The oxygen permeability (Dk) of ten 24-hr collagen shields was measured directly by polarographic methodology at approximately 2 hr of hydration. Edge and boundary effects were included in the calculations. Dk was found to be approximately 26 x 10(-11) cm ml O2/sec ml mmHg at 35 degrees C. Mean water content of the shields was 65.7% (SD = 1.0%) as measured by a hand refractometer. Therefore, th...

Face shields are personal protective equipment devices that are used by many workers (e.g., medical, dental, veterinary) for protection of the facial area and associated mucous membranes (eyes, nose, mouth) from splashes, sprays, and spatter of body fluids. Face shields are generally not used alone, but in conjunction with other protective equipment and are therefore classified as adjunctive pe...

the effects of including incoherent (bound-electron) and coherent (rayleigh) scattering in exposure buildup factor calculations for point isotropic gamma ray sources, penetrating a two-layer water-lead shield have been investigated in the gamma ray energy (e?) range of 40 kev to 3 mev. incoherent scattering decreases the values of these factors in both layers up to e? ~ 200 kev and the effect i...

Background: Polyethylene composites including boron can be used as an effective neutron shield. Our investigation focuses on manufacturing borated polyethylene nano-composite. The purpose of this study is to design a radiation shield for use in both neutron and gamma fields. Materials and Methods: Borated polyethylene shields containing 2%, and 5% weight percentage of Boron nano-particles w...

New concepts for protective shields for NASA’s Crew Exploration Vehicles (CEVs) and planetary probes offer improved mission safety and affordability. Hazards include radiation from cosmic rays and solar particle events, hypervelocity impacts from orbital debris/micrometeorites, and the extreme heating environment experienced during entry into planetary atmospheres. The traditional approach for ...

Placing shields around a victim signal line is a common way to enhance signal integrity while minimizing delay uncertainty. An analytic model of the peak noise is developed for shielded interconnects based on a model. A design methodology for inserting shields between coupled interconnects to reduce crosstalk noise is presented.

2014 Increasing demand for low-field regions of large volumes has resulted in the construction of many magnetically-shielded walk-in rooms. Most have been of the cubic, two-layer high-03BC type, but several have used three layers, including one built by this author about three years ago. This room used several innovations, including "shaking" to increase the permeability of the magnetic sheets....