Pairing effect on the giant dipole resonance width at low temperature

The width of the giant dipole resonance (GDR) at finite temperature T in Sn-120 is calculated within the Phonon Damping Model including the neutron thermal pairing gap determined from the modified BCS theory. It is shown that the effect of thermal pairing causes a smaller GDR width at T below 2 MeV as compared to the one obtained neglecting pairing. This improves significantly the agreement between theory and experiment including the most recent data point at T = 1 MeV.Comment: 8 pages, 5 figures to be published in Physical Review

Damping of giant dipole resonance in hot rotating nuclei

The phonon damping model (PDM) is extended to include the effect of angular momentum at finite temperature. The model is applied to the study of damping of giant dipole resonance (GDR) in hot and noncollectively rotating spherical nuclei. The numerical results obtained for Mo88 and Sn106 show that the GDR width increases with both temperature T and angular momentum M. At T > 4 MeV and M<= 60 hbar the increase in the GDR width slows down for Sn106, whereas at M<= 80 hbar the GDR widths in both nuclei nearly saturate. By adopting the nuclear shear viscosity extracted from fission data at T= 0, it is shown that the maximal value of the angular momentum for Mo88 and Sn106 should be around 46 and 55 hbar, respectively, so that the universal conjecture for the lower bound of the specific shear viscosity for all fluids is not violated up to T= 5 MeV.Comment: 19 pages, 6 figures, accepted in Phys. Rev.

Specific shear viscosity in hot rotating systems of paired fermions

The specific shear viscosity $\bar\eta$ of a classically rotating system of nucleons that interact via a monopole pairing interaction is calculated including the effects of thermal fluctuations and coupling to pair vibrations within the selfconsistent quasiparticle random-phase approximation. It is found that $\bar\eta$ increases with angular momentum $M$ at a given temperature $T$. In medium and heavy systems, $\bar\eta$ decreases with increasing $T$ at $T\geq$ 2 MeV and this feature is not affected much by angular momentum. But in lighter systems (with the mass number $A\leq$ 20), $\bar\eta$ increases with $T$ at a value of $M$ close to the maximal value $M_{max}$, which is defined as the limiting angular momentum for each system. The values of $\bar\eta$ obtained within the schematic model as well as for systems with realistic single-particle energies are always larger than the universal lower-bound conjecture $\hbar/(4\pi k_B)$ up to $T$=5 MeV.Comment: 19 pages, 7 figures, accepted for publication in Phys. Rev.

Local harmonic approaches with approximate cranking operators

Methods of large amplitude collective motion in the adiabatic limit are examined with a special emphasis on conservation laws. We show that the restriction to point transformations, which is a usual assumption of the adiabatic time-dependent mean-field theory, needs to be lifted. In order to facilitate the application of large amplitude collective motion techniques, we examine the possibility of representing the RPA normal-mode coordinates by linear combinations of a limited number of one-body operators. We study the pairing-plus-quadrupole model of Baranger and Kumar as an example, and find that such representations exist in terms of operators that are state-dependent in a characteristic manner

Komunikasi Instruksional Instruktur di Lindz Yoga Studio Pekanbaru

Yoga is one of the sports or physic exercises which is most wanted and popular nowadays. Yoga combines or unites mind, body and soul only by doing movements (asana) along with breathing technique and meditation. Yoga is lead by an instructor who gives the instruction for the members. In giving the instruction, the instructor uses instructional communication in doing exercise process. The purpose of this research is to know the instructional method, instructional communication media, and the communication obstacles which happen in Yoga exercise process.This research belongs to quantitative research method by using symbolic approach. The informants of this research were 3 instructors and 3 members at Lindz Yoga studio Pekanbaru, while the object of this research was the instructors instructional communication at Lindz Yoga studio Pekanbaru. The data collection technique was used by observation, interview and documentation. In order to get data validity in this research, the researcher used the extension of participation and triangulation.The result of this research showed that the instructors instructional communication to the members in doing Yoga exercise used three instructional communications, such as command method, exercise method and question answer method. The media that used were audio media, aids media and picture media. The most use media and also effective in the usage are audio and aids media. The obstacles which happened in instructional communication are the sources obstacle, the channels obstacle, the communicants obstacle and psychological obstacle. Instructor as the communicator used verbal and nonverbal in the activity of instructional communication.Keyword : Yoga, instructional communication, Lindz Yoga studio Pekanbar

A path planning control for a vessel dynamic positioning system based on robust adaptive fuzzy strategy

The thrusters and propulsion propellers systems, as well as the operating situations, are all well-known nonlinearities which are caused less accuracy of the dynamic positioning system (DPS) of vessels in the path planning control process. In this study, to enhance the robust performance of the DPS, we proposed a robust adaptive fuzzy control model to reduce the effect of uncertainty problems and disturbances on the DPS. Firstly, the adaptive fuzzy controller with adaptive law is designed to adjust the membership function of the fuzzy controller to minimize the error in path planning control of the vessel. Secondly, the H∞ performance of robust tracking is proved by the Lyapunov theory. Moreover, compared to the other controller, a simulation experiment comprising two case studies confirmed the efficiency of the approach. Finally, the results showed that the proposed controller reaches control quality, performance and stability