Hydrogen reliquefiers for lunar storage systems

Reliquifier application to eliminate propellant boil off losses in space and lunar storage system

Enhanced Andreev reflection in gapped graphene

We theoretically demonstrate unusual features of superconducting proximity effect in gapped graphene which presents a pseudospin symmetry-broken ferromagnet with a net pseudomagnetization. We find that the presence of a band gap makes the Andreev conductance of graphene superconductor/pseudoferromagnet (S/PF) junction to behave similar to that of a graphene ferromagnet-superconductor junction. The energy gap $\Delta_N$ enhance the pseudospin inverted Andreev conductance of S/PF junction to reach a limiting maximum value for $\Delta_N\gg \mu$, which depending on the bias voltage can be larger than the value for the corresponding junction with no energy gap. We further demonstrate a damped-oscillatory behavior for the local density of states of the PF region of S/PF junction and a long-range crossed Andreev reflection process in PF/S/PF structure with antiparallel alignment of pseudomagnetizations of PFs, which confirm that, in this respect, the gapped normal graphene behaves like a ferromagnetic graphene.Comment: 7.2 pages, 5 figures, accepted for publication in Phys. Rev.

Comment on "Competition between helimagnetism and commensurate quantum spin correlations in LiCu2O2"

The microscopic origin of the recently observed helical structure in LiCu2O2 [1] is considered. It is shown that the frustrated antiferromagnetic double chain scenario adopted in Ref.1 is unrealistic. It should be replaced by a frustrated single-chain (CuO2) scenario proposed in Ref. 2 with ferromagnetic nearest neighbor and antiferromagnetic next nearest neighbor exchange integrals \. [1] T. Masuda et al. Phys. Rev. Lett. 92 (2004), 177201. [2] A. Gippius et al. Phys. Rev. B 70 (2004), R01426; cond-mat/0312576.Comment: one page, one figur

Global Warming: Global Warning for Local Actions

After decades of global warming many are still in the dark as what needs to bedone to overcome this world threat that affects single citizen of the planet earth. The word ‘sustainability' has been used very loosely, some not knowing the exact meaning of it only with intentions to gain research grant for the academics, profit making by keeping by the general business environment, thus leading to dumping the market with green-washing products. Those who seriously know the true meaning are not many and many times frustrated with the doings of the many which do not. This presentation hopefully providesome useful insights as to what sustainability means and for the necessary green initiatives that need to be taken to reduce further aggravation of the borderless geographical environment. Future growth in all countries are converging into a common trend and therefore efforts need to be in tandem and synchronized for a more effective win against this pervasive war of the world. Most tangible efforts are normally easily observed in the socio economic trend that affects the built environment of individual countries. The commoncues of the world are that it is getting hot, flat and crowded and to overcome this force is no easy task for any nation since the rhythm and tempo of growth of each nation differs. But one thing is common, that the rate of urbanization is rapid throughout the world. It was reported that by about 2030 the land-use for urbanization will be about 75% all over the world and so a relook at the socio economic policies must be geared towards how urbanization do not worsen the already bad situation from global warming

Hematocrit Level on Blood flow through a Stenosed Artery with Permeable Wall: A Theoretical Study

The paper deals with the hematocrit level on resistance of flow, wall shear stress in a stenosed artery of permeable wall. In the paper we have developed and solved some theoretical formulas based on stenosis and hematocrit effects. The results highlight that the resistance of flow increases for increasing of stenosis height where the hematocrit level (35%-45%) has significant effects. Moreover, the effects of slip parameter and Darcy number due to permeability of the wall on resistance of flow have been investigated. The effects of hematocrit level, slip parameter and Darcy number have been focused on wall shear stress of the permeable inner surface of the artery which has a fashion of downwardly concave for increasing of the z-axis of the artery

Identifications and SEDs of the detected sources from the AKARI Deep Field South

In order to find counterparts of the detected objects in the AKARI Deep Field South (ADFS) in all available wavelengths, we searched public databases (NED, SIMBAD and others). Checking 500 sources brighter than 0.0482 Jy in the AKARI Wide-S band, we found 114 sources with possible counterparts, among which 78 were known galaxies. We present these sources as well as our first attempt to construct spectral energy distributions (SEDs) for the most secure and most interesting sources among them, taking into account all the known data together with the AKARI measurements in four bands.Comment: 4 pages, 10 figures, To appear in: the proceedings of the conference "AKARI, a light to illuminate the misty Universe", February 16-19 2009, Toky