896 research outputs found

    Small-Column Cesium Ion Exchange Elution Testing of Spherical Resorcinol-Formaldehyde

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    This report summarizes the work performed to evaluate multiple, cesium loading, and elution cycles for small columns containing SRF resin using a simple, high-level waste (HLW) simulant. Cesium ion exchange loading and elution curves were generated for a nominal 5 M Na, 2.4E-05 M Cs, 0.115 M Al loading solution traced with 134Cs followed by elution with variable HNO3 (0.02, 0.07, 0.15, 0.23, and 0.28 M) containing variable CsNO3 (5.0E-09, 5.0E-08, and 5.0E-07 M) and traced with 137Cs. The ion exchange system consisted of a pump, tubing, process solutions, and a single, small ({approx}15.7 mL) bed of SRF resin with a water-jacketed column for temperature-control. The columns were loaded with approximately 250 bed volumes (BVs) of feed solution at 45 C and at 1.5 to 12 BV per hour (0.15 to 1.2 cm/min). The columns were then eluted with 29+ BVs of HNO3 processed at 25 C and at 1.4 BV/h. The two independent tracers allowed analysis of the on-column cesium interaction between the loading and elution solutions. The objective of these tests was to improve the correlation between the spent resin cesium content and cesium leached out of the resin in subsequent loading cycles (cesium leakage) to help establish acid strength and purity requirements

    "The Bees' needs" : using molecular analysis of bee collected pollen to understand which plants play an important role in honey bee forage

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    Summary: Honey bees and other pollinators provide essential pollination services to agriculture and the environment; however they are under increasing pressure from changes in land management, disease and climate change. Current mitigation places emphasis on establishing flower meadows to improve nutritional diversity, but preserving what is already in place is also of importance. ‘CSI Pollen’ was a recent European citizen science project coordinated by COLOSS, investigating the diversity of pollen collected by honey bees in many countries across Europe. Volunteer beekeepers sampled pollen from colonies every three weeks during the foraging season over a two to three year period, creating a huge collection of data and samples. A selection of samples collected from 14 Scottish sites during the second year of study in 2015 were analysed by DNA fingerprinting to identify pollen gathered by honey bees at critical points of the colony’s life cycle; some results and potential implications for land use are discussed here

    Immune Reactivity and Pseudoprogression or Tumor Flare in a Serially Biopsied Neuroendocrine Patient Treated with the Epigenetic Agent RRx-001.

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    Neuroendocrine tumors (NETs) are grouped together as a single class on the basis of histologic appearance, immunoreactivity for the neuroendocrine markers chromogranin A and synaptophysin, and potential secretion of hormones, neurotransmitters, neuromodulators and neuropeptides. Nevertheless, despite these common characteristics, NETs differ widely in terms of their natural histories: high-grade NETs are clinically aggressive and, like small cell lung cancer, which they most closely resemble, tend to respond to cisplatin and etoposide. In contrast, low-grade NETs, which as a rule progress and behave indolently, do not. In either case, the treatment strategy, apart from potentially curative surgical resection, is very poorly defined. This report describes the case of a 28-year-old white male with a diagnosis of high-grade NET of undetermined primary site metastatic to the lymph nodes, skin and paraspinal soft tissues, treated with the experimental anticancer agent RRx-001, in the context of a phase II clinical trial called TRIPLE THREAT (NCT02489903); serial sampling of tumor material through repeat biopsies demonstrated an intratumoral inflammatory response, including the amplification of infiltrating T cells, which correlated with clinical and symptomatic benefit. This case suggests that pseudoprogression or RRx-001-induced enlargement of tumor lesions, which has been previously described for several RRx-001-treated patients, is the result of tumoral lymphocyte infiltration

    Spectroscopy of horizontal branch stars in NGC6752 - Anomalous results on atmospheric parameters and masses

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    We used the ESO VLT-FORS2 facility to collect low-resolution spectra of 51 targets distributed along the Horizontal Branch. We determined atmospheric parameters by comparison with theoretical models through standard fitting routines, and masses by basic equations. Results are in general in good agreement with previous works, although not always with theoretical expectations for cooler stars (Teff<15000 K). The calculated color excess is systematically lower than literature values, pointing towards a possible underestimation of effective temperatures. Moreover, we find two groups of stars at Teff=14000 K and at Teff=27000$ K that present anomalies with respect to the general trend and expectations. We suppose that the three peculiar bright stars at Teff=14000 K are probably affected by an enhanced stellar wind. For the eight Extreme Horizontal Branch stars at Teff=27000 K which show unusually high masses we find no plausible explanation. While most of our results agree well with the predictions of standard horizontal branch evolution, we still have problems with the low masses we derive in certain temperature ranges. We believe that Kurucz ATLAS9 LTE model atmospheres with solar-scaled abundances are probably inadequate for these temperature ranges. Concerning the group of anomalous stars at Teff=27000 K, a Kolmogorov-Smirnov test indicates that there is only an 8.4% probability that these stars are randomly drawn from the general distribution in the color-magnitude diagram. This is not conclusive but points out that these stars could be both (and independently) spectroscopically and photometrically peculiar with respect to the general Extreme Horizontal Branch population.Comment: 12 pages, 10 figures, accepted for pubblication in A&A. Replaced for typos and better LaTeX outpu

    Small-Column Ion Exchange Testing of Spherical Resorcinol-Formaldehyde -11379

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    ABSTRACT Ion exchange using the Spherical Resorcinol-Formaldehyde (SRF) resin has been selected by the U.S. Department of Energy&apos;s Office of River Protection (DOE-ORP) for use in the Pretreatment Facility (PTF) of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and for potential application in an at-tank deployment. Numerous studies have shown the SRF resin to be effective for removing Cs-137 from a wide variety of actual and simulated tank waste supernatants. Prior work focused primarily on the loading behavior for 5 M sodium (Na) solutions at 25°C and the eluting behavior of the loaded SRF resin with virgin 0.5 M HNO 3 . Recent proposed changes to the process baseline indicate that loading may include a broader range of sodium molarities (2 to 8 M) and higher temperatures (50°C) to alleviate post-filtration precipitation issues. In addition, elution will likely utilize variable-strength recycled nitric acid containing trace amounts of Cs-137. Cesium ion exchange loading and elution curves were generated for a 5 M Na, 2.4E-05 M Cs loading solution traced with Cs-134 followed by elution with variable HNO 3 (0.02, 0.07, 0.15, 0.23, and 0.28 M) containing variable CsNO 3 (5.0E-09, 5.0E-08, and 5.0E-07 M) and traced with Cs-137. The ion exchange system consisted of a pump, tubing, process solutions, and a single, small (~15 mL) bed of SRF resin with a water-jacketed column for temperature-control. The columns were loaded with approximately 250 bed volumes (BVs) of feed solution at 45°C and at 1.5 to 12 BV per hour (0.15 to 1.2 cm/min). The columns were then eluted with approximately 25 BVs of HNO 3 processed at 25°C and at 1.4 BV/hr. The two independent tracers allowed analysis of the on-column cesium interaction between the loading and elution solutions. The objective of these tests was to improve the correlation between the spent resin cesium content and cesium leached out of the resin in subsequent loading cycles (cesium bleed) to help establish acid strength and purity requirements

    Fire Safety Tests for Cesium-Loaded Spherical Resorcinol Formaldehyde Resin: Data Summary Report

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    A draft safety evaluation of the scenario for spherical resorcinol formaldehyde (SRF) resin fire inside the ion exchange column was performed by the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Fire Safety organization. The result of this draft evaluation suggested a potential change of the fire safety classification for the Cesium Ion Exchange Process System (CXP) emergency elution vessels, equipment, and piping. To resolve this question, the fire properties of the SRF resin were measured by Southwest Research Institute (SwRI) through a subcontract managed by Pacific Northwest National Laboratory (PNNL). The results of initial fire safety tests on the SRF resin were documented in a previous report (WTP-RPT-218). The present report summarizes the results of additional tests performed by SwRI on the cesium-loaded SRF resin. The efforts by PNNL were limited to summarizing the test results provided by SwRI into one consolidated data report. The as-received SwRI report is attached to this report in the Appendix A. Where applicable, the precision and bias of each test method, as given by each American Society for Testing and Materials (ASTM) standard procedure, are included and compared with the SwRI test results of the cesium-loaded SRF resin

    Ion Exchange Testing with SRF Resin FY2012

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    Ion exchange using spherical resorcinol-formaldehyde (SRF) resin has been selected by the U.S. Department of Energy’s Office of River Protection (DOE-ORP) for use in the Pretreatment Facility (PTF) of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) and for potential application in at-tank deployment. Numerous studies have shown SRF resin to be effective for removing 137Cs from a wide variety of actual and simulated tank waste supernatants (Adamson et al. 2006; Blanchard et al. 2008; Burgeson et al. 2004; Duignan and Nash 2009; Fiskum et al. 2006a; Fiskum et al. 2006b; Fiskum et al. 2006c; Fiskum et al. 2007; Hassan and Adu-Wusu 2003; King et al. 2004; Nash et al. 2006). Prior work at the Pacific Northwest National Laboratory (PNNL) has focused primarily on the loading behavior for 4 to 6 M Na solutions at 25 to 45°C. Recent proposed changes to the WTP ion exchange process baseline indicate that loading may include a broader range of sodium molarities (0.1 to 8 M) and higher temperatures (50°C) to alleviate post-filtration precipitation issues. This report discusses ion exchange loading kinetics testing activities performed in accordance with Test Plan TP-WTPSP-002, Rev. 3.0 , which was prepared and approved in response to the Test Specification 24590 PTF-TSP-RT-09-002, Rev. 0 (Lehrman 2010) and Test Exception 24590 PTF TEF RT-11-00003, Rev. 0 (Meehan 2011). This testing focused on column tests evaluating the impact of elevated temperature on resin degradation over an extended period of time and batch contacts evaluating the impact on Cs loading over a broad range of sodium concentrations (0.1 to 5 M). These changes may be required to alleviate post-filtration precipitation issues and broaden the data range of SRF resin loading under the conditions expected with the new equipment and process changes

    Technetium Removal Using Tc-Goethite Coprecipitation

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    This report describes the results from laboratory tests performed at Pacific Northwest National Laboratory for the U.S. Department of Energy (DOE) EM-31 Support Program (EMSP) subtask, “Low temperature waste forms coupled with technetium removal using an alternative immobilization process such as Fe(II) treated-goethite precipitation” to increase our understanding of 99Tc long-term stability in goethite mineral form and the process that controls the 99Tc(VII) reduction and removal by the final Fe (oxy)hydroxide forms. The overall objectives of this task were to 1) evaluate the transformation process of Fe (oxy)hydroxide solids to the more crystalline goethite (α-FeOOH) mineral for 99Tc removal and 2) determine the mechanism that limits 99Tc(IV) reoxidation in Fe(II)-treated 99Tc-goethite mineral and 3) evaluate whether there is a long-term 99Tcoxidation state change for Tc sequestered in the iron solids
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