Dynamical model for neck formation in the entrance channel of a heavy ion collision

The formation of the neck in the entrance channel is studied using a classical dynamical model. The dependence of neck radius on bombarding energy, mass or charge and angular momentum is discussed.     

Plastic deformation and springback of rectangular bars subject to combined torsion and tension

Springback of rectangular bars under combined torsion and tension is investigated. A theoretical model for springback is developed and evaluated by comparing calculated and experimental results. It is concluded that springback is analytically predictable. Both analysis and test data show that an axial tension always reduces angular springback in a twisted bar. The order of plastic deformation is found to be important : twist followed by pull produces smaller angular springback upon release of torque and force than does a deformation in the reverse order.     

The distribution of 3p12 strength in 209Bi

An optimized Woods-Saxon potential, which gives excellent fits to the observed proton states in ²⁰⁹Bi and ²⁰⁷Tl, is used to calculate the excitation energy of the unbound $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ proton state in ²⁰⁹Bi. Using the wave functions given by the above potential, the strength of the core-particle interaction is calculated. The effect of the vibration of the core on the fragmentation of the $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state is estimated. It is found that the $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state at 5.123 MeV loses more than 80% of its strength to five $\text{1}\text{2}{}^{\mathrm{?}}$ collective states in ²⁰⁹Bi and the observed $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state at 3.64 MeV is actually an almost equal mixture of the $\text{3p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ single-proton state and the ($\text{4}{}^{\mathrm{+}}\text{, 1}\text{h}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$) collective state.     

Probing CPT violation in neutrino oscillation: A three flavor analysis

We have studied CPT violation in neutrino oscillation considering three flavor framework with matter effect. We have constructed a new way to find the oscillation probability incorporating CPT violating terms without any approximation. Then CPT   violation with atmospheric neutrinos for a magnetized iron calorimeter detector considering the muons (directly measurable with high resolution) of the charge current events has been studied for zero and nonzero θ₁₃${\theta }_{13}$ values. It is found that a potential bound of δb₃₂?6×¹⁰⁻²⁴ GeV$\delta b_{32}?6\times {10}^{-24}\text{GeV}$ at 99% CL can be obtained with 1 Mton.year exposure of this detector; and unlike neutrino beam experiments, there is no possibility to generate ‘fake’ CPT violation due to matter effect with atmospheric neutrinos. The advantages of atmospheric neutrinos to discriminate CPT violation from CP violation and nonstandard interactions are also discussed.     

Kantowski-Sachs Universe Filled with Perfect Fluid in f(R,T) Theory of Gravity

The exact solutions of the field equations in respect of Kantowski-Sachs universe filled with perfect fluid in the framework of f(R,T) theory of gravity (Harko et al. in Phys. Rev. D 84:024020, 2011) is derived. A cosmological model with an appropriate choice of the function f(T) is constructed. The physical behavior of the cosmological model is studied. Some important features of astrophysical phenomena, like Hubble’s parameter H(z), luminosity distance (d _L ) and distance modulus μ(z) with red-shift are also discussed.     

Higher Dimensional Cosmological Models Filled with Perfect Fluid in f(R,T) Theory of Gravity

The new class of higher dimensional cosmological model of the early universe filled with perfect fluid source in the framework of f(R,T) theory of gravity (Harko et al. in Phys. Rev. D 84, 024020, 2011) is considered. A cosmological model with an appropriate choice of the function f(T) has been constructed. The physical behavior of the model is studied. The well known astrophysical phenomena, namely the Hubble parameter H(z), luminosity distance (d _L ) and distance modulus μ(z) with redshift are discussed.     

Holographic Dark Energy (DE) Cosmological Models with Quintessence in Bianchi Type-V Space Time

In this paper, author studied homogeneous and anisotropic Bianchi type-V universe filled with matter and holographic dark energy (DE) components. The exact solutions to the corresponding Einstein’s field equations are obtained for exponential and power-law volumetric expansion. The holographic dark energy (DE) EoS parameter behaves like constant, i.e. ω _Λ =?1, which is mathematically equivalent to cosmological constant (Λ) for exponential expansion of the model, whereas the holographic dark energy (DE) EoS parameter behaves like quintessence for power-law expansion of the model. A correspondence between the holographic dark energy (DE) models with the quintessence dark energy (DE) is also established. Quintessence potential and dynamics of the quintessence scalar field are reconstructed, which describe accelerated expansion of the universe. The statefinder diagnostic pair {r,s} is adopted to characterize different phases of the universe.     

Bionomic exploitation of a ratio-dependent predator–prey system

The present article deals with the problem of combined harvesting of a Michaelis–Menten-type ratio-dependent predator–prey system. The problem of determining the optimal harvest policy is solved by invoking Pontryagin's Maximum Principle. Dynamic optimization of the harvest policy is studied by taking the combined harvest effort as a dynamic variable. Computer simulations are carried out to illustrate our analytical findings. Biological and bioeconomical interpretations of the results are explained critically.     

Study of Neutron-Rich Hypernuclei by the (π −, K +) Reaction at J-PARC

We are planning to perform an experiment at J-PARC and produce new neutron-rich Λ hypernuclei by using the (π ^?, K ⁺) reaction (J-PARC E10). As the first step, we are planning to produce ${^6_{\Lambda}{\rm H}}$ hypernuclei with a ⁶Li target. To conduct this experiment, we are developing new detectors, those are scintillating fiber tracker, and silicon strip detector, for high rate operation to aim at increasing beam intensity up to 10⁷/spill. As a result of beam test in Jun 2012, we are going to use high-rate beam at least 10⁷/spill.     

Intercepted-Knoevenagel condensation for the synthesis of unsymmetrical fused-tricyclic 4H-pyrans

4H-Pyrans (4H-Pys) and 1,4-dihydropyridines (1,4-DHPs) are important classes of heterocyclic scaffolds in medicinal chemistry. Herein, an indium(III)-catalyzed one-pot domino reaction for the synthesis of highly functionalized 4H-Pys, and a model of 1,4-DHP is reported. This alternative approach to the challenging Hantzsch 4-component reaction enables the synthesis of fused-tricyclic heterocycles, and the mechanistic studies underline the importance of an intercepted-Knoevenagel adduct to achieve higher chemoselectivity towards these types of unsymmetrical heterocycles.