The oscillation of electrons, in a sufficiently intense pump wave, frustrates Debye shielding in the direction of the oscillation. One finds that such oscillating electrons cannot shield charge fluctuations over distances smaller than the distance they sample in a plasma period. One consequence is that the frequency of ion waves can be increased from the ion acoustic frequency to the ion plasma...

With the purpose of reducing stray radiation dose (SRD) in out-of-field region (OFR) during radiotherapy with 6 MV intensity-modulated radiation therapy (IMRT), a body-shielding device (BSD) was prepared according to the measurements obtained in experimental testing. In experimental testing, optimal shielding conditions, such as 1 mm lead, 2 mm lead, and 1 mm lead plus 10 mm bolus, were investi...

We demonstrate the feasibility of using a nonconforming nite element method on an unstructured grid in solving a magnetospheric physics problem. We use this approach to construct a global discrete model of the magnetic eld of the magnetosphere that includes the eeects of shielding currents at the outer boundary (the magnetopause). As in the approach of 17] the internal magnetospheric eld model ...

When considering the space limit of high energy LINAC facility in a hospital, the design of shielding wall is strongly required to optimize the wall thickness. Shielding wall usually consists of concrete, and iron plate is sometimes added in concrete to decrease the wall thickness. We investigated the optimum design of the shielding wall in medical LINAC facility by simulation. The calculations...

Katsumi Ohata* Junichi Sato* ABSTRACT: Magnetic shielding for strong magnets using a high-temperature superconductor that can be operated at liquid nitrogen temperature has been studied. Long and large-cross-section (9 mm wide and 0.5 mm thick) 54-filament Bi-2223/Ag tape was developed. Double pancake coils were wound using the tapes having sufficient bending strain tolerance for the react-and-...

In 1992, E.E.Podkletnov and R.Nieminen find that, under certain conditions, ceramic superconductor with composite structure has revealed weak shielding properties against gravitational force. In classical Newton’s theory of gravity and even in Einstein’s general theory of gravity, there are no grounds of gravitational shielding effects. But in quantum gauge theory of gravity, the gravitational ...

Parameter shielding refers to the situation that one test parameter disables others in test execution. The quality of test case generation techniques is limited by the wide existence of parameter shielding. It is challenging to automatically find out conditions that cause the parameter shielding. This paper presents a novel approach for exploring the shielding conditions of test parameters. Our...

An idealised, staggered array of 9 6m 3 cubes was built to gain an understanding of the influence of other buildings on the natural ventilation rate of a building. The instrumented cube contained 24 temperature measurements, 32 surface pressure taps, CO2 sensors and 2 sonic anemometers, with 5 more placed outside to measure wind velocities. Ventilation rate was measured when the cube was sealed...

The projected radiation levels within the International Space Station (ISS) have been criticized by the Aerospace Safety Advisory Panel in their report to the NASA Administrator. Methods for optimal reconfiguration and augmentation of the ISS shielding are now being developed. The initial steps are to develop reconfigurable and realistic radiation shield models of the ISS modules, develop compu...

/department of mechanical engineering Introduction Noise reduction is a key issue for High-tech and high precision instruments. To reduce the noise levels emitted by internal or external sources, porous materials can be used for acoustic shielding. The acoustic wave penetrates into the pore network, and part of its energy is dissipated as heat by viscous friction and thermal-elastic damping, ma...