Transient thermal response in nuclear waste repositories

In this paper, it is shown that a previously reported non-linear, one-dimensional, theoretical approximation simplifies — from a computational point of view — the calculation of the time-decay temperature field in nuclear waste repositories (NWR). This conclusion has been reached after solving, by using the control volume numerical method, the full three dimensional, transient, non-linear heat diffusion equation. The transient thermal field in a rock salt repository, is analytically solved and numerically predicted, along 100 years, after the disposal of a high-level waste (HLW). The nuclear waste, with a half-life of 32.9 years, releases an exponentially time dependent heat flux with 12 W m⁻² as the initial thermal load. Two cases are studied, in the first one it is assumed that the conductivity (k) and the volumetric heat capacity ρc_p of the host rock (diffusion domain) remain constant (linear case), whereas in the second one, a more realistic situation is analysed. In this last case, the conductivity of the rock salt varies as a function of the temperature field and the product ρ×c_p remains constant (non-linear case). In order to observe the effect of the salt conductivity (constant or variable) on the repository temperature distribution, a comparison of both cases is performed. It is concluded, that the theoretical model, which provides an analytical solution of the thermal fields may be a powerful low cost method for design purposes.     

Design considerations and electro-mechanical simulation of an inertial sensor based on a floating gate metal-oxide semiconductor field-effect transistor as transducer

Microsystem Technologies - In this paper, an analysis on the electrostatic actuation in capacitive complementary metal-oxide semiconductor and micro-electro-mechanical systems (CMOS–MEMS)...     

The role of sulphate reduction on the reductive S decolorization of the azo dye reactive orange 14.

The aim of this study was to investigate the impact of a broad range of sulphate concentrations (0-10g SO4(-2) L(-1)) on the reduction of an azo dye (reactive orange 14 (RO14)) by an anaerobic sludge. An increase in the sulphate concentration generally stimulated the reduction of RO14 by sludge incubations supplemented with glucose, acetate or propionate as electron donor. Sulphate and azo dye reductions took place simultaneously in all incubations. However, there was a decrease on the rate of decolorization when sulphate was supplied at 10g SO4(-2) L(-1). Abiotic incubations at different sulphide concentrations (0-2.5 g sulphide L(-1)) promoted very poor reduction of RO14. However, addition of riboflavin (20 microM), as a redox mediator, accelerated the reduction of RO14 up to 44-fold compared to a control lacking the catalyst. Our results indicate that sulphate-reduction may significantly contribute to the reduction of azo dyes both by biological mechanisms and by abiotic reductions implicating sulphide as an electron donor. The contribution of abiotic decolorization by sulphide, however, was only significant when a proper redox mediator was included. Our results also revealed that sulphate-reduction can out-compete with azo reduction at high sulphate concentrations leading to a poor decolorising performance when no sufficient reducing capacity is available.     

Simultaneous occurrence of B-cell chronic lymphocytic leukemia and chronic myeloid leukemia with further evolution to lymphoid blast crisis

The coexistence of chronic myeloid leukemia (CML) and B-cell chronic lymphocytic leukemia (CLL) in the same patient is rare. A 71-year-old woman developed a B-lineage lymphoid blast crisis at 18 months after diagnosis of Ph-positive CML. At this time, a lymphoid cell population with morphologic and immunophenotypic features of CLL was demonstrated. The retrospective review of the tests performed at diagnosis and thereafter disclosed the presence of lymphoid nodules in the initial bone marrow biopsy in the absence of lymphocytosis. Subsequently, there was an appearance of moderate lymphocytosis in the following months. Therefore, diagnosis of CML and coexistent CLL was established. Although a transient remission of blast crisis was achieved, blast cells reappeared two months later and the patient died shortly afterwards. Molecular studies of the immunoglobulin heavy chain gene (IH) rearrangement pattern point to the origin of the diseases in two different cell clones. In addition, previously published cases of simultaneous CLL and CML are reviewed.     

Non-Hodgkin's lymphoma associated with Gaucher's disease

Gaucher's disease is an uncommon disorder which has been reported to be associated with an increased risk of lymphoproliferative disorders, including Non-Hodgkin's lymphoma (NHL). A new instance of such an association is described here. This was a 58 year-old-patient with adult type I Gaucher's disease who, one and a half year after the above diagnosis, presented with supraclavicular lymphadenopathy, massive splenomegaly, prominent retroperitoneal lymphadenopathy and increased serum LDH levels. This led to the diagnosis of large-cell NHL of B-cell type, successfully treated with chemotherapy. The previously published cases of Gaucher's disease associated with NHL as well as the possible mechanisms leading to this association are reviewed here.     

Theoretical study of the reactive intermediate Si2Me4[(η5-C5H4) Fe(CO)2] 2 2−

In two previous papers (Kinget al., J. Organomet. Chem. 19, 327, 1969; Pannellet al., Organometallics 9, 859, 1990), the synthesis and X-ray structure of the two tetramethyl disilyl complexes [(η⁵-C₅H₅) Fe(CO)₂]₂Si₂Me₄ (I) and Si₂Me₄[(η⁵-C₅H₄) Fe(CO)₂CH₃]₂ (II) were reported. ComplexII is obtained fromI [2]. However, attempts to form other derivatives fromI have generally failed. In the chemical process to getII fromI, an intermediate complex, Si₂Me₄[(η⁵-C₅H₄) Fe(CO)₂] ₂ ^2? (III), is probably formed. This is similar to complexII without the two methyl groups bonded to the Fe atoms. Therefore, a theoretical study that may shed some light on the intermediate structure, stability, and reactivity is justified. We have developed theoretical studies consisting of extended Huckel electronic structure calculations on the simulated intermediate geometry. The results obtained from these calculations suggest that it might be stable enough to form during reactions of complexI. The more reactive sites, which suggest reaction alternatives, are pointed out.     

Bio‐lubricant flow behaviour in mini‐channels

One of the most common causes of failures in total joint replacements is the generation of wear particles within the joint. This contributes to bone lost and aseptic loosening of the implant, eventually requiring its replacement. Many studies have been carried out to improve the wear characteristics of bearing surfaces in total joint replacement. From the lubrication point of view, the friction behaviour of surfaces and rheology of the joint lubricant (synovial fluid) have been extensively studied. However, little attention has been paid to the interaction between the lubricant and the bearing surfaces. The aim of this study is to develop a methodology for studying the behaviour of bio‐based lubricant in mini‐channels. For this purpose, micro‐particle image velocimetry was used in order to characterise the lubricant behaviour. Channels made of relevant materials such as ultra‐high molecular weight polyethylene, cobalt–chromium–molybdenum alloy and titanium–aluminium–vanadium alloy with 1 and 1.5 mm width, 45 mm length and 2 mm depth were experimentally investigated. Results suggested that the used polymeric solution interaction with solid surfaces is very sensitive to the polymer concentration in the lubricant. Moreover, it was observed that there exist differences between water (Newtonian reference fluid) and the polymeric solution behaviour even at very simple movements; although usually, the properties of this lubricant at high shear rates are estimated by water properties. Copyright © 2015 John Wiley & Sons, Ltd.