Vacuum, loss

Cryogenic cold traps in Zone 2A. (Capture process radioactive noble gas in the vacuum system flow to control release.) Plugged trap or broken vacuum line Mechanical malfunction or worker error Control and monitoring system indications and periodic maintenance inspections Redundant cold traps provide multiple flow paths for vacuum. Loss of vacuum and potential release of noble gas. 

Whilst cake cracking and drop-off are piinc al sources of differences in the yield of actual plant, conq)ared with laboratory-scale tests, other considerations include (1) equality of the pressure differential available for cake formation and (2) equivalence of media condition and resistance. The latter will depend on the age of the medium and the effectiveness of cloth wadung operations. Filtration equipment is generally poorly instrumented. The location of the AP measuring device and the pressure (vacuum) losses present between the measurement and point of filtration will vary ftom station to station. 

Another version of the disc fiber is shown in Figure 11.14. Here, the discs are made firom porous ceramics [Ekberg Rantala 1991]. The latter have the property of permbhhg water flow whilst, by capillary pressure control, preventing passage of air. This reduces vacuum losses and costs better dewateiing/wa g performance is claimed. 

Reactor pressure increase Several events may cause this e.g., inadvertent closure of one turbine control valve, pressure regulator downscale failure, generator load rejection, turbine trip MSIV closure, loss of condenser vacuum, loss of nonemergency AC power to station auxiliaries, loss of feedwater etc. All these have been analysed. Features are included in the instrumentation and control systems or redundancies to maintain reactor pressure through a combination of component automatic responses or operator actions, depending on the identified cause. 

International practice considers the analysis of ATWS for a variety of initiating events such as loss of feedwater, loss of load, turbine trip, loss of condenser vacuum, loss of off-site power, closure of main steamline isolation valves, uncontrolled boron dilution, inadvertent control rod withdrawal, etc. ATWS analyses are performed in general by using best-estimate tools to determine the preventive (e.g. a diverse scram system) or mitigative measures (e.g. initiation of turbine trip and emergency feedwater supply) which need to be implemented for strengthening plants defence in depth. 

Vacuum Losses when Designing Moid Bottom Wrongiy... 

Vacuum losses are always the result of leakage they sometimes result from the mold construction and not from bad seals. 

F. is applied to distilled fatty acid mixtures of coconut or - pahn kernel oil (Ce-Cig) and separate unsaturated fatty acids from - rape-seed (C18-C22) oil, as well as for the separation of tall oil fatty acids. The fractionation of tallow, soybean, cottonseed and linseed fatty acids is practiced only in rare cases. High degrees of purity (up to 99%) are reached. F. is carried out in vacuum columns that are filled with internal packings and/ or trays. These necessary devices cause a pressure increase (vacuum loss) which has to be compen-... 

Sublimation of materials in vacuum Loss of structural strength... 

It is a simple matter now to calculate number of particles per unit area, per unit time, that pass tln-ough a small hole in the wall of the vessel. This quantity is called the rate of effusion, denoted by n, and it governs the loss of particles in a container when there is a small hole in the wall separatmg the gas from a vacuum, say. This number is in fact obtained by integrating the quantity, 8 Af(v) over all possible velocities having the proper direction, and then dividing this number by A5f Thus we find... 

The solution obtained is evaporated somewhat, cooled in a vacuum desiccator and the crystals of the tetraoxo-acid filtered off too drastic evaporation causes formation of the heptaoxodiphosphoric acid by loss of water. 

To a solution of 0.25 mol of the trimethylsilyl ether in 120 ml of dry diethyl ether was added in 20 min at -35°C 0.50 mol of ethyllithium in about 400 ml of diethyl ether (see Chapter II, Exp. 1). After an additional 30 min at -30°C the reaction mixture was poured into a solution of 40 g of ammonium chloride in 300 ml of water. After shaking, the upper layer was separated off and dried over magnesium sulfate and the aqueous layer was extracted twice with diethyl ether. The ethereal solution of the cumulenic ether was concentrated in a water-pump vacuum and the residue carefully distilled through a 30-cm Vigreux column at 1 mmHg. The product passed over at about 55°C, had 1.5118, and was obtained in a yield of 874. Distillation at water-pump pressure (b.p. 72°C/I5 mmHg) gave some losses due to polymerization. 

The relationship between the BET monolayer capacity of physically adsorbed water and the hydroxyl content of the surface of silica has been examined by Naono and his co-workers in a systematic study, following the earlier work by Morimoto. Samples of the starting material—a silica gel—were heated for 4 hours in vacuum at a succession of temperatures ranging from 25 to 1000°C, and the surface concentration of hydroxyl groups of each sample was obtained from the further loss on ignition at 1100°C combined with the BET-nitrogen area. Two complete water isotherms were determined at 20°C on each sample, and to ensure complete... 

Fig. 10. Long-term effect of aging in vacuum on flexibiUty of Parylenes C, D, and N at elevated temperature. Failure = 50% loss in tensile strength.

Continuous deaeration occurs when the viscose is warmed and pumped into thin films over cones in a large vacuum tank. The combination of the thinness of the Hquid film and the dismption caused by the boiling of volatile components allows the air to get out quickly. Loss of water and CS2 lower the gamma value and raise the cellulose concentration of the viscose slightly. Older systems use batch deaeration where the air bubbles have to rise through several feet of viscose before they are Hberated. 

Another option available with rotary vacuum dmm filters is fiiU enclosure. This enables operation under nitrogen or other atmospheres, for reasons such as safety, prevention of vapor loss, etc. Enclosure may also be used to prevent contamination of the material being filtered or to confine the spray from washing nozzles. The rotary dmm filter also can be enclosed in a pressure vessel and operated under pressure. 

The physical and chemical properties are less well known for transition metals than for the alkaU metal fluoroborates (Table 4). Most transition-metal fluoroborates are strongly hydrated coordination compounds and are difficult to dry without decomposition. Decomposition frequently occurs during the concentration of solutions for crysta11i2ation. The stabiUty of the metal fluorides accentuates this problem. Loss of HF because of hydrolysis makes the reaction proceed even more rapidly. Even with low temperature vacuum drying to partially solve the decomposition, the dry salt readily absorbs water. The crystalline soflds are generally soluble in water, alcohols, and ketones but only poorly soluble in hydrocarbons and halocarbons. 

Vacuum Outgassing and Permeability. Under vacuum, modified ethylene—tetrafluoroethylene copolymers give off Htde gas at elevated temperatures. The loss rate is about one-tenth of the acceptable maximum rates for spacecraft uses. Exposing 750-pm specimens for 24 h at 149°C to a high vacuum results ia a maximum weight loss of 0.12% volatile condensible material is less than 0.02%. 

Electrical. Glasses are used in the electrical and electronic industries as insulators, lamp envelopes, cathode ray tubes, and encapsulators and protectors for microcircuit components, etc. Besides their abiUty to seal to metals and other glasses and to hold a vacuum and resist chemical attack, their electrical properties can be tailored to meet a wide range of needs. Generally, a glass has a high electrical resistivity, a high resistance to dielectric breakdown, and a low power factor and dielectric loss. 

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