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The structure and magnetic properties of nanocrystalline PrCo3 prepared by high-energy milling technique have been investigated by means of x-ray diffraction using the Rietveld method coupled to Curie temperature and magnetic measurements. The as-milled samples were subsequently annealed in temperature range from 750 to 1050 °C for 30 min to optimize the extrinsic properties. From x-ray studies of magnetic aligned samples, the magnetic anisotropy of this compounds is found uniaxial. The Curie temperature is 349 K and no saturation reached at room temperature for applied field of 90 kOe. The coercive field of 55 kOe and 12 kOe measured at 10 K and 293 K, respectively is obtained after annealing at 750 °C for 30 min suggests that nanocrystalline PrCo3 are interesting candidates in the field of permanent magnets. We have completed this experimental study by simulations in the micromagnetic framework in order to get a qualitative picture of the microstructure effect on the macroscopic magnetization curve. From this simple model calculation, we can suggest that the after annealing the system behaves as magnetically hard crystallites embedded in a weakly magnetized amorphous matrix. [ABSTRACT FROM AUTHOR]

Neutron powder diffraction, magnetic measurements and electronic band structure calculations were performed on PrCo 3 − x Fe x compounds. Our study confirms that samples crystallize in the PuNi 3 -type structure (space group: R 3 ¯ m , 166) for x ≤ 1 . The substitution of iron for cobalt atom leads to an increase of the unit cell volume. Neutron powder diffraction measurements at room temperature on PrCo 2.5 Fe 0.5 demonstrate that iron atoms prefer to occupy the 18 h crystallographic site of the PuNi 3 structure ( R 3 ¯ m ). In addition to the experimental study, theoretical investigation of the electronic structure, stability as a function of x -rate, and magnetic property of the PrCo 3 − x Fe x compounds are studied by first-principle calculations. The density of states for the PrCo 3 − x Fe x compounds in the two directions of spin showed that the majority occupied states are dominated by the 3 d states of M atoms ( M =Co, Fe) with an electronic charge transfer from Pr to M . The magnetic anisotropy has been confirmed for PrCo 3 − x Fe x compounds, since non-collinear spin calculation with moment oriented along the c -axis has been found more stable than those along the ( a , b ) plane. [ABSTRACT FROM AUTHOR]

Abstract: We have studied nanocrystalline of PrCo3−x Fe x prepared by high energy milling technique. The as-milled samples were subsequently annealed in the temperature range from 873 to 1273K for 30min in order to optimize their extrinsic properties. Their structural and magnetic properties were investigated by means of X-ray diffraction (XRD) coupled with Curie temperature determination and magnetization measurements. These compounds crystallize in the PuNi3-type structure (space group: ) for . The composition is in a three phase field Pr(Co,Fe)3, Pr2(Co,Fe)17 and Pr(Co,Fe)2, for , and then is in two phase field Pr2(Co,Fe)17 and Pr(Co,Fe)2 for larger x. The Rietveld refinement showed that the substitution of cobalt by iron leads to an increase of the unit cell volume. The Curie temperature (T C ) of the PrCo3−x Fe x samples increases from 350K for PrCo3 to 580K for PrCo2Fe, the enhancement of T C is ruled by electronic and magnetovolumic effects. From X-ray studies of magnetically aligned samples, the magnetic anisotropy of these compounds changes from the c-axis to the cone anisotropy. The magnetization of the compounds increases as cobalt is replaced by iron and no saturation reached at room temperature for an applied field of 90kOe. The hard magnetic properties are obtained after annealing at 1023K for 30min where the coercivity achieved H C =5kOe. [Copyright &y& Elsevier]

Abstract: In nanocomposite magnetic materials the exchange coupling between phases plays a central role in the determination of the extrinsic magnetic properties of the material: coercive field,remanence magnetization. Exchange coupling is therefore of crucial importance in composite systems made of magnetically hard and soft grains or in partially crystallized media including nanosized crystallites in a soft matrix. It has been shown also to be a key point in the control of stratified hard/soft media coercive field in the research for optimized recording media. A signature of the exchange coupling due to the nanostructure is generally obtained on the magnetization curve M(H) with a plateau characteristic of the domain wall compression at the hard/soft interface ending at the depinning of the wall inside the hard phase. This compression/depinning behavior is clearly evidenced through one dimensional description of the interface, which is rigorously possible only in stratified media. Starting from a local description of the hard/soft interface in a model for nanocomposite system we show that one can extend this kind of behavior for system of hard crystallites embedded in a soft matrix. [Copyright &y& Elsevier]

Driving is often a highly complex task mainly because of the growing traffic density. Car manufacturers and equipment suppliers propose more and more driving assistance systems in order to keep safety at the higher possible level. Some of these assistance systems deal with longitudinal aspects of the driving task (ABS, ACC…) but few with lateral aspects. However, systems dedicated to the prevention of hazardous lane changes should significantly improve road safety. Our work focuses on this issue and aims, in a first step, at a better knowledge of driving behaviors during overtaking situations. [ABSTRACT FROM AUTHOR]

Abstract: The structure and magnetic properties of ball-milled and subsequently annealed Sm2Fe17–x M x compounds (M = Si, Ga, Co, Cr, Zr, Mo, for x = 2) were investigated by X-ray diffraction coupled with magnetic measurements and Mössbauer spectroscopy. Rietveld analysis have shown that all these samples crystallize in the Th2Zn17 type rhombohedral structure. The substituting elements Si, Ga, Co occupy the 18h atom site, while Cr, Zr, Mo prefer the 6c site. Mössbauer studies corroborate these results. The X-ray analysis cannot solve the possible M atom distribution over Fe atom sites when atomic factors of Fe and M are close. Mössbauer spectroscopy appears as the efficient tool to raise this ambiguity. The Curie temperature increases upon Zr and Cr substitution reaching a maximum for x = 1, then decreases because of magnetic dilution. [Copyright &y& Elsevier]

Background: Some patients have features that indicate possible difficulty with direct laryngoscopy for tracheal intubation. Prediction of the likely outcome and selection of patients for an enhanced management algorithm would reduce the possible harm from failed intubation attempts.Methods: Adult elective patients were assessed for seven features associated with difficult direct laryngoscopy, ranked in difficulty from 0 to 3. For a patient with at least one Class 3 feature, or two or more features of class 1 or higher, the enhanced management used a channelled videolaryngoscope Airtraq™ instead of a Macintosh laryngoscope. A long flexible angulated stylet and a flexible fibrescope would be used as the second and third steps. For patients with lesser difficulty scores, a Macintosh laryngoscope was used. Outcomes of enhanced management were analysed. Logistic regression and Random Forest algorithm, using the ranks of the predictive features, were used to predict difficulty during enhanced management.Results: We prospectively studied 16 695 patients. We selected 1501 (9%) for enhanced management, and tracheal intubation was successful in all of them. Of these, 73% were intubated in less than 30 s, and only 4.5% required more than 4 min for intubation. Progression to the second and third steps of enhanced management was predicted by restriction of mouth opening and reduced cervical spine mobility.Conclusions: An enhanced management algorithm allowed successful tracheal intubation of all patients with anticipated difficult laryngoscopy. The need to combine the use of a stylet and a fibrescope with the Airtraq™ could be predicted with a high degree of certainty. [ABSTRACT FROM AUTHOR]