Effect of cold stress on boro rice seedlings

Cold stress at seedling stage is a major constraint in boro rice production. Nine boro rice lines were crossed in diallel fashion excluding reciprocals to obtain 36 crosses. All the 36 crosses along with parents were grown in nursery in three seasons (boro-2014, kharif-2015 and boro-2015). Performance of seedlings for survival per cent, chlorophyll content, relative water content, membrane stability index was recorded just before transplanting in all the three seasons. Scoring for cold tolerance was done in both boro seasons. Gautam showed highest survival rate over three seasons. Among crosses, IR 64 x Krishna Hamsa showed highest survival (84%) in boro-2014, MTU 1010 x Jaya (86.33%) in boro-2015 and MTU 1010 x Krishna Hamsa (95.67%) in kharif-2015. Jaya x Krishna Hamsa was most cold tolerant cross over both boro seasons. Significant positive correlation was observed among survival per cent, chlorophyll content, relative water content and membrane stability index over seasons

Modeling Barkhausen Noise in Magnetic Glasses with Dipole-Dipole Interactions

Long-ranged dipole-dipole interactions in magnetic glasses give rise to magnetic domains having labyrinthine patterns. Barkhausen Noise is then expected to result from the movement of domain boundaries which is supposed to be modeled by the motion of elastic membranes with random pinning. We propose an atomistic model of such magnetic glasses in which we measure the Barkhausen Noise which indeed results from the movement of domain boundaries. Nevertheless the statistics of the Barkhausen Noise is found in striking disagreement with the expectations in the literature. In fact we find exponential statistics without any power law, stressing the fact that Barkhausen Noise can belong to very different universality classes. In this glassy system the essence of the phenomenon is the ability of spin-carrying particles to move and minimize the energy without any spin flip. A theory is offered in excellent agreement with the measured data without any free parameter.Comment: 5 Pages, 5 Figures, Submitted to EP

Combining ability and heterosis for yield, its component traits and some grain quality parameters in rice (Oryza sativa L.)

The experiment was conducted to estimate combining ability and heterosis for yield, yield attributing traits and few grain quality parameters in rice. The crosses were made among three CMS lines i.e., IR58025A, Pusa6A and IR68897A and seven pollen parents viz., Sarjoo-52, Jaya, Sasyashree, Swetha, HUR 5-2, PR-106 and BPT 5204. Twenty one hybrids were generated in line x tester design. The superior hybrids were identified on the basis of combining ability effect and heterosis. Cross combination IR68897A/Jaya and IR68897A/BPT 5204 exhibited good x good parental GCA effects suggesting that there is additive x additive type of gene action. The cross IR68897A/Jaya showed highest positive SCA effect. The higher magnitude of heterosis for all the yield and quality traits were not expressed in a single hybrid combination. It varied from cross to cross due to diverse genetic background of their parents. The two crosses IR68897A/Jaya and IR68897A/BPT 5204 were found to be heterotic for yield and yield traits as well as the grain quality characteristcs

Flux jumps, Second Magnetization Peak anomaly and the Peak Effect phenomenon in single crystals of YNi2B2CYNi_2B_2C and LuNi2B2CLuNi_2B_2C

We present magnetization measurements in single crystals of the tetragonal $YNi_2B_2C$ compound, which exhibit the phenomenon of peak effect as well as the second magnetization peak anomaly for H $>$ 0.5T (H $||$ c). At the lower field (50mT $<$ H $<$ 200mT), we have observed the presence of flux jumps, which seem to relate to a structural change in the local symmetry of the flux line lattice (a first order re-orientation transition across a local field in some parts of the sample, in the range of 100mT to 150mT). These flux jumps are also observed in a single crystal of $LuNi_2B_2C$ for H $||$ c in the field region from 2 mT to 25 mT, which are compatible with the occurrence of a re-orientation transition at a lower field in a cleaner crystal of this compound, as compared to those of $YNi_2B_2C$. Vortex phase diagrams drawn for H $||$ c in $LuNi_2B_2C$ and $YNi_2B_2C$ show that the ordered elastic glass phase spans a larger part of (H, T) space in the former as compared to latter, thereby, reaffirming the difference in the relative purity of the two samples.Comment: 11 pages, 14 figure

Investigation of the Dzyaloshinskii-Moriya interaction and room temperature skyrmions in W/CoFeB/MgO thin films and microwires

Recent studies have shown that material structures, which lack structural inversion symmetry and have high spin-orbit coupling can exhibit chiral magnetic textures and skyrmions which could be a key component for next generation storage devices. The Dzyaloshinskii-Moriya Interaction (DMI) that stabilizes skyrmions is an anti-symmetric exchange interaction favoring non-collinear orientation of neighboring spins. It has been shown that material systems with high DMI can lead to very efficient domain wall and skyrmion motion by spin-orbit torques. To engineer such devices, it is important to quantify the DMI for a given material system. Here we extract the DMI at the Heavy Metal (HM) /Ferromagnet (FM) interface using two complementary measurement schemes namely asymmetric domain wall motion and the magnetic stripe annihilation. By using the two different measurement schemes, we find for W(5 nm)/Co20Fe60B20(0.6 nm)/MgO(2 nm) the DMI to be 0.68 +/- 0.05 mJ/m2 and 0.73 +/- 0.5 mJ/m2, respectively. Furthermore, we show that this DMI stabilizes skyrmions at room temperature and that there is a strong dependence of the DMI on the relative composition of the CoFeB alloy. Finally we optimize the layers and the interfaces using different growth conditions and demonstrate that a higher deposition rate leads to a more uniform film with reduced pinning and skyrmions that can be manipulated by Spin-Orbit Torques

Graphene Transport at High Carrier Densities using a Polymer Electrolyte Gate

We report the study of graphene devices in Hall-bar geometry, gated with a polymer electrolyte. High densities of 6 $\times 10^{13}/cm^{2}$ are consistently reached, significantly higher than with conventional back-gating. The mobility follows an inverse dependence on density, which can be correlated to a dominant scattering from weak scatterers. Furthermore, our measurements show a Bloch-Gr\"uneisen regime until 100 K (at 6.2 $\times10^{13}/cm^{2}$), consistent with an increase of the density. Ubiquitous in our experiments is a small upturn in resistivity around 3 $\times10^{13}/cm^{2}$, whose origin is discussed. We identify two potential causes for the upturn: the renormalization of Fermi velocity and an electrochemically-enhanced scattering rate.Comment: 13 pages, 4 figures, Published Versio

Combining ability analysis for various yield and quality traits in rice (Oryza sativa L.)

An investigation was undertaken to assess the combining ability for yield and quality traits in rice. Three WA cytoplasmic male sterile lines of rice i.e., IR-58025A, IR-68897A and Pusa 6A were crossed with six restorer genotypes i.e., Sanwal Basmati, Pusa Sugandh-2, Pusa Sugandh-3, Pusa Sugandh-5, Pusa 2517-2-51-1 and HURJM- 59221 in line x tester design to generate 18 hybrids. Among the female parents, IR-58025A revealed significant desirable value of GCA effect for yield per plant and most of the quality traits. Among the pollen parents, Pusa Sugandh-3 revealed significant desirable value of GCA effect for most of the yield traits. However, Pusa Sugandh-5 revealed significant desirable value of GCA effect for most of the quality traits. Pusa 6A x Pusa Sugandh-2 evinced the highest significant value of SCA effect for grain yield followed by IR-58025A x Pusa Sugandh-5. However, IR- 68897A x Pusa 2517-2-51-1 followed by IR-58025A x Sanwal Basmati revealed the significant desirable value of SCA effect for most of the quality traits. For both yield and quality traits, IR-58025A x Pusa Sugandh-5, IR-68897A x HUR-JM-59221 and Pusa 6A x Pusa Sugandh-2 were found to be relatively better performing. Thus, present study aims to develop hybrids performing better for both yield and quality traits

Soft novel form of white-etching matter and ductile failure of carbide-free bainitic steels under rolling contact stresses

There has been a great deal of work on the formation of hard white-etching regions in conventional bearing steels such as 1C-1.5Cr wt% when subjected repeatedly to rolling contact stresses. The regions are a consequence of localised mechanical attrition across microcrack faces and mixing, which refine the local structure and force cementite to dissolve. This white-etching matter is often associated with brittle phenomena because the hardness can exceed 1100 HV. In contrast, carbide-free mixtures of bainitic ferrite and retained austenite when subjected to the same loading have been unexpectedly found not to develop the characteristic patches of hard material and to show instead signs of ductility in the attrited regions. The work presented here shows that the white-etching areas that develop in carbide-free bainite are $\textit{softer}$ than their surroundings, whether they are in hard nanostructured bainite destined for bearing applications or when the steel is designed for the manufacture of rails. Advanced characterisation tools were used for the first time to understand carbon redistribution during its formation. The deep interest about soft white-etching matter originates from the idea that it could lead to the reduction in premature failure of wind turbine gearbox bearings and white-etching layer grinding of rails.W. Solano-Alvarez appreciates and acknowledges funding by CONACYT, the Cambridge Overseas Trust, and the Roberto Rocca Education Programme. Part of this research was financed under EPSRC grant EP/M023303/1 “Designing steel composition and microstructure to better resist degradation during wheel-rail contact” in collaboration with the Rail Safety and Standards Board (RSSB), the Department of Transport, the University of Leeds, and Cranfield University for which we are thankful.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.actamat.2016.09.01