Simulated changes in fatty acid intake in humans through n‐3 fatty acid enrichment of foods from animal origin

The ratio of n‐6 over n‐3 fatty acids (FA) in the Western diet is today on average between 10 and 15, while evidence suggests that humans would benefit substantially from a more balanced intake. Different strategies to reverse this trend can potentially be adopted. This paper explores the effect of n‐3 enrichment at the level of primary animal production on human FA intake. Consumption data from adolescents were linked to ‘currently available’ and to simulated ‘enriched’ FA profiles of foods from animal origin (by feeding α‐linolenic‐rich diets to pigs, dairy and beef cattle, and broiler and layer chickens). Under enriched conditions, population intakes for α‐linolenic acid and for all n‐3 FA shifted to recommended values. For long‐chain n‐3 polyunsaturated FA, the favourable trend in intake was not sufficient to meet recommendations. The effect on other FA was small. The n‐6/n‐3 ratio decreased considerably from an average value of 6.6 to 4.6. It is concluded that feasible and realistic n‐3 FA enrichments of foods from animal origin can add substantially to the overall efforts for reducing the n‐6/n‐3 intake ratio in the population. However, foods rich in long‐chain n‐3 FA remain essential in the human diet under such conditions. Copyright © 2006 Society of Chemical Industry     

Dedensification and Anomalous Grain Growth during Sintering of Undoped Barium Titanate

Dedensification (up to 10% of the theoretical density in some instances) occurs at temperatures of .1320°C during the sintering of commercial undoped BaTiO₃ powders. The expansion of the rigid, interconnected network of large, rounded grains that grow by the Ostwald ripening effect can explain the dedensification that is observed. The isotropic anomalous grain growth results from the appearance of a liquid phase at } 1320°C and induces tensile stresses on the residual porous fine-grained matrix. No dedensification was observed at temperatures of, 1320°C, despite anisotropic anomalous grain growth.     

Internal stresses due to dislocation walls around second phase particles

Nickel base superalloys with large γ′ volume fractions exhibit a high threshold stress during a tensile test, and a large internal stress when tested in high temperature creep. Arrays of regularly spaced edge dislocations which develop during the first stages of creep have been observed. They lie in the γ-γ′ interfaces and form dipolar arrangements on opposite sides of the γ′ cuboids. The various components of the stress tensor are calculated for such a dipolar wall configuration and mapped by drawing equistress lines. The stress field resulting from such dislocation configurations has a very strong component along the tensile axis and opposes the applied stress. The shear component in the glide plane of similar dislocations is also very large between the precipitates and would tend to repel any new dislocation, in the absence of an external stress. The structural instability of these alloys under creep strain is also interpreted by this model.     

An analytical two-temperature model for convection-diffusion in multilayered systems: Application to the thermal characterization of microchannel reactors

The main purpose of this paper is to implement some convenient analytical solutions of the two-dimensional convection-diffusion equations in a multilayered system, in the form of some relationships between average temperature fields, based on the thermal quadrupole formalism. Some equivalent analogical networks are proposed in order to implement the model in a more convenient form, based on the electrical analogy. The important advantage of such approach is to connect different layers through simple network connections between the respective interface variables. Special emphasis is laid on the case where the lateral boundary conditions correspond to insulated walls. The transient case is also presented, for non-insulated lateral boundary conditions, coupled with a third layer. Some examples are given in order to illustrate the suitability of the proposed model in the case of temperature field image processing in a microfluidic chip.     

LIFETIME PREDICTION ON Cr-Mo-V AND 316L STEELS UNDER THERMAL AND MECHANICAL CYCLING

The thermal-mechanical fatigue resistance of a Cr-Mo-V steel and a 316L steel under combined complex mechanical strain and temperature cycling has been evaluated. The applicability to thermal-mechanical lifetime prediction of several isothermal fatigue damage concepts is investigated. From a designer viewpoint, some predictions are well acceptable, in particular with the Degallaix thermal activation model for which a recent development is reported.     

Etude et réalisation de diviseurs de fréquence analogiques à diode à avalanche

In this paper the potential interest of analog avalanche diode frequency dividers is demonstrated. Their fundamental operation principle relies on the use of an idler signal. Experiments performed on avalanche diode frequency dividers with division ratios of 2, 3 and 4 in the centimeter wave range have pointed out the possibility of wide instantaneous bandwidth and interestingrf conversion efficiencies.     

A two chips set — full parallel process for framing equipment in sdh compatible radiolinks

ccitt has standardised a new synchronous interface named sdh (Synchronous Digital Hierarchy). Considering the importance of transmission-medium compatibility between radio and optical fibre systems, Alcatel Telspace has developed sdh based digital radio systems. In order to provide a direct access to all the section overhead bytes (soh) in the stm-1 frame and the insertion/extraction of radio overhead bytes for media specific usage, two cmos integrated circuits were designed, operating in a parallel process at 40 MHz data rate, in order to respect a full transparency criterion, necessary for a short synchronisation time on the whole radio link.     

Filtre correcteur de phase pour égaliseurs sous-optimaux

We propose a receiver structure intended for high bit rate transmissions. In order to ensure a good compromise between performance and complexity, the receiver is composed of a transversal phase- corrective filter followed by an equaliser, which takes only partially the channel impulse response into account. We propose a non-iterative technique to adjust the filter tap coefficients, based on the cepstral properties of a minimum phase response. The performance of the filter is evaluated and shown by simulating a transmission system including a multipath mobile radio channel, the filter and a dfse equaliser (decision feedback sequence estimator).