Investigation of the Nuclear Gauge Density Calibration Method

Yin, Huiming; Luo, Zairen

doi:10.1080/14680629.2009.9690217

Cited by 7 publications

(5 citation statements)

References 8 publications

(10 reference statements)

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“…ETS-NOCV results in Table S5. 3.1 indicate that the selectivity might result from overall better π interactions, especially from better π3 interactions. Figure 6 and Tables S5.1.1 and S5.3.1 show that the electron-donating −NH 2 group improves the overall interactions including the π3 interaction energies that are significantly increased.…”

Section: Substitution Effectsmentioning

confidence: 99%

“…The special nuclear properties associated with 241 Am also find broad applications in the industry. For instance, the soft γ-radiation emitted from 241 Am finds applications in the determination of thicknesses of metal sheets, glasses, etc. − It also finds usage in compaction tests for soils. − The americium–beryllium (Am–Be) neutron sources are also deployed by the petroleum industry in neutron activation analyses for oil-well logging and drilling exploration. − Hence, identifying ways to improve americium separations can significantly impact americium processing efforts for 241 Am industrial usage.…”

Section: Introductionmentioning

confidence: 99%

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Advancing the Am Extractant Design through the Interplay among Planarity, Preorganization, and Substitution Effects

et al. 2022

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Advancing the field of chemical separations is important for nearly every area of science and technology. Some of the most challenging separations are associated with the americium ion Am(III) for its extraction in the nuclear fuel cycle, 241 Am production for industrial usage, and environmental cleanup efforts. Herein, we study a series of extractants, using first-principle calculations, to identify the electronic properties that preferentially influence Am(III) binding in separations. As the most used extractant family and because it affords a high degree of functionalization, the polypyridyl family of extractants is chosen to study the effects of the planarity of the structure, preorganization of coordinating atoms, and substitution of various functional groups. The actinyl ions are used as a structurally simplified surrogate model to quickly screen the most promising candidates that can separate these metal ions. The down-selected extractants are then tested for the Am(III)/Eu(III) system. Our results show that π interactions, especially those between the central terpyridine ring and Am(III), play a crucial role in separation. Adding an electron-donating group onto the terpyridine backbone increases the binding energies to Am(III) and stabilizes Am−terpyridine coordination. Increasing the planarity of the extractant increases the binding strength as well, although this effect is found to be rather weak. Preorganizing the coordinating atoms of an extractant to their binding configuration as in the bound metal complex speeds up the binding process and significantly improves the kinetics of the separation process. This conclusion is validated by the synthesized 1,2-dihydrodipyrido [4,3b;5,6-b]acridine (13) extractant, a preorganized derivative of the terpyridine extractant, which we experimentally showed was four times more effective than terpyridine at separating Am 3+ from Eu 3+ (SF Am/Eu ∼ 23 ± 1).

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Section: Substitution Effectsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Advancing the Am Extractant Design through the Interplay among Planarity, Preorganization, and Substitution Effects

et al. 2022

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“…These include using soft γ-radiation emitted from 241 Am to determine thicknesses of a wide range of materials (e.g., metal sheets, glass thickness, etc. ). ,− The 241 Am radionuclide is also used in performing compaction tests (e.g., for soils). − Other applications come from americium-beryllium (AmBe) neutron sources, which find use in neutron radiography, moisture analyses, − nuclear reactor start-up, and neutron activation analyses for oil-well logging and drilling exploration. ,, …”

Section: Introductionmentioning

confidence: 99%

Characterizing Extraction Chromatography for Large-Scale Americium-241 Processing

Arko

Dan

Adelman

et al. 2021

Ind. Eng. Chem. Res.

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The americium-241 ( 241 Am) radioisotope has valuable nuclear properties that find broad industrial usage. Ensuring stable supplies of 241 Am is critical for supporting (and expanding) the existing 241 Am-application space and enabling emerging 241 Amtechnologies that are important for economic growth, energy, and national security. Unfortunately, the United States halted 241 Am production in 1984 and the existing inventory was depleted in the early 2000s. This situation recently changed when the U.S. Department of Energy Isotope Program established 241 Am recovery at Los Alamos National Laboratory. Today, large-scale quantities of 241 Am are now obtained using the Chloride Extraction and Actinide Recovery (CLEAR) process. This method uses a resin that has the di-(4-t-butylphenyl)-N,N-di-iso-butylcarbamoylmethylphosphine oxide (m-CMPO) extractant adsorbed on a resin bead to harvest 241 Am from plutonium-containing waste streams. To maintain and improve CLEAR processing of 241 Am, we have evaluated the extraction of 241 Am by m-CMPO as a function of three important processing relevant variables: (1) HCl concentration, (2) metal contaminant concentration, and (3) contact time. The performance of the m-CMPO resin was additionally compared against commercially available resins, namely, rare earth (RE) resin and a selected series of diglycolamide (DGA) resins. Our results suggested that the m-CMPO resin outperformed most of the commercially available alternatives. However, tetraoctyl-DGA (TODGA) and tetraethyl-hexyl-DGA (TEHDGA) prevailed on several fronts. The TODGA and TEHDGA resins quantitatively released 241 Am at low HCl concentrations (<0.5 M), were less susceptible to deleterious side effects from metal contaminants in the mobile phase and bound 241 Am faster. Based on these results, we concluded that 241 Am recovery yields have the potential to improve if TODGA or TEHDGA is used in place of m-CMPO for large-scale CLEAR processing of 241 Am.

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“…These collisions depend on soil density. Thermalized neutrons emitted from the nuclear gauge collide with hydrogen atoms inside the soil ( 3 ). The higher the density is, the fewer photons will reach the detector.…”

mentioning

confidence: 99%

Impact of Fines on Various Base Material Properties

Morales,

Zuniga

2023

Transportation Research Record: Journal of the Transportation R

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The performance of the unbound aggregate base is affected by moisture content and fines (materials finer than No. 200 sieve) content. Proper moisture content and the proper amount of fines in a base material contribute to long-lasting pavements. This study evaluated an unbound aggregate base under different moisture contents and fines contents. The evaluation included the measurements of the electrical and electromagnetic properties with moisture content and fines content. The dielectric constants were measured with a percometer, and the resistivity values were measured using a Wenner probe. These measurements were correlated with the moisture content for all fines contents used in the study. Strength and modulus tests were also performed on the specimens using the unconfined compressive strength (UCS) tests and a lightweight deflectometer (LWD). The variations in these parameters with moisture content are also presented here for all fines content. A normalization scheme was used to allow for the data to be compiled and analyzed more easily. The dielectric constant increased as moisture was added with some dispersion, but no clear trend was seen among different fines contents. The resistivity decreased consistently as the moisture content increased. The peak UCS normally occurred at moisture contents of about 1% dry of optimum moisture content (OMC); specimens prepared with 1% less than optimum had higher UCS. LWD modulus tended to peak when prepared drier than OMC. The optimum strength and modulus were obtained with 5% and 10% fines contents for the unbound granular base used.

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Investigation of the Nuclear Gauge Density Calibration Method

Cited by 7 publications

References 8 publications

Advancing the Am Extractant Design through the Interplay among Planarity, Preorganization, and Substitution Effects

Advancing the Am Extractant Design through the Interplay among Planarity, Preorganization, and Substitution Effects

Characterizing Extraction Chromatography for Large-Scale Americium-241 Processing

Impact of Fines on Various Base Material Properties

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