Experimental determination of metal fuel point defect parameters

Nuclear metallic fuels are one of many options for advanced nuclear fuel cycles because they provide dimensional stability, mechanical integrity, thermal efficiency, and irradiation resistance while the associated pyro-processing is technically relevant to concerns about proliferation and diversion of special nuclear materials. In this presentation we will discuss recent success that we have had in studying isochronal annealing of damage cascades in Pu and Pu(Ga) arising from the self-decay of Pu as well as the annealing characteristics of non-interacting point defect populations produced by ion accelerator irradiation. Comparisons of the annealing properties of these two populations of defects arising from very different source terms are enlightening and point to complex defect and mass transport properties in the plutonium specimens which we are only now starting to understand as a result of many follow-on studies. More importantly however, the success of these measurements points the way to obtaining important mass transport parameters for comparison with theoretical predictions or to use directly in existing and future materials modelling of radiation effects in nuclear metallic fuels. The way forward on such measurements and the requisite theory and modelling will be discussed. We bring to the attention of the reader that this article is based wholly or in part on earlier publications of the authors.Ядерне металеве паливо є одним із багатьох варіантів прогресивного ядерного паливного циклу, оскільки воно забезпечує розмірну стабільність, механічну цілісність, тепловий коефіцієнт корисної дії і радіаційну стійкість, в той час, як піротехнологія технічно відноситься до проблем про розповсюдження спеціальних ядерних матеріалів та їх перенасичення. У даному повідомленні ми обговоримо останні успіхи, досягнуті нами при вивченні ізохронного відпалу каскадів пошкоджень в Pu і Pu(Ga), які виникають в результаті саморозпаду Pu, а також характеристики відпалу невзаємодіючих точкових дефектів, які утворились при опроміненні у прискорювачі іонів. Порівняння цих двох популяцій дефектів, виникаючих при різних вихідних умовах, проливають світло та вказують на складні властивості дефектів і масопередачі в зразках плутонію, які ми починаємо розуміти тільки зараз у результаті багатьох модифікованих досліджень, Однак, і це більш важливе, успіх цих вимірювань вказує шлях отримання важливих параметрів масо переносу для порівняння з теоретичними прогнозуваннями, або для безпосереднього використання при моделюванні радіаційних ефектів у вже існуючих та майбутніх матеріалах у якості ядерного металевого палива. Ми звертаємо увагу читача на те, що ця стаття заснована повністю або частково на більш ранніх публікаціях авторів.Ядерное металлическое топливо является одним из многих вариантов прогрессивного ядерного топливного цикла, поскольку оно обеспечивает размерную стабильность, механическую целостность, тепловой коэффициент полезного действия и радиационную стойкость, в то время, как пиротехнология технически относится к проблемам распространения специальных ядерных материалов и их перенацеливания. В данном сообщении мы обсудим последние успехи, достигнутые нами при изучении изохронного отжига каскадов повреждений в Pu и Pu(Ga), которые возникают в результате самораспада Pu, а также характеристики отжига невзаимодействующих точечных дефектов, образованных при облучении в ускорителе ионов. Сравнения этих двух популяций дефектов, возникающих при разных исходных условиях, проливают свет и указывают на сложные свойства дефектов и массопередачи в образцах плутония, которые мы только сейчас начинаем понимать в результате многих модифицированных исследований. Однако, что более важно, успех этих измерений указывает на путь получения важных параметров массопереноса для сравнения с теоретическими предсказаниями или для непосредственного использования при моделировании радиационных эффектов в уже существующих и будущих материалах в качестве ядерного металлического топлива. Мы обращаем внимание читателя на то, что эта статья основана целиком или частично на более ранних публикациях авторов

Existence of superposition solutions for pulse propagation in nonlinear resonant media

Existence of self-similar, superposed pulse-train solutions of the nonlinear, coupled Maxwell-Schr\"odinger equations, with the frequencies controlled by the oscillator strengths of the transitions, is established. Some of these excitations are specific to the resonant media, with energy levels in the configurations of $\Lambda$ and $N$ and arise because of the interference effects of cnoidal waves, as evidenced from some recently discovered identities involving the Jacobian elliptic functions. Interestingly, these excitations also admit a dual interpretation as single pulse-trains, with widely different amplitudes, which can lead to substantially different field intensities and population densities in different atomic levels.Comment: 11 Pages, 6 Figures, presentation changed and 3 figures adde

The gene expression barcode 3.0: improved data processing and mining tools

The Gene Expression Barcode project, http://barcode.luhs.org, seeks to determine the genes expressed for every tissue and cell type in humans and mice. Understanding the absolute expression of genes across tissues and cell types has applications in basic cell biology, hypothesis generation for gene function and clinical predictions using gene expression signatures. In its current version, this project uses the abundant publicly available microarray data sets combined with a suite of single-array preprocessing, quality control and analysis methods. In this article, we present the improvements that have been made since the previous version of the Gene Expression Barcode in 2011. These include a variety of new data mining tools and summaries, estimated transcriptomes and curated annotations

Distributed automated manufacturing of pluripotent stem cell products

Establishing how to effectively manufacture cell therapies is an industry-level problem. Decentralised manufacturing is of increasing importance, and its challenges are recognised by healthcare regulators with deviations and comparability issues receiving specific attention from them. This paper is the first to report the deviations and other risks encountered when implementing the expansion of human pluripotent stem cells (hPSCs) in an automated three international site–decentralised manufacturing setting. An experimental demonstrator project expanded a human embryonal carcinoma cell line (2102Ep) at three development sites in France, Germany and the UK using the CompacT SelecT (Sartorius Stedim, Royston, UK) automated cell culture platform. Anticipated variations between sites spanned material input, features of the process itself and production system details including different quality management systems and personnel. Where possible, these were pre-addressed by implementing strategies including standardisation, cell bank mycoplasma testing and specific engineering and process improvements. However, despite such measures, unexpected deviations occurred between sites including software incompatibility and machine/process errors together with uncharacteristic contaminations. Many only became apparent during process proving or during the process run. Further, parameters including growth rate and viability discrepancies could only be determined post-run, preventing ‘live’ corrective measures. The work confirms the critical nature of approaches usually taken in Good Manufacturing Practice (GMP) manufacturing settings and especially emphasises the requirement for monitoring steps to be included within the production system. Real-time process monitoring coupled with carefully structured quality systems is essential for multiple site working including clarity of decision-making roles. Additionally, an over-reliance upon post-process visual microscopic comparisons has major limitations; it is difficult for non-experts to detect deleterious culture changes and such detection is slow

Nonadiabatic approach to dimerization gap and optical absorption coefficient of the Su-Schrieffer-Heeger model

An analytical nonadiabatic approach has been developed to study the dimerization gap and the optical absorption coefficient of the Su-Schrieffer-Heeger model where the electrons interact with dispersive quantum phonons. By investigating quantitatively the effects of quantum phonon fluctuations on the gap order and the optical responses in this system, we show that the dimerization gap is much more reduced by the quantum lattice fluctuations than the optical absorption coefficient is. The calculated optical absorption coefficient and the density of states do not have the inverse-square-root singularity, but have a peak above the gap edge and there exist a significant tail below the peak. The peak of optical absorption spectrum is not directly corresponding to the dimerized gap. Our results of the optical absorption coefficient agree well with those of the experiments in both the shape and the peak position of the optical absorption spectrum.Comment: 14 pages, 7 figures. to be published in PR

An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

Multi-year interlaboratory exercises for the analysis of illicit drugs and metabolites in wastewater:development of a quality control system

Thirty-seven laboratories from 25 countries present the development of an inter-laboratory testing scheme for the analysis of seven illicit drug residues in standard solutions, tap- and wastewater. Almost 10 000 concentration values were evaluated: triplicates of up to five samples and 26 laboratories per year. The setup was substantially improved with experiences gained across the six repetitions (e.g. matrix type, sample conditions, spiking levels). From this, (pre-)analytical issues (e.g. pH adjustment, filtration) were revealed for specific analytes which resulted in formulation of best-practice protocols for inter-laboratory setup and analytical procedures. The results illustrate the effectiveness of the inter-laboratory setup to assess laboratory performance in the framework of wastewater-based epidemiology. The exercise proved that measurements of laboratories were of high quality (>80% satisfactory results for six out of seven analytes) and that analytical follow-up is important to assist laboratories in improving robustness of wastewater-based epidemiology results