Theoretical model for FCGR near the threshold

A theoretical model for fatigue crack growth rate at low and near threshold stress intensity factor is developed. The crack tip is assumed to be a semicircular notch of radius ρ and incremental crack growth occurs along a distance 4ρ ahead of the crack tip. After analysis of the stress and strain distribution ahead of the crack tip, a relationship between the strain range and the stress intensity range is proposed. It is then assumed that Manson-Coffin cumulative rule can be applied to a region of length 4ρ from the crack tip, where strain reversal occurs. Finally, a theoretical equation giving the fatigue crack growth rate is obtained and applied to several materials (316L stainless steel, 300M alloy steel, 70-30 α brass, 2618A and 7025 aluminum alloys). It is found that the model can be used to correlate fatigue crack growth rates with the mechanical properties of the materials, and to determine the threshold stress intensity factor, once the crack tip radius α is obtained from the previous data.     

Construction et validation du Questionnaire sur les réactions parentales aux émotions positives exprimées par l'enfant.

Studied the psychometric properties of the French-language Questionnaire on Parental Reactions to Children's Expression of Positive Emotions (QPRCEPE). The QPRCEPE includes 12 scenarios that may elicit positive affect in children. The scenarios are accompanied by 4 parental reactions: socialization, encouragement, reprimand, and discomfort. Two studies were conducted in Canada. The results of Study 1, performed with 164 mothers of children aged 4-7 yrs, showed good construct validity. The results of Study 2, performed with 200 mothers of children aged 4-7 yrs, showed that each QPRCEPE subscale had satisfactory internal consistency and high temporal stability. It is maintained that the findings are consistent with the model proposed by T. Dix (1991), according to which parents' emotional state affects their child rearing practices and their perception and interpretation of child behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Science in Africa: An overview of mainstream scientific output

The total scientific output of mainstream articles for the 15 most productive African countries for the period 1991 to 1997 was 45,080, with South Africa and Egypt publishing 15,725 and 10,433, respectively. The productions of these two top ranked countries varied little from 1991-1997 while others such as the Maghreb countries increased between 75-102%. Total contributions were mainly in the fields of Clinical Medicine (36%), Biology (17%), Chemistry (14%), and Biomedical Research (12%). Papers in international collaboration were overriding in Biomedical Research, Biology, Earth and Space Science, and Physics. Institutions in the US were the principal collaborators followed closely by those in France. This revised version was published online in June 2006 with corrections to the Cover Date.     

On the Relationship between Mechanical Properties and Mechanisms of Plastic Deformation in Metastable Austenitic Steels

The requirements of the automotive industry for materials exhibiting increased structural performances are continuously increasing. These materials must remain ductile during the forming operations while also exhibiting improved strength and energy absorption capacities. New highly alloyed steel grades have been studied for a few years now, due to their exceptional mechanical properties resulting from interactions between dislocation plasticity, transformation plasticity and mechanical twinning. This study deals with the mechanical properties of steel grades presenting high manganese compositions. At room temperature, several phase transformations (γ→α', γ→? and ?→α′) were found to occur when the samples are deformed. The effect of different annealing conditions on the mechanical properties and the transformation sequence is analysed. The evolution of the work‐hardening of the samples is interpreted in connection with the kinetics of the phase transformations.     

Analysis of lipids extracted from salmon (Salmo salar) heads by commercial proteolytic enzymes

Fresh salmon heads were submitted to controlled proteolysis using food‐grade commercial enzymes (Alcalase®, Neutrase® and Protamex?). The release of oil under mild conditions (60°, 2 h) compared favourably with organic solvent extraction (19.8% vs. 21.5%). Lipids extracted by solvent and lipids resulting from enzymatic processes displayed a similar content of PUFA (about 35%), mainly eicosapentaenoic acid (EPA; 8.4% vs. 7.7%) and docosahexaenoic acid (DHA; 12.1% vs. 11.9%). Thin‐layer chromatography (TLC‐FID Iatroscan) showed that the polar lipid fraction accounted for 55% of total lipids (phosphatidylethanolamine, 20.7%; phosphatidylcholine, 14.8%). Salmon head phospholipids may be more effective carriers of highly unsaturated fatty acids to specific tissues than triacylglycerols, as shown by their content in EPA (10.3 and 6.9%, respectively) and DHA (33.1 and 9.1%, respectively).     

Étude du codage acoustique effectué par la prothèse cochléaire Chorimac. Comparaison des résultats obtenus en reconnaissance automatique et humaine

The authors had studied the acoustic encoding performed by the Chorimac cochlear prosthesis for the utterances of the words of an artificial vocabulary. Then several automatic recognition policies had been studied. The following recognitions had been performed in using in different ways the prosthesis channels. Then the results had been compared with those obtained by an implanted patient in the following circumstances: all the prosthesis channels are used, or each channel is individually taken. The results show that: the automatic recognition is more efficient when all the channels are used, than with each individual channel; this is not the case for the tested implanted patient, the set of most efficient channels is shifted towards the high frequencies for the patient (compared with automatic recognition), the patient’s performances are below those obtained through automatic methods, mostly for the vowels [a], [i], [o], the utilization of too many channels on the prosthesis is not a benefit for the patient who cooperated to this study, the non transmission of the pitch leads to an important loss of information, and the phonemes perception do not match exactly the models in use; to take account of the patient’s knowledge should improve the quality of the recognition models.     

Limit of the solid fat content modification of butter

Three ways have been undertaken to modify solid fat content of butter oil: (i) interesterification, (ii) adjunction of high-melting glycerides and (iii) joint effect of adjunction of high-melting glycerides and interesterification. A solvent-free interesterification, carried out with 1,3-specific lipase fromMucor miehei, resulted in an increase of the solid fat content (SFC) by about 114% after 48 h of interesterification. The changes in triglyceride composition induced by this method were followed by quantitative determination of triglycerides of different equivalent carbon number (ECN) and different theoretical carbon number. The major changes in the triglyceride composition occurred mainly in the concentration of three groups of triglycerides with the same ECN (ECN=38). Adding high-melting glycerides trimyristin (MMM) and tripalmitin (PPP) led to an increase of the SFC measured at 20°C as these proportions increased in the mixture. The joint effect of the addition of MMM or PPP and interesterification was quite significant, mainly for triglycerides that included myristic and palmitic acids. As far as the increase of SFC is concerned, the effect of interesterification decreases when both substrate amounts increase.     

On the use of differential equations of nonentire order to generateentire domain basis functions with edge singularity

Entire domain analytical basis functions with edge singularity are a very useful tool for analysing planar transmission lines and planar rectangular or circular circuits in a moment method solution. Analytical basis functions are limited to separable geometry. In this paper we introduce new entire domain basis functions including edge singularity at the edges of a domain with arbitrary shape. These basis functions are derived from a differential equation of nonentire order which includes a fractional derivative. The one dimensional case is considered first. In the two dimensional case the basis functions are constructed numerically using the boundary element method and the Galerkin method. The basis functions are applied in a moment method solution to analyse a shielded microstrip. The current and the electric field are calculated and compared with the results obtained by analytical basis functions