Isotopic families of contact manifolds for elliptic PDE

A test for a function to be a solution of an elliptic PDE is given in terms of extensions, as solutions, from the boundaries inside the domains belonging to an isotopic family. It generalizes a result of Ehrenpreis for spheres moved along a straight line.

     

Polarized Lidar Reflectance Measurements of Vegetation at Near-Infrared and Green Wavelengths

There is growing interest in the use of lidar for remote sensing of vegetation owing to the emergence of reliable and rugged lasers and highly sensitive detectors. Lidar remote sensing has a distinct advantage over conventional techniques in vegetation remote sensing due to its capability for three-dimensional characterization of vegetative targets. The Multiwavelength Airborne Polarimetric Lidar (MAPL) system was developed primarily for vegetation remote sensing applications from an airborne platform of up to 1,000 -m altitude. The lidar system has full waveform capture and polarimetric measurement capability at two wavelengths in the near-infrared (1064 nm) and the green (532 nm) spectral regions. This study presents preliminary ground-based lidar reflectance measurements on a variety of deciduous and coniferous trees under fully foliated conditions with a view towards tree species discrimination. Variations in the reflectance characteristics of selected deciduous trees under unfoliated and fully foliated conditions were also investigated. Our study reveals distinct differences in the reflectance characteristics of various trees.     

Comments on quasiparticle models of quark–gluon plasma

Here we comment on the thermodynamic inconsistency problem and the reformulation of statistical mechanics of widely studied quasiparticle models of quark–gluon plasma. Their starting relation, the expression for pressure itself is a wrong choice and lead to thermodynamic inconsistency and the requirements of the reformulation of statistical mechanics. We propose a new approach to the problem using the standard statistical mechanics and is thermodynamically consistent. We also show that the other quasiparticle models may be obtained from our general formalism as a special case under certain restrictive condition. Further, as an example, we have applied our model to explain the nonideal behaviour of gluon plasma and obtained a remarkable good fit to the lattice results by adjusting just a single parameter.     

Cobalt Hexacyanoferrate-Modified Electrode for Amperometric Assay of Hydrazine

A graphite electrode modified with cobalt hexacyanoferrate by mechanical immobilization was used for amperometric determination of hydrazine. The modified electrode exhibits good catalytic activity for the oxidation of hydrazine at a reduced overpotential with remarkable sensitivity. The modified electrode showed a linear response for hydrazine in the concentration range of 2.0 × 10^–5 to 2.8 × 10^–4 M. The detection limit was 9.8 × 10^–6 M (S/N = 3). The proposed modified electrode was simple, sensitive, rapid, stable and promising.     

Topology evolution and gelation mechanism of agarose gel

Kinetics as well as the evolution of the agarose gel topology is discussed, and the agarose gelation mechanism is identified. Aqueous high melting (HM) agarose solution (0.5% w/v) is used as the model system. It is found that the gelation process can be clearly divided into three stages: induction stage, gelation stage, and pseudoequilibrium stage. The induction stage of the gelation mechanism is identified using an advanced rheological expansion system (ARES, Rheometric Scientific). When a quench rate as large as 30 deg C/min is applied, gelation seems to occur through a nucleation and growth mechanism with a well-defined induction time (time required for the formation of the critical nuclei which enable further growth). The relationship between the induction time and the driving force which is determined by the final setting temperature follows the 3D nucleation model. A schematic representation of the three stages of the gelation mechanism is given based on turbidity and rheological measurements. Aggregation of agarose chains is promoted in the polymer-rich phase and this effect is evident from the increasing mass/length ratio of the fiber bundles upon gelation. Continuously increasing pore size during gelation may be attributed to the coagulation of the local polymer-rich phase in order to achieve the global minimum of the free energy of the gelling system. The gel pore size determined using turbidity measurements has been verified by electrophoretic mobility measurements.     

Preparation and thermal stability of trioxalatocobaltates of bivalent metals KM2+ [Co(C2O4)3]·xH2O

Trioxalatocobaltates of bivalent metals KM²⁺[Co(C₂O₄)₃]·x H₂O, with M²⁺ = Ba, Sr, Ca and Pb, have been prepared, characterized and their thermal behaviour studied. The compounds decompose to yield potassium carbonate, bivalent metal carbonate or oxide and cobalt oxide as final products. The formation of the final products of decomposition is influenced by the surrounding atmosphere. Bivalent metal cobaltites of the types KM²⁺CoO₃ and M²⁺CoO_3—x are not identified among the final products of decomposition. The study brings out the importance of the decomposition mode of the precursor in producing the desired end products.     

On the claisen rearrangement of 1,4-diaryloxy-2-butynes

A proton nmr follow-up provided conclusive evidence for the involvement of two sequential Claisen rearrangements in the thermal rearrangement of 1,4-diaryloxy-2-butynes $\text{1}$to 11a-methylpterocarpans $\text{3}$. A detailed study of the rearrangement of 1,4-diaryloxy-2-butynes $\text{1}$ in polyethyleneglycol-200 (PEG-200), indicated a definite possibility of selective synthesis of either benzofuron (3,2-b )benzofuran $\text{4}$ or benzofuro(2,3-b)benzofuran $\text{5}$ by varying the temperature of the reaction alone     

Anion mediated polytype selectivity among the basic salts of Co(II)

Basic salts of Co(II) crystallize in the rhombohedral structure. Two different polytypes, 3R₁ and 3R₂, with distinct stacking sequences of the metal hydroxide slabs, are possible within the rhombohedral structure. These polytypes are generated by simple translation of successive layers by (2/3, 1/3, z) or (1/3, 2/3, z). The symmetry of the anion and the mode of coordination influences polytype selection. Cobalt hydroxynitrate crystallizes in the structure of the 3R₂ polytype while the hydroxytartarate, hydroxychloride and α-cobalt hydroxide crystallize in the structure of the 3R₁ polytype. Cobalt hydroxysulfate is turbostratically disordered. The turbostratic disorder is a direct consequence of the mismatch between the crystallographically defined interlayer sites generated within the crystal and the tetrahedral symmetry of the SO₄²⁻ ions.