Characterization of magnetic forces by means of suspended particles in paramagnetic solutions

A new technique, whereby the so-called "iso-directional-force lines" may be illustrated directly, is proposed. The method is based on the levitation forces acting on a particle immersed in paramagnetic fluid in nonhomogeneous magnetic field. An ordered set of capillaries, each containing a small particle suspended in the fluid, may be used to depict the iso-directional-force lines by the equilibrium positions of the particles. Once the field is mapped (by a selected standard system), its characteristics are known, with respect to any other fluid particle combinations. The latter is of significance for research and technology.     

Summary of the Intercomparison of the Force Standard Machines of the National Institute of Standards and Technology,USA, and the Physikalisch-Technische Bundesanstalt,Germany

A comparison of force measurements performed at the National Institute of Standards and Technology, USA, and at the Physikalisch-Technische Bundesanstalt, Germany is reported. The focus of the study was the intercomparison of the forces realized by the two Institutes rather than the measurement process. The transfer standards used in the comparison consisted of force transducers and associated readout instrumentation. The results of the intercomparison reveal that over a range of 50 kN to 4.5 MN, the forces realized at NIST and at PTB compare favorably. For forces up to 900 kN the agreement is within ±40 ppm; above 900 kN the agreement is within ± 100 ppm.     

Second-viscosity phenomena in dilute solutions of3He in superfluid4He

A theory of second-viscosity phenomena in dilute solutions of³He in superfluid⁴He is presented. The theory considers only phonon and³He quasiparticle excitations and is therefore valid at temperatures below about 0.6 K. It is shown, by an exact calculation, that within the framework of the Landau-Pomeranchuck model for the³He quasiparticle excitation energy, the four second-viscosity coefficients are related to one another and that only one of them is actually an independent kinetic coefficient. The relations between the second-viscosity coefficients are applied to analyze the expressions for the dissipative function and the first- and the second-sound attenuation coefficients. It is shown that the second-viscosity contribution to the second-sound attenuation is smaller by an order of magnitude than its contribution to the first-sound attenuation.     

The nuclear magnetic susceptibility of dilute solutions of3He in4He at low temperatures

A theory of the nuclear magnetic susceptibility of dilute solutions of ³ He in ⁴ He at low temperatures is presented. It is shown that ^–1 is a linear function of the corresponding inverse free fermion magnetic susceptibility. It is also shown that the experimental Curie constant differs from the theoretical one by an amount which is of the order of the ³ He concentration. It follows that the existing experimental results are not adequate for the calculation of the Fermi liquid magnetic susceptibility enhancement factor.     

Heat dissipation in graphene foams

Graphene foam(GF)—a three-dimensional network of hollow graphene branches—is a highly attractive material for diverse applications.However,to date,the heat dissipation characteristics of GFs have not been characterized.To fill this gap,we synthesized GF devices,subjected them to high temperatures,and investigated their thermal behavior by using infrared microthermography.We find that while the convective area of GF devices is comparable to that of bulk materials(such as metals),the coefficient of convection of these devices is several orders of magnitude higher than that of metals.In addition,the GF devices showed a reproducible thermal behavior,which we attribute to negligible temperature-induced morphological changes(as confirmed by Raman analysis).Taken together,our findings suggest GF as a promising candidate material for advanced cooling applications where efficient heat dissipation is needed,e.g.,in electrical circuits.     

Activation and metacognition of inaccessible stored information: Potential bases for incubation effects in problem solving.

Two experiments were conducted with a hybrid procedure that involved a battery of indirect criterion tests designed to study the activation and metacognition of inaccessible stored information. In each experiment, subjects first attempted to recall some rare target words in response to a series of definitions meant to cue retrieval from long-term semantic memory. For the words that could not be recalled initially, the subjects rated their feelings of knowing. They then performed a lexical-decision task in which the target words and other control words were presented. Reaction times were measured as a function of the feeling-of-knowing ratings and the length of the interval between the initial exposure to the definitions and the subsequent lexical decisions. Faster decisions occurred for the target words than for the controls, especially when strong feelings of knowing had been expresseed about the targets. Similar facilitation was obtained in a subsequent old-new recognition task. It appears that unsuccessful attempts to retrieve inaccessible stored information prime the later recognition of the information through a process of spreading activation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The oxidation mechanism of Fe-Ni-Co alloys

A mechanism of oxide film growth via outward iron cation migration during thermal oxidation of Fe-Ni-Co alloys in air, steam and carbon dioxide at 485°C is suggested. This mechanism is supported by literature data, and experimental results obtained by Auger electron spectroscopy and depth profile determination, SEM-XES analysis and X-ray diffraction.