Goal-Oriented Adaptivity and Multilevel Preconditioning for the Poisson-Boltzmann Equation

In this article, we develop goal-oriented error indicators to drive adaptive refinement algorithms for the Poisson-Boltzmann equation. Empirical results for the solvation free energy linear functional demonstrate that goal-oriented indicators are not sufficient on their own to lead to a superior refinement algorithm. To remedy this, we propose a problem-specific marking strategy using the solvation free energy computed from the solution of the linear regularized Poisson-Boltzmann equation. The convergence of the solvation free energy using this marking strategy, combined with goal-oriented refinement, compares favorably to adaptive methods using an energy-based error indicator. Due to the use of adaptive mesh refinement, it is critical to use multilevel preconditioning in order to maintain optimal computational complexity. We use variants of the classical multigrid method, which can be viewed as generalizations of the hierarchical basis multigrid and Bramble-Pasciak-Xu (BPX) preconditioners.     

Propriétés psychométriques d'une version canadienne-fran?aise du Questionnaire des expériences dépressives.

The present study evaluates a French-Canadian version of the Depressive Experiences Questionnaire, originally developed by Blatt, D'Afflitti, et Quinlan (1976), to measure two personality dimensions predisposing to depressive affect, Dependency and Self-Criticism. Factor analysis with 762 undergraduate students showed a very high degree of conformity with the original version in terms of the number of factors, variance explained and the pattern of factor loadings for each scale. Congruence of factor scores calculated with the solutions derived from the English and French principal component analysis was very high, but somewhat lower for the Self-critical dimension for male subjects. The scales of the French-Canadian Questionnaire des Expériences Dépressives correlated with a measure of depression, and showed adequate test-retest reliability over an 8-week period. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

L'adaptation de l'enfant à la séparation de ses parents: Sept hypothèses pour une compréhension approfondie.

Over the past few decades, researchers have tried to study children who grow up in separated families. This has allowed us to identify a number of factors that, alone or in interaction with others, can predict the child's adaptation to his or her parent's separation. Different explanatory perspectives have oriented the research in this field. These perspectives can be described as follows: the selection effect hypothesis, the developmental effect hypothesis, the stress hypothesis, the economic hypothesis, the parental practices hypothesis, the family constituants hypothesis and the parental conflict hypothesis. Children's adaptation to the couple's separation is examined with respect to each of these perspectives/hypotheses and in terms of the empirical support they have received in the literature. We conclude by stressing the importance of taking into account the child's active contribution to the resolution of this familial transition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Investigation of Urea-Melamine-Formaldehyde (UMF) resin penetration in Medium-Density Fiberboard (MDF) by High Resolution Confocal Laser Scanning Microscopy

A confocal laser scanning microscope (CLSM) was used to investigate the distribution and penetration of urea-melamine-formaldehyde (UMF) resin in the fiber when injected through blowline blending in a medium density fiberboard (MDF) pilot plant. Samples were prepared with respect to industrial parameters and were collected at the dryer’s end. The samples were later dyed in a Dye Star-Brilliant Red solution (0.01%) and rinsed with distilled water to remove excess. The samples were scanned with the CLSM to build three-dimensional reconstructions of MDF fiber cross-sections. With proper lenses and optimized CLSM settings, it was possible to obtain fiber reconstructions with a resolution greater than the laser wave length (514 nm). The Zeiss CLSM built-in software image analyzer enabled to rebuild them in rotation on any of the three axes with up to 64 images per rotation. The resin penetration sites were identified using this software option. The penetration sites were numerous and well dispersed. The largest openings (lumen, pits and cracks) were responsible for most of the resin lost by over-penetration. The presence of resin in the cell walls (detected with the CLSM) proves their porosity without giving much information about the resin concentration. Finally, the atomic force microscope (AFM) enabled to recreate the finest surface details for these fibers samples. It was found that the fibrils aggregates orientation and size can influence the resin penetration and distribution. It was concluded that the porous structure of wood fibers and their affinity to water enable the resin to penetrate through capillary force. This phenomenon is stimulated by the high pressure, saturated steam, turbulent flow and heat. When injected in the pilot plant blowline, UMF resin was uniformly distributed over the fiber surface (22.5% coverage). The resin penetration was however important and also occurred in nanometric defaults of the wood fibers. Thus, industrial panels made out of very porous, damaged or small fibers will need more resin to fill the gaps in order to make a strong board.     

The enhancement of hydration of fluidized bed combustion ash by sonication

The use of limestone to control SO2 emissions in fluidized bed combustors (FBC) results in high CaO content in the ashes. This presents challenges for their disposal including significant exothermic behavior and uncontrolled expansion in the landfill. Hydration of the ashes is required to convert the CaO, but the current two-step hydration process is not very effective. In the present work a new technique using ultrasound to promote the hydration was examined. Initial work was done using an ultrasonic bath and subsequently an ultrasonic probe. Hydration levels greater than 80% in 20-40 min with amplitudes of 40% or more were achieved with residues containing high levels of CaO. This is about twice what can be achieved using conventional hydration technique. Similar results were obtained using FBC ashes from four utility/industrial scale and one pilot plant scale FBC units. The mechanism for the promotion of hydration bythe ultrasound is also explored.     

A pilot scale evaluation of removal of mercury from pharmaceutical wastewater using granular activated carbon

Thimerosal (an organic mercury compound) is widely used in the pharmaceutical industry and hospitals. This study examines the removal of mercury (thimerosal and Hg(II)) from a pharmaceutical wastewater using F-400 granular activated carbon (GAC) at bench and pilot scales. Bench scale dynamic column tests are conducted with 30, 60, 90 and 120 min empty bed contact times (EBCTs). The pilot scale study is conducted using two GAC columns-in-series each of 30 min EBCT. The capital and operational cost analysis for the treatment system is performed. Simultaneous removal of copper, turbidity, phenol, and color from the wastewater by the pilot scale system is also reported.     

Relation entre les satisfactions liées à trois r?les sociaux et la satisfaction de vie chez les femmes au foyer.

Determined the roles of marital satisfaction, parental satisfaction, and satisfaction with housework in the prediction of life satisfaction among housewives. 177 women (aged 22–49 yrs) completed measures including the Life Satisfaction Scale (Blais et al, 1989), and the satisfaction score of the Dyadic Adjustment Scale (Baillargeon et al, 1986). Ss were divided into 3 groups according to stages of the family life cycle, based on the age of the oldest child in the family. Marital satisfaction was a predictor of life satisfaction for all 3 stages of family life cycle. Parental satisfaction was predictive of life satisfaction at stage 1 (oldest child younger than 5 yrs old), while satisfaction with housework had influence at stage 2 (oldest child 6-12 yrs old). For stage 3 (oldest child in adolescence) satisfaction with housework and parental satisfaction were predictors of life satisfaction. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Roasting metallic sulphides in a fluid column

The development of a new metallurgical roasting device is described. It consists of a refractory column into which air is injected at various levels, forming several superimposed fluidized beds with no supporting grates. When pelleted zinc sulphide concentrates are charged, the roasted product needs no further sintering before reduction to metal.     

A Low-Cost,Innovative Methodology for Teaching Engineering Through Experimentation

Combining LEGO® Dacta building blocks with LabVIEW^TM software produced a highly successful, low-cost (less than $500 per station excluding computer) alternative method of teaching engineering through hands-on experimentation. Dubbed LEGO® Data Acquisition and Prototyping System (or LDAPS), this combination of tools provides a highly capable workbench for students, yet brings a new level of creativity and fun into teaching engineering at the college level. In this paper we present the methodology and describe one class where it is currently in use. Student, faculty, and staff response to the class was very positive, partly due to the popularity of hands-on engineering and partly because LEGO® blocks allow the students to exercise their creativity and innovation. The strength in the LDAPS methodology lies in the power of the LEGO® bricks and the LabVIEW^TM software. LEGO® motors, sensors, and bricks are almost infinitely configurable, making each experiment unique. LabVIEW^TM is a powerful, visual programming language in which students can perform advanced signal processing with relatively few programming skills. We are currently extending this methodology to teach engineering to liberal arts majors as well as precollege students.     

Frequency locking of a 1324 nm DFB laser to an optically pumpedrubidium vapor

Some experimental results and a simple theoretical model on a dither-free frequency-locking technique of a DFB laser operating at 1324 nm are presented. A resonance observed through absorption in an ⁸⁷ Rb vapor optically pumped by a modulated 795-nm laser diode tuned to the D₁ line is used. This approach has the advantage of producing sub-Doppler resonances. Such a technique could be used to generate an unmodulated 1324-nm wavelength reference