Active protection systems applications

Although the first industrial application of anodic protection was as recent as 1954, it is now widely used, particularly in the USA and USSR. This has been made possible by the recent development of equipment capable of the control of precise potentials at high current outputs. It has been applied to protect mild-steel vessels containing sulphuric acid as large as 49 m in diameter and 15 m high, and commercial equipment is available for use with tanks of capacities from 38 000 to 7 600000 litre . A properly designed anodic-protection system has been shown to be both effective and economically viable, but care must be taken to avoid power failure or the formation of local active-passive cells which lead to the breakdown of passivity and intense corrosion. 

Where process, safety, and environmental considerations permit, vacuum protection may be provided by properly sized ever-open vents. Alternatively, active protective devices and systems are required. Vacuum breaker valves designed to open and admit air at a predetermined vacuum in the vessel are commonly used on storage tanks, but may not be suitable for some applications involving flammable liquids. Inert gas blanketing systems may be used if adequate capacity and reliability can be ensured. Where the source of the vacuum can be deenergized or isolated, suitably reliable safety instrumented systems (e.g, interlocks) can be provided. 

Water spray systems for hydrocarbon facilities are routinely specified because of the rapid application means the system can provide and the excellent heat absorption a water based system represents. Water sprays are also used when passive fire protection measures (i.e., fireproofing, spacing, etc.) cannot practically be utilized. The key to providing an effective system is to ensure the surfaces to be protected receive adequate water densities and that the arrangements to activate the system are equally fast acting. By far the highest... 

The required protection may be obtained by active, passive, or a combination of both protection systems. For example, steel support located in a fire exposed area within process unit battery limits may be protected by either a fixed water spray system or the application of fire resistant insulating material to the steelwork or possibly both. Note Passive protection is generally the preferable method for protecting structural steel. 

Fixed active fire protection systems incorporating both water spray and foam application... 

The carbides and nitrides of vanadium and titanium crystallize in the same face centered cubic (fee) system, and because of the closeness of their cell parameters (Table 15.1) form solid solutions. These ceramic materials exhibit interesting mechanical, thermal, chemical and conductive properties.1,2 Their high melting point, hardness and wide range of composition have therefore attracted considerable attention in the last decade. Moreover, their good abrasion resistance and low friction also make these ceramics attractive for protective coating applications.3-5 Chemical vapor deposition (CVD) is a commonly used technique for the production of such materials. In the conventional thermally activated process, a mixture of gases is used.6-9 In the case of TiC, TiN, VC and VN, this mixture is... 

Emulsion Adhesives. The most widely used emulsion-based adhesive is that based upon poly (vinyl acetate)—polytyinyl alcohol) copolymers formed by free-radical polymerization in an emulsion system Poly(vinyl alcohol) is typically formed by hydrolysis of the poly (vinyl acetate). The properties of the emulsion are derived from the polymer employed in the polymerization as well as from the system used to emulsify the polymer in water. The emulsion is stabilized by a combination of a surfactant plus a colloid protection system. The protective colloids are similar to those used paint (qv) to stabilize latex. For poly (vinyl acetate), the protective colloids are isolated from natural gums and cellulosic resins (carboxymethylcellulose or hydroxyethylcellulose). The hydrolized polymer may also be used. The physical properties of the poly (vinyl acetate) polymer can be modified by changing the co-monomer used in the polymerization. Any material which is free-radically active and participates in an emulsion polymerization can be employed. Plasticizers (qv), tackifiers, viscosity modifiers, solvents (added to coalesce the emulsion particles), fillers, humectants, and other materials are often added to the adhesive to meet specifications for the intended application. Because the presence of foam in the bond line could decrease performance of the adhesion joint, agents that control the amount of air entrapped in an adhesive bond must be added. Biocides are also necessary many of the materials that are used to stabilize poly (vinyl acetate) emulsions are natural products. Poly(vinyl acetate) adhesives known as "white glue" or "carpenter s glue" are available under a number of different trade names. Applications are found mostly in the area of adhesion to paper and wood (see VlNYL POLYMERS). 

Successful application of cathodic protection depends upon the selection, design, installation, and maintenance of the system. Before designing the cathodic protection systems, adequate field data must be collected, analyzed, and evaluated. Nature and conditions of the soil are reflected by field measurements like soil resistance, hydrogen ion activity (pH), and the redox potential. To understand the nature of the pipeline, potential measurements, coating resistance, and meaningful design current requirement tests must be conducted. 

Approaches to blast protection can be categorised as active (deployed upon detection of an explosion) or passive (always present). An example of an active mitigation system is the water deluge system used on offshore oil and gas platforms [9]. Upon detection of a gas leak, the entire area is showered with carefiilly sized water droplets in order to prevent ignition and remove the energy from a vapour cloud explosion. An active system can only work if the imminent explosion can be detected and a suitable system deployed in time. These systems work offshore because the gas leak, which accumulates relatively slowly, can be detected easily and the water system deployed. A number of researchers have worked on the detection and deployment of mitigation devices for explosive detonations with military applications [10,11]. Such systems have yet to be deployed in the military, and (at the time of writing) no such detection systems are available for the case of explosive detonation on board an aircraft. For such a system to be viable, it would need to be robust and inexpensive to install and operate. 

The ability of SPEs to form vesicles, which are strueturally comparable to liposomes, has opened a wide range of possibilities for the incorporation of active ingredients. Silicone vesicles can have a diameter from about 0.05 to 1 micron and an internal volume of lO pm. The membrane thickness of these vesicles is about 3 to 4 nm [56]. The main application of siloxane-based surfactants vesicles is in eosmetics. For example, using silicone vesicles, hydrophilic and hydrophobic active substances can be separated and protected from each other, thus reducing for example skin irritancy. Active delivery systems include non-aqueous emulsions of polyols in silicone fluids, multiple-phase emulsions, and polar solvent-in-oil emulsions. 

Phenomenal results were obtained by us in the case of application of system, including NaSt as Ni(II)(acac)2 (3.0-10 mol/1) + NaSt (3.0 10 mol/1) + PhOH (3.0 10 mol/1). Parameters C > 35% at the SpEfj max 85-87%, concentration [PEH] = 1.6 - 1.8 mol/1 (-27 mass ), S C - 30.1 10 (%,%) are much higher, than in the case of the other triple systems and the most active binary systems [99], These data and some of other effective triple systems (L LiSt, MP, HMPA) are protected by patent RU (2004) the authors are L.I. Matienko, L.A. Mosolova, patent holder is Emanuel Institute of Biochemical Physics, Russian Academy of Sciences. 

The driving state is normally continually monitored (by the driver and/or a system) in order to make corrections on any or all of these levels if required. Detailed applications, variations and refinements of this model can be found in the literature [4, 10-12]. Classically, active safety systems, e.g.. Dynamic Stability Control (DSC), have been designed to provide support at the stabilization level. At this level, the target quantities are generally well defined in terms of vehicle physics. Preventive pedestrian protection, which is in the focus of this thesis, addresses primarily the maneuvering level and thus involves additional eomplexities in control—particularly those involving the interpretation of driver behavior and the interaction of system actions with the driver. 

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