New Procedures for Uranium Isotope Ratio Measurements using the Triton Thermal Ionization Mass Spectrometer

In February 2004 the new Triton Thermal Ionization Mass Spectrometer from Thermo Electron has been installed at IRMM. For uranium isotope ratio measurements on the Triton at IRMM two basic techniques have been introduced and validated, namely the MTE- (¿Modified Total Evaporation¿) and the HI (¿High Intensity¿) techniques. The performance of these techniques is considered excellent for uranium isotope ration measurements to be performed at IRMM. Data obtained for the IRMM-183-187 series will be used to recertify the minor uranium ratios for these well know reference materialsJRC.D.4-Isotope measurement

Razvoj tehnologije Stirling sunčevog tanjura za buduću primjenu

The dish-Stirling technology for power generation, using a Stirling engine fed with a renewable energy such as solar, means a promising development regarding electricity generation. The dish-Stirling technology presents the highest efficiency, around 30%, in relation to other solar energy generation systems. However the technology status has not achieved enough advancement to be competitive with other renewable energy technologies. A state-of-the art review has been carried out in order to identify the developments needed to guarantee the feasibility of using the dish-Stirling technology. These are, on the one hand the system hybridization, in such a way that guarantees continuous operation, implying amortization improvement and on the other hand the thermal storage, providing system operation with stored energy during some periods such as transients. In this paper, a complete review of literature concerning the state-of-the-art and developments of dish-Stirling technology has been carried out, presenting the most outstanding issues considered for future implementation.Tehnologija Stirling sunčevog tanjura za proizvodnju električne energije, koristeći Stirling-ov motor napajan iz obnovljivog izvora energije kao što je sunce, predstavlja obećavajući razvoj u pogledu proizvodnje električne energije. S učinkovitošću od oko 30% tehnologija Stirling sunčevog tanjura jest najučinkovitiji solarni sustav za proizvodnju elekrične energije. Međutim, sadašnji napredak tehnologije nije dovoljan kako bi se postigla konkurentnost s drugim obnovljivim izvorima energije. Pregled trenutnog stanja tehnolgije je proveden kako bi se utvrdio potreban razvoj koji bi jamčio izvedivost korištenja tehnologije Stirling sunčevog tanjura. To su, s jedne strane sustav hibridizacije, osiguravanje njegovog kontinuiranog rada, poboljšanje amortizacije te s druge strane skladištenje topline, pod uvjetom osiguranja rada sustava u prijelaznim razdobljima sa skladištenom energijom. U ovom radu proveden je kompletan pregled literature o trenutnom stanju i razvoju tehnologije Stirling sunčevog tanjura, te navodi najistaknutija pitanja za njihovu buduću primjenu

The Author As A Producer: Construction of Authorial Figures and Critique of Commodification In Colombia, Brazil, and Peru (1924-1977)

I analyze the self-reflective dimension in three novels and one novella by Latin American writers from the twentieth century: La Vor&aacute;gine (1924), by the Colombian, Jos&eacute; Eustasio Rivera; Macuna&iacute;ma. O her&oacute;i sem nenhum car&aacute;ter. (1928), by the Brazilian, M&aacute;rio de Andrade; El zorro de arriba y el zorro de abajo (1971), by the Peruvian, Jos&eacute; Mar&iacute;a Arguedas; and A hora da estrela (1977), by the Brazilian, Clarice Lispector. . In the context of the uneven and combined modernization process that characterized the Latin American region, these long narratives share a critical perspective towards the increasing professionalization of literary writing and its incorporation into a market economy in two historical junctures (the 1920s and 1970s) and three different countries (Colombia, Brasil, and Peru). Moreover, this questioning is conducted through meta-fictional and inter-medial devices, which include the construction of authorial figures and cultural producers, as well as the comparison between literary writing and other forms of material and symbolic production in a capitalist economy. In a context of bigger circulation of commodities both material (rubber, coffee, fish meal) and symbolic (photography, folklore, culture industries), literary writing assumes a stance of resistance and negotiation towards the commodification process. Consequently, the four long narratives in my corpus highlight the importance of the politic, ethic, and ritual dimensions of the literary production. In iv other words, although the work of art participate in the circulation of commodities (books are purchased in the market), literary writing can surpass rigid economic demands. For instance, in the first two novels in my corpus, La vor&aacute;gine y Macuna&iacute;ma, literary writers become champions of nationality in the context of resource-based economies and the modernization of nation-states. In the two following long narratives, El zorro de arriba y el zorro de abajo and A hora da estrela, literary writers reject the professionalization achieved during the 1960s Latin American Boom, while paying attention to the experience of marginalized populations&mdash;namely, rural-urban migrants who start participating in capitalistic economies.</p

Preparation and Certification of IRMM-075

A set of 6 new synthetic mixtures with n(236U)/n(238U) isotope ratios varying from 10-4 to 10-9 has been prepared and certified. Natural uranium with low 236U isotope abundance and enriched 236U were both purified using well proven chemical methodology extensively tested in the preparation of other uranium synthetic mixtures such as IRMM-074. The purification involved separation on anion and cation columns followed by precipitation as peroxide. Manipulations were carried out in separate new glove-boxes to avoid cross contamination. The oxides were sintered into U3O8 in an oven installed in a glove-box with controlled humidity. Primary solutions of the same concentration were prepared by dissolving the oxides of 236U and natU. From the 236U solution four dilutions were made by weighing. Weighed amounts of the dilutions of 236U and weighed amounts of natU were mixed to form a set of 236U/238U mixtures at a concentration of 1 mg U*g-1. The final solutions were dispensed into quartz ampoules which were subsequently flame sealed. Verification of the mixtures IRMM-075/1-7 was performed by TRITON TIMS measurements using Faraday collectors and secondary electron multiplier in combination with an RPQ energy filter for improved abundance sensitivity. The results agreed well with the certified values obtained from the mixing calculations. The uncertainties contributing to the final uncertainties of the isotopic ratios are the weighing errors, the measured impurities in each starting material, the stoichiometry of the oxides and the isotopic abundances of each. The method for the preparation and mixing are described and the certification and verification procedures are reported.JRC.D.4-Isotope measurement

Variation of allozyme frequencies in Spanish field and cellar populations of D. melanogaster.

uploaded by Plazi from Taxodro

Modeling Digital Twin Data and Architecture: A Building Guide with FIWARE as Enabling Technology

The use of Digital Twins in the industry has become a growing trend in recent years, allowing to improve the lifecycle of any process by taking advantage of the relationship between the physical and the virtual world. Existing literature formulates several challenges for building Digital Twins, as well as some proposals for overcoming them. However, in the vast majority of the cases, the architectures and technologies presented are strongly bounded to the domain where the Digital Twins are applied. This article proposes the FIWARE Ecosystem, combining its catalog of components and its Smart Data Models, as a solution for the development of any Digital Twin. We also provide a use case to showcase how to use FIWARE for building Digital Twins through a complete example of a Parking Digital Twin. We conclude that the FIWARE Ecosystem constitutes a real reference option for developing DTs in any domain.Comment: 7 pages, 3 figure

Update on REIMEP-15: Isotopic Ratios of uranium in UF6

The REIMEP (Regular European Interlaboratory Measurement Evaluation Programme) campaign 15 for isotopic ratios of uranium in UF6 samples has been completed in 2002. The participants received 4 samples of low-enriched or slightly depleted uranium in the form of UF6 in standard monel capsules. The samples were prepared at IRMM by mixing uranium reference materials certified by gas mass-spectrometry in the form of UF6. The minor isotopes, 234U and 236U were certified at IRMM by Thermal Isotope Mass-spectrometry (TIMS) using a MAT262-RPQ mass spectrometer in ion counting mode. Certified values were sent to the participating laboratories immediately after receiving their measured results. The measured results and their comparison with the certified values allowed an overall view of the analytical capability in the nuclear field to measure uranium isotopic ratios in UF6 samples. However, for the so-called minor ratio 234U.238U the comparison of IRMM¿s certified values with all the participants results showed a significant relative deviation of about 2%, which is by far larger than the typical uncertainties expected for this kind of measurements. This significant deviation was considered disappointing for IRMM as the leading European nuclear safeguards metrology institute. This problem has now overcome first by measurements using the new TRITON TIMS at IRMM and second by a thorough investigation on the reasons for the deviation observed in the past.JRC.D.4-Isotope measurement