Brown tumors in dialyzed patients with secondary hyperparathyroidism: Report of 16 cases

Brown tumors (BTs) are relatively uncommon but they are serious complications of renal osteodystrophy. The objective of this study was to analyze the clinical, biological, and radiological characteristics of 16 patients with BTs provoked by secondary hyperparathyroidism (sHPT) and its response to the decrease in parathyroid hormone levels after parathyroidectomy (PTX). The management of that uncommon condition was also reviewed. We conducted a retrospective study including 16 end‐stage renal disease patients who underwent subtotal PTX between 1997 and 2007 for severe sHPT with BTs. Our study included 10 men and 6 women, whose average age was 34 years. All patients were on dialysis. Ten of them were on dialysis for more than 5 years. The median duration on dialysis was 84 months. Patients included suffered from swellings associated with functional limitations. BTs had multiple locations in 7 patients. Jaw was the most frequent location (62%). Radiography and tomodensitometry demonstrated a mixed radio lucent and radio‐opaque lesions with an expansion of the cortical bone. Bone scan demonstrated an increased uptake of lesions. Chirurgical treatment was indicated in all cases because of severe refractory sHPT with functional limitations and/or disfiguring deformities. In all cases, BTs stopped its progression and even decreased in size. However, it was insufficient in four cases, which required a surgical resection. PTX remains an efficacious approach in resistant cases of sHPT with persistent BTs.     

A geostatistical approach for groundwater head monitoring network optimisation: case of the Sfax superficial aquifer (Tunisia)

In many developing countries, the groundwater monitoring network is randomly designed, and consequently needs to be revised and optimised to reduce operation time and cost, remove redundant piezometric data, and strengthen sparseness data zone with supplementary observation well. The geostatistical approach used in this work is based on the universal kriging variance combined with cross‐validation test. Hence, a rational interpolation of water table elevations was performed to evaluate the accuracy of data employed in the piezometric head modelling. In this study, the groundwater monitoring network of the Sfax superficial aquifer in the south east of Tunisia was optimised. The elimination of five observation wells induces the invariability in the variance of estimate due to their less contribution in interpretations of the groundwater level behaviour. However, 38 wells were added at areas of high variance of the kriging in order to ameliorate the spatial coverage of the monitoring network.     

NEAR CRITICAL CARBON DIOXIDE FRACTIONATION OF CRUDE OIL I: DEPENDENCE OF THE MOLECULAR UEIGHT OF THE FRACTIONS ON THE PRESSURE USED.

A method is described for fractionation of crude oil using carbon dioxide near critical fluid conditions. The number average molecular weight of the fractions of the extracted hydrocarbons from crude oils differed markedly from those original oil. At 308.15K as the pressure increased from 96 bar to 115bar the molecular weights of the fractions increased from 210 to 414 g.mol.     

Reliability of photovoltaic modules I. Theoretical considerations

The effect of interconnection and bypass diodes on the reliability of photovoltaic modules and arrays have been evaluated. Analysis of different cell or panel interconnections for the determination of the optimum item configuration and circuit design strategies to achieve reliable modules and arrays has been carried out. A computer program for finding the optimum configuration which produce maximum module and array reliability is presented. The roll of bypass diodes for module and array reliability improvements have been studied theoretically and experimentally. It is found that module and array reliability depends on the item's (cells or panels) probability of failure, arrangement of the items, and failure mode. Discussion and suggestions for optimum design are presented.     

Calembour: an implicit method based on an enriched kinematical thin-plate model for sheet-metal forming simulation

In this paper, the main features of an implicit sheet-metal forming simulation code, named Calembour, are presented. Special emphasis is put on the way of expressing the contact conditions and of taking into account the geometrical non-linearity of which they comprise. An enriched kinematical thin-plate model, involving seven independent fields defined on the medium surface of the undeformed plate, is suggested. The constitutive laws used to model the material behavior and the friction phenomenon are given. A standard bilinear finite-element method is used to approximate the continuous total Lagrangian formulation of the global mechanical problem. Finally, some numerical results enlighting the effectiveness of the present approach are given.     

Error estimation and model adaptation for a stochastic‐deterministic coupling method based on the Arlequin framework

The paper deals with the issue of accuracy for multiscale methods applied to solve stochastic problems. It more precisely focuses on the control of a coupling, performed using the Arlequin framework, between a deterministic continuum model and a stochastic continuum one. By using residual‐type estimates and adjoint‐based techniques, a strategy for goal‐oriented error estimation is presented for this coupling and contributions of various error sources (modeling, space discretization, and Monte Carlo approximation) are assessed. Furthermore, an adaptive strategy is proposed to enhance the quality of outputs of interest obtained by the coupled stochastic‐deterministic model. Performance of the proposed approach is illustrated on 1D and 2D numerical experiments. Copyright © 2013 John Wiley & Sons, Ltd.     

Prediction of Long-term Immunity of a Phase-Locked Loop

Degradation mechanisms accelerated by harsh conditions (high temperature, electrical stress) can affect circuit performances. Submitted to electromagnetic interferences, aged components can become more susceptible, which stirs up questions about the safety level of the final application. Unfortunately, the impact of circuit aging on its susceptibility level remains under evaluated and is not taken into account at circuit design level. This paper presents a first attempt of a modeling methodology aiming at predicting the impact of circuit aging on the susceptibility to electromagnetic interferences. This methodology is applied to model and explain the measured variations of the susceptibility level of phase-locked loop after an accelerated-life test.     

Traitement de fondation du barrage Sidi Aïch par injection de coulis de ciment

A study of potential catchment areas in Tunisia recommended that a dam be constructed on the Sidi Aïch Oued in central Tunisia. Although this zone was known for its aridity, the dam would collect runoff waters during periods of exceptional rainfall with the principal aim of ensuring that the water table in the Gafsa was recharged. The geological and hydrogeologic conditions required particular attention to be paid to the foundations of the Sidi Aïch dam to take account of the lithological variability, fracture network and the faults that pass through the dam site. Two treatment techniques were found to be appropriate and were used to enhance the stability and watertightness of the ground in which the dam was to be constructed: contact-consolidation grouting and curtain grouting. Studies were made of the water absorption both before and after the grouting was undertaken. In order to verify the effectiveness of the treatment, cored boreholes were dug which showed the absence of permeable zones immediately below the deep grout curtain, confirming that the work had extended to an appropriate depth. The observed absorption variability in the foundation excavations indicated that a zone of potential high grout take would be encountered. The lateral heterogeneity, observed from one well to another, explained the variable level at which the dam was founded and the differing quantities of grout injected along the length of the grout curtain of the dam. The work concluded that, except for high absorption in localised areas, the main grout take was related to the fractures present in the rock mass.