ABSTRACT Problems of optimal reliability and redundancy allocation are not new. However, the literature describes two isolated situations, either when redundancy allocation is the target and the reliability metrics of the components are known, or focusing on the reliability allocation, that demands the metrics to be known in advance and the use of some optimization approach. In the present paper, we consider a combined situation, i.e., when both situations must be considered together. To guide the allocation process, we developed a cost function that considers the costs of acquisition, development and/or improvement as a function of monetary effort, along with the reliability target and expected failure costs. The results considering two classical test problems in the literature demonstrated the efficacy of the proposed approach to deal with similar situations.

Abstract Heavy-ion induced two-neutron transfer reactions (18O,16O) at 84 MeV were studied on several targets up to high excitation energy of the residual nucleus thanks to the use of the MAGNEX magnetic spectrometer to detect the ejectiles. The obtained results indicate of the important role played by the nuclear paring.

Resumen Se estudiaron reacciones de transferencia de dos neutrones inducidas por iones pesados (18O, 16O) a 84 MeV en varios blancos hasta una alta energía de excitación del núcleo residual gracias al uso del espectrómetro magnético MAGNEX para detectar los residuos eyectados. Los resultados obtenidos indican el importante papel desempeñado por el apareamiento nuclear.

Six new composites derived from the intercalation of the MPS3 phases (M = MnII, CdIII) with the macrocyclic manganese(III) complex [MnL(H2O)2].NO3(H2O) (LH2 = Schiff base macrocyclic ligand derived from the condensation of 2-hydroxy-5-methy1-1,3-benzene-dicarbaldehyde and 1,2-diamine-benzene) were obtained by two different synthetic procedures: a conventional and a microwave assisted method. The composites [MnL]0.25K0.15Mn0.80 PS3(H2O)~1.0 (1), and [MnL]0.25K0.15Cd 0. 80PS3(H2O)~0.5 (2) were obtained by the conventional method, after stirring a suspension of the corresponding potassium precursor and the macrocyclic complex for two weeks, while [MnL]0.35K0.15Mn0.80 PS3(H2O)~1.0 (3) and [MnL]0.25K0.15Cd 0. 80PS3(H2O)~0.5 (4) after stirring for four weeks at room temperature. Using a microwave assisted reaction permitted to obtain in a shorter period of time as compared with the conventional method, composites [MnL]0.20K0.15Mn0.80 PS3(H2O)~1.0 (5) and [MnL]0.15K0.15Cd 0. 80PS3(H2O)~0.5 (6). All the M = MnII, MnIII composites show a bulk antiferromagnetic behavior. However, the spontaneous magnetization present at low temperature in the potassium precursor K0.40Mn0.80 PS3(H2O)~1.0 is observable in composite [MnL]0.20K0.15Mn0.80 PS3(H2O)~1.0 (5), while it is completely absent in composites [MnL]0.25K0.15Mn0.80 PS3(H2O)~1.0 (1) and [MnL]0.35K0.15Mn0.80 PS3(H2O)~1.0 (3).

Neste trabalho foi desenvolvida uma rotina computacional para a modelagem da corrosão por pites em aços inoxidáveis com inclusões de MnS. A abordagem empregada baseou-se em modelos teóricos prévios com a introdução de efeitos metalúrgicos. A implementação permitiu visualizar a evolução do processo de pites para tempos de até 30 dias de exposição. Os resultados mostram a ocorrência de pites metaestáveis e estáveis. Além disto, quando eles se nucleiam em regiões onde existem inclusões de MnS a probabilidade de surgir pites estáveis é bastante aumentada.

A computational code was developed for the modeling of pitting corrosion in stainless steel with MnS inclusions. The approach used was based in previously existing theoretical models, with the inclusion of metallurgical effects. The implementation allowed the visualization of the pitting evolution process for times up to 30 days of exposure. The results have shown the occurrence of metastable and stable pits. Furthermore, when they are nucleated in regions in which there are MnS inclusions, the probability of stable pits occurrence is greatly increased.

A novel instrument capable of collecting the entire cathodoluminescence emission spectrum simultaneously with SEM scanning is presented in this work. The cathodoluminescence produced in a standard scanning electron microscope is collected and analyzed. The electronic signal used by the microscope to trigger the electron raster and produce an image is also used by the spectrograph to synchronize spectrum acquisition. At each point in the sample the complete spectrum is acquired. All the data are recorded and saved in an electronic file. With this information it is possible to reconstruct panchromatic and/or monochromatic images of the sample and correlate its optical properties with its microstructure. Instead of an elliptical mirror to collect the light in the conventional CL system, a single optical fiber is used. This new way of acquiring light permits a reduction in the work distance (down to 5 mm) in the microscope, thus achieving a better spatial resolution. Another advantage of this arrangement is that we can simultaneously use other detection modes such as backscattered electrons, x-rays etc. Examples showed here illustrate the capabilities of the instrument.

En este trabajo presentamos un novedoso instrumento capaz de colectar el espectro de emisión completo de cátodoluminiscencia, simultáneamente con imágenes de SEM. Se colecta y analiza la cátodoluminiscencia producida en un microscopio electrónico de barrido. La electrónica utilizada por el microscopio para barrer el haz de electrones y producir la imagen es utilizada por el espectrógrafo para sincronizar la adquisicion de espectros. En cada punto de la muestra se adquiere el espectro completo. Todos los datos son grabados y guardados en un archivo electrónico. Con esta información es posible reconstruir imágenes pancromáticas y/o monocromáticas de la muestra y correlacionar sus propiedades ópticas con la microestructura. En lugar de un espejo elíptico para colectar la luz, como en el sistema convencional de CL, se utiliza una sola fibra óptica. Esta nueva manera de adquirir la luz permite una reducción en la distancia de trabajo (menor a 5 mm) en el microscopio, logrando así una mejor resolucion espacial. Otra ventaja de este arreglo es que nosotros podemos usar otros modos de detección simultáneamente como los electrones retrodispersados, rayos X, etc. Se muestran algunos ejemplos para ilustrar las capacidades del instrumento.

We have determined the number of circulating T, B and natural killer cells in renal transplant recipients in order to detect changes during cytomegalovirus (CMV) infections. Serial blood samples were taken from 61 patients on standard triple immunosuppression therapy (cyclosporin A, azathioprine and prednisone). Using two-color flow cytometry analysis, the absolute number of CD3+, CD4+, CD8+, CD19+, CD3+HLA-DR+ and CD16+56+ cells was determined. Forty-eight patients (78.7%) developed active CMV infection, and all of them subsequently recovered. Twenty of the infected patients (32.8%) presented symptoms compatible with CMV disease during the infectious process. The number of lymphocytes and their main subpopulations were normal before the onset of CMV disease. During the disease there was a decrease followed by a significant increase (P<0.005) in the number of CD3+, CD4+, CD8+ and CD3+HLA-DR+ cells. No significant changes were observed in natural killer cells or B lymphocytes during the disease. We conclude, as observed in all viremic patients recovering from infection, that recovery is associated with an increase in the number of T cell subsets. The monitoring of different lymphocyte subsets along with antigenemia can be extremely useful in the detection of patients at high risk of developing CMV symptoms, allowing the early introduction of antiviral therapy or the reduction of immunosuppression therapy.