Modal analysis of wave propagation in dispersive media

Surveys on wave propagation in dispersive media have been limited since the pioneering work of Sommerfeld [Ann. Phys. 349, 177 (1914)] by the presence of branches in the integral expression of the wave function. In this article, a method is proposed to eliminate these critical branches and hence to establish a modal expansion of the time-dependent wave function. The different components of the transient waves are physically interpreted as the contributions of distinct sets of modes and characterized accordingly. Then, the modal expansion is used to derive a modified analytical expression of the Sommerfeld precursor improving significantly the description of the amplitude and the oscillating period up to the arrival of the Brillouin precursor. The proposed method and results apply to all waves governed by the Helmholtz equations.Comment: 10 pages, 9 figure

An Exactly Solvable Supersymmetric Model of Semimagic Nuclei

A simple model of nucleons coupled to angular momentum zero (s-pairs) occupying the valance shell of a semi-magic nuclei is considered. The model has a separable, orbit dependent pairing interaction which dominates over the kinetic term. It is shown that such an interaction leads to an exactly solvable model whose (0+) eigenstates and energies can be computed very easily with the help of the algebraic Bethe ansatz method. It is also shown that the model has a supersymmetry which connects the spectra of some semimagic nuclei. The results obtained from this model for the semimagic Ni isotopes from 58Ni to 68Ni are given. In addition, a new and easier technique for calculating the energy eigenvalues from the Bethe ansatz equations is also presented.Comment: Talk given at the International Conference on Nuclear Physics and Astrophysics: From Stable Beams to Exotic Nuclei, Cappadocia, June 200

Meningkatkan Hasil Belajar Siswa Pada Materi Konsep Volume Balok Dan Kubus Melalui Pendekatan Kontruktivisme Di Kelas IV SDN 3 Tonggolobibi

Permasalahan pada penelitian ini adalah rendahnya hasil belajar siswa kelas IV di SDN 3 Tonggolobibi. Tujuan penelitian ini adalah untuk meningkatkan hasil belajar siswa pada materi konsep volume balok dan kubus melalui pendekatan kontruktivisme di kelas IV SDN 3 Tonggolobibi. Penelitian ini menggunakan desain penelitian Kemmis dan Mc. Taggart yang terdiri atas dua siklus. Di mana pada setiap siklus dilaksanakan satu kali pertemuan di kelas dan setiap siklus terdiri empat tahap yaitu perencanaan, pelaksanaan, observasi, dan refleksi. Hasil penelitian menunjukkan bahwa pada tindakan siklus I diperoleh ketuntasan klasikal 35%. dan daya serap klasikal 46,5% Pada tindakan siklus II diperoleh ketuntasan klasikal 85% dan daya serap klasikal 75,5%. Hal ini berarti pembelajaran pada siklus II telah memenuhi indikator keberhasilan dengan nilai daya serap klasikal minimal 70% dan ketuntasan belajar klasikal minimal 80%. Berdasarkan nilai rata-rata daya serap klasikal dan ketuntasan belajar klasikal pada kegiatan pembelajaran siklus II, maka dapat disimpulkan bahwa perbaikan pembelajaran dengan menggunakan pendekatan pembelajaran konstruktivisme dapat meningkatkan Hasil belajar siswa kelas IV pada pembelajaran matematika materi konsep volume kubus dan balok di SDN 3 Tonggolobibi

Surgical treatment of giant cardiac aneurysm with pseudoaneurysm in a colon carcinoma patient

Left ventricular pseudoaneurysm is a rare and lethal condition associated with a high risk of rapid enlargement and rupture. It develops after transmural myocardial infarction (MI), cardiac surgery, trauma, or infection. When a left ventricular pseudoaneurysm is detected, surgical repair is recommended due to the high possibility of rupture. In this report, we present surgical treatment of a giant cardiac pseudoaneurysm that occurred after MI in a colon carcinoma patient

Experimental and numerical investigations of free convection heat transfer in solar oven

The use of solar energy for baking, heating or drying represents a sustainable way of solar energy applications with negligible negative effects. Solar oven is an alternative to conventional oven that rely heavily on coal and wood or Electric oven that uses the power from the National grid of which the end users have little or no control. Since the Solar oven uses no fuel and it cost nothing to run, it use are widely promoted especially in situations where minimum fuel consumption or fire risks are considered highly important. As useful as the Solar Oven proved, it major setback in the area of applications has been its future sustainability. For the use of Solar Oven/Cookers to be sustained in the future, the design and development of solar oven must rely on sound analytical tools. Therefore, this work focused on the design and development of the solar oven. To test the performance of the Small Solar Oven a 5000cm3 beaker of water was put into the Oven and the temperature of the water was found to reach 810C after about 3hrs under an average ambient temperature of 300C. On no load test, the oven reached a maximum temperature of 112oC in 6hrs. In order to carry out the parametric studies and improve the performance of the Solar Oven, Mathematical models were developed and solved by using Characteristics-Based Split (CBS) Finite Element Method. The Model results were compared with the Experimental results and a good agreement ware found between the two results

Classical Strongly Coupled QGP: VII. Energy Loss

We use linear response analysis and the fluctuation-dissipation theorem to derive the energy loss of a heavy quark in the SU(2) classical Coulomb plasma in terms of the $l=1$ monopole and non-static structure factor. The result is valid for all Coulomb couplings $\Gamma=V/K$, the ratio of the mean potential to kinetic energy. We use the Liouville equation in the collisionless limit to assess the SU(2) non-static structure factor. We find the energy loss to be strongly dependent on $\Gamma$. In the liquid phase with $\Gamma\approx 4$, the energy loss is mostly metallic and soundless with neither a Cerenkov nor a Mach cone. Our analytical results compare favorably with the SU(2) molecular dynamics simulations at large momentum and for heavy quark masses.Comment: 18 pages, 15 figures. v2: added references, changed title, replaced figures for Fig. 7, corrected typo