Mode Selection in the Spontaneous Motion of an Alcohol Droplet

An alcohol (pentanol) droplet exhibits spontaneous agitation on an aqueous solution, driven by a solutal Marangoni effect. We found that the droplet's mode of motion is controlled by its volume. A droplet with a volume of less than $0.1 \mu\rm{l}$ shows irregular translational motion, whereas intermediate-sized droplets of $0.1-200 \mu\rm{l}$ show vectorial motion. When the volume is above $300 \mu\rm{l}$, the droplet splits into smaller drops. These experimental results regarding mode selection are interpreted in terms of the wave number selection depending on the droplet volume.Comment: 4 pages, 5 figure

The magnetic anomaly and NRM directions of Odessa octahedrite

The magnetic anomaly of the Odessa octahedrite (3.7 kg, a single crystal) was measured at 1, 5, 10, and 40 cm from the surface using a uniaxial fluxgate magnetometer in a μ-metal magnetic shield environment. The NRM directions of cubic subsamples were measured to take into consideration the role of the octahedron crystallography during AF demagnetization. These results indicated that the observed anomalies are strongly controlled by the shape anisotorpy of the sample rather than the crystallography of the octahedrite, although weak complicated anomalies which may be related to structure appeared above 1 cm from the surface. The natural remanent magnetization of cubic subsamples was controlled by the octahedral γ(111) planes, as demagnetized directions occurred along these planes. Namely, the preferable direction of NRM is the intersection among the great circles of γ(111) crystallographic planes which are consistent with the result obtained by A. Brecher and L. Albright (J. Geomagn. Geoelectr., 29, 379, 1977). The origin of the stable NRM component was investigated using the results of microscopic analysis, thermomagnetic curve and hysteresis parameters. Consequently, we concluded that small amounts of taenite grains and lamellae carry the stable component which is distributed along the octahedral γ(111) planes

Magnetic properties of high petrologic grade L-LL chondrites: Tenham,Tuxtuac,Willard and Forrest(b)

Temperature dependence of the hysteresis parameters (saturation magnetization, Js; saturation remanent magnetization, Jr; coercivity, Hc; and initial susceptibility, Xi) were examined from room temperature to 780℃ for Tenham (L6), Tuxtuac (LL5), Willard (L6) and Forrest (b) (L6) chondrites. Their main magnetic minerals were determined from the analyses of transition temperatures (Θ_, Θ_, Θ_). The NRM characteristics of these chondrites were measured and are discussed on the basis of magnetic properties. The main magnetic minerals of the Tenham chondrite are taenite (γ-(Fe, Ni)) with 54 at % Ni and kamacite (α-(Fe, Ni)) with 7 at % Ni, and the main NRM carrier is taenite. Tenham has a stable NRM. Tuxtuac mainly contains tetrataenite and taenite (the ratio tetrataenite : taenite is 15 : 85,T. NAGATA et al., Mem. Natl Inst. Polar Res., Spec. Issue, 41,364,1986) and they both contribute to NRM. The NRM of Tuxtuac is rather unstable magnetically. The main magnetic minerals of the Willard chondrite are the same as those of Tenham, i. e. taenite with 54 at % Ni and kamacite with 7 at % Ni. The main NRM carrier is taenite. Willard has an unstable NRM. Forrest is suggested to have experienced some alteration, on the basis of the analysis of the Js-T curve, and may have acquired a secondary NRM of probable terrestrial origin

Magnetic contaminations of small iron meteorites, Odessa and Gibeon

Small samples of Odessa iron meteorites and Gibeon iron meteorites were studied to assess any magnetic contaminations acquired after the meteorites reached the surface of the earth. Odessa showed a stable component of natural remanent magnetization (NRM) present during AF demagnetization up to 50mT. The NRM intensity decreased from one side to the other side with the exception of an interior sample. These variations in NRM might be acquired by artificial magnetic contamination, which is supported by the REM (the ratio of NRM to saturation isothermal remanent magnetization (SIRM)) value proposed by WASILEWSKI and DICKINSON (1998). The Gibeon\u27s subsample directions with stronger NRM intensities made one cluster and those weaker intensities clustered at a different site. According to the REM values, the more intense NRM\u27s might be the result of a magnetic contamination overprint. From these experimental subsamples analyses, from small iron meteorites, we find that the possibility of magnetic contamination must be considered during NRM analyses of meteorite magnetism

Drift instability in the motion of a fluid droplet with a chemically reactive surface driven by Marangoni flow

We theoretically derive the amplitude equations for a self-propelled droplet driven by Marangoni flow. As advective flow driven by surface tension gradient is enhanced, the stationary state becomes unstable and the droplet starts to move. The velocity of the droplet is determined from a cubic nonlinear term in the amplitude equations. The obtained critical point and the characteristic velocity are well supported by numerical simulations.Comment: 9 pages, 4 figure

Magnetic properties of the mixtures of Fe-Ni alloys simulated to Y-74354, Y-74362 and Y-74190 chondrites

The magnetic properties of the mixtures of Fe-Ni alloys simulated to Y-74354,Y-74362 and Y-74190 chondrites have been investigated by magnetic measurements and the Mossbauer effect. It was explained from the martensitic transformation that the intensity of RM decreased after cooling at 77K in zero magnetic field and was enhanced by cooling in geomagnetic field. The phase changes were observed by the Mossbauer effect. The thermo-magnetic properties were also discussed

Genome-Wide Association Study of Coronary Artery Disease

Coronary artery disease (CAD) is a multifactorial disease with environmental and genetic determinants. The genetic determinants of CAD have previously been explored by the candidate gene approach. Recently, the data from the International HapMap Project and the development of dense genotyping chips have enabled us to perform genome-wide association studies (GWAS) on a large number of subjects without bias towards any particular candidate genes. In 2007, three chip-based GWAS simultaneously revealed the significant association between common variants on chromosome 9p21 and CAD. This association was replicated among other ethnic groups and also in a meta-analysis. Further investigations have detected several other candidate loci associated with CAD. The chip-based GWAS approach has identified novel and unbiased genetic determinants of CAD and these insights provide the important direction to better understand the pathogenesis of CAD and to develop new and improved preventive measures and treatments for CAD