Shielding fabrics

The collagen shield, fabricated from procine scleral tissue, is a spherical contact lens-shaped film whose thickness can be made to vary from 0.027 to 0,071 mm. It has a diameter of 14.5 mm and a base curve of 9 mm. Once the shield is hydrated by tear fluid and begins to dissolve, it softens and conforms to the corneal surface. Dissolution rates can be varied from 2 to as long as 72 hr by exposing the shields to ultraviolet radiation in order to achieve varying degrees of crosslinking. 

The authors would like to thank M. R. Daniel for the magnetic measurements, A. S. Venturino for his assistance in. the shield fabrication, and A. Hovanec for his assistance in the composite fabrication. 

The effectiveness of reducing radiation doses due to nuclear criticality accidents was determined for various shields fabricated of materials used to construct shipping containers and storage facilities for radioactive isotopes. These data are based on experimental results obtained during seventeen nuclear accident dosimetry (NAD) intercomparison studies conducted since 1965 at the Oak Ridge National Laboratory. ... 

Vladimir, A., Chirkov, A., 1999. EMI shielding fabric and fabric articles made therefrom. U.S. Patent US5968854. 

Nuclear Applications. Powder metallurgy is used in the fabrication of fuel elements as well as control, shielding, moderator, and other components of nuclear-power reactors (63) (see Nuclearreactors). The materials for fuel, moderator, and control parts of a reactor are thermodynamically unstable if heated to melting temperatures. These same materials are stable under P/M process conditions. It is possible, for example, to incorporate uranium or ceramic compounds in a metallic matrix, or to produce parts that are similar in the size and shape desired without effecting drastic changes in either the stmcture or surface conditions. OnlyHttle post-sintering treatment is necessary. 

Typical equipment made from tantalum includes heat exchangers, reaction vessels liners, thermowells, and heating elements or heat shields for high temperature vacuum sintering furnaces. Tantalum fabricated parts are found in the manufacturing of pharmaceuticals, explosives, insecticides, dyes, acidic baskets for silver cyanide barrel platers, and in hydrochloric and hydrobromic acid condensers. 

Most carrier-active compounds ate based on aromatic chemicals with characteristic odor. An exception is the phthalate esters, which are often preferred when ambient odor is objectionable or residual odor on the fabric caimot be tolerated. The toxicity of carrier-active compounds and of their ultimate compositions varies with the chemical or chemicals involved. The environment surrounding the dyeing equipment where carriers are used should always be weU-ventilated, and operators should wear protective clothing (eg, mbber gloves, aprons, and safety glasses or face shields, and possibly an appropriate respirator). Specific handling information can be obtained from the suppHer or manufacturer. 

CP-1 was assembled in an approximately spherical shape with the purest graphite in the center. About 6 tons of luanium metal fuel was used, in addition to approximately 40.5 tons of uranium oxide fuel. The lowest point of the reactor rested on the floor and the periphery was supported on a wooden structure. The whole pile was surrounded by a tent of mbberized balloon fabric so that neutron absorbing air could be evacuated. About 75 layers of 10.48-cm (4.125-in.) graphite bricks would have been required to complete the 790-cm diameter sphere. However, criticality was achieved at layer 56 without the need to evacuate the air, and assembly was discontinued at layer 57. The core then had an ellipsoidal cross section, with a polar radius of 209 cm and an equatorial radius of309 cm [20]. CP-1 was operated at low power (0.5 W) for several days. Fortuitously, it was found that the nuclear chain reaction could be controlled with cadmium strips which were inserted into the reactor to absorb neutrons and hence reduce the value of k to considerably less than 1. The pile was then disassembled and rebuilt at what is now the site of Argonne National Laboratory, U.S.A, with a concrete biological shield. Designated CP-2, the pile eventually reached a power level of 100 kW [22]. 

The SP-ablator allows higher aerodynamic loads with lower surface/mass ratio for heat shields, and should be ideally suited for moon, mars, or other interplanetary return missions. These shields are also suitable for cost-effective flight models of winged reentry capsules. A large application potential can be seen for nozzles and combustion chambers or housings of rocket engines. Dornier plans to manufacture a heat shield for the Mirka capsule one meter in diameter. The C/SiC-cover will be fabricated in one piece. 

Naturally occurring boron consists of approximately 20% of 10B and 80% of UB, leading to an average atomic mass of 10.8 amu. Because 10B has a relatively large cross-section for absorption of slow (thermal) neutrons, it is used in control rods in nuclear reactors and in protective shields. In order to obtain a material that can be fabricated into appropriate shapes, boron carbide is combined with aluminum. 

After the design of the shield has satisfied the requirements, and the prototype shield has been fabricated, reference 1 specifies the testing to which it must be subjected. The prototype operational shield must be tested by creating an MCI in a simulated operational environment. 

SUMMARY. The safety record associated with the use of APE operated remotely or within operational shields is excellent. Operational shields that are properly designed, fabricated, and tested do provide operators with adequate protection, and ensures their safety during hazardous operations. 

The fabrication of the sensor system was described in Sect. 4.1.2, since this microsystem also features a circular microhotplate. A micrograph of the complete microsystem (die size 6.8 x 4.7 mm ) is shown in Fig. 5.2. The microhotplate is located in the upper section of the chip. The analog circuitry and the A/D and D/A converters are clearly separated and shielded from the digital circuitry. The bulk-chip temperature sensor is located close to the analog circuitry in the center of the chip. The distance between microhotplate and circuitry is comparatively large owing to packaging requirements, as will be explained in Sect. 5.1.6. 

Boron nitrate (B + N —> BN) is a white powder used to line high-temperatures furnaces, to make heating crucibles, for electrical and chemical equipment, for heat shields on spacecraft nosecones, and to make high-strength fabrics. 

Flame shields on the underside of cable trays have been used effectively to deflect flames or heat emanating from fires below. Flame shields should be fabricated of Xein (1.6-mm) thick steel plate or equivalent mounted below the cable tray and extending a minimum of 6 in (152 cm) beyond the tray side rails. These shields can improve tray survivability usually in concert with water spray systems. Flame shields alone (with no water spray) can provide only brief fire protection and are not normally used in this manner. Flame shields coated with... 

One area that illustrates aspects important to energy dissipation is the fabrication of protective armor. Such armor includes helmets, vests, vehicle exteriors and interiors, riot shields, bomb blankets, explosive containment boxes (aircraft cargo), and bus and taxi shields. In each case energy dissipation is a critical element in the desired behavior of the device. To illustrate this let us look at body armor. 

From a shop-fabricated tank manufacturer s perspective, a diked AST generally refers to a steel tank within a factory-fabricated steel box, or dike. An example of a diked AST is the STl F911 standard, providing an open-topped steel rectangular dike and floor as support and secondary containment of a UL 142 steel tank. The dike will contain 110 percent of the tank capacity as rainwater may already have collected in the dike, the additional 10 percent acts as freeboard should a catastrophic failure dump a full tank s contents into a dike. Many fabricators offer steel dikes with rain shields to prevent precipitation from collecting. 

Another dramatic effect is in the retention time in the irradiator cell and thus in irradiator cell costs. The high specific activity would be fabricated into a plaque only 2.4 feet long, the intermediate specific activity would require a plaque 24 feet long whereas the low specific activity would require a plaque 240 feet long. The strawberries would reside in the irradiator for one hour for the long plaque, 6 minutes for the intermediate, and 36 seconds for the short plaque. The cost for irradiator shielding would vary from about 20,000 for the high specific activity source, to about 30,000 for the intermediate activity, and to about 240,000 for the low specific activity. 

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