Ballast weight

Ba.lla.sted. A ballasted roof assembly consists of a membrane or membrane and substrate material (insulation, sHp sheet, etc) loosely laid over a deck with the assembly held in place using ballast. A minimum ballast weight of 48.9 kg/m or 10 pounds per square foot (PSF) is used. The ballast can consist of smooth rounded stone, cmshed stone (a separator sheet must be used between the cmshed stone and the membrane), or pavers (both standard and lightweight). Both stone and pavers come in a wide variety of colors. The membrane is affixed to the building only at the deck perimeter (roof edge) and at various penetrations. Wall and penetration flashings are typically fuUy adhered and sealed to prevent water entry into the roof assembly. The maximum slope a ballasted system should be installed over is 16.7 cm/m. 

At this stage in the installation procedure it is important to monitor the tendency of the platform to tilt owing to eccentric resistance of the seafloor materials to the skirt penetration. This should preferably be controlled by eccentric ballasting to keep the platform vertical. It may be difficult to correct tilt at a later stage if most of the ballast weight has been utilized. 

Natural (NU or Unat), depleted (DU), low-enriched (LEU), and high-enriched (HEU) uranium the content of the only natural fissile isotope, U—is an important feature of uranium applications and value. In natural uranium, the content of this isotope is 0.720 atom % or 0.711 wt% (Table 1.2). LEU is defined as U content between 0.720% and just below 20%, while HEU encompasses uranium with U content above 20%. The 20% borderline between LEU and HEU is artificial and was based on the assumption that nuclear weapons with 20% or less U would not be efficient. The waste, or tails, of the isotope enrichment process contains less U than in natural uranium and is defined as depleted uranium (DU). The U-235 content in DU is usually in the range of 0.2%-0.4%. DU is used mainly in armor piecing ammunition, in reactive armor of tanks, in radiation shielding, and is also used as ballast weights in aircraft. In addition, many of the commercially available fine chemicals of uranium compounds are based on the tails of uranium-enrichment facilities and usually labeled as not of natural isotope composition. 

In modem PMR constmction, thermal iasulation that is unaffected by water or that can be kept dry ia some manner is required. Extmded polystyrene (XEPS) foam iasulation boards ate commonly employed (see Insulation, thermal). They ate placed on top of the waterproofing roof membrane, which is next to the deck. The iasulation should not be adhered to the membrane. Ballast at the rate of >48.8 kg/m (1000 lb/100 ft ) holds the iasulation ia place and offers protection from the sun. The iasulation joiats ate open and drainage must be provided. Various other materials, eg, patio blocks and concrete slabs, ate also used as sutfaciags and ballast. The extra weight imposes mote exacting requirements on constmction. 

RPs have already been used in different structural applications, to replace conventional metal in seawater-compressed air surfacing ballast tanks in the Alvin depth vehicle. This vehicle, a first-generation deep research vehicle, also used RP in its outer hull construction to enclose the pressure tanks and aluminum frame. In the unmanned acoustical research vehicle of the Ordnance Research Laboratory called Divar, an RP cylinder with a 16 in. OD, 3/4 in. wall thickness, I2V2 in. ID with nine ribs, a 60 in. length and weight of 180 pounds went to depths of 950 m (6,500 ft.). 

DIVER METHOD- This is a modification of the hydrometer method. Variation in effective density i and hence concn, is measured by totally immersed divers. These are small glass vessels of approximately streamline shape, ballasted to be in stable equilibrium, with the axis vertical, and to have a known density slightly greater than that of the sedimentation liq. As the particles settle, the diver moves downwards in hydrodynamic equilibrium at the appropriate density level. The diver indicates the position of a weight concn equal to the density difference between the diver and the sedimentation liq. Several divers of various densities are required, since each gives only one point on the size distribution curve... 

The domestic use pattern for lead in 1990 was as follows lead-acid storage batteries, used for motor vehicles, motive power, and emergency back-up power, accounted for 80% of total lead consumption ammunition, bearing metals, brass and bronze, cable covering, extruded products, sheet lead, and solder, represented 12.4% the remaining 7.6% was used for ceramics, type metal, ballast or weights, tubes or containers, oxides, and gasoline additives (USDOC 1992). 

Solid wastes that contain lead are produced primarily as a result of domestic ore production and ammunition use. Other sources include solder, weights and ballasts, bearing metals, and iron and steel production. These sources of lead-contaminated waste are concentrated primarily in landfills. 

The low molecular weight alkanes such as methane and butane can be pumped with the gas ballast valve closed or using Inert gas as the gas ballast and/or at inaeased temperature of the pump. But important -Increased explosion hazard ... 

Once operating temperature has been reached, methanol and ethanol can be extracted without using gas ballast (N 62 pump oil). To pump higher molecular weight alcohols (e.g. butanol) the gas ballast valve will have to be opened or other protective measures will have to be implemented to prevent condensation. 

Aluminum alloys have been used to fabricate heating coils for tankers in which crude oil and sea-water ballast are alternate cargoes. Savings in weight and in losses due to corrosion are reported to be very favorable compared with mild steel. 

Utility telecommunication and railway right-of-ways may be contaminated by leaching of CDDs associated with chlorophenol-treated railway ties and utility poles. A study in British Columbia showed that CDDs and CDFs were not detected in parkland ditch sediments (control area), but were detected in farmland, utility, and railway right-of-way ditch sediments (Wan and van Oostdam 1995). Total mean CDD concentrations (mainly OCDD and HpCDD) ranged from 18.8 to 277 ng/kg (ppt) (dry weight) in ditch sediments and ballasts respectively. Concentrations of CDDs were much higher in ditch sediment... 

Figure 6.114 Pendant light fitting. Lamp rating up to 250 W Lamp type TC-DEL up to 42 W HME, HIE, HSE up to 250 W Induction lamp 85 W and 165 W Rated luminous flux of induction lamps 85W 6000lm 165W 120001m IP protection code IP 67 Diameter, max. 320 mm Height 420 mm Weight 14.5 kg or 16.2 kg, depending on lamp and ballast Type of protection EEx de IIC T4/T5/T6 (terminal compartment in e ) ...

Booms are sometimes constructed with ballast or weights designed to maintain the boom in an upright position. Lead weights have been used for this, but steel chain in the bottom of the boom often serves as both ballast and tension member. A few booms also use a chamber filled with water as ballast. Many booms nowadays are constructed without ballast, however, and their position in the water is maintained by balancing the forces on the top and bottom of the boom. Another construction feature common in larger booms is the addition of stiffeners or rigid strips, often... 

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