Hydrogen diffusion in Zr-2.5Nb pressure tubes specimens between 300°C-400°C by in-situ neutron imaging experiments

Zirconium (Zr) alloys are widely used in nuclear power plants as fuel cladding and are susceptible to hydrogen (H) degradation. For long operational service, Zr-based components can suffer a mechanism known as Delayed Hydride Cracking (DHC) associated to an increase of the crack propagation velocity by the re-orientation and precipitation of Zr hydride. In this process, the H mobility has a great influence. In the present work, the isothermal diffusion of H in Zr-2.5%Nb specimens obtained from a CANDU pressure tube were studied at consecutive temperatures of 300°C, 350°C, 375°C and 400°C. H content and mobility were quantified by in-situ neutron imaging experiments performed on ANTARES, the cold neutron imaging facility of FRM II. The time evolution of the H concentration across the specimen allowed the determination of diffusion coefficients, and an assessment of the limitations of existing models commonly used to describe H diffusion

Non-destructive characterisation of a Villanovan sword using time-of-flight neutron diffraction

In the present work we report an example application of time-of-flight neutron diffraction for the non-destructive characterisation of ancient bronzes. A Villanovan sword tightly joined to its scabbard by corrosion has been investigated. Data on alloy composition of the different parts and information about the manufacturing techniques have been successfully achieved. The present study is part of an extensive non-destructive investigation program concerning bronze productions of Central Italy during the Iron Age

The impact of secondary cytoreductive surgery on survival in first recurrence of platinum sensitive epithelial ovarian cancer

Objective: Analyze the effect on survival of secondary cytoreduction surgery (SCS) in treatment of first recurrence platinumsensitive epithelial ovarian cancer (REOC). Methods: Retrospective analysis of patients with first REOC who had platinum timefree interval (TFIp) > 6 months and were treated either with SCS followed by chemotherapy or chemotherapy only (CT). Clinical data such as patient’s performance status and number of sites with metastases were specifically assessed. The primary endpoint was overall survival (OS). Results: Seventyone patients were treated either by SCS (n = 37) or CT (n = 34). Complete resection after SCS was achieved in 89% of patients. After a median followup of 51.2 months, median OS, and progressionfree survival (PFS) were 68.2 and 21.6 months, respectively, for the whole series of the SCS patients had better survival and disease progression survival than the CT only patients (HR: 0.33, 95%CI: 0.170.6; p= 0.001) and (HR: 0.28, 95%CI: 0.150.5; p= 0.001), respectively. TFIp < 12 months and multiple metastases were most important prognostic factors for risk of death (HR: 7.7 and 6.2, respectively) and recurrence (HR: 5.8 and 3.8, respectively). Probability to undergo successful SCS is related to oligometastatic disease and no residual disease after first surgery (OR: 30.0 and 5.9, respectively). Conclusions: In women with REOC oligometastatic disease and no residual disease at first surgery are associated with successful SCS. In these patients oligometastatic disease and long platinum TFI are associated with improved probability of survival

A randomized controlled trial assessing the effect of intermittent and abrupt cessation of milking to end lactation on the well-being and intramammary infection risk of dairy cows

The objectives were to compare the effects of an intermittent milking schedule with a thrice daily milking schedule during the final week of lactation on the well-being, udder health, milk production, and risk of culling of dairy cows. We hypothesized that cows subjected to an intermittent milking schedule would experience less udder engorgement and pain, lower concentrations of fecal glucocorticoid metabolites (11,17-dioxoandrostanes; 11,17-DOA concentration) after dry-off, lower risk of an intramammary infection during the dry period, higher milk production and lower somatic cell count in the subsequent lactation, and lower culling risk compared with herd mates milked 3 times daily and dried off by abrupt cessation. In a randomized controlled field study, Holstein cows (n = 398) with a thrice daily milking schedule were assigned to treatment and control groups. The treatment consisted of an intermittent milking schedule for 7 d before dry-off (gradual cessation of milking, GRAD). Gradual-cessation cows were milked once daily until the day of dry-off, whereas cows in the control group (abrupt cessation of milking, APT) were milked 3 times daily until the day of dry-off. Udder firmness and pain responses of the udder 3 d after dry-off, as well as the percentage change in fecal 11,17-DOA concentration (3 d after dry-off compared with the dry-off day), were used to assess the well-being of the animals. Compared with cows in the GRAD group, the odds [95% confidence interval (CI)] of udder firmness were 1.55 (0.99–2.42) for cows in the APT group, and the odds of a pain response were 1.48 (0.89–2.44) for cows in the APT group. The least squares means (95% CI) of the percentage change in 11,17-DOA concentration were 129.3% (111.1–150.4) for the APT group and 113.6% (97.5–132.4) for the GRAD group. Quarter-level culture results from the periods before dry-off and after calving were compared, to assess the likelihoods of microbiological cure and new infection. Cows in the APT group had lower odds of a new intramammary infection in the dry period [odds ratio, 95% CI: 0.63 (0.37–1.05)], whereas we observed no meaningful differences in the microbiological cure likelihood among groups. The least squares means (95% CI) for somatic cell counts (log10-transformed) were 4.9 (4.8–5.0) in the APT group and 4.9 (4.8–5.0) in the GRAD group. The odds (95% CI) of clinical mastitis in the first 30 d postcalving were 1.32 (0.53–3.30) in the APT group compared with the GRAD group. We observed no meaningful differences in milk production at the first test date postcalving or the culling risk among groups. We conclude that the gradual-cessation protocol tested herein failed to significantly improve animal well-being, udder health, milk production, and survival in the tested study cohort. However, the observed differences in udder firmness, as well as the numerical differences in udder pain and the percentage change in fecal 11,17-DOA concentrations suggest that this line of research may be useful. Future research is needed to develop drying-off strategies that are appropriate for lowering milk production at the end of the lactation and improve animal well-being without compromising udder health

Difractómetro de grandes componentes para el reactor RA-10

En CNEA se encuentra en ejecución el ?Proyecto RA-10? para la construcción de un reactor multipropósito. Entre los objetivos principales del RA-10 está la provisión de haces de neutrones para la realización de experimentos dentro de un amplio espectro de disciplinas científicas y tecnológicas. Por sus múltiples aplicaciones, la difracción de neutrones es una de las técnicas neutrónicas más populares. El gran poder de penetración de los neutrones (del orden de cm) permite investigar el interior de un objeto sin necesidad de cortarlo. Así es posible estudiar en forma no-destructiva objetos macroscópicos y cuantificar la variación espacial de las fases cristalinas que lo componen, las orientaciones de esos cristalitos, y su nivel de deformación plástica y elástica.En particular, es posible determinar las tensiones internas en componentes mecánicos de gran porte, un tema de gran importancia dentro de la industria metal-mecánica. En este caso los planos cristalinos son utilizados como extensómetros microscópicos, y las pequeñas variaciones que existen en las distancias interplanares para las distintas direcciones de un objeto son utilizados para cuantificar el tensor completo de deformación elástica.La posibilidad de realizar experimentos de difracción sobre objetos intactos ha despertado también gran interés dentro de la comunidad dedicada al estudio y la conservación del patrimonio cultural.Presentamos aquí el diseño básico de un difractómetro para el estudio de grandes componentes, para ser instalado en un haz térmico de la sala del reactor RA-10, es decir, directamente contra la pared del mismo.Se propone equiparlo con dos monocromadores diferentes, para poder optar entre mayor intensidad o mayor resolución. Los monocromadores propuestos son doblemente curvados, a fin de enfocar el haz sobre la posición de medición y optimizar la resolución del equipo para la reflexión de mayor interés. Un componente central del instrumento es el portamuestras, consistente en una mesa con capacidad de posicionar componentes de hasta ~300kg de peso con una precisión de ~20um, una resolución espacial de ~1mm, y rotar los mismos a fin de explorar distintas direcciones. Presentaremos además avances realizados sobre un prototipo a menor escala, que comparte algunas características del diseño propuesto, que será instalado en el reactor RA-6 del Centro Atómico Bariloche.Fil: Santisteban, Javier Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Sanchez, F.. Comisión Nacional de Energía Atómica; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; ArgentinaFil: Moreira, F.. Comisión Nacional de Energía Atómica; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Gomez, S.. Comisión Nacional de Energía Atómica; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Tartaglione, Aureliano. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Malamud, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Vicente Alvarez, Miguel Angel. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gimenez, M.. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Vizcaino, Pablo. Comision Nacional de Energia Atomica. Gerencia de Area de Aplicaciones de la Tecnología Nuclear. Gerencia Ciclo del Combustible Nuclear. Laboratorio D/mat.d/la Fabrica de Aleaciones Especiales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Cosmic Ray Rejection and Readout Efficiency for Large-Area Arrays

We present an algorithm to optimally process uniformly sampled array image data obtained with a nondestructive readout. The algorithm discards full wells, removes cosmic ray (particle) hits and other glitches, and makes a nearly optimum estimate of the signal on each pixel. The algorithm also compresses the data. The computer requirements are modest, and the results are robust. The results are shown and compared to results of Fowler sampled and processed data. Non-ideal detector performance may require some additional code, but this is not expected to cost much processing time. Known types of detector faults are addressed.Comment: This paper has been accepted for publication in the PAS