. Planned process upgrades include a new horizontal thin film evaporator. Temperature of brine at discharge end of the new evaporator will be near boiling point. Introduction of hot water to cement can degrade the monolithic waste form. However, the RFP salt waste contains high concentrations of compounds known to retard hydration. This paper discusses impact of introducing high temperature waste to cement. The study evaluated three waste compositions: (1) highest probable nitrate composition, (2) highest probable chloride composition, and (3) current composition. Results showed that compressive strength of final waste form increased with brine temperature, and waste forms from brine at the boiling point exhibited a near ...

1993-03-01

274

Environmental Research Database

ObjectivesThe specific objectives of the research are to: 1. Determine the concentrations of N2O, NO and NO2 in tropical coastal waters in relation to nutrients and salinities. 2. Determine, with excess nitrate present, the potential for nitrate reduction and denitrification in sediments along tropical estuaries, and whether NO, NO2, N2O, N2 or NH4+ are significant products. 3. Establish the balance between denitrification, nitrate ammonification and anammox in tropical estuarine sediments, relative to [continued...]DescriptionThe coastal zone is extremely important in the biogeochemical processes which control the natural cycle of elements of the Earth. In particular, the coastal zone contributes significantly to the nitrogen cycle, removing nitrogen washed in from the land by rivers and so reducing its fertilizing impact on the coastal seas. However, these removal processes, driven by microorganisms, also contribute to ...

2009-01-31

275

[Study on denitrification characteristics of dynamic membrane based on nitrate liquid-membrane microelectrodes].

The use of domestic microwave oven in experimental classes of organic chemistry: salicylaldehyde nitration; O uso de aparelhos de micro-ondas domesticos em aulas experimentais de quimica organica: nitracao de salicilaldeido

Nitrate microelectrodes and ORP microelectrodes were fabricated to study the denitrification characteristics of dynamic membrane at different COD loadings. The denitrification process was found at 0.6-1 mm depth beneath the interface of biofilm/bulk. The results of ORP microelectrode also demonstrated that the ORP value in the range of denitrification area was between 88.6 approximately -128.4 mV which was appropriate to denitrification. When the COD loading was 0.45 kg/(m3 x d), the denitrification rate (NO3- -N) was the maximum of 0.6347 x 10(-6 mol/(L x s). With the increase of COD loading, the denitrification area was increasing and two layers with different denitrification rates emerged in the dynamic membrane. The phenomenon implied the effect of organic concentration, oxygen concentration and bacterial competition on the denitrification rate. PMID:17117632

2006-09-01

276

The use of microwave in chemistry has known benefits over conventional heating methods, e.g. reduced reaction times, chemical yield improvement and the possibility if reducing or eliminating the use of organic solvents. We describe herein a procedure for the nitration of salicylaldehyde in water using a domestic microwave oven, which can be used as an experiment in the undergraduate chemistry laboratory. The experiment involves safe and rapid preparation and identification of the position isomers by thin layer chromatography and {sup 1}H NMR, or by their melting points. (author)

2010-07-01

277

Tetrazine explosives

Subcritical measurements with a cylindrical tank of Pu-U nitrate

The synthesis and properties of various 1,2,4,5-tetrazine explosives and energetic materials are described. These are the nitrate and perchlorate salts of 3,6-diguanidino-1,2,4,5-tetrazine, the nitrate and perchlorate salts of 3,6-diguanidino-1,2,4,5-tetrazine-1,4-di-N-oxide, 3,6-bis(1H-1,2,3,4-tetrazol-5-ylamino)-1,2,4,5-tetrazine and its 1,4-di-N-oxide derivative, 3,3'-azobis(6-amino-1,2,4,5-tetrazine) and its oxidation products. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

2004-08-01

278

Research and development for treatment and disposal technologies of TRU waste

This series of measurements with a mixed Pu-U nitrate solution (280 g Pu/liter, 180 g U/liter) in a 35.54-cm-diam cylindrical tank provides a wide variety of experimental data for subcritical configurations that can be used to verify calculational methods and nuclear data. The Pu contained 7.85 wt% {sup 240}Pu and the uranium was natural uranium. The measurements performed were: inverse count rate, prompt neutron decay constants, inverse kinetics, and frequency analysis by the {sup 252}Cf source driven method. These data are presented in sufficient detail that the results of the experiments can be calculated directly. For purposes of extrapolating to the delayed critical height the ratio of spectral densities was linear with height and thus provided the best estimate of critical height.

1997-04-01

279

Preparation of some nuclear fuel materials on A pilot scale

After the publication of the 2nd progress report of geological disposal of TRU waste in Japan, policy and general scheme of future study for the waste disposal in Japan was published by ANRE and JAEA. This annual report summarized aim and progress of individual problem, which was assigned into JAEA in the published policy and general scheme. The problems are as follows; characteristics of TRU waste and its geologic disposal, treatment and waste production, quality control and inspection methodology for waste, mechanical analysis of near-field, data acquisition and preparation on radionuclides migration, cementitious material transition, bentonite and rock alteration in alkaline solution, nitrate effect, performance assessment of the disposal system and decomposition of nitrate as an alternative technology. (author)

2007-04-22

280

Polymeric nanosponges as an alternative carrier for improved retention of econazole nitrate onto the skin through topical hydrogel formulation

This study started with a comprehensive and critical review of the published information of relevance to the different methods to produce uranium dioxide from raw materials. we have chosen this method 'flame denitration' or flame process to produce Uo_2. from its compounds, uranyl nitrate Uo_2 ( NO_3) _2 .6H_2o) prepared from raw uranium 'yellow cake'. This method in short produces uranium dioxide from aqueous uranyl nitrate by contacting the atomized liquid which has 40 #mu# in diameter with hot reducing gases (butane and oxygen mixture) till we obtain a suitable and yellow red colour light for the flame and this is a prof that there is carbon monoxide and hydrogen, the temperature of the reactor at is least 950 degree C.

1979-01-01

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281

British Library Electronic Table of Contents (United Kingdom)

The present study was carried out to exploit the feasibility of using polymeric nanosponges as an alternative carrier for targeting econazole nitrate (EN) to the skin through topical hydrogel formulation. Nanosponges prepared by emulsion solvent diffusion method were evaluated for various physicochemical parameters and in vitro drug release. The nanosponges of EN were discrete free flowing nanosized particles with perforated orange peel like morphology as visualized by SEM. The nanosponge formulated using PVA:EC (3:2) displayed highest in vitro release after 12 ?h in phosphate buffer (pH 6.8) that fitted matrix model. Selected nanosponge was formulated as Carbopol 934 NF hydrogel using varying concentrations of permeation enhancers propylene glycol and N-methyl-2-pyrrolidone. The EN nanosp...

2011-01-01

282

Inhibiting pitting corrosion in carbon steel exposed to dilute radioactive waste slurries

Banana peel extract mediated novel route for the synthesis of silver nanoparticles

Dilute caustic high-level radioactive waste slurries can induce pitting corrosion in carbon steel. Cyclic potentiodynamic polarization tests were conducted in simulated and actual waste solutions to determine minimum concentrations of sodium nitrate which inhibit pitting in ASTM A537 class 1 steel exposed to these solutions. Susceptibility to pitting was assessed through microscopic inspection of specimens and inspection of polarization scans. Long-term coupon immersion tests were conducted to verify the nitrite concentrations established by the cyclic potentiodynamic polarization tests. The minimum effective nitrite concentration is expressed as a function of the waste nitrate concentration and temperature.

1991-01-01

283

British Library Electronic Table of Contents (United Kingdom)

Bio-inspired silver nanoparticles were synthesized with the aid of a novel, non-toxic, eco-friendly biological material namely, banana peel extract (BPE). Boiled, crushed, acetone precipitated, air-dried peel powder was used for reducing silver nitrate. Silver nanoparticles were formed when the reaction conditions were altered with respect to pH, BPE content, concentration of silver nitrate and incubation temperature. The colorless reaction mixtures turned brown and displayed UV-visible spectra characteristic of silver nanoparticles. Scanning electron microscope (SEM) observations revealed the predominance of silver nanosized crystallites after short incubation periods. When the reaction mixtures were incubated for 15 days, some micro-aggregates were also observed. Energy dispersive spectr...

2010-01-01

284

Adsorption of iodine ions in modified activated charcoal

A new zinc hydroxide nitrate heterogeneous catalyst for the esterification of free fatty acids and the transesterification of vegetable oils

Shaped activated charcoal is modified by 02 and N2 processing for producing coal compounds with higher acidic or basic properties. Nitrated activated charcoal has properties of a weak anionite with a substantially increased ion exchange capacity with an increase in the concentration of the hydrogen ions in the electrolyte and adsorbs iodine ions well from aqueous solutions at a pH of less than 5. A layer of nitrated charcoal is a very effective sorbent in the process of dynamic sorption of iodine anions from acetic solutions of KI. It is also established that the sorption of iodine ions in the activated charcoal modified by 02 occurs in accordance with an ion exchange mechanism (and possibly, selective sorption). This refutes literature data which ascribe the determining participation in the process to the reaction of oxidation of iodides on the surface (Pv) of the coal into free I2.

1983-01-01

285

British Library Electronic Table of Contents (United Kingdom)

A new heterogeneous catalyst for the esterification of free fatty acids and the transesterification of vegetable oils is reported. The layered compound zinc hydroxide nitrate (Zn5(OH)8(NO3)22H2O) was very effective in the alcoholysis of palm oil and the esterification of lauric acid with m(ethanol), even when hydrated ethanol was used. Over the range of 100-140degreeC, the ester yield was the highest at 140degreeC, while the catalyst concentration had a much greater effect on ester yields than the molar ratio of alcohol to acid did. Total ester contents above 95wt% were obtained in both reactions and 93.2wt% glycerin streams were recovered as a result of methanolysis.

2008-01-01

286

/sup 252/Cf-source-driven neutron noise measurements of subcriticality for a slab tank containing aqueous Pu-U nitrate

Radionuclide Distribution Coefficients for Sediments Collected from Borehole 299-E17-21: Final Report for Subtask 1a

In order to study nuclear criticality safety related to the development of fast breeder technology, /sup 252/Cf-source-driven neutron noise analysis measurements were performed with a Pu-U nitrate solution in a slab tank of various heights and thickness varying 11.43 cm to 19.05 cm. The results and conclusions of these experiments are (1) a capability to measure the subcriticality of a multiplying system of slab geometry to a k/sub eff/ as low as 0.7 was demonstrated, (2) calculated neutron multiplication factors agreed with those from the experiments within approx.0.02, and (3) the applicability of the method for plutonium solution systems was demonstrated. This paper describes measurements in which the height of the slab was varied for a fixed thickness and the thickness varied for a fixed height, which are the first applications of this measurement method to slab geometry.

1987-08-01

287

Waste treatment by dialysis. (Latest citations from Pollution abstracts). Published Search

Over 360 distribution coefficients (KJ for cesium, iodine, selenium, Strontium, technetium, and uranium were measured in fiscal year 1998 using 20 sediments collected fkom borehole 299-El 7-21 on the Hanford Site as part of the Immobilized Low-Activity Waste-Performance Assessment (ILAW-PA). Additionally, the pH and cation-exchange capacity (a measure of the total quantity of cations that a sediment can adsorb) of these sediment samples were measured. The sediment samples originated from the Hanford formation (informal name). Statistical analyses, using Student's t-test and correlation were conducted with the measured values. There were no significant differences between layers 1 and 2 for the selenium, strontium, technetium, and uranium & values (statistics could not be applied to evaluate layer 3 &values). Significant differences between the cesium and iodine&values for layem 1 and 2 were observed. However, these ...

1998-10-14

288

Use of alkali nitrate molten salts as electrolytes in intermediate temperature lithium batteries

The bibliography contains citations concerning the use of dialysis in the treatment of wastewaters. Techniques for the removal of metals, ammonia, waste acids, nitrates, and phosphates are described. Special attention is given to the desalination of liquid wastes. Applications of this technology to the treatment of effluent from the agrochemical, petrochemical, tanning, and electroplating industries are discussed. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

1996-02-01

289

The research on new production technique of yellow cake

Advanced lithium batteries presently under development operate either at the high temperatures associated with the LiCl-KCl molten salt (350-450/degree/C), or at ambient temperatures employing organic solvent based electrolytes. An intermediate temperature lithium battery is proposed as an alternative if it reduces corrosion problems present at high temperatures and improved kinetic performance with respect to ambient temperature cells. 17 refs.

1981-01-01

290

Synthesis, properties and biologic activity of nitro-benzo (B) of thiophene- and 2,3-di-hydro-benzo (B) thiophene-1,1-dioxides

As a new production technique of yellow cake, resorption with loaded resin-elution with acid ammonium nitrate-precipitation in two steps is studied. The results show that the produced yellow cake by the new production technique has better performance of settlement, filtration and dehydration. Each index of yellow cake accords with the first grade level issued by CNNC without washing, uranium and water content are 70% and 25%, respectively

2001-11-01

291

Sputter coating of tantalum and tantalum compounds. (Latest citations from the Compendex database). Published Search

The purpose of work is systematical studying of benzo (B) of thiophene-1,1-dioxides and their 2,3-di-hydro derivatives behaviour in the reactions of electrophflic, radical, nucleophilic nitration, reduction of nitro group, embodiment of synthesis of N-amino derivatives, investigation of sulfur containing hetero-cyclic compounds, including of residues of some steroids

1998-01-01

292

Range and energy loss rate of 118 MeV "2"8Si in some polymers

The bibliography contains citations concerning the properties of tantalum and tantalum compound films formed by sputtering techniques. Topics include processes, and electrical, magnetic, and dielectric properties of the sputtered films. Tantalum compounds studied include nitrates, oxides, and aluminides. The structural properties of sputtered films are also discussed. (Contains a minimum of 105 citations and includes a subject term index and title list.)

1993-06-01

293

Inhaled plutonium nitrate in dogs

In the present work, range and energy loss rate of "2"8Si in four dielectric track detectors viz: Makrofol-KG (MFKG), Makrofol-G (MFG), Triafol-BN (TBN) and LR-115 (cellulose nitrate) have been measured. To calculate these parameters, a curve fitting method was proved to be very useful and easier with more accuracy. (author)

1999-01-01

294

Hydrogen, Oxygen, and Carbon Isotope Ratios of Cellulose from Submerged Aquatic Crassulacean Acid Metabolism and Non-Crassulacean Acid Metabolism Plants

Beagle dogs given a single inhalation exposure to "2"3"9Pu(NO_3)_4 are being observed for life-span dose-effect relationships. Over half of the dogs planned for "2"3"9Pu(NO_3)_4 exposure have been exposed and the remaining dogs will be exposed as they reach adult age.

1977-05-01

295

Comparison between NO_x Evolution Mechanisms of Wild-Type and nr₁ Mutant Soybean Leaves ¹

Isotope ratios of cellulose and cellulose nitrate from aquatic Crassulacean acid metabolism (CAM) and non-CAM plants were determined. Cellulose oxygen istope ratios for all plants that grew together...Full Text Available

1984-09-01

296

Chloropicrin formation during oxidative treatments in the preparation of drinking water

The nr₁ soybean (Glycine max [L.] Merr.) mutant does not contain the two constitutive nitrate reductases, one of which is responsible for enzymic conversion of nitrite to...Full Text Available

1990-05-01

297

Alkane degradation under anoxic conditions by a nitrate-reducing bacterium with possible involvement of the electron acceptor in substrate activation

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.

1985-12-01

298

Study on warm caliber rolling of magnesium alloy

Microorganisms can degrade saturated hydrocarbons (alkanes) not only under oxic but also under anoxic conditions. Three denitrifying isolates (strains HxN1, OcN1, HdN1) able to grow under anoxic conditions...Full Text Available

2011-02-01

299

Stearic acid gel derived MgTiO{sub 3} nanoparticles: A low temperature intermediate phase of Mg{sub 2}TiO{sub 4}

The warm caliber rolling was experimented using the AZ31 magnesium alloy round bar of 20 mm in diameter machined from cast ingot materials. In warm caliber rolling in final size of 10 mm in diameter at 623 K via 8passes, each width-spreading, the change of each microstructure, X-ray analysis of final texture and final mechanical properties were investigated. Microstructure, texture and mechanical properties of warm caliber rolled round bar at 473 K via latter 4passes were compared with those at 623 K consistently. Obtained results are as follows: (1) The width-spreading in caliber rolling of round bar is relatively large, compared with that in flat rolling of the flat bar. The largeness of width-spreading of round bar makes the shape control of cross section difficult, and causes the cracks around the free surface. (2) Finer microstructure and inclined c axis of hexagonal lattice of 10 degrees to vertical direction of the rolled surface are obtained in warm caliber ...

2003-07-01

300

Research on deformation characteristic of AZ31Mg alloy and its constitutive equations

Stearic acid gel is employed to study the phase evolution of MgTiO{sub 3} nanoparticles by thermal gravimetric analysis, X-ray diffraction, and Fourier transform infrared. During the preparation of stearic acid gel, tetrabutyl titanate easily absorbed moisture to hydrolyze into Ti(OH){sub 4} firstly, and then reacts with stearic acid and magnesium stearate to form magnesium-titanium oxide network polymer gel, meanwhile n-butanol is generated. When stearic acid gel is calcined in air, a series of oxidation and combustion reactions occur, meanwhile apparent heat is given off. The results show that a metastable intermediate phase Mg{sub 2}TiO{sub 4} is generated at 450 {sup o}C and nearly disappeared at 550 {sup o}C. Simultaneously, a new solid phase of MgTiO{sub 3} appears. The metastable intermediate phase Mg{sub 2}TiO{sub 4} is successfully identified in the current work.

2010-03-04

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301

Recrystallization in AZ31 magnesium alloy during hot deformation

Superplasticity of polycrystalline metallic materials is a phenomenon which shows hundreds to thousands of percents of large plastic deformation without necking in a steady state of low stress, when the uni-axial tensile loading is done in some special thermo-mechanical conditions (some limited ranges of properly high temperature and low strain rate). The main mechanism of superplastic phenomenon is the grain boundary sliding, while the main mechanism of usual plastic deformation is the trans-granular sliding. In this research, the possibility of superplastic deformation in a magnesium alloy (AZ31Mg alloy) was experimentally investigated, because generally speaking, the magnesium alloy whose atomic structure is hexagonal does not have enough formability in a form of trans-granular sliding mechanism. In this paper, the detail of experimental results are shown and discussed. Moreover, the constitutive equations of Mg alloy are proposed on the ...

2004-07-01

302

Oxidative dimerization of methane over lead-magnesium mixed oxide catalysts

In this study, isothermal torsion tests were carried out on magnesium AZ31B alloy under constant strain rate conditions, in the range of 250 to 400 C at 0.01, 0.1, and 1.0 s{sup -1}. Alloy flow stress dependence on strain rate and temperature can be described by a power law with activation energy of 130 kJ/mol. Microstructural examination of hot deformed samples shows very fine recrystallized grains decorating grain boundaries of larger gains in the form of a necklace. These fine grains are produced by dynamic recrystallization at the grain boundaries of original grains. Microstructure evolution, based on samples quenched at different strain levels, indicates that increasing deformation strain has little effect on recrystallized grain size but widens the recrystallized region, with full recrystallization achieved at a certain high strain level. Recrystallized grain size increases with increasing deformation temperature and strain rate. The latter suggests ...

2005-07-01

303

On methods for improving the fatigue performance of the wrought magnesium alloys AZ31 and AZ80

Our goal was a process to convert methane to higher hydrocarbons oxidatively, since this circumvents thermodynamic yield limits of a strictly degydrogenative process. Keller and Bhasin converted thermodynamic yield limits of a strictly dehydrogenative process. Keller and Bhasin converted methane to higher hydrocarbons by using metal oxides as oxidants, without co-fed oxygen. They stated that selectivity is necessarily poor if gaseous oxygen is present. Jones and Sofranko have also used reducible metal oxides as oxidants in a group of their parents, but later used some of those materials with continuous O{sub 2} feed without much loss of selectivity. Baerns, Lunsford and Otsuka have shown that high selectivity could be possible with co-fed O{sub 2} at least for low O{sub 2} partial pressures, over PbO-A1{sub 2}O{sub 3}, Li-MgO and rare earths. The performance of a group of multicomponent oxide catalysts, containing lead and magnesium oxides, for oxidative conversion ...

1987-08-01

304

Method for preparing drilling solutions that are resistant in Zechstein deposits

The tensile and compressive properties as well as LCF and HCF performance of the extruded magnesium alloys AZ31 and AZ80 were determined in extrusion (L) and long-transverse (T) directions. Owing to marked crystallographic textures, both alloys showed pronounced directional mechanical properties in monotonic as well as cyclic loading with strength values in L-direction being significantly superior to those in T-direction. Thermomechanical treatments such as pressing, swaging and rolling were found to increase yield stresses and HCF strengths and to alter the directionality in properties due to textural modifications. To further improve HCF strengths, mechanical surface treatments such as shot peening, roller-burnishing and deep rolling were utilized. The results indicate marked improvements provided that suitable process parameters are used. The improvement of the HCF strengths is explained by the process-induced changes in near-surface dislocation densities and ...

2003-07-01

305

Influence of second phase particles on fracture toughness in AZ31 magnesium alloys

The patent is for a method of preparing drilling muds that are notable for their chemical resistance to Zechstein deposits, especially to magnesium, carbonate and carboxylic acid ions. To achieve chemical resistance of the drilling mud to Zechstein deposits, it is suggested to saturate them with salt (the amount of added salt depends on the absorption properties of the solution), and then to process them with caustic soda or potassium oxide hydrate and lime in proportions that would cause filtrate alkalinity not to exceed 0.5. For example, to prepare drilling solution to bore through mediums containing magnesium salts, potassium salts, rock salt, anhydrate, dolomite, limestone, red salt clay: add 340 kg potassium chloride into 1 m/sup 3/ drilling solution with weighed bentonic clay, 10 kg. ferro-chromate lignosulfite, 7 kg. unslaked lime, 2 kg. sodium hydroxide, 5 kg. carboxy-methyl-cellulose, 5 kg. carboxy-methyl-hydroxylethyl-cellulose, 50 ...

1980-05-31

306

Improvement in mechanical properties of magnesium alloy (AZ31) sheet fabricated by casting and subsequent plastic working

Three kinds of thin AZ31 wrought magnesium alloys sheets were used in order to investigate the influence of the second phase particles on fracture toughness. From the theoretical model, the ratio of {lambda}{sub p}/d{sub p} would be estimated 5 {proportional_to} 6. On the other hand, from the microstructural observation, average particle spacing on each material was sample A: 13.1 {mu}m, sample B: 14.1, and sample C: 12 {mu}. In addition, average particle size on each sample was sample A: 2.1, sample B: 1.9, and sample C: 2.3 {mu}m. Therefore, the ratio of {lambda}{sub p}/d{sub p} calculated from fracture surface observation would be predicted 6 {proportional_to} 7. In comparison with the result of the prediction by theoretical analysis was in good agreement with the result of fracture toughness observation. It was found that the variation in plane-strain fracture toughness on AZ31 were affected by both of particle spacing and particle size. (orig.)

2004-07-01

307

Grain refinement in magnesium alloy AZ31 during hot deformation

In order to enhance the mechanical properties of magnesium alloy (AZ31) sheet, an integrated sheet-making process including billet casting, extrusion and rolling was attempted. Microstructural analysis was carried out and the mechanical properties at each processing step were also investigated by tensile tests. By an extrusion process of ingot-processed billet, average grain size of billet was reduced from 91.2 to 28.2 {mu}m, and a further reduction in grain size to 16.9 {mu}m was obtained by subsequent rolling of extruded 5 mm thin slab. In the final step, a rolled sheet of 1 mm showed a remarkable refinement in grain size down to 8.8 {mu}m. Regarding mechanical properties, tensile strength and elongation for as-cast billet, as-extruded thin slab and as-rolled sheet increased from 189, 258 to 234 MPa, and from 13, 16.5 to 23%, respectively. (orig.)

2003-07-01

308

Enhancing compressive response of AZ31B using nano-Al2O3 and copper additions

The deformation behavior and structure changes of magnesium alloy AZ31 were studied in compression at temperatures ranging from 523 K to 673 K and at a strain rate of 3 x 10{sup -3} s{sup -1}. They depend sensitively on deformation temperature. At high temperatures, grain fragmentation takes place due to frequent formation of kink bands initially at corrugated grain boundaries and then in grain interiors, followed by full development of new grains in high strain. At lower temperatures, in contrast, twinning takes place in rather coarse grains and kink bands are formed mainly in finer original ones in low strain. It is concluded that new grain evolution can be controlled by a deformation-induced continuous reaction resulting in grain fragmentation by kink bands, i.e. continuous dynamic recrystallization (cDRX). The latter is discussed comparing with conventional, i.e. discontinuous, DRX. (orig.)

2004-07-01

309

British Library Electronic Table of Contents (United Kingdom)

In the present study, new light weight nano-composites (AZ31B-3.3Al2O3-Cu) based on magnesium alloy AZ31B are developed using disintegrated melt deposition technique. Microstructural characterization studies revealed grain refinement and significant increase in amount of second phases as a result of increasing presence of copper. All the samples exhibited minimal porosity and good matrix-second phase interfacial integrity. The results also showed that addition of both nano-Al2O3 and Cu led to a simultaneous improvement in 0.2% yield compressive strength (0.2%YCS), ultimate compressive strength (UCS) and work of fracture (WoF) of the AZ31B magnesium alloy while failure strain was marginally affected. The results of this study clearly illustrate the capability of AZ31B-Al2O3-Cu formulations ...

2010-01-01

310

Effect of field natural rubber latex with different ammonia contents and storage period on physical properties of latex concentrate, stability of skim latex and dipped film

British Library Electronic Table of Contents (United Kingdom)

The effect of ammonia treatment in field natural rubber (NR) latex with different storage period time on the properties of concentrated NR latex and stability of skim latex was investigated. Fresh NR latex was treated with various ammonia contents such as 0.35, 0.60 and 0.80% w/w, and then they were centrifuged to get the concentrated NR latex with 60% dry rubber content (DRC) containing 0.16, 0.18 and 0.25% w/w, respectively and skim NR latex with roughly 5% DRC containing 0.42, 0.60 and 0.80% w/w, respectively. The effect of storage times with ?0, 15, 30 and 45 days for concentrated NR latex with different ammonia contents on their properties such as alkalinity, magnesium content and viscosity was observed. It was found that generally, magnesium content in field NR latex and latex...

2009-01-01

311

Dynamic nucleation of new grains in magnesium alloy during hot deformation

Anisotropy of tensile properties of extruded magnesium alloy AZ31

Microstructure evolution under hot deformation was investigated in compression of a magnesium alloy AZ31 at 673 K (0.73T{sub m}). Two kinds of samples were machined along the parallel and transverse direction of the extruded rods. New fine grains are evolved at corrugated grain boundaries at low strains and developed rapidly in grain interiors in the medium range of strain, finally leading to a roughly full evolution of equiaxial fine grains. Kink bands are evolved at corrugated grain boundaries and in grain interiors at low strains. The boundary misorientation of kink band increases rapidly with increasing strain. These characteristics of new grain evolution process are not changed by the orientation of the samples, while the flow behaviors clearly depend on it. It is concluded that new grain evolution can be controlled by a deformation-induced continuous reaction resulting in grain fragmentation by kink bands, i.e. continuous dynamic recrystallization (DRX). The ...

2003-07-01

312

Uptake of cesium and strontium by crystalline silicotitanates from radioactive wastes

The mechanical behaviour of wrought magnesium alloy AZ31 has been characterised by tensile testing at room temperature. Tests were carried out at various strain rates between 0.00003 s{sup -1} and 0.01 s{sup -1} on material which had been extruded to a bar of approximately 6 mm thick, and 80 mm wide. Specimens were machined from three orientations relative to the extrusion direction: parallel, perpendicular, and 45 from the extrusion direction. Significant variations of the properties were observed depending on the extrusion orientation and strain rate. At all strain rates the yield stress declined as the test orientation was rotated away from the extrusion direction. Parallel to the extrusion direction, the yield stress was found to increases markedly with increasing strain rate, whereas at 45 and 90 a lesser influence of strain rate was observed. The work hardening exponent was also influenced by the test orientation. Metallographic studies revealed a ...

2003-07-01

313

British Library Electronic Table of Contents (United Kingdom)

Crystalline silicotitanate inorganic ion exchanger, with a sitinakite structure is candidate material for remediation of aqueous nuclear waste streams. The syntheses of crystalline silicotitanate (CST) and Nb-substituted crystalline silcotitanate (Nb-CST) were carried out under hydrothermal conditions and the products were characterized using techniques viz., XRD, SEM/EDS, DTA/TGA, surface area respectively. Batch experiments were carried out to study the kinetics of uptake of 137Cs and 90Sr, to estimate the decontamination factor (DF) values and distribution coefficients (K d) for the above synthesized CST and Nb-CST samples from actual radioactive waste solutions. The DF values for uptake of Cs and Sr by Nb-CST after 24?h of equilibration was 355 and 136 whereas for CST it was found to b...

2011-01-01

314

Study of even-A zirconium and strontium isotopes with the (d,"6Li) reaction

Rb-Sr isotopic studies on granodioritic rocks from the Mecsek mountains, Hungary

All stable even-A molybdenum isotopes and sup(90,92)Zr have been investigated with the (d, "6Li) reaction at Esub(d) = 45 MeV to study proton- and neutron-pair correlations. Differential cross sections were measured for states up to Esub(x) = 3 MeV in "8"6Sr, sup(88,92,94,96)Zr and up to 6 MeV in "8"8Sr and "9"0Zr. Particular attention was paid to the comparison of #alpha#-pickup data with two-nucleon pickup data. The population of low-lying 0"+ and 5"- states for two-neutron and four-nucleon pickup reactions was calculated using simple phenomenological wave functions for the initial and final states. The results of these calculations are in satisfactory agreement with the data. (orig.).

315

Migration of strontium in the food chain of plants, animals and man - problems and risks

New isotopic age determinations carried out with the rubidium-strontium method on granodioritic basement rocks from the Mecsek Mountains in Southeastern Transdanubia give further support to assumptions on a polyphase development of the Mecsek crystalline. As shown by initial Sr isotopic ratios, the protolith of the granodioritic assemblage of polymetamorphic-anatectic origin must have been strongly basic in its composition. The scatter of individual model ages obtained on total rock samples reflects the polymetamorphic-polytectonized character of the basement, and suggests that following a primary granitization process secondary events might have led to the total or partial recrystallization of the rocks in question. The tectonic development of the basement crystalline as reflected in the isotopic age data closed at about 270+-20 million years ago, with processes causing retrograde changes in the crystalline as a whole but leading to the development of dyke rocks ...

1981-01-01

316

Mass transfer and sorptive properties of geological samples from the Drigg site

The aims of investigation were to follow the Sr transport in the food chain from the flora to the fauna and humans, and its dependence on the geological origin og the plant site, industrial emissions, the age and site of plants, the part of plant used for nutrition and the strontium content in the drinking water, to determine the Sr intake of humans with the help of the duplicate method, and to estimate the apparent absorption rate and balance of strontium depending on of the form of diet (mixed or ovolactovegetarian), sex, season, age, region (geological origin of the living space) and method of intake measurement (duplicate or basket method). Strontium, an ultra trace element widespread in the earth's crust, is not essential and only mildly toxic for plants, animals and man according to current knowledge. The biological essentiality of Sr has not been investigated yet. Amoeba species living in sea water use Sr for the ...

2008-10-15

317

Hanford Waste Management Plan, 1987

This report presents the results of an experimental programme to determine the mass transfer and sorptive properties of selected glacial sand and clays from the Drigg Disposal Site operated by British Nuclear Fuels plc. The hydraulic conductivity of both the sand and clay has been determined and the sensitivity of this parameter to changing water chemistry investigated. The hydrodynamic dispersion properties of the glacial sand were measured in order to aid the interpretation of column sorption experiments. The sorption of strontium and uranium from groundwater onto clay and sand samples has been studied using through-diffusion, column and batch techniques. Employing the batch technique, the effect of a series of humic acid concentrations on distribution ratios for uranium and plutonium has also been investigated. Groundwater and trench leachate were used with both clay and sand. (author).

1990-02-01

318

Electrochemical and gas phase parameters of cathodes for intermediate temperature solid oxide fuel cells

The purpose of the Hanford Waste Management Plan (HWMP) is to provide an integrated plan for the safe storage, interim management, and disposal of existing waste sites and current and future waste streams at the Hanford Site. The emphasis of this plan is, however, on the disposal of Hanford Site waste. The plans presented in the HWMP are consistent with the preferred alternative which is based on consideration of comments received from the public and agencies on the draft Hanford Defense Waste Environmental Impact Statement (HDW-EIS). Low-level waste was not included in the draft HDW-EIS whereas it is included in this plan. The preferred alternative includes disposal of double-shell tank waste, retrievably stored and newly generated TRU waste, one pre-1970 TRU solid waste site near the Columbia River and encapsulated cesium and strontium waste.

1987-01-01

319

Doppler-free optogalvanic spectroscopy of sup(88,86)Sr I and II

A series of cyclic voltammetry, chronoamperometry and electrochemical impedance experiments have been carried out in order to investigate the effect of cathode composition and porosity on the electrochemical characteristics of strontium-doped lanthanum, praseodymium and gadolinium cobaltite cathodes. The impedance responses at different electrode potentials of the half cell and symmetric single cell setups are compared and analyzed by the equivalent circuit modeling method. The deconvolution of impedance spectra for single cell cathode and anode reactions contributions based on the results of simultaneous analysis of half cells and symmetric single cells has been made by differential impedance real part vs. ac frequency plot analysis method. Noticeable influence of cathode chemical composition, meso-porosity and macro-porosity on the electrochemical activity of the oxygen electroreduction has been demonstrated. Seeming activation energy values have been calculated ...

2010-11-01

320

A calf for all seasons? The potential of stable isotope analysis to investigate prehistoric husbandry practices

We have measured the isotope shifts of some dipole transitions between excited states of the even strontium isotopes 88 and 86 by applying the technique of Doppler-free intermodulated optogalvanic spectrocopy to a heat-pipe discharge. We were also able to investigate the isotope shift of the Sr II resonance line at 4216.6 A optogalvanically in the mentioned pair of isotopes. Because the 5 snf"1F_3 series appear to have zero level isotope shifts for n>=6, we can give residual level isotope shifts (RLIS) of several odd-parity states of sup(88,86) Sr I. The RLIS of the 5 snp "1P_1 series show pronounced configuration mixing around n=7. (orig.).

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

321

British Library Electronic Table of Contents (United Kingdom)

The Early Bronze Age barrows at Irthlingborough and Gayhurst in central England are notable for the large number of cattle (Bos taurus) remains associated with their human Beaker burials. Previous work using strontium isotope analysis has indicated that most of the cattle analysed, and one aurochs (Bos primigenius), were of local origin [Towers, J., Montgomery, J., Evans, J., Jay, M., Parker Pearson, M., 2010. An investigation of the origins of cattle and aurochs deposited in the Early Bronze Age barrows at Gayhurst and Irthlingborough. Journal of Archaeological Science 37, 508-515.]. In this study, stable isotope analysis of enamel and bone was carried out to investigate whether the mature cattle had experienced similar husbandry practices, climate and environment. Bulk carbon, nitrogen a...

2011-01-01

322

Texture development of AZ31 magnesium alloy during ECAE processing

Stabilisation of #alpha#-Sialons using multiple additives

Mg-3%Al-1%Zn (AZ31) alloy was subjected to ECAE processing at 523 and 573 K. Microstructure observation and texture analysis were carried out using optical microscope and SEM-EBSD technique in order to investigate the process of microstructural changes including texture development during ECAE processing. Grain refinement during ECAE processing is enhanced by dynamic continuous recrystallization. The texture of the ECAE-processed AZ31 alloy specimens change with ECAE processing temperature, and the textural changes relate to deformation mechanisms that change with ECAE processing temperature. (orig.)

2003-07-01

323

Probable role of trace elements of some medicinal plants in cardio-vascular diseases

Multi-cation #alpha#-Sialon ceramics were prepared using mixtures of samarium with calcium, magnesium, yttrium and ytterbium, and compared with a pure Sm-Sialon of equivalent total stabilising cation composition. A ratio of 80eq% samarium to 20eq% of the second stabilising additive was used. Samples were fired at 1820 deg C and subsequently heat treated at 1450 deg C. XRD phase analysis showed that all additives resulted in greater #alpha#-Sialon stability, and that calcium was the most effective additive for the stabilisation of the #alpha#-Sialon phase. Copyright (1998) Australasian Ceramic Society

1998-09-28

324

Flue gas desulfurization system capabilities for coal-fired steam generators. Volume II. Technical report. Final task report apr-dec 77

A number of herbal drugs are used in the Unani (Greco-Arab) System of Medicine for cardiovascular diseases. The herbs were analyzed by flame AAS and ICP-AES to determine if their therapeutic actions can be associated with the elements present in them. Cadmium, cobalt, chromium, copper, iron, potassium, magnesium, manganese, sodium, nickel, phosphorus, lead and zinc were some of the elements which play various roles in cardiovascular affections. An effort was made to correlate the role of these elements in cardiac diseases. (Auth.). 2 tabs., 32 refs.

325

FFTF reactor immersion heaters. Revision 1

The availability of technology for reducing SO2 emissions from coal-fired steam generators using flue gas desulfurization (FGD) systems is discussed. Foreign and domestic lime, limestone, double alkali, magnesium slurry, and Wellman-Lord FGD systems are described, and the design parameters and operating experiences are discussed. Steps that have been taken to achieve high system operability are discussed. Also, disposal of FGD system wastes is discussed briefly.

1978-03-01

326

Continuous wave operation (77 K) of yellow (583. 6 nm) emitting AlGaInP double heterostructure laser diodes

This specification establishes requirements for design, testing, and quality assurance for electric heaters that will be used to maintain primary Sodium temperature in the Fast Test Facility (FFTF) reactor vessel. The Test Specification (WHC-SD-FF-SDS-003) has been revised to Rev. 1. This change modifies the fabrication of approximately 25 feet of the subject heater using ceramic insulators over the heater lead wire rather than compressed magnesium oxide. Also, 304 or 316 stainless steel can be used for the heater sheath. This change should simplify fabrication and improve the heater operational reliability.

1994-08-26

327

Anodic oxide coatings on metals and anodic protection /2nd revised and enlarged edition/. Anodnye oksidnye pokrytiia na metallakh i anodnaia zashchita /2nd revised and enlarged edition/

Continuous wave lasing operation with the shortest wavelength for semiconductor lasers was obtained from AlGaInP double heterostructure lasers at 77 K. The structure was grown by metalorganic vapor phase epitaxy. Lasing wavelength was 583.6 nm (yellow). Threshold current was 43 mA (1.9 kA/cm/sup 2/). Magnesium was adopted as a p-type dopant, and was proved to be preferable for a high aluminum composition AlGaInP cladding layer.

1986-03-03

328

Adsorption properties of. cap alpha. -modification of boron nitride

The theoretical principles underlying the formation of oxide and, in particular, anodic oxide coatings on metals produced by chemical oxidation, anodizing in solutions, and anodizing in cold plasmas are reviewed. The mechanisms and conditions of anodic oxidation are described, and the structure of anodic oxide coatings on aluminum, magnesium, beryllium, zinc, cadmium, iron, cobalt, nickel, titanium, zirconium, tantalum, and chromium alloys is examined. Attention is also given to various applictins of anodized coatings. 54 references.

1985-01-01

329

Adsorption properties of #alpha#-modification of boron nitride

The adsorption properties of four samples of ..cap alpha..-BN were studied by means of gas chromatography. The particles of ..cap alpha..-BN particles, according to data obtained by electron microscopy, have the shape of thin platelets. A sample of ..cap alpha..-BN prepared from magnesium polyboride was found to be the most nearly homogeneous adsorbent. For a number of n-alkanes, benzene, and alkylbenzenes, data have been obtained on the retention volumes (Henry constants) and the differential heats of adsorption for surface coverages approaching zero. These thermodynamic data on the adsorption showed that ..cap alpha..-BN, like graphitized thermal carbon black, is a nonspecific adsorbent.

1986-11-01

330

Adsorption of ammonia and pyridine on copper(II)-doped magnesium-exchanged smectite clays studied by electron spin resonance

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

331

Drinking water composition and incidence of urinary calculus: introducing a new index.

The interaction between N-donor adsorbates such as ammonia and pyridine with Cu(II)-exchanged montmorillonite, beidellite, flourohectorite into smectite clays has been studied by electron spin resonance. Cu(II) cations exchanged into smectites coordinate five ammonia or pyridine molecules in beidellite, four ammonia of pyridine molecules in hydroxyhectorite. Thus, the Cu(II) cations bound to the interior surfaces of these smectite clays constitute strong Lewis acid sites. 26 refs., 7 figs., 1 tab.

1993-01-14

332

Strontium removal from caustic carbonate waste solutions using carrier coprecipitation

INTRODUCTION. We searched for a pathophysiologically based feature of major water electrolytes, which may define water quality better than the water hardness, respecting urinary calculus formation. MATERIALS AND METHODS. Utilizing a multistage stratified sampling, 2310 patients were diagnosed in the imaging centers of the provincial capitals in Iran between 2007 and 2008. These were composed of 1755 patients who were settled residents of 24 provincial capitals. Data on the regional drinking water composition, obtained from an accredited registry, and their relationships with the region's incidence of urinary calculi were evaluated by metaregression models. The stone risk index (defined as the ratio of calcium to magnesium-bicarbonate product in drinking water) was used to assess the risk of calculus formation. RESULTS. No correlation was found between the urinary calculus incidence and the amount of calcium, bicarbonate, or the total hardness of the drinking water. ...

2011-01-01

333

Spectroscopy of /sup 87,88,89/Sr with (n,. gamma. ) and (d,p) reactions

A carrier coprecipitation procedures has been developed for the removal of radioactive strontium from caustic liquid low-level waste (LLLW) generated at Oak Ridge National Laboratory. The two-step treatment process involves the addition of normal Sr (as SrCl{sub 2}) to the waste matrix, which is composed primarily of 0.3 M NaOH and 0.6 M Na{sub 2}CO{sub 3}. The active Sr equilibrates with the normal Sr carrier and coprecipitates as SrCO{sub 3} at pH 13. A liquid/solid separation is made before the pH of the supernate is reduced to pH 8 with sulfuric acid. During the neutralization step, the aluminum is the waste precipitates as Al(OH){sub 3}. Further Sr decontamination is achieved as traces of active Sr sorb to the Al(OH){sub 3} that precipitates during the neutralization step. A final liquid/solid separation is made at pH 8 to remove the sorbed active Sr. Maximum Sr decontamination of the LLLW is obtained when at least 50 ppm normal Sr is added to the waste. ...

1994-12-31

334

Spectroscopy of /sup 87,88,89/Sr with (n,#gamma#) and (d,p) reactions

Over the recent years the nuclear structure around the N = 50 shell closure, which is very pronounced in the strontium and zirconium isotopes, has been the subject of extensive experimental and theoretical work. On the proton side Z = 38 and Z = 40 provide fairly closed sub-shells. In the strontium isotopes the lg/sub 9/2/ neutron shell is closed at /sup 88/Sr, supplying relatively pure neutron-hole and neutron-particle states with large spectroscopic factors in /sup 87/Sr and /sup 89/Sr, as well as core-coupled states. The mass region is thus ideally suited to examine the transition from a correlated to an uncorrelated (chaotic.) excitational behavior. These two types are characterized e.g. by the density of excited states, the transition strengths, and the spectroscopic factors observed in transfer reactions. We conducted (n,..gamma..) and (d,p) reactions leading to /sup 87,88,89/Sr in addition to /sup 88/Sr(d,t)/sup 87/Sr and 24 keV neutron ...

1988-01-01

335

Rb-Sr isotope systematics of granitic soil chronosequence: The importance of biotite weathering

Over the recent years the nuclear structure around the N = 50 shell closure, which is very pronounced in the strontium and zirconium isotopes, has been the subject of extensive experimental and theoretical work. On the proton side Z = 38 and Z = 40 provide fairly closed sub-shells. In the strontium isotopes the lg/sub 9/2/ neutron shell is closed at "8"8Sr, supplying relatively pure neutron-hole and neutron-particle states with large spectroscopic factors in "8"7Sr and "8"9Sr, as well as core-coupled states. The mass region is thus ideally suited to examine the transition from a correlated to an uncorrelated (chaotic?) excitational behavior. These two types are characterized e.g. by the density of excited states, the transition strengths, and the spectroscopic factors observed in transfer reactions. We conducted (n,#gamma#) and (d,p) reactions leading to /sup 87,88,89/Sr in addition to "8"8Sr(d,t)"8"7Sr and 24 keV neutron capture in "8"8Sr. The ...

1988-04-24

336

Growth and characterization of new semi-organic L-proline strontium chloride monohydrate single crystals

The Rb-Sr isotope systematics of bedrock, soil digests, and the cation exchange fraction of soils from a granitic glacial soil chronosequence in the Wind River Mountains, Wyoming, USA, were investigated. Six soil profiles ranging in age from 0.4 to {approximately}300 kyr were studied and revealed that the {sup 87}Sr/{sup 86}Sr ratio of exchangeable strontium in the B-horizons decreased from 0.7947 to 0.7114 with increasing soil age. Soil digests of the same samples showed much smaller variation in {sup 87}Sr/{sup 86}Sr from 0.7272 to 0.7103 and also generally decreased with increasing soil age. Elevation of the {sup 87}Sr/{sup 86}Sr ratios of Sr released by weathering over the soil digest and bedrock values results from the rapid weathering of biotite to form hydrobiotite and vermiculite in the younger soils. Biotite is estimated to weather at approximately eight times the rate of plagioclase (per gram of mineral) in the youngest soil profile and decreases to a ...

1997-08-01

337

Decontamination of cesium, strontium, and cobalt from aqueous solutions by bentonite

The present communication deals with the synthesis, single crystal growth and characterization of a new nonlinear optical material L-proline strontium chloride monohydrate (L-PSCM). Single crystals have been grown using the slow solvent evaporation technique. Single crystal XRD analysis confirmed that the crystal belongs to the orthorhombic structure with lattice parameter a=6.6966(3) A, b=12.4530(5) A, c=15.2432(5) A and space group P2_12_12_1. Presence of various functional groups in L-PSCM and protonation of the ions were confirmed by Fourier transform infrared spectroscopy (FT-IR) analysis. The melting point of the single crystal was found to be 126 "oC using DSC. Ultraviolet-visible spectral analyses showed that the crystal has low UV cut-off at 226 nm combined with very good transparency of 90% in a wide range. The optical band gap was estimated to be 5.82 eV. Capacitance and dielectric-loss measurements were carried out at different temperatures in the ...

2011-01-01

338

Comparison of bone cancer risks in beagle dogs for inhaled plutonium-238 dioxide, inhaled strontium-90 chloride, and injected strontium-90

Sorption studies of cesium, strontium, and cobalt (Cs, Sr, and Co) on bentonite under various experimental conditions, such as contact time, pH, sorbent and sorbate concentration, and temperature, have been performed. The sorption data for all these metals have been interpreted in terms of Freundlich, Langmuir, and Dubinin-Radushkevich equations. Thermodynamics parameters, such as heat of sorption {Delta}H{degrees}, free energy change {Delta}G{degrees}, and entropy change {Delta}S{degrees}, for the sorption of these metals on bentonite have been calculated. The value of {Delta}H{degrees} shows that the sorption of Cs was exothermic, while the sorption of Sr and Co on bentonite were endothermic in nature. The value of {Delta}G{degrees} for their sorption was negative, showing the spontaneity of the process. The maximum loading capacity of Cs, Sr, and Co were 75.5, 22, and 27.5 meq, respectively, for 100 g of bentonite. The mean free energy E of Cs, Sr, and Co ...

1996-12-31

339

{sup 99m}TC tetrofosmin cardiac tomography after nitrate administration in patients with coronary artery disease and left ventricular dysfunction; Tomografia cardiaca {sup 99m}Tc tetrofosmina dopo somministrazione di nitrati in pazienti con cardiopatia ischemica e disfunzione ventricolare sinistra

There is a continuing need to understand dose-response relationships for ionizing radiation in order to protect the health of the public and nuclear workers from undue exposures. However, relatively few human populations have been exposed to doses of radiation high enough to cause observable, long-term health effects from which to derive dose-response relationships. This is particularly true for internally deposited radionuclides, although much effort has been devoted to epidemiological studies of the few types of exposures available, including lung cancers in uranium miners form the inhalation of the radioactive decay products of Ra, liver cancers in patients injected with Thorotrast X-ray contrast medium containing Th, bone cancers in radium dial painters who ingested Ra, and bone cancers in patients who received therapeutic doses of Ra. These four types of exposures to internally deposited radionuclides provide a basis for understanding the health effects of many other radionuclides ...

1995-12-01

340

Theoretical simulation of SDS - 2 actuation in 540 MWe PHWR

The work examines twenty-two patients with coronary artery disease, previous myocardial infarction and LV dysfunction, using the technetium-99m ({sup 99m}Tc) tetrofosmin (SPECT) associated with nitrate administration in the detection of hypoperfused but still viable myocardium. The method allows the detection of this disease. [Italian] Il lavoro analizza i risultati degli esami condotti su 22 pazienti con cardiopatia ischemica cronica e ridotta funzione ventricolare sinistra sottoposti a tomografia computerizzata con emissione di fotone singolo (SPECT) cardiaca con tecnezio-99m ({sup 99m}Tc) tetrofosmina associata alla somministrazione di nitrati nella differenziazione tra tessuto miocardico ipoperfuso ma ancora vitale e tessuto miocardico necrotico. La metodologia usata consente di identificare la presenza di tessuto miocardico vitale in territori vascolari severamente ipoperfusi.

2000-04-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

341

Size-dependent surface plasmon resonance in silver silica nanocomposites

The 540 MWe PHWR has two fully independent shutdown systems. The first shutdown system (SDS-1) comprises of 28 spring assisted, vertical gravity drop shut-off rods, each consisting of a cadmium absorber sandwiched between stainless steel tubes. The second shutdown system (SDS-2) constitutes six poison tanks connected to respective zircaloy injection tubes. This system is capable of high speed injection of gadolinium nitrate solution (in D2O) into the moderator through these tubes. Theoretical estimation was carried out at different injection pressures and different concentration of gadolinium nitrate solution to arrive at the limiting value of these parameters from reactivity consideration point of view. The plant measurements of SDS-2 actuations at 60 and 80 Kg/cm2 pressure of helium was used to validate and upgrade the estimation model. The paper gives the details of the validation details of SDS-2 actuation. (author)

2006-11-13

342

Responses to ammonium and nitrate additions by boreal plants and their natural enemies

Silver silica nanocomposites were obtained by the sol-gel technique using tetraethyl orthosilicate (TEOS) and silver nitrate (AgNO{sub 3}) as precursors. The silver nitrate concentration was varied for obtaining composites with different nanoparticle sizes. The structural and microstructural properties were determined by x-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). X-ray photoelectron spectroscopic (XPS) studies were done for determining the chemical states of silver in the silica matrix. For the lowest AgNO{sub 3} concentration, monodispersed and spherical Ag crystallites, with an average diameter of 5 nm, were obtained. Grain growth and an increase in size distribution was observed for higher concentrations. The occurrence of surface plasmon resonance (SPR) bands and their evolution in the size range 5-10 nm is studied. For decreasing nanoparticle size, a redshift and ...

2008-02-20

343

Pretreatment with U(IV) solution for improving the decontamination of ruthenium

Separate effects of ammonium (NH{sub 4} {sup +}) and nitrate (NO{sub 3} {sup -}) on boreal forest understorey vegetation were investigated in an experiment where 12.5 and 50.0 kg nitrogen (N) ha{sup -1} year{sup -1} was added to 2 m{sup 2} sized plots during 4 years. The dwarf-shrubs dominating the plant community, Vaccinium myrtillus and V. vitis-idaea, took up little of the added N independent of the chemical form, and their growth did not respond to the N treatments. The grass Deschampsia flexuosa increased from the N additions and most so in response to NO{sub 3} {sup -}. Bryophytes took up predominately NH{sub 4} {sup +} and there was a negative correlation between moss N concentration and abundance. Plant pathogenic fungi increased from the N additions, but showed no differences in response to the two N forms. Because the relative contribution of NH{sub 4} {sup +} and NO{sub 3} {sup -} to the total N deposition on a regional scale can vary substantially, the ...

2006-05-15

344

Preparation and physical properties of U{sub 3}O{sub 8}

The ruthenium decontamination factor in Purex process falls quickly in successive TBP cycles. So, it is necessary to change the chemical states of RuNO complexes in order to improve DF_R_u in the uranium purification cycle. Hydrazine nitrate is being used to transform RuNO complexes into in-extractable Ru(III)and Ru(IV). However, hydrazine nitrate may be inverted into hydrazoic acid which is dangerous and can bring an unstable factor. Pretreatment using U(IV) solution provides another method to improve the decontamination of ruthenium in Purex process. 0.02 mol/lU(IV) solution can transform RuNO complexes into inextricable species by heating in water bath. The D_R_u can be decreased by a factor of 10-20. U(IV) pretreatment does not bring any harmful chemical in process. The acidity has a very large influence on the effect of pretreatment. The higher the acidity is, the worse the effect will be.

345

Photochemical synthesis of ZnO/Ag nanocomposites

Uranyl nitrate solution from 200-Area processing of spent SRP fuel tubes is now sent to Oak Ridge Y-12 for conversion of uranium metal. However, after implementation of the powder metallurgy (P/M) process, U{sub 3}O{sub 8} powder will be needed at SRP but not uranium metal. U{sub 3}O{sub 8} powder for fabrication and irradiation tests was produced during development of P/M at SRL by firing UO{sub 3}, obtained from Y-12, at 800{degrees}C for 6 hours in a low grade nitrogen atmosphere. The UO{sub 3} powder was produced by denitration of unsulfated uranyl nitrate solution. The stoichiometry, particle size distribution, surface area and density of the Y-12 and SRL powders were measured. A comparison was then made between SRL U{sub 3}O{sub 8} produced at 800{degrees}C in nitrogen and in air and U{sub 3}O{sub 8} produced at Y-12 at other heating temperatures.

1983-01-31

346

Mullite long fibres prepared by sol-gel method using water solvent systems

Composite ZnO/Ag nanoparticles have been formed via the photocatalytic reduction of silver nitrate over the ZnO nanocrystals, their optical, electrophysical and photochemical properties have been investigated. Mie theory has been applied to analyze the structure of the absorption spectra of ZnO/Ag nanocomposite. The irradiation effects upon the optical properties of ZnO/Ag nanostructure have been investigated. It has been found that the irradiation of ZnO/Ag nanoparticles results in electrons accumulation by both the semiconductor and the metallic components of the nanocomposite. It has been found that silver nitrate can be photochemically deposited onto the surface of ZnO nanoparticles under the illumination with the visible light in the presence of the sensitizer - methylene blue. Kinetics of the sensitized Ag(I) photoredution has been studied. It has been concluded that the key stage of this process is the electron injection from ...

2007-06-15

347

Influence of thin oxide films on pitting corrosion of CrNi steels. Beeintraechtigung der Lochkorrosionsbestaendigkeit von CrNi-Staehlen durch duenne Oxidschichten

Mullite long fibres, which are a candidate for high temperature applications were prepared by sol-gel method from water solvent systems. They were synthesized from three different combinations of raw materials as follows: (1):Al(O{sub 1}C{sub 3}H{sub 7}){sub 3}, Al-nitrate and Si(OC{sub 2}H{sub 5}){sub 4} (TEOS), (2):Al metal, Al-chloride and TEOS, (3):Al metal, Al-nitrate and TEOS. In the methods (1) and (2), very fine SiO{sub 2} aerosol particles were also used partially replacing TEOS. The prepared solutions were condensed and examined the spinability by a hand drawing method. Dense and crack free mullite fibres were prepared from the methods (1) and (3) by firing up to 1100 C. Whereas the fibres prepared from the method (2) were less SiO{sub 2} than mullite composition and were porous by the firing due to evaporation of residual Cl ions at high temperature. (orig.) 10 refs.

1997-12-31

348

Formation of colloidal silver nanoparticles stabilized by Na+-poly(gamma-glutamic acid)-silver nitrate complex via chemical reduction process.

Chloride-induced pitting corrosion of stainless steel (Materials No. 1.4301 and 1.4571) was investigated with the aid of chronopotentiostatic tests. Oxide films upon the surface (temper colours), addition of inhibitors (sulphate and nitrate) and temperature were the testing variables. Two different critical pitting potentials have been found, which give information on the potential ranges for stable passivity, latent and stable pitting corrosion. The results only indicate a small effect of Mo content of the material and test temperature. The inhibitors (sulphate and nitrate) have a marked effect. Specimens with a clean surface produced by pickling are markedly more resistant against pitting corrosion than specimens with a yellow temper colour, whereas the difference in corrosion resistance between yellow and blue films is relatively small. The width of the critical potential range for pitting corrosion generally increases with increasing oxide ...

1993-09-01

349

Analysis of lagoon sludge characteristics for choice of treatment process

Macromolecular and polyanionic Na(+)-poly(gamma-glutamic acid) (PGA) silver nitrate complex acted as both a metal ion provider and a particle protector to fabricate nanosized silver colloids under chemical reduction by dextrose. The formation and size of particles have been characterized from transmission electron microscopy (TEM), dynamic light scattering analysis and UV-vis spectrophotometer. The results showed that the average particle size was 17.2+/-3.4 to 37.3+/-5.5 nm, apparently depending on the complex concentration. It was found that the rate constant and conversion of silver nanoparticles were proportional to the concentration of PGA. The growth mechanism of nanosized silver colloid was fully discussed. In addition, the in vitro cytotoxicity evaluated by L929 fibroblasts proliferation and antibacterial activity against Gram-positive strain (methicillin-resistant S. aureus (MRSA)) and Gram-negative strain (P. aeruginosa) bacteria have been assessed. ...

2007-05-18

350

A lysimeter study of nitrate leaching, optimum fertilisation rate and growth responses of corn (Zea mays L.) following soil amendment with water-saving super-absorbent polymer

The Korea Atomic Energy Research Institute has launched a decommissioning program of uranium conversion plant. One of the important tasks in the decommissioning program is the treatment of the sludge, which was generated during operation and stored in the two ponds of the lagoon. The treatment requires the volume reduction of lagoon sludges for the low cost of the program and the conversion of the chemical forms, including uranium, for the acceptance at the final disposal site. The physical properties, such as densities, were measured and chemical compositions and radiological properties were analyzed. The denitration was a candidate process which would satisfy the requirements for sludge treatment, and the characteristics of thermal decomposition and dissolution with water were analyzed. The main compounds of the sludge were ammonium and sodium nitrate from conversion plant and calcium nitrate, calcium carbonate from Ca precipitation and ...

2002-04-01

351

British Library Electronic Table of Contents (United Kingdom)

Abstract BACKGROUND: Nitrate leaching and the resulting groundwater contamination from intensive cereal production has become a major concern for long-term farmland efficiency and environmental sustainability in northern China. The aim of this study was to evaluate a water-saving super-absorbent polymer (SAP) for minimising NO3- leaching from soil and optimising corn growth and yield. Thirty-six undisturbed soil lysimeters were installed in a field lysimeter facility in drought-affected northern China to study the growth and yield characteristics of summer corn (Zea mays L.) as well as the amount of NO3-leaching losses under different fertiliser (standard, medium or 75% and low, or 50% of conventional fertilisation rate) and SAP (control, 0; level-1, 15 kg ha-1 and level-2, 30 kg ha-1) tre...

2011-01-01

352

Wastewater treatment of industrial effluent using activated dolomite adsorption

Environmental Research Database

SummaryInitial results from the use of activated dolomite from QUESTOR project L1 have proved extremely encouraging in terms of metallic ion (also phosphate, nitrate and dye) removal from wastewater, with capacities in some instances in excess of commercially available activated carbons.This new project involves investigating actual plant effluent in laboratory scale columns and the design of a pilot scale rig for on site trials. The project also involves investigating disposal options and an economic [continued...

2007-01-01

353

Tetracycline in uranyl nitrate intoxication: Its action on renal damage and U retention in bone

Stress corrosion cracking susceptibility of #beta# titanium alloy 38-6-44

In acute intoxication, uranium (U) not only inhibits bone formation but its excretion in urine also causes renal damage. The former effect is ameliorated by tetracycline (TC), probably due to its chelation property, which might also prevent U deposition in bone. Chemical determination of U incorporated in bone and a histological study of the kidneys were performed on animals injected with U and then treated with TC. The results showed that TC was unable to prevent the binding of U to bone while it exacerbated U-induced renal damage.

1989-09-01

354

Selective extraction of U(VI) and some other metals from nitric acid media by poly-phosphine poly-oxides

The threshold stress intensities for stress corrosion crack propagation in beta titanium alloy 38-6-44, Ti3Al-8V-6Cr-4Mo-4Zr, has been determined in salt water and methanolic solutions. The alloy was immune to stress corrosion cracking (SCC) in aqueous sodium chloride solutions (marine atmosphere). However, in methanolic solutions, the alloy was very susceptible to SCC. This marked susceptibility in methanolic solutions can be mitigated by the addition of an inhibitor: sodium nitrate. Crack extension in the alloy was transgranular and failure occurred by brittle quasi-cleavage in methanolic solutions.

355

Review of experience gained in fabricating nuclear grade uranium and thorium compounds and their analytical quality control at the Instituto de Energia Atomica, Sao Paulo, Brazil

For the selective extraction of radionuclides from nitrate media, the extractabilities of organo-poly-phosphine poly-oxides were examined in the form of impregnated resins. It was found that the extractability of 1,1,3,5,5-pentaphenyl-1,3,5-tri-phospha-pentane trioxide (PPTPT) for U(VI) is quite unusual with very high values at both low and high concentrations of nitric acid, which is not observed for other types of extractants. Thus, this extractant might be promising for the selective extraction of U(VI) in very high concentrations of HNO3. (authors)

2008-09-15

356

Oxygen evolution studies on perovskite films in alkaline media

The main activities developed at 'Instituto de Energia Atomica' Sao Paulo, Brazil, on the recovery of uranium from ores, the purification of uranium and thorium raw concentrates and their transformation in nuclear grade compounds, are reviewed. The design and assemble of pilot facilities for ammonium diuranate (ADV) uranium tetrafluoride, uranium trioxide, uranium oxide microspheres, uranyl nitrate denitration, uranim hexafluoride and thorium compounds are discussed. The establishment of analytical procedures are emphasized.

1980-08-22

357

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.

1999-08-01

358

Emulsion explosives

Combustion flames of high energy substance

Emulsion explosives were discovered by Richard S Egley in 1961, but remained little known prior to rapid commercial development in the late 1970s. Their introduction has a significance that may in future be compared with the formulation of dynamite by Nobel in 1867 and the development of ammonium nitrate explosives in the mid 1950s. For the mining engineer emulsion explosives provide advantages of being inherently waterproof and having high strength with a high and stable velocity of detonation giving good fragmentation in hard rock. This is available at moderate cost, from an explosive that typically does not contain any self explosive ingredients and with fume properties that offer considerable advantages over other explosives. 2 figs., 1 tab.

1989-01-01

359

Atmospheric carboxylic acids in southern California

The currently available propellants achieve about 95% of the combustion performance which can be expected theoretically at this time, consequently a technological breakthrough concerning new propellants have been demanded. Among high energy substances which are being studied, polymer azide which can continue combustion without relying on the oxidation reaction is a typical high energy substance to be used for a propellant of the next generation. The composite propellant which has polymer azide as fuel component and ammonium nitrate as oxidizer is considered to be the extremely promising propellant, since it provides no combution product which causes the environmental destruction. (6 figs, 4 refs)

1988-04-30

360

Subcriticality measurements for two coupled uranyl nitrate solution tanks using /sup 252/Cf-source-driven neutron noise analysis methods

Intensive measurements of organic acids, inorganic acids, aldehydes and peroxyacetyl nitrate (PAN) in urban air were carried out at a Southern California smog receptor site, Glendora, CA, August 12-22, 1986. The objective of this project was to augment the data base regarding organic acids in urban air and to assess their role with emphasis on ambient levels, diurnal variations, phase distribution, emissions, in-situ formation and removal. The relative abundance of organic acids and inorganic acids was determined for the first time from simultaneous measurements carried out during this study.

1988-09-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

361

Safe conditions for contacting nitric acid or nitrates with tri-n-butyl phosphate (TBP)

The subcriticality of two interacting solution tanks was determined using /sup 252/Cf-source-driven neutron noise analysis methods. These experiments were the first test of this method for an interacting system with materials (in this case, uranyl nitrate) typical of nuclear materials in processing plants. The experiments were performed to test the conclusions from previous interaction experiments with uranium metal discs for a fissile system with moderation, and to provide data to test theoretical models for coupled systems. The uranium metal experiments showed that the subcritical neutron multiplication factor, k/sub eff/, could be determined using point kinetics without any correction for spatial effects from measurements with the source and detectors located adjacent to the same cylinder, whereas for source-detector configurations with either the source and/or detectors adjacent to different cylinders, a model which incorporates the coupling is required to ...

1986-01-01

362

Preparation of uranium (IV) from uranium (VI) by using an electrodialysis technique

In response to a request from DOE-SR, the current state of knowledge of the reactions between TBP and aqueous nitrate solutions is critically reviewed, and recommendations are made for the safe operation of SRS separations equipment in which this combination of chemicals may be present. The existing limits for evaporation are validated. Guidelines are presented for cases in which general limits do not apply. The rate of reaction between nitric acid and TBP appears to be controlled by the rate of TBP hydrolysis. The hydrolysis reaction produces dibutyl phosphate and n-butanol. The hydrolysis rate is a strong function of temperature, and becomes very fast at temperatures in the range 130{degrees} to 150{degrees}C. The resulting n-butanol is volatile at high temperatures, boiling at 117.5{degrees}C, but is also subject to exothermic oxidation by nitric acid or nitrates. If oxidation occurs before the n-butanol evaporates, the heat of oxidation may ...

1994-01-01

363

Physical and electrochemical characterization of CdS hollow microspheres prepared by a novel template free solution phase method

Preparation of a uranous nitrate solution from the reduction process of a uranyl nitrate solution by using electrodialysis technique with a cation exchange membrane has been studied. Uranyl ions were reduced into uranous ions in a nitric acid solution stabilized by hydrazine sulfate in a two-compartment electrolytic cell made from flexiglass. Platinum and carbon or stainless steel were used as anode and cathode, respectively. The electrodialysis process was carried out at room temperature. A piece of cation exchange membrane was inserted between the two compartments and the distance between electrode and membrane was 1.5 cm and this was kept constant throughout the experiment. A 100 ml of a nitric acid 1.4 M solution was in the anode chamber as analyte, whilst a 100 ml of a uranyl nitrate solution with the uranium concentration of 23.97 g/l was in the cathode chamber containing hydrazine sulfate. The parameters tasted were ...

2000-03-08

364

Nitrogen utilization during spring phytoplankton bloom development in the southeast Bering Sea

Novel CdS hollow microspheres have been successfully synthesized via a facile template-free solution-phase reaction from cadmium nitrate and thioacetamide precursors. The morphology of CdS hollow microspheres depends strongly on the ratio between the precursors, cadmium nitrate to thioacetamide ratio. The physical properties of the hollow microspheres have systematically been studied by different characterization methods. The stoichiometry of the hollow microspheres studied by the energy dispersive X-ray diffraction spectroscopy confirmed that the synthesized CdS hollow microspheres are nearly stoichiometric bulk like CdS. The morphology of the hollow microspheres studied by high resolution scanning electron microscopy and transmission electron microscopy observations showed that the CdS hollow microspheres of the size of 2.5 ?m have hollow structure and are constructed by several nanoparticles of the size between 30 and 40 nm. The UV-visible ...

2010-12-15

365

Development of a microbiological ammonium to nitrate recycling bioreactor for space capsules

Interactions beween a high latitude, continental shelf, spring phytoplankton bloom and water column physics and chemistry were studied using /sup 15/N measured rates of nitrogen uptake. Peak bloom conditions commenced when the mixed layer shallowed and minimized respirational losses. Integrative light-mixing growth models were accurate during early bloom stages. An advection-diffusion model associated peak bloom nitrate uptake with pycnocline mixing rates of 2.1 m d/sup -1/ in an 18 m mixed layer. Maximum nitrogen specific uptake rates (hr/sup -1/), unlike those of carbon, coincided with peak bloom conditions. Although species compositions among peak bloom periods were similar, particulate C/N ratios were not. Apparently, both intercellular factors and prevailing mixing conditions influence specific uptake rates and cell composition. A large proportion of new (nitrate) to total productivity was associated with the dominance of the early bloom ...

1983-01-01

366

CHEMICAL TECHNOLOGY DIVISION, UNIT OPERATIONS SECTION MONTHLY PROGRESS REPORT, JULY 1960

Since 1988, the Expertise group of Molecular and Cellular Biology (MCB) is an important partner in the development of the Micro-Ecological Life Support System Alternative (MELiSSA). The MELiSSA was designed to allow a small crew to survive on an Antarctic, lunar or Mars outpost, and is a joint research project currently fostered by the European Space Agency, ESA. The MELiSSA functions through a series of five interconnected compartments, of which four are microbial bioreactors and was engineered to degrade organic waste, regenerate the outpost's atmosphere and water, and provide the crew with an additional vegetarian diet. The bioreactor of the third compartment provides the edible cyanobacteria and plants of the fourth compartment with nitrate instead of ammonium as a source of nitrogen. The two bacteria responsible for the biological transformation of ammonium to nitrate (nitrification) are Nitrosomonas europaea and Nitrobacter winogradskyi. ...

2009-09-01

367

The deformation texture in an AZ31B magnesium alloy

A critical review of the literature revealed no experiments on uranyl ion transfer from an aqueous to a tributyl phosphate phase which positively measured the kinetics of the chemical reaction at the interphase. Drawing isorhythmic lines on a three component diagram gives a complex correlation for the compaction of three sizes of glass beads. Neither the use of thoria sols nor high feed solution concentrations of thorium nitrate gave any significant increase in mean particle diameters over those obtained from nitrate solutions of lower concentrations in flame denitration. A hydraulic film resistance has been detected in the anion exchange of uranyl sulfate into Dowex 2lK, and chloride elution was found to give a higher apparent uranium diffusion coefficient than nitrate elution. The rate of dissolution of mixed thorium-uranium oxides was determined as a function of the per cent of mixed oxides ...

1960-10-27

368

Study of phase composition and mechanical properties of Al-Mg alloys doped with Ce and Y after various conditions of heat treatment

Extruded and hot-rolled 200 C {proportional_to} 500 C AZ31B plates were studied their texture using ODFs analysis. The as-extruded specimen has the strongest intensity of (0001)-ND fiber and 300 C and 400 C hot-rolled ones have the next, but the 200 C hot-rolled one has the lowest intensity. Compared with the corresponding tensile properties, this feature evidents that a pronounced (0001) basal texture will reduce ductility of AZ31B alloy. The ODFs results also indicate that (05 anti 52)- and (01 anti 10)-ND fibers are related to the ductility of AZ31B alloy. (orig.)

2003-07-01

369

Pilot testing of sodium thiosulfate

By means of the light microscopy and by the measurement of the mechanical properties one investigated into the phase composition and the properties of Al-Mg-Ce and Al-Mg-Y system alloys. One plotted the isothermal cross sections of the mentioned systems under 430 and 275 deg C temperatures at up to 16% magnesium concentration and up to 0.7% yttrium concentration. One determined the yield limit and strength, the relative elongation of Al-Mg base hardened and deformed alloys containing 7.0-9.9% Mg and Ce, Y, Mn, Zr dopes upon ageing under 175, 200, 250 and 300 deg C temperatures within the ageing time ensuring the hardening maximum effect

370

Pilot testing of sodium thiosulfate

Pilot plant tests have been conducted to evaluate sodium thiosulfate as an oxidation inhibition additive in five lime/limestone slurry flue gas desulfurization processes. It was found that the oxidation rate of absorbed sulfur dioxide (SO)/sub 2/ was reduced by more than 50 percent in the presence of 100 to 200 ppm of thiosulfate ion in the scrubbing slurry. Calcium sulfate dihydrate (gypsum) scaling was eliminated and the unsaturated (with respect to gypsum) operation mode was maintained by the addition of sodium thiosulfate. Other benefits of sodium thiosulfate addition observed at the pilot plant included improvement in solids dewatering properties for limestone processes and improvement in SO/sub 2/ removal efficiency for magnesium-enhanced lime/limestone processes.

1986-11-01

371

Pilot testing of sodium thiosulfate

The article gives results of pilot-plant tests to evaluate sodium thiosulfate as an oxidation-inhibition additive in five lime/limestone slurry flue-gas desulfurization processes. It was found that the oxidation rate of absorbed SO/sub 2/ was reduced by more than 50% in the presence of 100-200 ppm of thiosulfate ion in the scrubbing slurry. Calcium sulfate dihydrate (gypsum) scaling was eliminated and the unsaturated (with respect to gypsum) operation mode was maintained by the addition of sodium thiosulfate. Other benefits of sodium thiosulfate addition observed at the pilot plant included improvement in solids dewatering properties for limestone processes and improvement in SO/sub 2/ removal efficiency for magnesium-enhanced lime/limestone processes.

1986-01-01

372

Pilot project ''measurement of efficacy'' - biological monitoring of antimony pollution in the Munich test area using a standardized grass culture

The article gives results of pilot-plant tests to evaluate sodium thiosulfate as an oxidation-inhibition additive in five lime/limestone slurry flue-gas desulfurization processes. It was found that the oxidation rate of absorbed SO/sub 2/ was reduced by more than 50% in the presence of 100-200 ppm of thiosulfate ion in the scrubbing slurry. Calcium sulfate dihydrate (gypsum) scaling was eliminated and the unsaturated (with respect to gypsum) operation mode was maintained by the addition of sodium thiosulfate. Other benefits of sodium thiosulfate addition observed at the pilot plant included improvement in solids dewatering properties for limestone processes and improvements in SO/sub 2/ removal efficiency for magnesium-enhanced lime/limestone processes.

1986-11-01

373

Nomographs for the rapid prediction of salt quality and influent water quality impacts on hardness leakage in steamflood water

This pilot project was carried out for the purpose of testing methods for active biological monitoring. It covered a period of three years (until September 1994), including two years of exposure. The measurements served to determine pollutant levels in plants used as animal fodder and dust-borne heavy metal concentrations in different sites and, on this basis, to obtain indirect information on human exposure. Among others, the pilot project investigated the suitability of Italian rye-grass as a biological indicator for aluminium, arsenic, cadmium, cobalt, chromium, copper, iron, mercury, magnesium, manganese, nickel, lead, platinum, antimony, titanium, and zinc. (orig./GL).

374

Mineral carbonation accelerated by dicarboxylic acids as a disposal process of carbon dioxide

Counter-current regeneration of 2-stage sodium zeolite softeners has been employed in reducing hardness leakage level of steamflooding water to less than 1 ppm when raw water contains as much as 5,000 ppm of the total dissolved solids. Hardness leakage is caused by sodium displacement of calcium and magnesium from the bottom of the exchanger bed. This study presents nomographs providing for rapid calculations to be made, for which a convenient operational mode does not already exist. The nomographs relate the hardness leakage as a function of salt quality and influent water quality and present solutions for predicting the leakage level, salt quality requirement or the treatability of raw water required for steamflooding projects.

1982-08-01

375

British Library Electronic Table of Contents (United Kingdom)

Mineral carbonation is based on the reaction of carbon dioxide with metal-oxide bearing minerals, usually containing magnesium or calcium silicate, to form hardly soluble carbonates and other solid byproducts. The concept is based on acceleration of the naturally occurring rock weathering process. In the present work the calcium silicate is present in the mineral, wollastonite. To accelerate the process and make it potentially useful for practical applications, mineral carbonation is conducted here using an indirect two-step route in which the reactive component (Ca^2^+ ions in considered case) is first extracted from the mineral matrix and afterwards carbonated. Two solid byproducts are formed in this process: silica in the extraction step and calcium carbonate in the carbonation step. In...

2011-01-01

376

Microstructure and mechanical properties of magnesium alloy AZ31B laser beam welds

Microstructure and mechanical behaviour of an elevated temperature Mg-rare earth based alloy

Microstructure and properties of a Mg AZ31B laser beam weld without filler are studied using electron microscopy, X-ray diffraction and mechanical tests. The microstructure of the weld is characterized by a narrow heat affected zone, columnar grains and precipitate coarsening in the fusion zone. Texture in the fusion zone is significantly different from the texture of the base material. The residual stress distribution observed is similar at the top and the bottom of the weld, maximum tensile residual stress values are observed in the fusion zone. Tensile tests reveal differences in the mechanical behavior of the fusion zone and the parent material, which can be related to the differences of texture and the resulting deformation mechanisms.

2008-06-25

377

Micro-analysis of ?salt weathering? on cement paste

AM-SC1 is a heat treatable magnesium alloy that has been specifically developed to achieve the elevated temperature strength and creep properties necessary for engine block applications. This paper describes the interrelationship between the microstructure and the mechanical properties of AM-SC1. The compressive and tensile strengths are relatively insensitive to temperature up to and including 450 K and the tensile yield behaviour deviates from a standard Hall-Petch relationship at grain sizes below 200 ?m. The microstructural features contributing to the creep resistance are both inter- and intra-granular in nature and are on length scales from nanometers to micrometers. The creep behaviour at 423 K and 450 K is diffusion controlled, with any contribution from the grain boundaries being negligible.

2009-04-15

378

British Library Electronic Table of Contents (United Kingdom)

Normally, concrete technologists attribute salt weathering, salt crystallization or physical attack to the deterioration of concrete that is partially exposed to sulfate environment. However, there are few convincing evidences supporting this view. The purpose of this paper is to check by means of extensive micro-analysis if traces of sulfate crystals are present in the paste. This would enable to verify in a direct way whether salt weathering really causes cement paste damage or not.In this research, cement paste and cement?fly ash paste specimens were partially exposed to sodium sulfate and magnesium sulfates solution under a constant storage condition (20 ? 2 ?C, and 60 ? 5% RH) and a sharply fluctuating environment (40 ? 2 ?C and 35 ? 5% RH for 24 h, then 10 ? 1 ?C and 85 ? 5% RH, also...

2011-01-01

379

Materials for cold neutron sources: Cryogenic and irradiation effects

Isotopes and groundwater management strategies under semi-arid area: Case of the Souss upstream basin (Morocco)

Materials for the construction of cold neutron sources must satisfy a range of demands. The cryogenic temperature and irradiation create a severe environment. Candidate materials are identified and existing cold sources are briefly surveyed to determine which materials may be used. Aluminum- and magnesium-based alloys are the preferred materials. Existing data for the effects of cryogenic temperature and near-ambient irradiation on the mechanical properties of these alloys are briefly reviewed, and the very limited information on the effects of cryogenic irradiation are outlined. Generating mechanical property data under cold source operating conditions is a daunting prospect. It is clear that the cold source material will be degraded by neutron irradiation, and so the cold source must be designed as a brittle vessel. The continued effective operation of many different cold sources at a number of reactors makes it clear that this can be accomplished. 46 refs., 8 ...

1990-01-01

380

Interactions at the cofired interface of Ag/Pd electrode and lead-based ferroelectrics

This study concerns the Souss upstream basin. The objective is to investigate the characteristics of surface water and groundwater, to assess the impact of artificial recharge as reinforcement of the natural replenishment and assess the renewal of groundwater under semi-arid area. Two major water types are observed: (i) surface waters and upstream springs (least mineralized) and (ii) all groundwater samples (prevailing calcium and magnesium bicarbonate water type). Water isotopes show a low evaporation of precipitations during infiltration. Impoverishment in heavy isotopes is the characteristic of mountain rainfalls, or of a climate colder and wetter than present. Carbon-14 activities (34-94 pmc) indicate a long residence time. The artificial recharge is low compared to the reservoir volume, due to which the renewal rate is also low.

2011-07-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

381

Inhibitor effect on corrosion of titanium alloys in muriatic solutions of titanium-magnesium production

In the present study, element interdiffusions at the cofired interface of 9/1 Ag/Pd electrode and lead magnesium niobate (PMN)-based ferroelectrics were investigated using Auger Electron Spectroscopy (AES). Intense interdiffusions at the interface were observed while Ag and Pd could penetrate into the ceramics for about 1 {mu}m. Ag-doping experiments were carried out to further study the effects of Ag diffusion on electrical properties of the ceramics. The results showed that Ag could be incorporated into solid solution of the ceramics as Ag{sup +}. As a whole, the Curie temperature (Tc) and dielectric constant of the ceramics decreased with Ag addition. However, Ag addition had no obvious effect on the insulation resistivity. The results inferred that Ag{sup +} could substitute for Pb{sup 2+} at A site of ABO{sub 3} lattice, thereby oxygen vacancies were generated.

2003-05-25

382

Influence of annealing on the microstructure of commercial Mg alloy AZ31 after mechanical forming

Corrosion tests of titanium alloys VTI-0, OT4, VT5-1 and steel Kh18N1OT in 10% and 18% HCl with additions of carnallite at 40 deg C have been carried out. It has been established that titanium alloys in 10% and 18% HCl containing 5 and 10% carnallite are sufficiently corrosion resistant in the presence of 0.1-1% FeCl or HNO_3 and can be used for manufacturing the equipment of recirculation gas scrubbers. Steel Kh18N10T is unstable in all the media tested. It is subjected to intensive pitting. Specimens of steel Kh18N10T have also revealed edge cracking.

383

Improving the sheared edge in the blanking of commercial AZ31 sheet through texture modification

The microstructure of commercial rolled magnesium alloy AZ31B (nominal composition Mg-3Al-0.9Zn-0.15Mn in wt.%) was investigated with the help of light microscopy, electron backscatter diffraction (EBSD) and X-ray diffraction technique after annealing in the temperature range from room temperature (RT) to 400 deg. C. Tensile tests at RT were performed to show the influence of the microstructure on mechanical properties. Static recrystallization (SRX) was observed during annealing of as-received alloy at and above 150 deg. C. Twins play an important role during SRX and serve as nucleation sites and preferred paths for growth of grains. The strong basal texture caused by rolling was weakened by SRX. Significant differences in the stress strain curves were observed for as-received and annealed specimens.

2006-09-25

384

British Library Electronic Table of Contents (United Kingdom)

Commercial rolled magnesium sheets of alloys AZ31 (Mg-3 mass%Al-1 mass%Zn) and ZE10 (Mg-1 mass% Zn-<1 mass% Rare Earths) in O-temper condition were used for blanking experiments near room temperature. A serrated fracture surface can be observed in case of AZ31 but not in case of ZE10. During the shearing process of the AZ31 sheet, many micro cracks parallel to the sheet plane are generated in the shearing zone. These micro cracks lead to the formation of loose particles during the shearing operation, which interfere with further processing of the part and incur additional costs by increasing the scrap rate. It is found that the strong basal texture of this alloy is an important reason for the generation of such serrated cracks. In this paper a new method of selective texture modification i...

2011-01-01

385

Grain size effects on the tensile properties and deformation mechanisms of a magnesium alloy, AZ31B, sheet

Elimination of Separation Processes for Post-Consumer Polyolefin Waste: Reactive Blending Using 1,3-Phenylene Dimaleimide in Presence of Filler

The grain size dependence of the tensile properties and the deformation mechanisms responsible for those properties are examined for Mg alloy, AZ31B, sheet. Specifically, the Hall-Petch effect and strain anisotropy (r-value) are characterized experimentally, and interpreted using polycrystal plasticity modeling. {1 0 . 2} extension twins, {1 0 . 1} contraction twins, and so-called 'double-twins' are observed via microscopy and diffraction-based techniques, and the amount of twinning is found to increase with increasing grain size. For the sheet texture and tensile loading condition examined, {1 0 . 2} extension twinning is not expected, yet the polycrystal plasticity model predicts the observed behavior, including this 'anomalous' tensile twinning. The analysis shows that the Hall-Petch strength dependence, of the polycrystal as a whole, is primarily determined by the grain size dependence of the strength of the prismatic slip systems.

2008-07-15

386

British Library Electronic Table of Contents (United Kingdom)

A novel approach using reactive processing is explored that eliminates the labour-intensive separation of post-consumer polyolefin waste from the mixed plastics waste stream. The reactive compatibiliser BMI has been used to form a modified blend of PCPW with 40% improved tensile strength relative to the uncompatibilised control. Addition of 60 wt.-% magnesium hydroxide [Mg(OH)2] during reactive compatibilisation with BMI gave rise to an even more significant enhancement (up to 100%) of the tensile strength. BMI was also able to usefully enhance the properties of a composite based on calcium carbonate and the polyolefin waste.

2009-01-01

387

Double promotion of palladium/silica catalysts by iron and magnesium oxide in the synthesis of methanol from carbon monoxide and hydrogen

Corrosion and drug release properties of EN-plating/PLGA composite coating on MAO film

The structure and catalytic properties of 2 wt.-% Pd/SiO/sub 2/ catalysts promoted with 2 wt.-% MgO and 0.2-5 wt.-% iron have been investigated. Catalysts were characterized by TPR, hydrogen chemisorption, and Moessbauer spectroscopy and their catalytic performance in methanol formation was also measured. At 16 at.-% iron a sharp maximum was observed in the activity which can be interpreted as being due to simultaneous promotion with iron and MgO. Independent mechanisms of promotion were found for the two modifiers: iron influenced the metallic component by forming bimetallic PdFe particles while MgO changed the properties of silica in a favourable way. 6 figs., 29 refs., 1 tab.

1988-12-01

388

British Library Electronic Table of Contents (United Kingdom)

The electroless nickel plating/poly(dl-lactide-co-glycolide) composite coating (EN-plating/PLGA composite coating) was fabricated on the surface of the micro-arc oxidation (MAO) film of the magnesium alloy AZ81 to double control the corrosion and drug release in the hanks' solution. The EN-plating was fabricated on the MAO coating to improve the corrosion resistance by overlaying most pores and micro-cracks on the surface of the MAO film. Meanwhile, a double layered organic poly(dl-lactide-co-glycolide)/paclitaxel (PLGA/PTX) drug releasing coating with a top layered PLGA drug controlled releasing coating on EN plating was prepared to control the drug release rate by adjusting the different lactide: glycolide (LA:GA) ratio of PLGA. Scanning electron microscopy (SEM) and the X-ray powder dif...

2011-01-01

389

Chemical plant factors affecting resistance in sugarcane in against Scirpophaga Nivella f

Characterization of the deviation of the ideality of concentrated electrolytic solutions: plutonium 4 and uranium 4 nitrate salts study; Contribution a la caracterisation de l'ecart a l'idealite des solutions concentrees d'electrolytes: application aux cas de nitrates de plutonium (4) et d'uranium (4)

The study was conducted during 2000 to determine the role of various chemical plant factors viz., total minerals, nitrogen, fat contents, carbohydrate, macro an micro nutrients in the leaves of five genotypes of sugarcane i.e., BF-162, SPSG-26, L-118, CP-43/33 and CP-72/2086 by correlating the infestation of top borer, Scirpophaga Nivella F. at tillering stage. None of the genotype was found completely resistant to the pest. CP-43/33 and BF-162 proved susceptible and resistant varieties, respectively. Total mineral, manganese and copper contents did not show significant correlation with the pest infestation, whereas nitrogen, potassium, calcium, magnesium and ferrous contents played a positive and significant role. Phosphorous, carbohydrates, fats and zinc contents played a significant and negative effect on the pest infestation at tillering stage. (author)

390

Waste treatment process for removal of contaminants from aqueous, mixed-waste solutions using sequential chemical treatment and crossflow microfiltration, followed by dewatering

The purpose of this work was to establish a new binary data base by compiling the activity coefficients of plutonium and uranium at oxidation state +IV to better account for media effects in the liquid-liquid extraction operations implemented to reprocess spent nuclear fuel. Chapter 1: first reviews the basic thermodynamic concepts before describing the issues involved in acquiring binary data for the tetravalent actinides. The difficulties arise from two characteristics of this type of electrolyte: its radioactive properties (high specific activity requiring nuclearization of the experimental instrumentation) and its physicochemical properties (strong hydrolysis). After defining the notion of fictive binary data, an approach based on the thermodynamic concept of simple solutions is described in which the activity coefficient of an aqueous phase constituent is dependent on two parameters: the water activity of the system and the total concentration of dissolved constituents. The method ...

2000-07-01

391

Waste treatment process for removal of contaminants from aqueous, mixed-waste solutions using sequential chemical treatment and crossflow microfiltration, followed by dewatering

In processes of this invention aqueous waste solutions containing a variety of mixed waste contaminants are treated to remove the contaminants by a sequential addition of chemicals and adsorption/ion exchange powdered materials to remove the contaminants including lead, cadmium, uranium, cesium-137, strontium-85/90, trichloroethylene and benzene, and impurities including iron and calcium. Staged conditioning of the waste solution produces a polydisperse system of size enlarged complexes of the contaminants in three distinct configurations: water-soluble metal complexes, insoluble metal precipitation complexes, and contaminant-bearing particles of ion exchange and adsorbent materials. The volume of the waste is reduced by separation of the polydisperse system by cross-flow microfiltration, followed by low-temperature evaporation and/or filter pressing. The water produced as filtrate is discharged if it meets a specified target water quality, or else the filtrate is ...

1994-01-01

392

Two-nucleon multiplets near mass A = 88 and the implication for the residual nucleon-nucleon interaction

In processes of this invention aqueous waste solutions containing a variety of mixed waste contaminants are treated to remove the contaminants by a sequential addition of chemicals and adsorption/ion exchange powdered materials to remove the contaminants including lead, cadmium, uranium, cesium-137, strontium-85/90, trichloroethylene and benzene, and impurities including iron and calcium. Staged conditioning of the waste solution produces a polydisperse system of size enlarged complexes of the contaminants in three distinct configurations: water-soluble metal complexes, insoluble metal precipitation complexes, and contaminant-bearing particles of ion exchange and adsorbent materials. The volume of the waste is reduced by separation of the polydisperse system by cross-flow microfiltration, followed by low-temperature evaporation and/or filter pressing. The water produced as filtrate is discharged if it meets a specified target water quality, or else the filtrate is ...

1994-11-22

393

Two-nucleon multiplets near mass A = 88 and the implication for the residual nucleon-nucleon interaction

The low excitation energy spectroscopy of /sup 86/Sr, /sup 88/Sr, /sup 89/Sr, /sup 86/Rb, and /sup 87/Rb nuclear systems was studied via one-nucleon transfer reactions. The strontium isotopes, /sup 87/Sr and /sup 88/Sr, were used as targets in this study. Spectroscopic strengths were extracted from the measured transfer reaction cross sections and the distorted wave Born approximation (DWBA) analysis. Efforts have been made to accomplish a complete detection of spectroscopic strengths through the excitation energy region where levels can be resolved and identified. A shell model sum rule analysis is then made. Diagonal matrix elements for the effective two-nucleon interaction were deduced from empirical energy centroid. Matrix elements normalized by their empirical monopole energy was plotted against the semiclassical angle between two spins. They were compared with various analytical function forms of the effective two-nucleon interaction depending on their spins, ...

1987-01-01

394

Radiostrontium clearance and bone formation in response to simulated internal screw fixation

The low excitation energy spectroscopy of "8"6Sr, "8"8Sr, "8"9Sr, "8"6Rb, and "8"7Rb nuclear systems was studied via one-nucleon transfer reactions. The strontium isotopes, "8"7Sr and "8"8Sr, were used as targets in this study. Spectroscopic strengths were extracted from the measured transfer reaction cross sections and the distorted wave Born approximation (DWBA) analysis. Efforts have been made to accomplish a complete detection of spectroscopic strengths through the excitation energy region where levels can be resolved and identified. A shell model sum rule analysis is then made. Diagonal matrix elements for the effective two-nucleon interaction were deduced from empirical energy centroid. Matrix elements normalized by their empirical monopole energy was plotted against the semiclassical angle between two spins. They were compared with various analytical function forms of the effective two-nucleon interaction depending on their spins, isospins, and parities.

395

Propagation of an alkaline wave with a short contact time through an argilite sample from the Meuse-Haute Marne underground laboratory; Propagation d'une onde alcaline a temps de contact court a travers un echantillon d'argilite de l'est

Changes in radiostrontium clearance (SrC) and bone formation (tetracycline labeling) were observed in the femurs of skeletally mature dogs following the various operative steps involved in bone screw fixation. Drilling, but not periosteal stripping, produced a small but statistically significant increase in SrC and endosteal bone formation in the distal third of the bone. Strontium clearance values equivalent to those produced by drilling alone were recorded after screw fixation at low or high torque (5 versus 20 inch pounds), as well as by the insertion of loosely fitting stainless steel implants. Bone formation (equals the percentage tetracycline-labeled trabecular bone surfaces) was increased by 30% when SrC values exceeded 3.5 ml/100 g bone/min, and the relationship was linear when SrC values ranged between 1.0 and 7.0 ml/100 g bone/min. The changes in SrC and bone formation one-week after bone screw application are primarily those associated with a response to ...

1987-06-01

396

Preparation of multication #alpha#-SiAlON containing strontium

In the framework of the feasibility study of radioactive waste disposal in deep geologic formations, a clay formation (named 'argilite de l'Est') has been selected in the Meuse-Haute Marne region (France) for the construction of an underground laboratory. The percolation of alkaline solutions through the argilite has been studied using column experiments with short residence times (30 min). These experiments simulate the leaching of a cement which could be used in the building materials of the laboratory. The alkaline solutions used are mono-cationic solutions of calcium, sodium and strontium. The behaviour of calcium is differentiated from the other cations. For all alkaline solutions (NaOH, Ca(OH){sub 2} or Sr(OH){sub 2}) chemical reactions consuming both hydroxide ions and their associated cations have been evidenced. These reactions are heterogenous reactions of surface adsorption by site ionization. The calcium has a different ...

2001-07-01

397

Photo-induced transformation of close Frenkel pairs in strontium fluoride

The possibility of having Sr as an interstitial metal cation in #alpha#-SiAlON has been investigated in two systems: a single-cation system (Si_3N_4-SrO-AlN) and a multication system (Si_3N_4-(Y_2O_3/SrO/CaO)-AlN). It was found that Sr alone does not form #alpha#-SiAlON and that Sr could only be accommodated in #alpha#-SiAlON in conjunction with Y and Ca. The Sr content of #alpha#-SiAlON increased as the total content of (Y + Ca) increased and appeared to reach a limit at 0.5 at.%, or 0.15 atom per #alpha#-SiAlON. Unexpectedly, some of the #alpha#-SiAlON that contained (Sr + Y + Ca) was present as laths or fibers with the c-axis perpendicular to the hot-press direction.

398

IAEA RESEARCH CONTRACTS SECOND ANNUAL REPORT. Technical Reports Series No. 9

Laser-induced change is studied of the optical absorption and luminescence due to F-H pairs generated by an electron pulse in SrF_2. It is found that laser irradiation near 2.34 eV at a delay of 26 #mu#s after an electron pulse by which F-H pairs are generated reduces the component I of the pairs that has a decay time of 59 #mu#s and optical absorption bands at 2.34 and 4.13 eV and enhances the component II that has a decay time of 7.7 ms and has optical absorption bands at 2.7 and 3.35 eV. Laser irradiation near 2.7 eV at a delay of 4 ms after the electron pulse is found to induce the reverse reaction. Studies of dichroism of the laser-induced reduction and enhancement of the optical absorption bands and the luminescence reveal that the direction of the #SIGMA#-#SIGMA# transition of the F_2"- molecular ion is converted by the transformation from I to II and vice versa. It is suggested that the component I corresponds to the F-H pairs at nearest-neighbour and II to those at the ...

399

Enhanced sludge washing evaluation plan

Summaries are presented for those research contracts which expired between December 31, 1960 and December 31, 1981. Topics covered include: factors controlling distribution of fission products in biosphere, non-destructive methods of evaluating the U/sup 235/ and Pu content of irradiated fuel elements, studies of contamination in local marine resources, tracer studies of anemia, non-destructive analysis of irradiated fuel elements using a flux integrating monitor, mechanism of proteolysis of I/sup 131/-labeled fibrinogen, radiosensitivity of spermatogonia of Drosophila melel elements by gamma scanning, uptake and loss of radioactive material by marine bacteria, factors which influence the movement of radioactive strontium from soils to plants, biological concentration of fission products in mollusks from water, decay scheme of Tl/sup 210/, calcium balance in metabolic bone disease, development of radioactive drugs with special reference ...

1962-01-01

400

Electron affinity of strontium

The Tank Waste Remediation System (TWRS) Program mission is to store, treat, and immobilize highly radioactive Hanford Site waste (current and future tank waste and the strontium/cesium capsules) in an environmentally sound, safe, and cost-effective manner. The scope of the TWRS Waste Pretreatment Program is to treat tank waste and separate that waste into HLW and LLW fractions and provide additional treatment as required to feed LLW and HLW immobilization facilities. Enhanced sludge washing was chosen as the baseline process for separating Hanford tank waste sludge. Section 1.0 briefly discusses the purpose of the evaluation plan and provides the background that led to the choice of enhanced sludge washing as the baseline process. Section 2.0 provides a brief summary of the evaluation plan details. Section 3.0 discusses, in some detail, the technical work planned to support the evaluation of enhanced sludge washing. Section 4.0 briefly discusses the potential ...

1994-09-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

401

Effect of dysprosium doping on the optical properties of SrS:Dy,Cl phosphor

We have observed a threshold in the electron photodetachment cross section of {sup 88}Sr{sup {minus}} ions at a photon energy {ital h}{nu}=1.820 eV and assign it to a {ital p}-wave transition from the 5{ital s}{sup 2}5{ital p}{sup 2}{ital P} ground state in Sr{sup {minus}} to the 5{ital s}5{ital p}{sup 3}{ital P} state in neutral Sr. The measurement was made with a new technique combining the tunable laser photodetachment threshold method with accelerator mass spectrometry. We determine for the first time the electron affinity of Sr to be 48{plus_minus}6 meV, much smaller than predicted in recent calculations. The {sup 2}{ital P}{sub 1/2}-{sup 2}{ital P}{sub 3/2} fine splitting of the Sr{sup {minus}} ground state is estimated to be 26{plus_minus}8 meV.

1995-07-17

402

Dating techniques in fault investigations

The fundamental optical properties of dysprosium (Dy) doped strontium sulfide bulk samples for various dopant concentrations from 0.1 to 1.0 at.% were investigated by X-ray diffraction (XRD), electron paramagnetic resonance spectroscopy (EPR), room temperature photoluminescence (PL), photoluminescence excitation (PLE) and diffuse reflectance spectroscopy (DRS). Investigations by electron paramagnetic resonance yielded the state of Dy in the sample as Dy3+. An additional ESR line due to F+ center was observed. The PL emission spectrum consisted of several intense lines and a number of weaker ones which were identified as transitions between energy levels of Dy3+. The optimum doping concentration for maximum intensity was found to be 0.25 at.%. Blue shift of the absorption edge energy and red shift of the PLE spectrum were observed with increasing doping concentration. The former is due to Burstein-Moss (BM) effect and the latter is attributed due to the presence of ...

2010-08-13

403

Cross-section measurements for (n, 2a) (n, p) and (n, #alpha#) reactions on strontium isotopes at the neutron energy about 14 MeV

Determining the time of most recent fault movement is an important part of assessing a possible site for a nuclear power plant. The purpose of this paper is not to present research information but to provide a practical guide to some of the dating techniques available to the engineering geologist working on nuclear power plant siting. Emphasis is placed on the practical aspects, such as usable minerals, conditions necessary for them to yield correct dates, degree of accuracy, sample collection, sample size, and sample packaging. In this paper, the usual geologic field techniques are taken for granted (such as those used in stratigraphy, paleontology, and structural analysis) for assessing fault history. Laboratory techniques used in conjunction with or supplemental to field methods are discussed. The specific radiometric methods discussed are "1"4C(carbon-14), fission track, K-Ar (potassium-argon), thermoluminescense, Rb-Sr (rubidium-strontium), and U-Th ...

404

Actinide, strontium, and cesium removal from Hanford radioactive tank sludge

Cross-sections for "8"4Sr(n, 2n)"8"3Sr, "8"6Sr(n, 2n)"8"5"mSr, "8"6Sr(n, 2n)"8"5Sr, "8"8Sr(n, 2n)"8"7"mSr, "8"4Sr(n, p)"8"4Rb, "8"6Sr(n, p)"8"6Rb, "8"8Sr(n, p)"8"8Rb and "8"8Sr(n, #alpha#)"8"5"mKr reactions have been measured at neutron energies from 13.5 to 14.6 MeV using activation technique and by means of #gamma#-ray spectrometry. The neutron flux was determined using the monitor reaction "9"3Nb(n, 2n)"9"2"mNb and the neutron energies were measured by the method of cross-section ratios for "9Zr(n, 2n)"8"9Zr to "9"3Nb (n, 2n)"9"2"mNb reactions. The results of present work are compared with data published previously.

2006-01-01

405

FT-IR spectroscopic studies of methane adsorption on magnesium oxide

A pretreatment flowsheet was tested for separating key radionuclide components from the sludge stored in one of the high level waste tanks (B-110) at the Hanford Site; this sludge resulted primarily from the bismuth phosphate process, which was one of the three major plutonium separation processes used at Handford. This test involved (1) washing with water, (2) caustic leaching, (3) acid dissolution, (4) separation of transuranic elements (TRUs) by extraction with octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide(CMPO), (5) separation of Sr by extraction with di-t-butylcyclohexano-18-crown-6, (6) separation of Cs from the acid-dissolved sludge solution by treatment with ammonium molybdophosphate (AMP), and (7) separation of Cs from the sludge wash and caustic leach solutions by ion exchange using a phenol-formaldehyde resin (CS-100). The results of the radionuclide separation steps indicated that the proposed flowsheet is a viable approach to pretreating the sludge stored in ...

406

Materials used in new generation vehicles: supplies, shifts, and supporting infrastructure

Adsorpt1on of CH[sub 4] and coadsorption of CH[sub 4] and CO on differently treated magnesium oxide have been studied by FT-IR spectroscopy at 173-273 K. Five IR bands at 3008, 3000, 2900, 2890, and approximately 1306 cm[sup [minus]1] were observed when well-outgassed MgO was exposed to CH[sub 4] at 173 K. The bands at 3008 and 3000 cm[sup [minus]1] are assigned to a degenerate stretch vibration of CH[sub 4], and those at 2900 and 2890 cm[sup [minus]1] originate from an infrared-forbidden mode at 2917 cm[sup [minus]1] of free CH[sub 4]. These bands became noticeably stronger with the outgassing temperature of MgO but could be sufficiently reduced as MgO was pretreated in air or under water vapor. Adsorbed CO on MgO gives two IR bands at 2161 and 2155 cm[sup [minus]1] which exhibit a parallel variation with those bands of adsorbed CH[sub 4] with the different pretreatments of MgO. Coadsorption of CH[sub 4] and CO indicated that adsorbed CO can deplete part of the ...

1994-02-17

407

Solution conformations of CaCl sub 2 and Ca(NO sub 3 ) sub 2 complexes of chiral tetramethyl 18-crown-6 macrocycles: A 1D and 2D sup 1 H and sup 13 C NMR investigation

The Partnership for a New Generation of Vehicles (PNGV) program intends to develop new designs for automobiles that will reduce fuel consumption by two thirds but otherwise have price, comfort, safety, and other measures of performance similar to the typical automobile now on the market. PNGV vehicle designs are expected to substitute lightweight materials, such as aluminum, magnesium, carbon-reinforced polymer composites, glass-reinforced polymer composites, and ultra- light steel, for heavier materials such as steel and iron in automobile components. The target mass of a PNGV vehicle is 1,960 pounds, as compared to the average current vehicle that weights 3,240 pounds. Other changes could include the use of different ferrous alloys, engineering changes, or incorporation of advanced ceramic components. Widespread adoption of these vehicle designs would affect materials markets and require concurrent development and adoption of supporting technologies to supply the ...

1997-08-01

408

Wastewater treatment; Abwasserreinigung

One- and two-dimensional NMR techniques have been used to investigate the solution structures of (2S,6S,11S,15S)-2,6,11,15-tetramethyl-1,4,7,10,13,16-hexaoxacyclooctadecane (I) and (2R,3R,11R,12R)-2,3,11,12-tetramethyl-1,4,7,10,13,16-hexaoxyacyclooctadecane (II) macrocycle complexes of CaCl{sub 2} and Ca(NO{sub 3}){sub 2} in CDCl{sub 3}. Previous chiroptical studies of these and similar crown complexes by circularly polarized luminescence (CPL), total luminescence (TL), and circular dichroism (CD) spectroscopy have shown that the macrocycle asymmetric carbons in these complexes constrain the ring such that the sense of the ring twist in the S chiral ring complexes is opposite to that in the R chiral ring complexes. These studies have also shown that there is an added chirality element in the di- and trivalent (alkaline earth and lanthanide metal, respectively) nitrate complexes of I and II associated with the twist of the nitrate anions ...

1989-10-04

409

Thermal denitration and mineralization of waste constituents

The methods introduced for the field of cleaning waste water can be classified under various processes. Chemical oxidation is done with ozone, hydrogen peroxide and ultraviolet irradiation with subsequent biological decomposition. Another method is ultra-filtration with recovery of valuable materials or waste water ponds with algae biomass to decompose ammonium compounds, nitrates and phosphates. (EF) [Deutsch] Die auf dem Gebiet der Abwasserreinigung vorgestellten Methoden kann man in verschiedene Verfahren einordnen. Die chemische Oxidation erfolgt mit Ozon, Wasserstoff-Peroxid, UV Bestrahlung und anschliessenden biologischen Abbau. Eine andere Methode ist die Ultrafiltration mit Rueckgewinnung von Wertstoffen oder Abwasserteiche mit Algenbiomasse zum Abbau von Ammoniumverbindungen, Nitraten und Phosphaten. (EF)

1994-11-01

410

The solubilities of significant organic compounds in HLW tank supernate solutions

In order to produce a quality grout from LLW using hydraulic cements, proper conditioning of the waste is essential for complete cement curing. Several technologies were investigated as options for conditions. Since the LLW is dilute, removal of all, or most, of the water will significantly reduce the final waste volume. Neutralization of the LLW is also desirable since acidic liquids to not allow cement to cure properly. The nitrate compounds are very soluble and easily leached from solid waste forms; therefore, denitration is desirable. Thermal and chemical denitration technologies have the advantages of water removal, neutralization, and denitration. The inclusion of additives during thermal treatment were investigated as a method of forming insoluable waste conditions.

1997-08-01

411

The role of surfactant in synthesis of magnetic nanocrystalline powder of NiFe2O4 by sol-gel auto-combustion method

Large quantities of organic chemicals used in reprocessing spent nuclear-fuels at the Hanford Site have accumulated in underground high-level radioactive waste tanks. The organic content of these tanks must he known so that the potential for hazardous reactions between organic components and sodium nitrate/nitrite salts in the waste can he evaluated. The solubilities of organic compounds described in this report will help determine if they are present in the solid phases (salt cake and sludges) as well as the liquid phase (interstitial liquor/supernate) in the tanks. The solubilities of five significant sodium salts of carboxylic acids and aminocarboxylic acids [sodium oxalate, formate, citrate, nitrilotriacetate (NTA) and ethylendiaminetetraacetate (EDTA)] were measured in a simulated supernate solution at 25 degrees C, 30 degrees C, 40 degrees C, and 50 degrees C.

1994-08-21

412

British Library Electronic Table of Contents (United Kingdom)

In this work, a new sol-gel auto-combustion method has been performed to synthesize single phase nickel ferrite nanocrystalline powders by using n-cetyltrimethylammonium bromide, as a cationic surfactant. The gels were prepared from ferric and nickel nitrates and citric acid. Ammonia was used as pH adjusting agent as well. The effects of the surfactant on the after combustion calcination process and the reduction of the resulting powder crystallite size which affects the magnetic properties of the material were investigated by XRD and DTA/TGA techniques. The results showed that the ignition of the gels in air have a self-propagating behavior. Addition of surfactant to the starting solution affected the crystallite size of the synthesized powders and their phase constitution. The crystallit...

2008-01-01

413

The NCRP wound model: development and application.

Synthesis of ceramic powders by novel microwave-hydrothermal processing

The US National Council on Radiation Protection and Measurements, in collaboration with the International Commission on Radiological Protection, has been developing a biokinetic and dosimetric model for radionuclide-contaminated wounds. The finalised model is described briefly in this paper, together with the scientific basis and application. The multicompartment model uses first-order linear biokinetics to describe the retention and clearance of a radionuclide deposited in a wound site using seven default retention categories. Examples using plutonium nitrate in colloidal form and uranium in metal fragments show the behaviour of the less soluble forms of radionuclides in wounds, in which long-term retention is predicted. Using uranium as an example, the wound model is coupled to a uranium International Commission on Radiological Protection systemic model to predict urinary excretion patterns for different physicochemical forms of uranium. The latter application is ...

2007-08-31

414

Sensitive characteristics of BAMO/NMMO/AN propellants; BAMO/NMMO/AN kei suishinyaku no kando tokusei

Microwave-hydrothermal processing was compared with conventional hydrothermal processing in the crystallization of hematite from 1M ferric nitrate and hydroxyapatite from calcium oxide and phosphoric acid. Microwave-hydrothermal processing led to the crystallization of hematite while convention-hydrothermal process led to the crystallization of a mixture of goethite and hematite under the same temperature conditions. Thus the crystallization of hematite which is the stable iron oxide phase at high temperatures has been catalyzed by microwaves. Microwave-hydrothermal processing also led to highly crystalline hydroxyapatite powders compared to the conventional hydrothermal processing which also points to the catalytic role of microwaves. The microwave induced effects may be attributed to the generation of localized high temperatures at the reaction sites which enhance reaction rates.

1996-06-01

415

Recent activities of the nuclear fuel technology department of Cekmece Nuclear Research and Training Center

Very important performances in the practical use of solid propellants are combustion and physical properties. Among the present solid propellants, composite propellants used ammonium perchlorate (AP) as oxidizers are adopted widely now due to these excellent performances. Recently, a combination of ammonium nitrates (AN) as oxidizers and azido polymers as binders in expected as the propellants which control decrease of combustion properties and satisfy unsensitivity. However, in order to use these azido polymers/AN propellants in practice, further, it is necessary to improve the specific impulse and the burning rate. In this report, aiming to improve the combustion properties of BAMO/NMMO/AN propellants, the sensitivity and the combustion properties of propellants added high energetic plasticizers in binders, further, displaced a part of AN to cyclotetramethylenetetranitramine (HMX) and double based base-grain (BG) are described. 8 refs., 3 figs., 3 tabs.

1998-01-01

416

Properties of wood-plastic composites: effect of inorganic additives

The Nuclear Fuel Technology Department (NFTD) in CNRTC is a unique unit in Turkey in charge of performing all activities in nuclear fuel field. It has a pilot plant on uranium refining and conversion to UO{sub 2} since 1986. Presently, its R and D activities are focused on pellet manufacturing and characterization: UO{sub 2}, ThO{sub 2}and (Th,U)O{sub 2}. The studies on thorium dioxide fuel include to obtain ThO{sub 2} pellets from thorium nitrate and mixed (Th,U)O{sub 2} pellets. A study on evaluation of different fuel cycle options in accordance with nuclear energy planning in Turkey is also going on. (author)

1997-07-01

417

Preparation of AgCl Nanoparticles@Ancient Textile with Antibacterial Activity under Ultrasound Irradiation

Wood-plastic composites from Syrian tree species (white poplar, cypress tree, and white willow) were prepared using gamma-ray irradiation. Dry wood was impregnated with acrylamide or butylmethacrylate at various methanol compositions as the swelling solvent. Effect of inorganic additives and co-additives such as lithium nitrate (LiNO_3), copper sulfate (CuSO_4) and sulfuric acid (H_2SO_4), used at a very low concentration (1%), on the polymer loading (PL) and the compression strength (CS) was also investigated. It has been found that all the additives and co-additives, except Cu"2"+, increase the PL values and only Li"+ has a positive effect on CS. (Author)

2003-01-01

418

British Library Electronic Table of Contents (United Kingdom)

The growth of silver chloride nanoparticles on ancient textile was achieved by sequential dipping steps in alternating bath of potassium chloride and silver nitrate under ultrasound irradiation. The effect of ultrasound irradiation and sequential dipping steps in growth of the AgCl nanoparticles has been studied. These systems depicted a decrease in the particles size accompanying a decrease in the sequential dipping steps. The samples were characterized with powder X-ray diffraction (XRD) and scanning electron microscopy. XRD analyses indicated that the prepared AgCl nanoparticles on fiber were crystalline. The textile samples containing AgCl nanoparticles were tested for their antibacterial efficacy against Escherichia coli and were found to possess significant antibacterial activity.

2011-01-01

419

Preparation and applications of novel fluoroalkyl end-capped vinyltrimethoxysilane oligomer/hydroxyapatite nanocomposites

British Library Electronic Table of Contents (United Kingdom)

Novel fluoroalkyl end-capped vinyltrimethoxysilane oligomer/hydroxyapatite (HAp) nanocomposites were prepared by the reaction of calcium nitrate tetrahydrate and phosphoric acid in the presence of the corresponding oligomer. These fluorinated oligomer/HAp composites thus obtained are nanometer size-controlled fine particles (83-173 nm), and were found to exhibit good dispersibility in methanol, ethanol, and isopropyl alcohol. These fluorinated HAp nanocomposites were applied to the surface modification of glass and poly(methyl methacrylate) (PMMA) to exhibit good hydro- and oleophobic characteristics imparted by fluorine on their surface. In addition, the surface structural changes of the modified polyethylene terephtalate and PMMA films treated with these fluorinated nanocomposites before...

2009-01-01

420

Mechanical wounding induces a nitrosative stress by down-regulation of GSNO reductase and an increase in S-nitrosothiols in sunflower (Helianthus annuus) seedlings

British Library Electronic Table of Contents (United Kingdom)

Nitric oxide (NO) and related molecules such as peroxynitrite, S-nitrosoglutathione (GSNO), and nitrotyrosine, among others, are involved in physiological processes as well in the mechanisms of response to stress conditions. In sunflower seedlings exposed to five different adverse environmental conditions (low temperature, mechanical wounding, high light intensity, continuous light, and continuous darkness), key components of the metabolism of reactive nitrogen species (RNS) and reactive oxygen species (ROS), including the enzyme activities L-arginine-dependent nitric oxide synthase (NOS), S-nitrosogluthathione reductase (GSNOR), nitrate reductase (NR), catalase, and superoxide dismutase, the content of lipid hydroperoxide, hydrogen peroxide, S-nitrosothiols (SNOs), the cellular level of N...

2011-01-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

421

Influence of some chemical compounds on germination and early seedling growth of two range species under allelopathic conditions

British Library Electronic Table of Contents (United Kingdom)

Seed priming technique has been known to improve germination and seedling emergence under different environment stresses. The objective of this study was to evaluate the effectiveness of seed priming in improving the seed germination and seedling vigor of Agropyron elongatum and Bromus inermis in response to five concentrations of the allelopathic extract of Thymus kotschyanus (0, 5%, 25%, 50% and 75%) under laboratory conditions. Pretreatments included gibberellic acid (250, 500 and 1000 ppm), potassium nitrate (0.1%, 0.2% and 0.3%) and salicylic acid (100, 200 and 300 mg/L). This experiment was carried out as a factorial experiment based on a completely randomized design with four replications. The results showed that seed germination, germination speed and seedling vigor were significan...

2011-01-01

422

In situ synthesis of silver chloride nanoparticles into bacterial cellulose membranes

British Library Electronic Table of Contents (United Kingdom)

In situ synthesis of silver chloride (AgCl) nanoparticles was carried out under ambient conditions in nanoporous bacterial cellulose (BC) membranes as nanoreactors. The growth of the nanoparticles was readily obtained by alternating dipping of BC membranes in the solution of silver nitrate or sodium chloride followed by a rinse step. X-ray diffraction (XRD) patterns indicated the existence of AgCl nanoparticles in the BC and scanning electron microscopy (SEM) images showed that the AgCl nanoparticles well dispersed on the surface of BC and penetrated into the BC network. The AgCl nanoparticle-impregnated BC membranes exhibited high hydrophilic ability and strong antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). The preparative proced...

2009-01-01

423

Impregnation of silver nanoparticles into bacterial cellulose for antimicrobial wound dressing

British Library Electronic Table of Contents (United Kingdom)

Bacterial cellulose was produced by Acetobacter xylinum (strain TISTR 975). Bacterial cellulose is an interesting material for using as a wound dressing since it provides moist environment to a wound resulting in a better wound healing. However, bacterial cellulose itself has no antimicrobial activity to prevent wound infection. To achieve antimicrobial activity, silver nanoparticles were impregnated into bacterial cellulose by immersing bacterial cellulose in silver nitrate solution. Sodium borohydride was then used to reduce the absorbed silver ion (Ag+) inside of bacterial cellulose to the metallic silver nanoparticles (Ag0). Silver nanoparticles displayed the optical absorption band around 420nm. The red-shift and broadening of the optical absorption band was observed when the mole rat...

2008-01-01

424

Gadolinium (III) chelates of O, N-donor Schiff bases derived from 2, 3-dimethyl-4-formyl-1-phenyl-3-pyrazoline-5-one and certain aromatic amines

FB-Line resin testing final report

New Schiff base chelating ligands were synthesized by reacting equimolar quantities of 2,3-dimethyl-4-formyl-1-phenyl-3-pyrazoline-5-one and o-anisidine, p-anisidine, m-anisidine, o-toluidine, p-toluidine, m-toluidine, 2,6-xylidine or 2,4-xylidine in ethanol medium. Their subsequent reaction with gadolinium (III) nitrate hexahydrate in 2:1 molar ratio gave complexes that were characterized by elemental analyses, molar conductances, magnetic measurements, electronic and I.R. spectral studies. All the chelates were found to be non-electrolytic in nature. (author). 15 refs., 1 fig., 1 tab.

1994-01-01

425

FB-Line resin testing final report

The Dowex 50W-X8 and 50W-Xl2 resin samples are both strong acid cation materials in the hydrogen form. Each material has a water retention capacity characteristic of its respective marketed degree of cross-linking. Dowex 21K gives confirmatory responses to tests for a strong anion exchange resin in the nitrate form. All three resins have the manufacturer's specified ionic type and form, and the Dowex 50W resins have characteristic water retention capacities. These tests conclude that the ion exchange resins in use in FB-Line meet the approved safety document criteria for cross-linking, ionic form, and resin type.

1992-01-23

426

Extraction of rare earths by carbonic acids melts

The Dowex 50W-X8 and 50W-Xl2 resin samples are both strong acid cation materials in the hydrogen form. Each material has a water retention capacity characteristic of its respective marketed degree of cross-linking. Dowex 21K gives confirmatory responses to tests for a strong anion exchange resin in the nitrate form. All three resins have the manufacturer`s specified ionic type and form, and the Dowex 50W resins have characteristic water retention capacities. These tests conclude that the ion exchange resins in use in FB-Line meet the approved safety document criteria for cross-linking, ionic form, and resin type.

1992-01-23

427

Energy saving in existing buildings. Experiences with 'Therma' buildings. Energieeinsparung im Bestand. Erfahrungen mit den Therma-Bauten

Extraction of rare earths (La, Ce, Pr, Eu, Gd, Er, Yb) from nitrate solutions by melts of carboxylic acids of the C/sub 17/-C/sub 20/ fraction and stearic acid with paraffin, depending on the temperature (60-90 deg), phase contact time and their volume ratio (O:B from 1:5 up to 1:100), pH of the aqueous phase (2-6), rare earth concentration (10/sup -6/-10/sup -3/ m) is studied. It is shown that in the whole concentration range investigated rare earths are extracted quantitatively into the carboxylic acid melt of C/sub 17/-C/sub 20/ fraction at the equilibrium value of pH>=3.8, while into the melt of 0.1 M stearic acid in paraffin at pH>=4.5.

1980-10-01

428

Effect of some reducing and complexing agents on the extraction behavior of technetium in the TBP-HNO3 system

A number of buildings dating from the 1950s and 1960s were retrofitted with thermal insulation in order to cut energy consumption. This took place within the building competition 'Therma' nitrated by the Federal Ministry of Regional Planning, Building and Town Planning in 1974. Result at that time were so encouraging that now, 15 years later the results were checked again with special attention to the long-term performance of the thermal insulation measures. Laboratory tests prove that the building materials are still in good condition and that humidity has not increased with age. Cracks in the surface plaster of the compound insulation systems occurred at different frequencies and intensities and usually caused by thermal tensions. (BWI).

1992-04-01

429

British Library Electronic Table of Contents (United Kingdom)

The effect of a series of complexing and reducing agents on the extraction-chemical behavior of technetium as applied to extraction splitting of uranium and plutonium in the Purex process was examined. Kinetic parameters of the catalytic decomposition of N2H5NO3 under the action of Tc in the presence of these agents were evaluated. Variation of the ratio of the oxidized and reduced Tc species in the course of the process and in the hydrazine-free systems was determined. Reagents preventing oxidation of the reduced technetium and decomposition of N2H5NO3 in nitric acid solutions (acetohydroxamic acid, hydroxylamine, ascorbic acid, etc.), inhibiting the reduction of Tc with hydrazine nitrate (H2O2, HN3, etc.), and known as complexing agents toward quadrivalent actinides but indifferent to Tc...

2011-01-01

430

Development of anion-exchange resins for separations of actinides

Cleansing of soils and underground waters in Japan; La depollution des sols et des eaux souterraines au Japon

The evolution of these new ion-exchange resins hinges upon an understanding of the chemistry of actinide metal complexes as they exist in solution and when interacting with the cationic sites. Molecular modeling of electrostatic interactions between the metal complex and the cationic substrate is used to help visualize uptake mechanisms and, eventually, to predict optimized coordination sites. Thus, these new materials integrate the fields of ion-specific chelation and ion-exchange technology. Synthesized resins contain cationic sites designed to facilitate the uptake of plutonium nitrato complexes from high-nitrate solutions, and they exhibit distribution coefficients that are up to 10 times higher than those observed for commercial resins. Additionally, some new resins show surprisingly large Kd`s for anionic complexes of Am(III) and U(VI).

1997-12-31

431

Bioconvertion of spent cellulose sausage casings

Japanese companies have developed suitable cleansing technologies and export their know-how. Some original technologies are developed today, like: in-situ chemical oxidation, iron confinement, hot-soil process, low-temperature catalytic decomposition or dechlorination of dioxins. However, some pollutions are still poorly considered (nitrates) or badly mastered (dioxins). This situation is partly due to late legal decisions and to limited pollution abatement measures. Japan is also very active in bio-cleansing research, and this, despite the lack of dialogue and directives at the national level. Several research programs with important funds have started since 1995. However, Japan is still at the preliminary stage in open-field applications of cleansing methods. (J.S.)

1999-11-01

432

British Library Electronic Table of Contents (United Kingdom)

Cellulose sausage cellulose casings are used extensively in the manufacture of sausages in meat packaging. After stripping the meat, spent casings mainly contain cellulose and residual meat juice with salt, nitrate and nitrite. Disposal of spent sausage casings has serious economic and environmental concerns for the sausage industry. This work describes bioconversion of spent cellulose casings (SCC) into enzymes, lactic acid and ethanol by using cellulolytic fungi, lactobacillus and yeasts. The solid substrate cultivation (SSC) of Trichoderma reesei RUT C-30 on SCC and blends gave a maximum of 152 filter paper cellulase (FPase) activity and about 100 carboxymethylcellulase activity (CMCase)/g dry weight substrate. The SSC produced enzyme-rich casing with 50 FPase when directly mixed as suc...

2008-01-01

433

Bactericidal effects of different silver-containing materials

British Library Electronic Table of Contents (United Kingdom)

The evaluation of the bactericidal effect of different silver-containing materials where silver is available as Ag^+ (silver nitrate and different silver-exchanged zeolites), as metallic Ag^0 (commercial silver nanoparticles) or as oxide (silver (I) oxide) was carried out in order to elucidate the importance of the bioavailability of silver (i.e., as free ions, metallic particles, combination of them, clusters, complexes, partially soluble or insoluble salts, etc.) on its bactericidal action. For the different materials tested, their bactericidal effect is ordered in the following sequence: AgNO"3>Ag-ZSM-5>Ag"2O>commercial silver-exchanged zeolite (granular)>commercial silver-exchanged zeolite (pellets)>Ag nanoparticles. In general, as the content of bioavailable ionic silver increases, th...

2011-01-01

434

Antimicrobial silver-montmorillonite nanoparticles to prolong the shelf life of fresh fruit salad

British Library Electronic Table of Contents (United Kingdom)

In this work, silver-montmorillonite (Ag-MMT) antimicrobial nanoparticles have been obtained by allowing silver ions from nitrate solutions to replace the Na^+ of natural montmorillonite and then to be reduced by a thermal treatment. Ag-MMT were used as active antimicrobial compounds to improve the shelf life of fresh fruit salad. In order to assess their influence on product shelf life, sensorial and microbiological quality has been monitored during the storage. The microbiological quality was determined by monitoring the principal spoilage microorganisms (mesophilic and psychrotrophic bacteria, coliforms, lactic acid bacteria, yeasts and molds). Additionally, the evolution of sensorial quality was assessed by monitoring color, odor, firmness and product overall quality. The Ag-MMT nanopa...

2011-01-01

435

Anion capture with calcium, aluminium and iron containing layered double hydroxides

British Library Electronic Table of Contents (United Kingdom)

The competitive adsorption of nitrate, chloride and carbonate in layered double hydroxides (LHD) with the general formula Formula Not Shown was investigated. Both normal ion exchange by exposure to a solution containing different anions, as well as addition of calcined material to solution thereby exploiting the memory effect of LDHs was studied. Changes in the interlayer anion changed the interlayer spacing of the LDH. The order of preference of intercalation was Formula Not Shown . When multiple anions were present in the exchange solution, LDHs with several distinct interlayer spacing were produced indicating that LDHs with different anions in the interlayer existed at the same time. However for extended exchange times (14days) where high concentrations of carbonate anion were present, ...

2011-01-01

436

Some properties of explosive mixtures containing peroxides

Off-gas behavior in the Harvest pot vitrification process

This study concerns mixtures of triacetone triperoxide (3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexoxonane, TATP) and ammonium nitrate (AN) with added water (W), as the case may be, and dry mixtures of TATP with urea nitrate (UN). Relative performances (RP) of the mixtures and their individual components, relative to TNT, were determined by means of ballistic mortar. The detonation energies, E_0, and detonation velocities, D, were calculated for the mixtures studied by means of the thermodynamic code CHEETAH. Relationships have been found and are discussed between the RP and the E_0 values related to unit volume of gaseous products of detonation of these mixtures. These relationships together with those between RP and oxygen balance values of the mixtures studied indicate different types of participation of AN and UN in the explosive decomposition of the respective mixtures. Dry TATP/UN mixtures exhibit lower RP than analogous mixtures TATP/AN ...

2008-06-15

437

Off-gas behavior in the HARVEST pot vitrification process

The conversion of highly radioactive waste liquor into glass by the pot vitrification process has been studied at Harwell using a full-scale inactive pilot plant. A summary of the off-gas behavior and its interpretation is presented. Experimental runs were carried out on 3 representative wastes (MAGNOX - thermal reactor, metal fuel, THORP - thermal oxide fuel and PFR - fast reactor oxide fuel) using 2 methods of feeding the glass-formers (slurry and crizzle). Materials were carried over from the vitrification vessel into the off-gas system by entrainment supplemented by volatilization. The overall behavior of the off-gas was consistent with the presence in it of 5 separate aerosols of particulate matter. Sources of entrainment gave rise to 3 aerosols, and a further 2 aerosols were formed as a result of chemical reaction (Ru) and condensation (Cs) processes involving the volatile species. Entrainment was enhanced when the feed contained free alkali nitrate. The Ru ...

1983-06-01

438

Microbial water diversion technique-designed for near well treatment in low temperature sandstone reservoirs in the North Sea

A summary of the off-gas behavior in the HARVEST pot vitrification process is presented. Experimental runs were carried out on 3 representative wastes (MAGNOX - thermal reactor, metal fuel, THORP - thermal oxide fuel and PFR - fast reactor oxide fuel) using 2 methods of feeding the glass-formers (slurry and crizzle). Materials were carried over from the vitrification vessel into the off-gas system by entrainment supplemented by volatilization. The main volatile elements were Ru, B, Cs. Some volatility was also shown by Na and Li. The overall behavior of the off-gas was consistent with the presence in it of 5 separate aerosols of particulate matter. Sources of entrainment gave rise to 3 aerosols, and a further 2 aerosols were formed as a result of chemical reaction (Ru) and condensation (Cs) proceses involving the volatile species. Entrainment was enhanced when the feed contained free alkali nitrate. The Ru volatility correlated directly with the amount of salt ...

1983-06-01

439

Microbial oxidation of soluble sulfide in produced water from the Bakkeen Sands

A Norwegian Research Program on Improved Oil Recovery (IOR) in North Sea reservoirs was launched in 1992. Microbial methods, applied in this context, is a part of this program. The scope, the methodological approach, and results from the three first years are presented. Water profile control, using biomass to block high permeable zones of a reservoir, has been investigated using nitrate-reducing bacteria in the injected sea water as plugging agents. Emphasis has been put on developing a process that does not have disadvantages secondary to the process itself, such as souring and impairment of the overall injectivity of the field. Data from continuous culture studies indicate that souring may successfully be mitigated by adding nitrite to the injected seawater. The morphology and size of generic-nitrate-reducing seawater bacteria have been investigated. Screening of growth-promoting nutrients has been carried out, and some sources were detected ...

1995-12-31

440

Ion-exchange scheme for selective removal of gadolinium nitrate from the moderator system of 540 MWe Indian PHWRs using macroporous strong acid cation and macro porous weak base anion resins

The presence of soluble sulfide in produced water results in problems for the petroleum industry due to its toxicity, odor, corrosive nature, and potential for wellbore plugging. Sulfide oxidation by indigenous nitrate-reducing bacteria (NRB) present in brine collected from wells at the Coleville Unit (CVU) in Saskatchewan, Canada, was investigated. Sulfide oxidation took place readily when nitrate and phosphate were added to brine enrichment cultures, resulting in a decrease in sulfide levels of 99-165 ppm to nondetectable levels (< 3.3 ppm). Produced water collected from a number of producing wells was screened to determine the time required for complete sulfide oxidation, in order to select candidate wells for treatment. Three wells were chosen, based on sulfide removal in 48 hours or less. These wells were treated down the backside of the annulus with a solution containing 10 mM KNO{sub 3} and 100 {mu}M NaH{sub 2}PO{sub 4}. Following a ...

1995-12-31

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

441

Investigating the applicability of anions as indicators for verification of consistency of declarations

Gadolinium nitrate has been employed in Indian nuclear reactors for the first time as soluble neutron poison in the heavy water moderators of the 540 MWe PHWRs TAPS 3 and 4, as a fast acting secondary shut down system (SDS-2); and also for reactivity shim. For this purpose, the moderator purification system is currently equipped with special ion-exchange columns/schemes, developed by present authors. However, for gadolinium removal from moderator in the post SDS-2 scenario, the two stage ion-exchange - cation bed operation followed by mixed bed operation - results in low pH conditions persisting in the moderator for a few hours, which gives rise to certain operational problems. The present paper describes a mixed bed ion-exchange scheme employing macro-porous strong acid cation and macro-porous weak base anion resins, which has been developed to eliminate acidic conditions and gives a better pH control. The cation to anion capacity ratio in the mixed bed was ...

2008-12-01

442

Final report on low-cycle fatigue and creep-fatigue testing of salt-filled alloy 800 specimens

Full text: Nuclear material is subjected to chemical processing throughout the entire fuel cycle. Traces of the chemical reagents and solvents are left behind in the nuclear material. So far essentially metallic impurities or light elements have been investigated for their potential in providing clues on the type of process they originate from. In the present investigation, the applicability of anions for attributing nuclear material to a certain chemical process has been investigated. Anions (e.g. nitrate, sulphate, phosphate, chloride) originate from acids or salt solutions that are used for processing of solutions containing uranium or plutonium. The study presented in this paper focuses on yellow cake samples originating from different mines applying different chemical processes for leaching, dissolving and precipitating the uranium. Consequently, the anionic patterns should be different. The concentrations of different anionic species were measured by ion ...

2006-10-16

443

Evolution of nitrogen oxide(s) during in vivo nitrate reductase assay of soybean leaves

Uniaxial low-cycle fatigue and creep-fatigue tests have been carried out on hollow alloy 800 specimens that were either filled with air or with a molten mixture of sodium nitrate, potassium nitrate and an oxidizer. Low-cycle fatigue tests were carried out at 1200/sup 0/F and 650/sup 0/F by cycling the strain continuously between equal mangitude of tensile and compressive values at a rate of 4 x 10/sup -3/sec/sup -1/ until failure. The creep-fatigue tests were carried out at 1200/sup 0/F. The loading cycle differed from that of low-cycle fatigue testing only in the imposition of a hold at the peak compressive strain in each cycle. Cracks always initiated on the inner surface of the hollow specimen, and therefore, corrosive effects on crack propagation and initiation were controlled by the environment within the specimen cavity. In common with tests carried out earlier on steam-filled alloy 800 specimens, at 1200/sup 0/F in the presence of molten ...

1982-05-01

444

Trace metal characterization of the U-Al matrix by atomic spectroscopy

Studies were conducted to quantitate the evolution of nitrogen oxides (NO/sub (x)/) from soybean (Glycine max (L.) Merr.) leaves during in vivo nitrate reductase (NR) assays with aerobic and anaerobic gas purging. Anaerobic gas purging (N/sub 2/ and argon) consistently resulted in greater NO/sub (x)/ evolution than did aerobic gas purging (air and O/sub 2/). The evolution of NO/sub (x)/ was dependent on gas flow rate and on NO/sub 2//sup -/ formation in the assay medium; although a threshold level of NO/sub 2//sup -/ appeared to exist beyond which the rate of NO/sub (x)/ evolution did not increase further. The loss of NO/sub (x)/ from in vivo NR assays under gas purging explains partially, but not stoichiometrically, the decrease of NO/sub 2//sup -/ accumulation in in vivo NR assay medium with young soybean leaves. The lack of stoichiometry between NO/sub (x)/ evolution and apparent NO/sub 2//sup -/ loss suggests that other mechanisms are also involved in loss of ...

1981-12-01

445

Study on the correlation between chemical and mineral composition of coal ashes; Sekitanbaibun no kobutsu soseigakuteki kento kagakubutsu sosei to kobutsugakuteki sosei no sokan

Uranium-aluminum alloys with a significant enrichment of uranium with "2"3"3U or "2"3"5U serve as nuclear fuels in research reactors. The quality assurance of this fuel requires, among other things, precise knowledge that all trace metal constituents that affect neutron economy, fuel integrity, and fuel fabrication process parameters are well within the specification limits. Trace metal characterization of "2"3"5U-Al alloy has been carried out by atomic spectrometry. The trace metal constituents of interest are grouped into common metals (silver, boron, calcium, cadmium, cobalt, chromium, copper, iron, magnesium, manganese, molybdenum, sodium, nickel, lead, silicon, tin, titanium, vanadium, tungsten, and zinc) and lanthanides (cerium, dysprosium, europium, gadolinium, holminium, lutetium, samarium, and terbium). The elements yttrium and zirconium are grouped with the latter in view of the chemical separation procedure used. The alloy samples are dissolved in 6 M ...

446

Role of minerals in carbonaceous adsorbents for removal of Pb(II) ions from aqueous solution

Coal ash is a substance that has been mixed into minerals in the earth`s crust during their coalification process. Estimation was made on what kinds of mineral composition have been mixed into coals. Noted first was the kinds of compounds contained in the ash, wherein the ratios of mass in the compounds and minerals were correlated, and selection was made on minerals which are thought correlated. The selection criterion was based on minerals containing silica, alumina, iron oxide, lime and magnesium as compounds. Then, a phase equilibrium line diagram was used to estimate compositions and melting points of minerals which are thought to have been produced from these compounds. By comparing the estimation with the measured melting points of the ashes, mineral compositions thought reasonable were all selected. Assumption was possible on minerals that are thought to have been transferred into coal ash. Compound indications of ashes from 29 kinds of the world`s typical ...

1996-10-28

447

Results of in-house cone-cup testing of low to high temperature SPF-alloys

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

2005-11-01

448

Microstructure evolution and fracture behavior in superplastic deformation of hot-rolled AZ31 Mg alloy sheet

Material testing of SPF-sheet is usually done with coupon hot tensile testing. The optimum range of strain rates is determined with stepped strain tests. To overcome the problem of very few available testing facilities and time consuming and costly procedure, cone cup testing has been developed since long. This test can be generated directly in the workshop, no machining of samples is necessary and it is very much related to the real SPF-process. The analysis of suitable temperature and strain rate is done by simple measurement of resulting cone height. This paper describes a unique and novel variant of the above mentioned baseline design. It provides on-line data of the actual status of the cone cup forming resulting from the applied, constant pressure. Strain rate variations as a result from texture or from the alloy-related behaviour is detectable. Thinning and ''hardening'' behaviour of different alloys up to maximum failure strain can be ...

2004-07-01

449

Kinetics of complexing activation by the magnesium ion on green crab (Scylla serrata) alkaline phosphatase.

Fine-grained AZ31 magnesium alloy sheets were prepared through hot rolling process. The superplastic properties of hot-rolled AZ31 Mg alloy was examined by uniaxial tensile tests at a temperature range 250{proportional_to}450 C and strain rate range 0.7 x 10{sup -3}{proportional_to}1.4 x 10{sup -1} s{sup -1}. Optical and scanning electronic microscope (SEM) were used to observe the microstructure evolution and fracture behavior in superplastic deformation of AZ31 Mg alloy and the values of deformation activation energy at various temperatures were calculated. It is demonstrated that, the hot-rolled AZ31 alloy begins to exhibit superplasticity from 300 C and a maximum elongation of 362.5% is obtained at 400 C and 0.7 x 10{sup -3} s{sup -1}. In the temperature range 300{proportional_to}400 C, the dominant superplastic deformation mechanism is grain boundary sliding (GBS) controlled by grain boundary diffusion and the influence of temperature on the fracture behavior ...

2005-07-01

450

Formation of high resistivity regions in [ital p]-type Al[sub 0. 5]In[sub 0. 5]P by ion implantation

As with mammalian enzymes, green crab (Scylla serrata) alkaline phosphatase can be activated by Mg2+ through a time-dependent course. The activation is mainly a Vmax effect. Tsou's method was used to study the kinetic course of activation. The results show that the enzyme was activated by a complexing scheme that had not been previously identified: the enzyme first reversibly and quickly binds Mg2+ and then undergoes a slow reversible course to activation, with a relatively high activation energy (78 +/- 4 kJ/mol) and a slow conformational change. The activation reaction is a single molecule reaction, and the apparent activation rate constant is independent of Mg2+ concentration if the concentration is sufficiently high. The microscopic rate constants of activation and the association constant were determined from the measurements. The proposed scheme may also be applied to the Mg2+ activation mechanism for mammalian enzyme, to explain why the activation rate is time-dependent and not ...

2001-01-01

451

Flue gas desulfurization pilot study. phase i. survey of major installations. report no. 95. summary of survey reports on flue gas desulfurization processes

Ion implantation has been applied to magnesium-doped Al[sub 0.5]In[sub 0.5]P to produce high resistivity regions for the first time. Hydrogen, oxygen, and argon ions were implanted at a base dose ranging from 5[times]10[sup 12] to 5[times]10[sup 14] cm[sup [minus]2] and annealed from 400 to 900 [degree]C. Hydrogen did not appreciably compensate the In[sub 0.5]Al[sub 0.5]P layer while oxygen and argon produced sheet resistances up to 1[times]10[sup 9] [Omega]/[open square]. After annealing at 800 [degree]C, regions with high dose oxygen implants maintained a sheet resistance above 1[times]10[sup 7] [Omega]/[open square], while regions with high dose argon implants recovered most of the unimplanted conductivity.

1993-12-06

452

Enhancing stability of austenitic stainless steels to intergranular corrosion in strongly-oxidising media by regulating composition of impurities

Appendices to this summary consist of twelve individual status reports that will be available through the National Technical Information Service (NTIS) in the United States and of course limited copies will be available through NATO. The twelve report titles which are appendices to the summary are: (A) Status Report on the Limestone/Sludge Flue Gas Desulfurization Process; (B) Status Report on the Lime/Sludge Flue Gas Desulfurization Process; (C) Status Report on the Double Alkali/Sludge Flue Gas Desulfurization Process; (D) Status Report on the Sea Water Scrubbing Flue Gas Desulfurization Process; (E) Status Report on the Limestone/Gypsum Flue Gas Desulfurization Process; (F) Status Report on the Lime/Gypsum Flue Gas Desulfurization Process; (G) Status Report on the Double Alkali/Gypsum Flue Gas Desulfurization Process; (H) Status Report on Flue Gas Desulfurization by Scrubbing with Dilute Sulfuric Acid; (I) Status Report on the Magnesium Oxide Flue Gas ...

1979-01-01

453

Electrochemical corrosion behavior of AZ91D alloy in ethylene glycol

Separate effect of impurities and alloying additions of phosphorus, silicon, boron, carbon, sulphur, magnesium, copper, aluminium and molybdenum on the tendency to intergranular corrosion (IGC) of quenched highly pure steel Fe-20% Cr-20Ni in boiling solution 27% HNO_3+40 g/l Cr"6"+, as well as in sulphuric and nitric acids mainly at potentials, corresponding to repassivation range, has been studied. It is shown that steel susceptibility to IGC depends on impurity nature and to a high extent is determined by the potential value independent of the way of its achieving. The most unfavourable effect on stability of grain boundaries is produced by microadditions of boron as well as by impurities of phosphorus and silicon. To ensure increased corrosion resistance of the investigated steel against IGC in highly oxidative media the pontent of phosphorus and silicon impurities unit should not exceed 0.01 and 0.2% respectively. At that, boron introduction into steel as a ...

1984-01-01

454

Electrochemical corrosion behavior of AZ91D alloy in ethylene glycol

The effect of concentration on the corrosion behavior of Mg-based alloy AZ91D was investigated in ethylene glycol-water solutions using electrochemical techniques i.e. potentiodynamic polarization, electrochemical impedance measurements (EIS) and surface examination via scanning electron microscope (SEM) technique. This can provide a basis for developing new coolants for magnesium alloy engine blocks. Corrosion behavior of AZ91D alloy by coolant is important in the automotive industry. It was found that the corrosion rate of AZ91D alloy decreased with increasing concentration of ethylene glycol. For AZ91D alloy in chloride >0.05 M or fluoride <0.05 M containing 30% ethylene glycol solution, they are more corrosive than the blank (30% ethylene glycol-70% water). However, at concentrations <0.05 for chloride or >0.05 M for fluoride containing ethylene glycol solution, some inhibition effect has been observed. The corrosion of AZ91D alloy ...

2009-11-01

455

Effect of Li-Al co-doping on the energy gaps of MgB2

The effect of concentration on the corrosion behavior of Mg-based alloy AZ91D was investigated in ethylene glycol-water solutions using electrochemical techniques i.e. potentiodynamic polarization, electrochemical impedance measurements (EIS) and surface examination via scanning electron microscope (SEM) technique. This can provide a basis for developing new coolants for magnesium alloy engine blocks. Corrosion behavior of AZ91D alloy by coolant is important in the automotive industry. It was found that the corrosion rate of AZ91D alloy decreased with increasing concentration of ethylene glycol. For AZ91D alloy in chloride >0.05 M or fluoride 0.05 M for fluoride containing ethylene glycol solution, some inhibition effect has been observed. The corrosion of AZ91D alloy in the blank can be effectively inhibited by addition of 0.05 mM paracetamol that reacts with AZ91D alloy and forms a protective film on the surface at this concentration as confirmed by surface ...

2009-11-01

456

Drying characteristics and nitrogen loss of biogas digestate during drying process

We studied the effects of co-doping with Li and Al on the energy gaps of MgB2 by performing point-contact Andreev-reflection spectroscopy (PCAR) in polycrystalline Mg1-x(Al?Li1-?)xB2 samples with x?0.4. Even though the lattice parameters and the critical temperature of the compound simply scale with the effective Al content ?x, irrespective of the Li concentration, the energy gaps do not. In particular, for a given effective Al content, the comparison with Mg1-y(Al)yB2 with y = ?x shows that the ? bandgap is practically the same while the ? bandgap is higher. A clear gap merging is observed in the most doped sample (x = 0.4) when Tc<20 K. The results are discussed within the two-band Eliashberg theory and compared to the outcomes of first-principles calculations of the effects of Li and Al co-doping on the electronic structure of magnesium diboride.

2009-02-01

457

Crystal structure of ball-milled mixture of sodium chloride and magnesium chloride-ethanol adduct

The cost of transporting biogas digestate can be decreased by reducing its water content. However, the digestate emits volatile compounds during drying. This study investigated the drying behaviour and the change of digestate composition. Drying took place in a hybrid solar/waste-heat dryer that used solar energy as well as waste heat from a combined heat and power unit (CHP) and the exhaust air of a microturbine. The experiment involved the use of 60 t of liquid digestate. Climatic conditions were measured inside and outside the drying hall. Dry matter (DM) and organic dry matter (ODM) were also measured on a daily basis. In addition, the energy consumption of waste and solar heat were recorded and related to the quantity of dried feedstock. The total nitrogen, ammonium, phosphate, potassium oxide, magnesium oxide and calcium oxide in the digestate were subjected to chemical analysis before and after the drying process. Losses of nitrogen were calculated. Specific ...

2010-07-01

458

Salt decontamination demonstration test results

NaCl doped MgCl_2.nEtOH adducts were prepared by ball-milling MgCl_2.2.5EtOH with NaCl. Both the ball-milled MgCl_2.nEtOH/NaCl mixture and pure MgCl_2.2.5EtOH adducts were analyzed by X-ray diffraction (XRD), transmission electron microscope (TEM), thermogravimetry (TG) and differencial scanning calorimetry (DSC). A simple MgCl_2.nEtOH/NaCl mixture without ball-milling treatment was also studied for comparison. Two kinds of mixed crystals, Na_2MgCl_4 and NaMgCl_3, were found to be formed in a ball-milled mixture that contained 16 mol.% NaCl. TG and DSC analysis of the samples also provided indirect evidences supporting the presence of the mixed crystals in the ball-milled mixture. Adding certain amounts of NaCl in MgCl_2.2.5EtOH adduct, either by co-milling or by simple mixing, greatly increased the thermal stability of the adduct, but thermal decomposition behaviour of the ball-milled mixture was still different from that of a simple mixture.

2008-02-05

459

SUPPLEMENTAL COLUMBIA RIVER PROTECTION ACTIVITIES AT THE DEPARTMENT OF ENERGY HANFORD SITE: 2006 TECHNICAL PEER REVIEW

The Salt Decontamination Demonstration confirmed that the precipitation process could be used for large-scale decontamination of radioactive waste sale solution. Although a number of refinements are necessary to safely process the long-term requirement of 5 million gallons of waste salt solution per year, there were no observations to suggest that any fundamentals of the process require re-evaluation. Major accomplishments were: (1) 518,000 gallons of decontaminated filtrate were produced from 427,000 gallons of waste salt solution from tank 24H. The demonstration goal was to produce a minimum of 200,000 gallons of decontaminated salt solution; (2) cesium activity in the filtrate was reduced by a factor of 43,000 below the cesium activity in the tank 24 solution. This decontamination factor (DF) exceeded the demonstration goal of a DF greater than 10,000; (3) average strontium-90 activity in the filtrate was reduced by a factor of 26 to less than 10"3 d/m/ml versus ...

460

Preparation and biodistribution of yttrium-90 lipiodol in rats following hepatic arterial injection

Prompted by a $10 million Congressional allocation to identify supplemental actions to protect the Columbia River from groundwater contamination beneath the Hanford Reservation, the U. S. Department of Energy (DOE) Environmental Management (EM) Office of Clean-up Technology identified twenty-three potential technical projects and then down-selected ten of these for further evaluation. An independent expert peer review was conducted for the ten down-selected proposals. The review panel consisted of twenty-three recognized subject matter experts that broadly represented academia, industry, and federal laboratories. Of the initial ten proposals reviewed, one was given unconditional support, six were given conditional support, and three were not supported as proposed. Three additional proposals were then submitted by DOE for review--these proposals were structured, in part, to respond to the initial round of technical peer review comments. Peer reviews of these additional proposals ...

2006-12-20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

461

Liquid radwaste processing with spiral wound reverse osmosis

We labelled Lipiodol with yttrium-90 and analysed the biodistribution in rats after intrahepatic arterial injection. An RP-18 column was used to separate {sup 90}Y from strontium-90. {sup 90}Y was retained on the column, which had been pretreated with yttrium-selective extraction reagent, di(2-ethylhexyl) phosphate, while {sup 90}Sr was washed out. A hexadentate nitrogen-donor chelating ligand N,N,N`,N`-tetrakis(2-benzymidazolylmethyl)-1,2-ethanediamine (EDTB) was synthesized by condensation of 1,2-benzenediamine and ethylene diamine tetra-acetic acid (EDTA). Lipiodol was covalently conjugated with EDTB. The final product was obtained by eluting the retained {sup 90}Y from the RP-18 column with EDTB-Lipiodol. Sixteen male rats (Sprague-Dawley) were sacrificed at 1 h, 24 h, 48 h and 72 h (four rats at each time) after injection of approximately 0.1 mCi {sup 90}Y-Lipiodol via the hepatic artery. Samples of liver, spleen, muscle, lung, kidney, bone, whole blood and ...

1995-03-01

462

Investigation of selected trace elements as nuclear forensics signatures

Two different reverse osmosis systems were investigated. The first was a 50-element plant-scale system that is used to treat 2200 m"3 of AECL liquid radwastes annually.It uses thin-film composite (TFC) membranes and operates at an applied pressure of 2760 kPa, with a fixed crossflow of about 40 L/min. The other system uses the same thin-film composite membranes for waste processing but is a two-element pilot-scale system. It is operated at pressures m ranging between 1500 and 7000 kPa, at a fixed crossflow of 55 L/min. The average lifetime of the thin-film composite membranes in the plant-scale processing application at AECL is about 3000 h. After this service life has expired the rejection efficiency declines rapidly from 99.5% to about 95% as the membranes become impaired from chemical cleaning procedures that are required after each 100 m"3 of waste is treated. The permeation flux for the plant-scale system decreases from about 2.2 L/min/element to below 0.5 L/min/element at the end ...

1996-02-25

463

Immobilization of strontium, cesium and rhenium into #alpha#-SiAlON ceramics assisted with co-doping of yttrium

Nuclear material is either a product of technological processing of natural source material or it is entirely of anthropogenic origin. Consequently, nuclear material carries 'tool-marks' or 'fingerprints' of the process it was subjected to. Uranium fuels are examples of the first category, while plutonium belongs to the second category. The nature of these production processes is reflected in the elemental and isotopic composition of the material as well as in its microscopic and macroscopic appearance. All of these parameters can be determined using appropriate analytical techniques and they may result in important conclusions on the history and on the origin of the material. Therefore, they provide the most essential contribution to the prevention of future diversions of nuclear material from the same source. So far, essentially metallic impurities or light elements have been investigated for their potential in providing clues either on the type of process they originate from or on ...

464

Evaluation of a novel radiopacifiying agent on the physical properties of surgical spineplex.

Immobilization of long-lived fission products (LLFP) such as radioactive Tc, Cs and Sr into #alpha#-SiAlON ceramics was evaluated using stable isotopes instead of radioactive isotopes, and the applicability of #alpha#-SiAlON ceramics as the inert matrix for transmutation of LLFP was investigated. In the case of single addition of SrO, SrCO_3, Cs_2CO_3 or ReO_2 to the starting materials, #alpha#-SiAlON, single phase was not formed after hot-pressing. When Y_2O_3 was added with SrO, SrCO_3 or Cs_2CO_3 to the starting materials (#alpha#-Si_3N_4, AlN and #alpha#-Al_2O_3) in optimum compositions, #alpha#-SiAlON single phase was obtained after hot-pressing at 1700degC or 1800degC. From the EDS analysis, Sr and Y were detected from grains. It is suggested that Y would assist the expansion of interstices of #alpha#-SiAlON lattice, resulting in the incorporation of Sr"2"+ into #alpha#-SiAlON lattice. In the case of Cs addition with Y, Cs was not incorporated into interstices due to much larger ...

2008-06-01

465

Elastic recoil detection analysis of ferroelectric films

Polymethlylmethacrylate (PMMA) is the most frequently used cement for percutaneous vertebroplasty and kyphoplasty. To aid visualisation during surgery cements are doped with radiopacifying agents such as Barium sulphate (Ba(2)SO(4)) or Zirconium Dioxide (ZiO(2)). Mounting research suggests that these agents may impair the biocompatibility of the cements. However, incorporating an alternative radiopacifier agent with excellent biocompatibility would be a significant step forward. Bioactive radiopaque glasses incorporating elements such as strontium (Sr) and zinc (Zn), known to have beneficial and therapeutic effects on bone, are of great interest in this respect. In this study, the Ba(2)SO(4) of the commercially available Spineplex was incrementally replaced with a radiopaque therapeutic glass composition. The resulting effects on cement setting time, peak isotherm, ultimate compressive strength, Young's modulus (up to 30 days cement maturation) and radiopacity were ...

2009-08-18

466

Effect of various coal contaminants on the performance of solid oxide fuel cells: Part I. Accelerated testing

There has been considerable progress in developing SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub O.7}Sr{sub O.3}TiO{sub 3} (BST) ferroelectric films for use as nonvolatile memory chips and for capacitors in dynamic random access memories (DRAMs). Ferroelectric materials have a very large dielectric constant ( {approx} 1000), approximately one hundred times greater than that of silicon dioxide. Devices made from these materials have been known to experience breakdown after a repeated voltage pulsing. It has been suggested that this is related to stoichiometric changes within the material. To accurately characterise these materials Elastic Recoil Detection Analysis (ERDA) is being developed. This technique employs a high energy heavy ion beam to eject nuclei from the target and uses a time of flight and energy dispersive (ToF-E) detector telescope to detect these nuclei. The recoil nuclei carry both energy and mass information which enables the determination of separate energy spectra ...

1996-12-31

467

Chemical evolution of formation waters in the Palm Valley gas field, Northern Territory

The contaminants that are potentially present in the coal-derived gas stream and their thermochemical nature are discussed. Accelerated testing was carried out on Ni-YSZ/YSZ/LSM solid oxide fuel cells (YSZ: yttria stabilized zirconia and LSM: lanthanum strontium manganese oxide) for eight main kind of contaminants: CH{sub 3}Cl, HCl, As, P, Zn, Hg, Cd and Sb at the temperature range of 750-850 C. The As and P species, at 10 and 35 ppm, respectively, resulted in severe power density degradation at temperatures 800 C and below. SEM and EDX analysis indicated that As attacked the Ni region of the anode surface and the Ni current collector, caused the break of the current collector and the eventual cell failure at 800 C. The phosphorous containing species were found in the bulk of the anode, they were segregated and formed ''grain boundary'' like phases separating large Ni patches. These species are presumably nickel ...

2009-09-05

468

X-ray diffraction analysis of corrosion products of Fe-Ni-Cr alloys formed in molten nitrate salts

The chemical composition and evolution of formation waters associated with gas production in the Palm Valley field, Northern Territory, has important implications for reservoir management, saline water disposal, and gas reserve calculations. Historically, the occurrence of saline formation water in gas fields has been the subject of considerable debate. A better understanding of the origin, chemical evolution and movement of the formation water at Palm Valley has important implications for future reservoir management, disposal of highly saline water and accurate gas reserves estimation. Major and trace element abundance data suggest that a significant component of the highly saline water from Palm Valley has characteristics that may have been derived from a modified evaporated seawater source such as an evaporite horizon. The most dilute waters probably represent condensate and the variation in the chemistry of the intermediate waters suggests they were derived from a mixture of the ...

469

THOR Bench-Scale Steam Reforming Demonstration

Chemical phase identifications of complex, multilayered corrosion products formed on Fe-Ni-Cr alloys immersed in molten NaNO/sub 3/-KNO/sub 3/ and LiNO/sub 3/-NaNO/sub 3/-KNO/sub 3/ were obtained by X-ray diffraction analysis. Diffraction analyses performed after successive material removal steps provided depth profiles of corrosion products and identified the dominant phases as NaFeO/sub 2/, Fe/sub 3/O/sub 4/, and Cr/sub 2/O/sub 3/ for Alloy 800 and 316SS after immersion in NaNO/sub 3/-KNO/sub 3/. In LiNO/sub 3/-NaNO/sub 3/-KNO/sub 3/, the major corrosion products identified on Alloy 800 were LiFeO/sub 2/, Fe/sub 3/O/sub 4/, and Cr/sub 2/O/sub 3/. X-ray diffraction results were supplemented by electron microprobe analyses that revealed the solid solution nature of several of the oxide phases.

1984-08-01

470

Subcritical measurements using the /sup 252/Cf source-driven neutron noise analysis method

The Idaho Nuclear Technology and Engineering Center (INTEC) was home to nuclear fuel reprocessing activities for decades at the Idaho National Engineering and Environmental Laboratory. As a result of the reprocessing activities, INTEC has accumulated approximately one million gallons of acidic, radioactive, sodium-bearing waste (SBW). The purpose of this demonstration was to investigate a reforming technology, offered by THORsm Treatment Technologies, LLC, for treatment of SBW into a ''road ready'' waste form that would meet the waste acceptance criteria for the Waste Isolation Pilot Plant (WIPP). A non-radioactive simulated SBW was used based on the known composition of waste tank WM-180 at INTEC. Rhenium was included as a non-radioactive surrogate for technetium. Data was collected to determine the nature and characteristics of the product, the operability of the technology, the composition of the off-gases, and the fate of key radionuclides ...

2003-05-21

471

Remediation of contaminated agricultural soils near a former Pb/Zn smelter in Austria: Batch, pot and field experiments

This paper describes recent measurements of the subcritical neutron multiplication factor using the /sup 252/Cf source-driven neutron noise analysis method. This work was supported by a program of collaboration between the United States Department of Energy and the Power Reactor and Nuclear Fuel Development Corporation of Japan related to the development of fast breeder technology. The experiment reported consists of a configuration of two interacting tanks of uranyl nitrate aqueous solution with different uranium concentrations in each tank. The /sup 252/Cf-source-driven neutron noise analysis method obtains the subcriticality from the signals of three detectors: the first, a parallel plate ionization chamber with /sup 252/Cf electroplated on one of its plates that is located in or near the system containing the fissile material, and produces an electrical pulse for every spontaneous fission that occurs and thereby serves as a timed source of fission neutrons; and ...

1985-01-01

472

Radon concentrations and absorbed dose measurements in a Pleistocenic cave

Metal contaminated crops from contaminated soils are possible hazards for the food chain. The aim of this study was to find practical and cost-effective measures to reduce metal uptake in crops grown on metal contaminated soils near a former metal smelter in Austria. Metal-inefficient cultivars of crop plants commonly grown in the area were investigated in combination with in-situ soil amendments. A laboratory batch experiment using 15 potential amendments was used to select 5 amendments to treat contaminated soil in a pot study using two Barley (Hordeum vulgare L.) cultivars that differed in their ability to accumulate cadmium. Results from this experiment identified 3 of these amendments for use in a field trial. In the pot experiment a reduction in ammonium nitrate extractable Cd (<41%) and Pb (<49%) compared to the controls was measured, with a concurrent reduction of uptake into barley grain (Cd < 62%, Pb < 68%). In the field extractable fractions ...

2006-11-01

473

Preparation of CaWO{sub 4}:Ln{sup 3+} SiO{sub 2} (Ln=Tb, Dy and Ho) nanoparticles by a combustion reaction and their optical properties

Radon concentration measurements were carried out using solid-state nuclear track-etch detectors (SSNTDs) type CA 80-15 cellulose nitrate films, in a Pleistocenic cave at Petralona, in Halkidiki, Northern Greece, at 55 km from the city of Thessaloniki. Radon levels as high as 88 kBqxm"-"3 (2.38 nCi x l"-"1) have been recorded inside the cave equivalent to 11.90 WL in terms of occupational exposure to radon and its decay products. Absorbed dose rates were performed using TL dosimeters, type TLD-200 (CaF_2-Dy) in a continuous monitoring program (integrated measurements). Dose rate levels as high as 110 nGy x h"-"1 were recorded inside the cave. In interpreting the high levels of radiation doses, radioactivity measurements regarding the naturally occurring "2"3"8U, "2"3"2Th and "4"0K radionuclides were carried out in various speleothems found at different sites in the cave. (author)

2003-10-01

474

Preparation of CaWO_4:Ln"3"+ SiO_2 (Ln=Tb, Dy and Ho) nanoparticles by a combustion reaction and their optical properties

The CaWO{sub 4}:Ln{sup 3+} SiO{sub 2} (Ln=Tb, Dy and Ho) nanoparticles were synthesized via a combustion process at 800 {sup o}C, using citric acid as chelating agent and fuel, ammonium nitrate as fuel, boric acid as flux material and silica as supports. The persistent phosphor nanoparticles were characterized by X-ray diffraction (XRD), reflectance UV-vis and fluorescence spectroscopy (PL) and transmission electron microscopy (TEM) techniques. XRD patterns indicated that crystalline calcium tungstate with scheelite structure was produced. The reflectance UV-vis spectra showed the broad absorption band of WO{sub 4}{sup 2-} groups and the PL spectra showed the WO{sub 4}{sup 2-} wide excitation band, broad emission band of WO{sub 4}{sup 2-} and characteristic emissions of Ln{sup 3+} ions. The average particle sizes were determined by TEM, which are about 50 nm.

2010-11-15

475

Preparation and characterization of lithium-ion-conductive Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} thin films by the solution deposition

The CaWO_4:Ln"3"+ SiO_2 (Ln=Tb, Dy and Ho) nanoparticles were synthesized via a combustion process at 800 "oC, using citric acid as chelating agent and fuel, ammonium nitrate as fuel, boric acid as flux material and silica as supports. The persistent phosphor nanoparticles were characterized by X-ray diffraction (XRD), reflectance UV-vis and fluorescence spectroscopy (PL) and transmission electron microscopy (TEM) techniques. XRD patterns indicated that crystalline calcium tungstate with scheelite structure was produced. The reflectance UV-vis spectra showed the broad absorption band of WO_4"2"- groups and the PL spectra showed the WO_4"2"- wide excitation band, broad emission band of WO_4"2"- and characteristic emissions of Ln"3"+ ions. The average particle sizes were determined by TEM, which are about 50 nm.

2010-11-01

476

Preparation and characterization of lithium-ion-conductive Li_1_._3Al_0_._3Ti_1_._7(PO_4)_3 thin films by the solution deposition

Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} thin films were successfully prepared by the solution deposition using lithium acetate, aluminum nitrate, ammonium dihydrogen phosphate and titanium butoxide as starting materials. The structure, surface morphology, electrochemical window, and ionic conductivity of the films were studied by X-ray diffraction, scanning electron microscopy, cyclic voltammetry and AC impedance. The results showed that Li{sub 1.3}Al{sub 0.3}Ti{sub 1.7}(PO{sub 4}){sub 3} thin films annealed between 750 deg. C and 900 deg. C prepared by this method were well crystallized, homogenous and crack-free. The electrochemical window was beyond 2.4 V and the ionic conductivity was approximately 1.57x10{sup -5} S/cm at room temperature for the film annealed at 800 deg. C for 30 min.

2003-02-03

477

Photocatalytic activities of AgSbO3 under visible light irradiation

Li_1_._3Al_0_._3Ti_1_._7(PO_4)_3 thin films were successfully prepared by the solution deposition using lithium acetate, aluminum nitrate, ammonium dihydrogen phosphate and titanium butoxide as starting materials. The structure, surface morphology, electrochemical window, and ionic conductivity of the films were studied by X-ray diffraction, scanning electron microscopy, cyclic voltammetry and AC impedance. The results showed that Li_1_._3Al_0_._3Ti_1_._7(PO_4)_3 thin films annealed between 750 deg. C and 900 deg. C prepared by this method were well crystallized, homogenous and crack-free. The electrochemical window was beyond 2.4 V and the ionic conductivity was approximately 1.57x10"-"5 S/cm at room temperature for the film annealed at 800 deg. C for 30 min.

2003-02-03

478

British Library Electronic Table of Contents (United Kingdom)

A novel visible light sensitive photocatalyst, AgSbO3 was prepared by a conventional solid-state reaction method. This oxide belonging to a cubic-pyrochlore structure can absorb visible light with wavelength up to about 480nm. From the band structure calculation, we found that the top of the valence band consists of the hybridized Ag 4d and O 2p orbitals and the bottom of the conduction band mainly consists of the Ag 5s and the Sb 5s orbitals. Photocatalytic activities were evaluated using O2 evolution from an aqueous silver nitrate solution and decomposition of gaseous 2-propanol under visible light irradiation. We found that AgSbO3 shows a higher O2 evolution activity than WO3 and 2-propanol can be mineralized by the AgSbO3 photocatalysis under visible light irradiation.

2008-01-01

479

Passivation behavior of SUS 304 stainless steel in neutral solutions at elevated temperature

Oxidation and chromium depletion of Alloy 800 and 316SS by molten NaNO/sub 3/-KNO/sub 3/ at temperatures above 600/degree/C

Cyclic voltammograms of SUS 304 stainless steel in various neutral solutions such as Na_2SO_4 at high temperature were measured, as a successive study to previous report in which effects of temperature and pH on polarization behavior of stainless steel were studied. In this measurement Ag/AgCl reference electrode and platinum counter electrode were used in a static autoclave lined with inconel. Passive films formed in various conditions were analysed by electron diffraction and Auger spectroscopy. Results obtained were compared with anodic behavior of iron, chromium and nickel and with thermodynamical stabilities of their compounds. The main results are summarized as follows. (1) Stainless steel shows such electrochemical behavior as active dissolution, passivation and transpassivation in a deaerated neutral solution at 250"0C after fully reductive treatment of the specimen. In air-saturated solution, the peak of active dissolution is not observed. In the passive range there are ...

1981-01-01

480

Microrheological Studies of Regenerated Silk Fibroin Solution by Video Microscopy

The corrosion behavior of Alloy 800 and Type 316 stainless steel in molten NaNO/sub 3/-KNO/sub 3/ was studied at temperatures from 605/degree/C to 630/degree/C. Corrosion behavior was significantly different from that previously reported in nitrate melts at temperatures up to 600/degree/C and involved a combination of oxidation, internal nitridation and sodium metallate formation. Corrosion kinetics, determined metallographically, switched from a parabolic to a linear rate equation as temperature increased. Corrosion was uniform and resulted in metal losses on the order of 100 micronsyear at 630/degree/C. Among the alloying elements, chromium was depleted from the alloy as the result of a basic fluxing process. The kinetic equations describing chromium depletion also changed from parabolic to linear with increasing temperature. The effect of the equilibrium chemistry of the melt on the corrosion behavior of the alloys is analyzed and possible corrosion mechanisms ...

1987-01-01

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

481

CERN Document Server

We have carried out studies on the rheological properties of regenerated silk fibroin (RSF) solution using video microscopy. The degummed silk from the Bombyx mori silkworm was used to prepare RSF solution by dissolving it in calcium nitrate tetrahydrate-methanol solvent. Measurements were carried out by tracking the position of an embedded micron-sized polystyrene bead within the RSF solution through video imaging. The time dependent mean squared displacement (MSD) of the bead in solution and hence, the complex shear modulus of this solution was calculated from the bead's position information. An optical tweezer was used to transport and locate the bead at any desired site within the micro-volume of the sample, to facilitate the subsequent free-bead video analysis. We present here the results of rheological measurements of the silk polymer network in solution over a frequency range, whose upper limit is the frame capture rate of our camera, at full resolution. By ...

2007-01-01

482

Microaerophilic growth and induction of the photosynthetic reaction center in Rhodopseudomonas viridis

Measurement of oxidation rate of sulfite in rain water in Yokohama, Japan

Rhodopseudomonas viridis was grown in liquid culture at 30 degrees C anaerobically in light (generation time, 13 h) and under microaerophilic growth conditions in the dark (generation time, 24 h). The bacterium could be cloned at the same temperature anaerobically in light (1 week) and aerobically in the dark (3 to 4 weeks) if oxygen was limited to 0.1%. Oxygen could not be replaced by dimethyl sulfoxide, potassium nitrate, or sodium nitrite as a terminal electron acceptor. No growth was observed anaerobically in darkness or in the light when air was present. A variety of additional carbon sources were used to supplement the standard succinate medium, but enhanced stationary-phase cell density was observed only with glucose. Conditions for induction of the photosynthetic reaction center upon the change from microaerophilic to phototrophic growth conditions were investigated and optimized for a mutant functionally defective in phototrophic growth. R. viridis ...

1989-05-01

483

Local and regional ozone production: Chemistry and transport

In recent years, the influences of acid rain such as the acidification of lake water, on bio-system by the heavy metals from effluent of soils with acid rain and also on the structural materials of buildings are seriously discussed. Sulfur and nitrogen that are contained in fossil fuels are released into the atmosphere by the fuel combustion as their oxides dissolve in rain drops as sulfite and nitrous ions, where they are further oxidized into sulfate and nitrate ions These ions lower the pH of rain water resulting so-called acid rain. Therefore, it is important to accurately determine these ions in rain water for the investigation of reality of acid rain. However, it is not easy to accurately determine these ions, especially for sulfite ions in rain water, since they are quickly oxidized by the catalytic action of metallic ions such as ferric and manganous ions. And light, temperature, pH of solution and also species and concentrations of dissolved metallic ions ...

1986-04-01

484

Influence of hormones and medium components on expression of dipyranocoumarins in cell suspension cultures of Calophyllum inophyllum L.

The EUROTRAC sub-project ''Tropospheric Ozone Research'' (TOR) follows a dual strategy: - Observation of the chemical processes contributing to the oxygen balance directly in the atmosphere; - Establishment of a validated data base for model calculations. Both tasks require simultaneous measurements of a wide range of chemical and meteorological components. In the case of the investigation of the chemical processes, it is also desirable to measure the free radicals directly involved in ozone production. In the project described, a measuring station was set up. For a period of two years and a half, continuous measurements were made of ozone and its chemical precursors (NO, NO_2, NO_y, VOC, CO), as well as other photooxidants (H_2O_2 and organic hydroperoxides, organic nitrates), the photolysis frequency of NO_2, and meteorological parameters (wind, temperature, moisture, aerosols). The station was located on the Schauinsland mountain in the southern Black Forest, at ...

485

British Library Electronic Table of Contents (United Kingdom)

Cell suspension cultures were initiated separately from leaf and nodal/internodal calluses for the study of influence of hormones and medium components on biomass growth and expression of dipyranocoumarins. Highest 6.2 times biomass was enhanced in suspension cultures of nodal/internodal callus supplemented with threefold total sulphate. Picloram 8.28mM along with BAP 8.88mM enhanced 295.05 times inophyllum A in suspension cultures of leaf callus whereas IBA 14.70mM along with BAP 4.44mM in suspension cultures of leaf callus enhanced 1065 times inophyllum B. IBA 4.90mM alone in suspension cultures of nodal/internodal callus enhanced maximum 616 times inophyllum C. Only IBA 9.80mM in suspension cultures of leaf callus enhanced 23.22 times inophyllum P. Variation in nitrate and sulphate had ...

2009-01-01

486

In situ studies with Asian clams (Carbacula fluminea) detect acid mine drainage and nutrient inputs in low-order streams

In Situ Remediation Integrated Program: FY 1994 program summary

This study evaluates the correlation between transplanted Asiatic clam and indigenous community responses to acid mine drainage and nutrient loading in first-to-third-order streams, by comparing the toxicological endpoints of clam survival and growth with benthic macro-invertebrate community indices as community responses to both acid mine drainage and nutrient loading. Clam survival was found to be positively correlated with water column pH and negatively correlated with conductivity and metal concentrations. There was also a positive correlation with the relative abundance of the macro-invertebrate Ephemeroptera, the most sensitive taxonomic group, to acid mine drainage in this watershed. No correlation was found between clam growth and acid mine drainage inputs, but there was evidence of positive correlation with nitrate concentrations and the relative abundance of collector-filterer functional feeding groups. These results suggest that clam growth is related to ...

2001-03-01

487

Improvement of wood quality used in Syria by irradiation polymerization

The US Department of Energy (DOE) established the Office of Technology Development (EM-50) as an element of the Office of Environmental Management (EM) in November 1989. In an effort to focus resources and address priority needs, EM-50 introduced the concept of integrated programs (IPs) and integrated demonstrations (IDs). The In Situ Remediation Integrated Program (ISR IP) focuses research and development on the in-place treatment of contaminated environmental media, such as soil and groundwater, and the containment of contaminants to prevent the contaminants from spreading through the environment. Using in situ remediation technologies to clean up DOE sites minimizes adverse health effects on workers and the public by reducing contact exposure. The technologies also reduce cleanup costs by orders of magnitude. This report summarizes project work conducted in FY 1994 under the ISR IP in three major areas: treatment (bioremediation), treatment (physical/chemical), and containment ...

1995-04-01

488

Hanford low-level waste process chemistry testing data package

Wood plastic composites (WPC) have been prepared with five low-grade woods, native to Syria, and with Okoume (aucoumea klaineana pierre) imported to Syria in large quantities. Three monomer systems; acrylamide, butylmethacrylate, and styrene were used. polymerization was induced at various radiation doses (10, 20, and 30 kGy) to study the role of radiation doses using a "6"0Co gamma radiation source. Some physical properties of WPC, namely polymer loading and compression strength or tensile strength of the obtained wood polymer composites (WPC) were studied. The effect of the additives, sulfuric acid (H"+), N-vinyl pyrrolidone (NVP), trimethyolpropane triacrylate (TMPTA), urea (U), lithium nitrate (LiNo_3), copper sulfate (CuSO_4) and co-additives on monomer system polymerization were also investigated. Methanol, water and water/methanol mixtures were used as the swelling agents. In general, the use of additives and co-additives brought about an enhancement of ...

2010-04-01

489

Groundwater quality assessment plan for single-shell tank waste management Area U at the Hanford Site

Recently, the Tri-Party Agreement (TPA) among the State of Washington Department of Ecology, U.S. Department of Energy (DOE) and the US Environmental Protection Agency (EPA) for the cleanup of the Hanford Site was renegotiated. The revised agreement specifies vitrification as the encapsulation technology for low level waste (LLW). A demonstration, testing, and evaluation program underway at Westinghouse Hanford Company to identify the best overall melter-system technology available for vitrification of Hanford Site LLW to meet the TPA milestones. Phase I is a {open_quotes}proof of principle{close_quotes} test to demonstrate that a melter system can process a simulated highly alkaline, high nitrate/nitrite content aqueous LLW feed into a glass product of consistent quality. Seven melter vendors were selected for the Phase I evaluation: joule-heated melters from GTS Duratek, Incorporated (GDI); Envitco, Incorporated (EVI); Penberthy Electomelt, Incorporated (PEI); ...

1996-03-01

490

Evaluation of value for hydrogen release from high-level liquid waste. 4. Hydrogen release rate for {gamma}-ray radiolysis of simulated purex waste solutions

Waste Management Area U (WMA U) includes the U Tank Farm, is currently regulated under RCRA interim-status regulations, and is scheduled for closure probably post-2030. Groundwater monitoring has been under an evaluation program that compared general contaminant indicator parameters from downgradient wells to background values established from upgradient wells. One of the indicator parameters, specific conductance, exceeded its background value in one downgradient well triggering a change from detection monitoring to a groundwater quality assessment program. The objective of the first phase of this assessment program is to determine whether the increased concentrations of nitrate and chromium in groundwater are from WMA U or from an upgradient source. Based on the results of the first determination, if WMA U is not the source of contamination, then the site will revert to detection monitoring. If WMA U is the source, then a second part of the groundwater quality ...

2000-03-21

491

Evaluation of value for hydrogen release from high-level liquid waste. 4. Hydrogen release rate for #gamma#-ray radiolysis of simulated purex waste solutions

The rates of hydrogen release from simulated high-level liquid waste (SHLLW) during irradiation of {sup 60}Co {gamma}-rays have been studied using a laboratory-scale apparatus. The SHLLW used was made up of 28 different metal elements, the concentrations of which were determined from a computed data (ORIGEN-2) for a Purex spent fuel (burn-up of 4.5 GWd/t, cooling time of 4 years) except for those of corrosion products (Fe, Cr and Ni) and of chemical process additive (P). The nitrate ion concentration of the SHLLW was 4.97 M. The G-value of hydrogen release was 0.0164 for stirred conditions, but for nonstirred conditions with dose rate : 2.8 kGy/h and with the SHLLW solution height more than 8 cm, the following relation was found between the G-value and the solution height (d cm); G(H{sub 2}) = 0.100 d{sup -1.6}. The G-values of oxygen and nitrogen releases were also determined. (author)

1997-12-01

492

Complexation study on no-carrier-added astatine with insulin: A candidate radiopharmaceutical

The rates of hydrogen release from simulated high-level liquid waste (SHLLW) during irradiation of "6"0Co #gamma#-rays have been studied using a laboratory-scale apparatus. The SHLLW used was made up of 28 different metal elements, the concentrations of which were determined from a computed data (ORIGEN-2) for a Purex spent fuel (burn-up of 4.5 GWd/t, cooling time of 4 years) except for those of corrosion products (Fe, Cr and Ni) and of chemical process additive (P). The nitrate ion concentration of the SHLLW was 4.97 M. The G-value of hydrogen release was 0.0164 for stirred conditions, but for nonstirred conditions with dose rate : 2.8 kGy/h and with the SHLLW solution height more than 8 cm, the following relation was found between the G-value and the solution height (d cm); G(H_2) = 0.100 d"-"1"."6. The G-values of oxygen and nitrogen releases were also determined. (author).

1997-01-01

493

Complexation study on no-carrier-added astatine with insulin: A candidate radiopharmaceutical

No-carrier-added astatine radionuclides produced in the {sup 7}Li-irradiated lead matrix were separated from bulk lead nitrate target by complexing At with insulin, followed by dialysis. The method offers simultaneous separation of At from lead as well as its complexation with insulin. The At-insulin complex might be a potential radiopharmaceutical in the treatment of hepatocellular carcinoma. The stability of At-insulin complex was checked by dialysis against deionized water and Ringer lactate (RL) solution. It has been found that the half-life of At-insulin complex is about {approx}12 h, when dialyzed against deionized water and is only 6 h, when dialyzed against RL solution having the same composition as blood serum. The 6 h half-life of this Insulin-At complex is perfect for killing cancer cells from external cell surfaces as the half-life of internalization of insulin molecule inside the cell is 7-12 h.

2008-12-15

494

Climate change and water resources in Britain

No-carrier-added astatine radionuclides produced in the "7Li-irradiated lead matrix were separated from bulk lead nitrate target by complexing At with insulin, followed by dialysis. The method offers simultaneous separation of At from lead as well as its complexation with insulin. The At-insulin complex might be a potential radiopharmaceutical in the treatment of hepatocellular carcinoma. The stability of At-insulin complex was checked by dialysis against deionized water and Ringer lactate (RL) solution. It has been found that the half-life of At-insulin complex is about #approx#12 h, when dialyzed against deionized water and is only 6 h, when dialyzed against RL solution having the same composition as blood serum. The 6 h half-life of this Insulin-At complex is perfect for killing cancer cells from external cell surfaces as the half-life of internalization of insulin molecule inside the cell is 7-12 h.

2008-12-01

495

CO2 Capture by Absorption with Potassium Carbonate

This paper explores the potential implications of climate change for the use and management of water resources in Britain. It is based on a review of simulations of changes in river flows, groundwater recharge and river water quality. These simulations imply, under feasible climate change scenarios, that annual, winter and summer runoff will decrease in southern Britain, groundwater recharge will be reduced and that water quality - as characterised by nitrate concentrations and dissolved oxygen contents - will deteriorate. In northern Britain, river flows are likely to increase throughout the year, particularly in winter. Climate change may lead to increased demands for water, over and above that increase which is forecast for non-climatic reasons, primarily due to increased use for garden watering. These increased pressures on the water resource base will impact not only upon the reliability of water supplies, but also upon navigation, aquatic ecosystems, ...

1998-05-01

496

/sup 252/Cf-source-driven neutron noise analysis method

The objective of this work is to improve the process for CO{sub 2} capture by alkanolamine absorption/stripping by developing an alternative solvent, aqueous K{sub 2}CO{sub 3} promoted by piperazine. In Campaign 3 of the pilot plant, the overall mass transfer coefficient for the stripper with 7 m MEA decreased from 0.06 to 0.01 mol/(m{sup 3}.s.kPa) as the rich loading increased from 0.45 to 0.6 mol CO{sub 2}/mol MEA. Anion chromatography has demonstrated that nitrate and nitrite are major degradation products of MEA and PZ with pure oxygen. In measurements with the high temperature FTIR in 7 m MEA the MEA vapor pressure varied from 2 to 20 Pa at 35 to 70 C. In 2.5 m PZ the PZ vapor pressure varied from 0.2 to 1 Pa from 37 to 70 C.

2005-01-26

497