Underwater construction

Nuclear weapons (war)d d Underwater construction d Sport parachutes d Coal mining accidents d General aviation... 

Direct. The team is asked to think of a completely different situation where the same phenomena or symptoms exist The task is then to see if they can be applied to the current problem. This is much the easiest area for scientists and technologists to find analogies. There are many examples in the history of scientific innovations. The classic, often quoted example, is that of Brand s invention of the caisson for underwater construction which was based on his observation of shipworms tunnelling into timber. 

Besides borehole sealants for the oil industry, CBS may have other mining and civil engineering applications. These include reinforcement of mined out structures, water shut off, and underground and underwater construction, etc. 

Determination of the residual pore water pressure. (From Kirkpatrick, W.M., and Retmie, I.A., Stress relief effects in deep sampling operations, Proceedings Underwater Construction Conference, University College, Cardiff, 1975.)... 

The method and means may be used for welding repair in hard-accessible places of underwater constructions. Seawater may be used as an electrolyte however, in some cases, it is advantageous to use concentrated NaNOs solution in order to accelerate the process of metal anodic dissolution. It is necessary to use the electrolyte flow systems. 

Though pyrotechnic festeners are not generally part of one s everyday Ufe, for those in the rocketry or underwater-construction field, engineering to make these chemical reactions safer and more effective is always welcome. 

Shallow foundations are generally more economical to design and construct. Therefore, shallow foundations are often preferred over deep foundation if the geomaterials at shallow depths are firm and suitable for supporting the anticipated structure loads. Even in firm ground, use of shallow foundations may not be feasible due to other considerations such as the unusually high loads, vertical or lateral or both, difficult underwater construction conditions, and limited right-of-way. 

The distance between the structure and fixed impressed current anodes is an important factor. The number of anodes has to be small so the anodes need to be relatively large, which will result in too negative a potential if the distance is not sufficiently great. A minimum distance of 1.5 m is prescribed [1-3], but this involves considerable construction effort due to the effects of heavy seas. Besides the so-called restriction on impressed current installations, there is the requirement that the corrosion protection be switched off when diving work is being carried out [14]. This regulation is not justifiable. Work on the underwater region of production platforms takes place continuously, as far as the weather allows if the protection must be switched off each time, the impressed current protection becomes very limited. 

Aluminum (Al) is a silver-colored light and soft metal used as a major component of aluminum alloys, which are used to construct aircraft and vehicles, similar to Mg alloys. However, Al is known as a readily combustible metal. Thus, Al particles are used as major fuel components of pyrolants. Al particles are mixed with ammonium perchlorate particles and polymeric materials to form solid propellants and underwater explosives. The reaction between aluminum powder and iron oxide is known as a high-temperature gasless reaction and is represented by ... 

These obviously include UXO,1 IEDs,2 and other ERW,3 but also may include similar objects underwater, buried in the seabed. There are also abandoned mining and construction sites that may need to be searched for old explosives. No matter which type object we may hypothesize as the source of molecules found, we need to follow similar reasoning to locate that source. 

LMC is used in underwater concrete for both new construction and repair. The important requirements to obtain antiwashout capability, such as segregation resistance, flowability, self-leveling characteristics and lower bleeding are provided by the addition of viscosity-enhancing polymeric admixtures at polymer-cement ratios of 0.2-2.0%. These admixtures are water-soluble polymers, and classified under two groups, viz., cellulose types such as methyl cellulose and hydroxy ethyl cellulose and polyacrylamide types such as polyacrylamide and polyacrylamide-sodium acrylate [101]. 

Other applications include the construction of floor slabs where manipulation of the level of the admixture in the concrete will result in the production of bleed water should it be required to enhance finishing. The use of VEAs in grouting and underwater concrete applications is discussed below. 

In the oil and gas industry, the term abandonment generally refers to the activities undertaken to remove the structures used to sustain oil and gas production after the production is ceased. The structures range from a few tonnes of steel on the seabed to a complete platform constructed from around 30000 tonnes of steel framework. The task of removal requires extremely detailed and careful planning as well as substantial resources. Explosives are very efficient tools for cutting steel underwater and have been the preferred choice of many offshore operators for over 40 years. Also explosives offer the flexibility of a single controlled cut or multiple simultaneous cuts for remote and safe toppling of very large structures [129]. 

A third type of security glass is installed in modem penal institutions. This product is utilized for prisoner detention and obviates iron bars and their demeaning aspect. Typical construction utilizes three or more layers with at least one ply of thick PVB. Other constructions utilize polycarbonates, polyurethanes, and modified acrylics. Strengthened glass and electrically conductive circuits for alarms may be included. Large, heavy sections of similar construction have been used for underwater windows for boats, submarines, and aquariums. Four plies of fully tempered, 10-mm glass plus three plies of PVB totaling 44.5 mm in thickness has a modulus of rupture of 172 MPa (25,000 psi) (39). 

Syntactic foams are used extensively for the construction of boats and deep-water submarines46155,58,79,127 142-169). They are also used to make floats, buoys, underwater rescue apparatus, and equipment for raising sunken ships 153,176). Other applications include cements and putties for repairing hydraulic structures, submarine bodies and bulkheads127). 

Several possible applications of concrete-polymer material includes sewer and pressure pipe, building material for housing, underwater structures, railroad ties, and chemically resistant material of construction for large desalination plants. The incorporation of colored dyes with the monomer allows concrete-polymer material to be considered for various esthetic applications, such as in decorative wall and floor tile. 

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