Collapse of the charge ordering gap of Nd_{0.5}Sr_{0.5}MnO_{3} in an applied magnetic field

We report results of tunneling studies on the charge ordering compound Nd_{0.5}Sr_{0.5}MnO_{3} in a magnetic field up to 6T and for temperature down to 25K.We show that a gap (2\Delta_{CO} \approx 0.5eV opens up in the density of state (DOS) at the Fermilevel (E_F) on charge ordering (T_{CO}=150K) which collapses in an applied magnetic field when the charge ordered state melts. There is a clear correspondence between the behavior of the resistivity and the gap formation and its collapse in an applied magnetic field. We conclude that a gap in the DOS at E_F is necessary for the stability of the charge ordered state.Comment: 4 pages REVTeX, 5 postscript figures included, submitted to Phys. Rev. Let

Experimental Investigation on the Effect of Casting Parameters on Thin walled Castings of Metal Matrix (LM21-SiC) Composite

 Metal matrix composites (MMCs) are widely used in several applications owing to their high strength, high specific stiffness, greater wear resistance and light weight. Normally, MMCs are processed through stir casting which exhibits poor wet ability and bonding between metal matrix and ceramic reinforcement, porosity and hot tears. These drawbacks can be overcome by squeeze casting process. Here an attempt was made on processing LM21-Sic composite for making hollow casting through squeeze casting process. Four process parameters are chosen namely squeeze pressure, stirring speed, melt temperature and reinforcement percentage. The primary objective was to experimentally investigate the influence of casting parameters on hardness & wear. Samples were cast for each experiments condition based on L9 orthogonal array. From the analysis of variance (ANOVA), it was observed that stirring speed, reinforcement percentage and Squeeze load were the process parameters making a noticeable improvement in hardness and wear. The mechanical properties such as hardness and wear are evaluated and optimum casting condition was obtained

Optimization of Process Parameters in Stir Casting of Hybrid Metal Matrix (LM25/SiC/B4C) Composite Using Taguchi Method

Aluminium based composites exhibit many attractive material properties such as increased stiffness, wear resistance, specific strength and vibration damping and decreased co-efficient of thermal expansion compared with the conventional aluminium alloys. Aluminium Matrix Composites consist of non-metallic reinforcement which offers advantageous properties over base material. Reinforcements like SiC, B4C and Al2O3 are normally preferred to improve the mechanical properties. Here Aluminum LM25 is selected as matrix material while Silicon carbide and Boron carbide are selected as reinforcement material. The fabrication of aluminium matrix was done by stir casting method. In the present study an attempt has been made to investigate the effect of three major stir casting parameters (stir speed, stir duration and preheated temperature of reinforcement material) on stir casting of Aluminium LM25 - SiC - B4C composite. Experiments were conducted based on Taguchi methodology. Taguchi quality design concepts of L9 orthogonal array has been used to determine S/N ratio and through S/N ratio a set of optimum stir casting parameters were obtained. The experimental results confirmed the validity of Taguchi method for enhancing tensile strength of castings.&nbsp

Effect of fertigation on the productivity of coconut

An experiment to study the effect of fertigation on the productivity of coconut was laid out at Horticulture Research Station, Arsikere, Karnataka during 2007-08 to 2011-12. Application of 25, 50, 75 and 100 per cent of recommended NPK through drip irrigation system was compared with the soil application of recommended NPK as well as control with no fertilizer application. Fertilizers were given through drip irrigation system throughout the year in ten equal splits at monthly interval excluding peak rainfall months of May and October. Application of 100 per cent NPK through drip irrigation recorded significantly higher number of female flowers and nut setting percentage compared to control and application of 25 per cent NPK through drip irrigation. The mean nut and copra yield per palm over five years was significantly higher with the application of 100 per cent NPK through drip irrigation compared to control and application of 25 and 50 per cent NPK through drip irrigation. However, the copra content was not significantly influenced by the fertigation treatments. Application of 75 per cent NPK through drip irrigation recorded nut and copra yield per palm on par with the application of 100 per cent NPK through drip irrigation and 100 per cent NPK through soil. The net returns and benefit-cost ratio in 75 per cent NPK through drip irrigation were also on par with the application of 100 per cent NPK through drip irrigation, but significantly higher than 100 per cent NPK through soil application. The study indicated the possibility of saving 25 per cent of the recommended fertilizers by adopting fertigation which ensures higher productivity in coconut

Intercropping of medicinal and aromatic plants in coconut gardens

A field study was conducted at Horticulture Research Station, Arsikere, Karnataka during 2006-07 to 2008-09 to identify suitable medicinal and aromatic plants for intercropping in coconut gardens of maidan tract of Karnataka. The experiment consisted of 14 medicinal and aromatic crops viz., Kalmegh (Andrographis paniculata), Makoi (Solanum nigrum), Coleus (Coleus forskohlii), Garden rue (Ruta graveolens), Lepidium (Lepidium sativum), Tulsi (Ocimum sanctum), Arrow root (Maranta arundinaceae), Kacholam (Kaemferia galanga), Cowhage (Mucuna pruriens), Roselle (Hibiscus sabdariffa), Ambrette (Abelmoschus moschatus), Citronella (Cymbopogon winteranus), Lemon grass (Cymbopogon flexuosus) and Vetiver grass (Vetiveria zizanoides). The yield of all the medicinal and aromatic crops grown as intercrop in coconut garden were reduced compared to their sole crop yields. The reduction in yield was less in lemon grass (6.4 %), tulsi (23.5 %), arrow root (23.9 %), vetiver grass (25.1 %), kalmegh (25.7 %), makoi (29.1 %), citronella (30.2 %) and garden rue (30.5 %). The nut yield of coconut was improved with intercropping of medicinal and aromatic crops. The andrographolide content in kalmegh (4.40 to 3.20 %), rutin alkaloids in garden rue (1.68 to 1.40 %) and oil content in lepidium (19.60 to 17.23 %) were significantly reduced when grown as intercrops in coconut garden as compared to sole crop. However, the forskohlin content in coleus (0.43 to 0.61 %) and essential oil content in ambrette (0.24 to 0.29 %) were significantly increased by intercropping. In other medicinal and aromatic crops, the quality parameters were not significantly influenced by intercropping. The intercropping system of growing lemon grass under coconut recorded the highest net income (Rs. 91,561/ha) and B:C ratio (2.89) followed by garden rue (Rs. 81,865/ha and 2.79), tulsi (Rs. 77,472/ha and 2.71), kalmegh (Rs. 75,163/ha and 2.56), arrow root (Rs. 72,211/ha and 2.28) and makoi (Rs. 67,058/ha and 2.68). Hence, intercropping of lemon grass, garden rue, tulsi, kalmegh, arrow root and makoi with coconut can be recommended for maidan tract of Karnataka

Kinetics of DNA methylation inheritance by the Dnmt1-including complexes during the cell cycle

<p>Abstract</p> <p>Background</p> <p>The clonal transmission of lineage-specific DNA methylation patterns in a mammalian genome during the cellular division is a crucial biological process controlled by the DNA methyltransferase Dnmt1, mainly. To investigate possible dynamic mechanisms of DNA methylation inheritance during the cell cycle, we used a Proximity Ligation <it>In Situ </it>Assay (P-LISA) to analyze the kinetic of formation and DNA recruitment of Dnmt1-including complexes.</p> <p>Results</p> <p>P-LISA, sequential chromatin immunoprecipitation and quantitative methylation specific PCR revealed that the Dnmt1/PCNA/UHRF1-including complexes are mainly formed and recruited on DNA during the S-phase of cell cycle, while the formation and the DNA recruitment of several Dnmt1/transcription factors-including complexes are not S-phase dependent but are G0/G1 and/or G2/M phases dependent.</p> <p>Conclusion</p> <p>Our data confirm that DNA methylation inheritance occurs in S-phase, and demonstrate that DNA methylation inheritance can also occur in G0/G1 and G2/M phases of the cell cycle.</p

Magnetic Properties of TbNi1 xAuxIn Compounds

Polycrystalline samples of $TbNi_{1-x}Au_{x}In$ for x = 0.1, 0.2, 0.4, 0.6 and 0.8 were prepared and studied by powder X-ray and neutron diffraction and ac magnetic susceptibility measurements. These compounds crystallize in the hexagonal ZrNiAl-type structure. With increasing Au content a change in the magnetic structure is observed. For x = 0.1, 0.2 and 0.4 the magnetic order is described by the propagation vector k = (1/2, 0, 1/2) while for x = 0.8 by k = (0, 0, 1/2). Between 1.5 K and the Néel temperature the magnetic order is stable

Cooling rate dependence of the antiferromagnetic domain structure of a single crystalline charge ordered manganite

The low temperature phase of single crystals of Nd$_{0.5}$Ca$_{0.5}$MnO$_3$ and Gd$_{0.5}$Ca$_{0.5}$MnO$_3$ manganites is investigated by squid magnetometry. Nd$_{0.5}$Ca$_{0.5}$MnO$_3$ undergoes a charge-ordering transition at $T_{CO}$=245K, and a long range CE-type antiferromagnetic state is established at $T_N$=145K. The dc-magnetization shows a cooling rate dependence below $T_N$, associated with a weak spontaneous moment. The associated excess magnetization is related to uncompensated spins in the CE-type antiferromagnetic structure, and to the presence in this state of fully orbital ordered regions separated by orbital domain walls. The observed cooling rate dependence is interpreted to be a consequence of the rearrangement of the orbital domain state induced by the large structural changes occurring upon cooling.Comment: REVTeX4; 7 pages, 4 figures. Revised 2001/12/0