Rare Earth Tracers Research Articles

Release kinetics of rare earth tracer from polymer-coated proppants for hydraulic fracture analysis

Horizontal well staged fracturing has been unlocking natural gas and oil in shale and reshaping the energy supply worldwide. With the updating technology of the integrated fracturing engineering, prolymer-coated proppants not only prevent fracture closure but also hold oilfield tracers which can be released under certain conditions, offering a viable strategy to report the information of proppants, fractures and fluids in reservoir based on tracer flowback data. But release kinetics of tracers from functional proppants, which is a fundamental and critical issue in the application of the tracer-released proppant, is yet to be discussed. Here, coupled with rare earth tracer, poly(ethyl acrylate-co-methyl methacrylate-co-trimethylammoniethyl methacrylate chloride) is taken as an example to build a model tracer-releasedproppant. Release curves of tracers, under reservoir conditions (salinity and temperature conditions), were studied to reveal the release mechanism, and the potential applicability of the rare earth tracer-released proppants for reporting the proppants position and fluid contribution in multi-staged fracturing monitoring was confirmed in laboratory flow experiment.

Backside wear of tibial polyethylene components is affected by gait pattern: A knee simulator study using rare earth tracer technology.

The aim of this study was to determine the effect of two in-vivo-determined gait patterns, one with low and one with high anteroposterior (AP) motion, on total and backside polyethylene insert wear in comparison with the ISO (International Organization for Standardization) standard 14243-3. In order to differentiate and accurately quantify topside and backside wear, a novel technique was employed where different lanthanide tracers were incorporated into the polyethylene during manufacture. Wear particle analysis was conducted following established protocols. For all tested liners and motion protocols, the chemically calculated wear rates correlated closely with gravimetrically determined wear. Both in vivo motion groups displayed higher wear rates than the ISO group following the order of the AP motion amplitudes. Backside wear for ISO constituted 2.76% ± 0.90% (mean ± SE) of the total wear, increasing significantly to 15.8% ± 3.2% for the low AP and further increasing to 19.3% ± 0.95% for the high AP motion protocol. The mean wear particle sizes were under 200 nm for all three motion patterns, being largest for the protocol with high AP motion. Particle release from the low and high AP gait patterns was 1.9 to 2.8 times that from the ISO protocol. Testing for the proportion of backside wear across various activities of daily living should be an important consideration in evaluating knee prostheses wear.

Study of the cyclotron production of 172Lu: an excellent radiotracer

172Lu due to its suitable (T1/2 = 6.7 days) and high detection sensitivity, is used as a radiotracer in different fields. 172Lu appears to be suitable as a long-lived rare-earth tracer for compound labelling and biodistribution studies. In the present study, excitation functions via 172Yb(p,n)172Lu, natYb(p,xn)172Lu, 172Yb(d,2n)172Lu and natYb(d,xn)172Lu reactions were calculated by ALICE/91, ALICE/ASH and TALYS-1.2 codes. Deposition of natYb2O3 on Cu substrate was carried out via sedimentation method for the production of 172Lu. Cementation separation process and liquid–liquid extraction (LLX) of no-carrier-added (nca) radiolutetium from irradiated ytterbium(III)oxide target hydrochloric solution was described using Na(Hg) amalgam, α-hydroxyisobutyric acid (α-HIB) and di-(2-ethylhexyl)phosphoric acid (HDEHP).

Use of rare earth tracers for the study of diesel emissions in the atmosphere

The emissions of diesel vehicles mainly contain soot, which is difficult to distinguish from soot originating from other sources. The use of a tracer which can be detected in extremely low mass concentrations and does not occur normally in the atmospheric aerosol can help to differentiate between aerosols from different sources. The rare earth element Dysprosium has proven useful for this purpose. It can be detected by neutron activation analysis in quantities of nanograms and does not occur naturally. An organic, diesel soluble Dysprosium compound was added to the fuel. During the combustion process the Dysprosium is oxidized and attaches to the formed soot particles. For the atmospheric filter samples an extraction technique was used. This marking method has been successfully applied for an extended field experiment.

Use of ascorbic acid as an eluent for cation exchange separation of rare earth tracers

A simple cation exchange procedure for effective separation of rare earths in a mixture using ascorbic acid as a complexing agent has been demonstrated. Sodium ascorbate solution of 0.5% concentration at pH 6.5–7.0 was found to be most effective in separating the radioactive species, namely, 170Tm, 160Tb, 153Sm and 141Ce from their mixture under the experimental conditions. The method described was specifically applied to the separation of tracers, without resorting to carrier materials.

The production, recovery, and purification of 172Hf for utilization in nuclear medicine as the generator of 172Lu

172Hf is of potential value in nuclear medicine research as the generator of its daughter nuclide, 172Lu. The latter isotope, a heavy rare-earth tracer, could have applications in compound labelling, pre-clinical biodistribution studies, and other areas of investigation. 172Hf is produced by inducing spallation reactions in Ta targets with medium-energy protons at LAMPF, and a chemical procedure has been developed for the separation of radiohafnium from the bulk target material and various spallogenic impurities. Nuclide identification was accomplished by gamma-ray spectrometry, and radiochemical yields of nine different elements in the analytical scheme were measured. 172Hf is thus recovered quantitatively (93% chemical yield) and is sufficiently decontaminated for use in generator development.

Use of nitrilotriacetic acid and different retaining ions in the separation of rare earths in tracer scale by ion exchange

A mixture of rare earth tracers, e.g. 170Tm, 160Tb, 153Sm and 141Ce was adsorbed on a Dowex 50W-X8 cation exchange column and elution was then carried out by using 1% solution of disodium salt of nitrilotriacetic acid at pH 6.5. The effect of the use of various mono- and divalent ions as the retaining ions was studied and it was found that Cs + and Cd 2+ ions amongst them appear to be most effective.

Synergistic solvent extraction of adducts formed by Di- n-butyl sulphoxide and rare-earth tris-thenoyltrifluoroacetonates

Extraction equilibrium constants, K 3,n ∗ , and organic phase adduct formation constants, β 3, n , have been determined by liquid-liquid distribution of radioactive rare-earth tracers between 1 M (H, Na)ClO 4 and CCl 4 with 0·2 M HTTA and ⪯0·2 M DBSO at (23±2)°C. A comparative study on the synergistic extraction with DBSO and TBP as neutral ligands is reported. Tetravalency of Ce and Tb is discussed in connection with their extraction properties.