A basis for the synthesis of quasicrystals

It has been established that quasicrystals with icosahedral point group symmetry occur in a rapidly solidified Mg32 (Al, Zn)49 alloy chosen on the basis of its equilibrium crystal structure. This alloy has a natural tendency to form icosahedral atomic clusters stabilised by size difference amongst constituent atoms. Results highlight the relationship between equilibrium crystal structure and the tendency to form quasicrystals

Variation in viscous fingering pattern morphology due to surfactant-mediated interfacial recognition events

The study of the formation of finger-like patterns during displacement of a viscous fluid by a less viscous one is of technological importance. The morphology of the viscous-finger patterns generated is a function of many parameters such as the flow rate, difference in viscosities of the two fluids and the interfacial tension. We demonstrate herein that the morphology of patterns formed during viscous fingering in a Hele-Shaw cell during displacement of paraffin oil by aqueous solutions of the surfactant sodium dodecyl sulphate (SDS), is extremely sensitive to interfacial tension variation brought about by complexation of divalent cations with the surfactant SDS. The variation in morphology of the patterns formed has been quantified by measuring the fractal dimensions of structures formed in a radial Hele-Shaw cell as well as the average finger width in a linear Hele-Shaw cell. This technique shows promise for studying other interfacial phenomena in chemistry such as biorecognition as well as dynamic processes occurring at interfaces

Origin for the enhanced copper spin echo decay rate in the pseudogap regime of the multilayer high-T_c cuprates

We report measurements of the anisotropy of the spin echo decay for the inner layer Cu site of the triple layer cuprate, Hg_0.8Re_0.2Ba_2Ca_2Cu_3O_8 (T_c=126 K) in the pseudogap T regime below T_pg ~ 170 K and the corresponding analysis for their interpretation. As the field alignment is varied, the shape of the decay curve changes from Gaussian (H_0 \parallel c) to single exponential (H_0 \perp c). The latter characterizes the decay caused by the fluctuations of adjacent Cu nuclear spins caused by their interactions with electron spins. The angular dependence of the second moment (T_{2M}^{-2} \equiv ) deduced from the decay curves indicates that T_{2M}^{-2} for H_0 \parallel c, which is identical to T_{2G}^{-2} (T_{2G} is the Gaussian component), is substantially enhanced, as seen in the pseudogap regime of the bilayer systems. Comparison of T_{2M}^{-2} between H_0 \parallel c and H_0 \perp c indicates that this enhancement is caused by electron spin correlations between the inner and the outer CuO_2 layers. These results provide the answer to the long-standing controversy regarding the opposite T dependences of (T_1T)^{-1} and T_{2G}^{-2} in the pseudogap regime of bi- and trilayer systems.Comment: 4 pages, 4 figure

Growth of carbon nanotubes on quasicrystalline alloys

We report on the synthesis of carbon nanotubes on quasicrystalline alloys. Aligned multiwalled carbon nanotubes (MWNTs) on the conducting faces of decagonal quasicrystals were synthesized using floating catalyst chemical vapor deposition. The alignment of the nanotubes was found perpendicular to the decagonal faces of the quasicrystals. A comparison between the growth and tube quality has also been made between tubes grown on various quasicrystalline and SiO2 substrates. While a significant MWNT growth was observed on decagonal quasicrystalline substrate, there was no significant growth observed on icosahedral quasicrystalline substrate. Raman spectroscopy and high resolution transmission electron microscopy (HRTEM) results show high crystalline nature of the nanotubes. Presence of continuous iron filled core in the nanotubes grown on these substrates was also observed, which is typically not seen in MWNTs grown using similar process on silicon and/or silicon dioxide substrates. The study has important implications for understanding the growth mechanism of MWNTs on conducting substrates which have potential applications as heat sinks

Regeneration Guidelines Finger Millet

Finger millet (Eleusine coracana (L.) Gaertn.) is an important subsistence cereal in parts of Africa and south Asia. The species has two subspecies, africana (Kenn.-O’Byrne) K.W. Hilu & de Wet and coracana (L.) Gaertn. Subspecies africana has two Finger millet (Eleusine coracana (L.) Gaertn.) is an important subsistence cereal in parts of Africa and south Asia. The species has two subspecies, africana (Kenn.-O’Byrne) K.W. Hilu & de Wet and coracana (L.) Gaertn. Subspecies africana has two races, africana and spontanea, while subspecies coracana has four races: elongata, plana, compacta and vulgaris (Prasada Rao et al. 1993). Finger millet is mostly self-pollinating, with some amount of cross-pollination (1%) mediated by wind (Jansen and Ong 1996; Purseglove 1972). Finger millet is very adaptable to a wide range of environmental and climatic conditions, thrives at higher elevations than most other tropical cereals and tolerates salinity better than most cereals. races, africana and spontanea, while subspecies coracana has four races: elongata, plana, compacta and vulgaris (Prasada Rao et al. 1993). Finger millet is mostly self-pollinating, with some amount of cross-pollination (1%) mediated by wind (Jansen and Ong 1996; Purseglove 1972). Finger millet is very adaptable to a wide range of environmental and climatic conditions, thrives at higher elevations than most other tropical cereals and tolerates salinity better than most cereals

Regeneration guidelines: sorghum.

orghum (Sorghum bicolor (L.) Moench.) belongs to the Poaceae family and is widely cultivated. It is considered to be one of the most important cereal crops in the world. There are about 30 Sorghum species; S. bicolor is cultivated for grain and forage while S.halepense (L.) Pers. (Johnson grass) and S. propinquum (Kunth) Hitchc. are cultivated only for forage. Wild relatives of sorghum include S. bicolor subsp. verticilliflorum (Steud.) de Wet ex Wiersema & J. Dahlb. (common wild sorghum; synonym: S. arundinaceum), Sorghum purpureosericeum (Hochst. ex A. Rich.) Asch. & Schweinf. and Sorghum versicolor (Andersson). Sorghum is an important part of the diet for many of the world’s population. It is mainly consumed as flat bread or porridge. It is also used as a forage crop (ICRISAT 2008) and sweet sorghum is grown to produce sorghum syrup. Sorghum is extremely drought-tolerant, making it an excellent choice for semi-arid and dry areas. Most cultivars are annuals although some are perennial. Sorghum stems may reach over 4 m height, with small grains of 3–4 mm diameter. It is usually grown in clumps. The inflorescence varies greatly in size and shape, ranging from loose drooping branches to a compact-oval shape (IBPGR and ICRISAT 1993). Although it is mostly self-pollinating, protogyny may cause at least 5% natural cross- pollination (Purseglove 1972). The genetic integrity of sorghum accessions is thus maintained by selfing