813 research outputs found

    Design and Analysis of Tripple Band Koch Fractal Yagi Uda Antenna

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    The proposed antenna is Koch fractal printed Yagi-Uda antenna fed by SMA connector. The radiation characteristics of the antenna are simulated by CST Microwave Studio and analysed with the help of simulated results. The antenna's currents distribution becomes more uniform after being fractal, which is conducive to increase the antenna’s radiation directivity. The proposed Koch fractal Yagi-Uda antenna resonance at frequency of 7.81 GHz, 8.54 GHz and 9.42 GHz with gain of 9.67 dB, 10.4 dB and 10.61dB respectively. Parameter of antenna such as return loss, input impedance, smith chart, radiation pattern is analyzed for performance evaluation of Koch fractal Yagi-Uda antenna.DOI:http://dx.doi.org/10.11591/ijece.v3i4.257

    Mass spectra of doubly heavy Omega_QQ' baryons

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    We evaluate the masses of baryons composed of two heavy quarks and a strange quark with account for spin-dependent splittings in the framework of potential model with the KKO potential motivated by QCD with a three-loop beta-function for the effective charge consistent with both the perturbative limit at short distances and linear confinement term at long distances between the quarks. The factorization of dynamics is supposed and explored in the nonrelativistic Schroedinger equation for the motion in the system of two heavy quarks constituting the doubly heavy diquark and the strange quark interaction with the diquark. The limits of approach, its justification and uncertainties are discussed. Excited quasistable states are classified by the quantum numbers of heavy diquark composed by the heavy quarks of the same flavor.Comment: 14 pages, revtex4-file, 3 eps-figures, 5 tables, typos correcte

    Linear Stability of Equilibrium Points in the Generalized Photogravitational Chermnykh's Problem

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    The equilibrium points and their linear stability has been discussed in the generalized photogravitational Chermnykh's problem. The bigger primary is being considered as a source of radiation and small primary as an oblate spheroid. The effect of radiation pressure has been discussed numerically. The collinear points are linearly unstable and triangular points are stable in the sense of Lyapunov stability provided μ<μRouth=0.0385201\mu< \mu_{Routh}=0.0385201. The effect of gravitational potential from the belt is also examined. The mathematical properties of this system are different from the classical restricted three body problem

    Generalized Gravi-Electromagnetism

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    A self consistant and manifestly covariant theory for the dynamics of four charges (masses) (namely electric, magnetic, gravitational, Heavisidian) has been developed in simple, compact and consistent manner. Starting with an invariant Lagrangian density and its quaternionic representation, we have obtained the consistent field equation for the dynamics of four charges. It has been shown that the present reformulation reproduces the dynamics of individual charges (masses) in the absence of other charge (masses) as well as the generalized theory of dyons (gravito - dyons) in the absence gravito - dyons (dyons). key words: dyons, gravito - dyons, quaternion PACS NO: 14.80H

    Oilseed brassica in India: Demand, supply, policy perspective and future potential☆

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    India is the largest agrarian subcontinent supporting 26% world’s agricultural population on 12% arable land. India is also the fifth largest vegetable oil economy accounting 7.4% oilseeds, 5.8% oils and 6.1% oil meal production, and 9.3% of edible oil consumption in the world. Oilseeds are the second most important agricultural economy in India next to cereals growing at a pace of 4.1% per annum in the last three decades. Oilseed brassica shares 23.5% area and 24.2% production of total oilseeds in the country. Despite being the third largest producer (11.3%) of oilseed brassica after Canada and China in the world, India meets 57% of the domestic edible oil requirements through imports and ranked 7th largest importer of edible oils in the world. Oilseed brassica achieved significant growth in India in the past, however, the productivity levels are still low owing to large cultivation under rainfed situation, biotic and abiotic stresses, and resources crunch. It is also facing the challenges of low genotypic potential, climate change and price fluctuation. Though, it embraces the immense scope to increase the production in traditional and non-traditional areas in India with proper inputs, technological interventions, and suitable policy framework. This needs to develop strategies in a well-planned, targeted manner with multi-scientific inputs, policy interface and stable price systems to bring the desired growth in oilseeds brassica production, and to reduce the import of edible oils in the country

    Electric field gradients in MgB2_2 synthesized at high pressure: 111^111Cd TDPAC study and ab initio calculation

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    We report the high-pressure synthesis of novel superconductor MgB2_2 and some related compounds. The superconducting transition temperature of our samples of MgB2_2 is equal to 36.6 K. The MgB2_2 lattice parameters determined via X-ray diffraction are in excellent agreement with results of our ab initio calculations. The time-differential perturbed angular correlation (TDPAC) experiments demonstrate a small increase in quadrupole frequency of 111^111Cd probe with decreasing temperature from 293 to 4.2 K. The electric field gradient (EFG) at the B site calculated from first principles is in fair agreement with EFG obtained from 11^11B NMR spectra of MgB2_2 reported in the literature. It is also very close to EFG found in our 111^111Cd TDPAC measurements, which suggests that the 111^111Cd probe substitutes for boron in the MgB2_2 lattice.Comment: 10 pages, 3 figure

    Evaluation of global composite collection reveals agronomically superior germplasm accessions for chickpea improvement

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    The rich genetic diversity existing within exotic, indigenous, and diverse germplasm lays the foundation for the continuous improvement of crop cultivars. The composite collection has been suggested as a gateway to identifying superior germplasm for use in crop improvement programs. Here, a chickpea global composite collection was evaluated at five locations in India over two years for five agronomic traits to identify agronomically superior accessions. The desi, kabuli, and intermediate types of chickpea accessions differed significantly for plant height (PLHT) and 100-seed weight (100 SW). In contrast, the intermediate type differed substantially from kabuli for days to maturity (DM). Several highly significant trait correlations were detected across different locations. The most stable and promising accessions from each of the five locations were prioritised based on their superior performance over the best-performing check cultivar. Accordingly, the selected germplasm accessions of desi type showed up to 176% higher seed yield (SY), 29% lower flowering time, 21% fewer maturity days, 64% increase in PLHT, and 183% larger seeds than the check cultivar JG11 or Annigeri. The prioritised kabuli accessions displayed up to 270% more yield, 13% less flowering time, 8% fewer maturity days, 111% increase in PLHT, and 41% larger seeds over the check cultivar KAK2. While the intermediate type accessions had up to 169% better yield, 1% early flowering, 3% early maturity, 54% taller plants, and 25% bigger seeds over the check cultivar JG 11 or KAK2. These accessions can be utilised in chickpea improvement programs to develop high-yielding, early flowering, short duration, taller, and large-seeded varieties with a broad genetic base

    The Effect of Radiation Pressure on the Equilibrium Points in the Generalised Photogravitational Restricted Three Body Problem

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    The existence of equilibrium points and the effect of radiation pressure have been discussed numerically. The problem is generalized by considering bigger primary as a source of radiation and small primary as an oblate spheroid. We have also discussed the Poynting-Robertson(P-R) effect which is caused due to radiation pressure. It is found that the collinear points L1,L2,L3L_1,L_2,L_3 deviate from the axis joining the two primaries, while the triangular points L4,L5L_4,L_5 are not symmetrical due to radiation pressure. We have seen that L1,L2,L3L_1,L_2,L_3 are linearly unstable while L4,L5L_4,L_5 are conditionally stable in the sense of Lyapunov when P-R effect is not considered. We have found that the effect of radiation pressure reduces the linear stability zones while P-R effect induces an instability in the sense of Lyapunov

    The Influence of Free Quintessence on Gravitational Frequency Shift and Deflection of Light with 4D momentum

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    Based on the 4D momentum, the influence of quintessence on the gravitational frequency shift and the deflection of light are examined in modified Schwarzschild space. We find that the frequency of photon depends on the state parameter of quintessence wqw_q: the frequency increases for −1<wq<−1/3-1<w_q<-1/3 and decreases for −1/3<wq<0-1/3<w_q<0. Meanwhile, we adopt an integral power number aa (a=3ωq+2a = 3\omega_q + 2) to solve the orbital equation of photon. The photon's potentials become higher with the decrease of ωq\omega_q. The behavior of bending light depends on the state parameter ωq\omega_q sensitively. In particular, for the case of ωq=−1\omega_q = -1, there is no influence on the deflection of light by quintessence. Else, according to the H-masers of GP-A redshift experiment and the long-baseline interferometry, the constraints on the quintessence field in Solar system are presented here.Comment: 12 pages, 2 figures, 4 tables. European Physical Journal C in pres

    Relativistic wave equations for interacting massive particles with arbitrary half-intreger spins

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    New formulation of relativistic wave equations (RWE) for massive particles with arbitrary half-integer spins s interacting with external electromagnetic fields are proposed. They are based on wave functions which are irreducible tensors of rank n(n (n=s-\frac12$) antisymmetric w.r.t. n pairs of indices, whose components are bispinors. The form of RWE is straightforward and free of inconsistencies associated with the other approaches to equations describing interacting higher spin particles
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