Methods of repair

Rehabilitation of Kpelines Using Fiber-reinforced Polymer (FRP) Composites 

Upon initial entry of each pipe repair area, inspectors walk the entire length of the pipe from the access point to the location of air supply and note the presence of any leaks and the amount of residual water. Then, pumps and other water-removal equipment are started and removal of the residual water commences. Crews typically constmct temporary bulkheads as necessary to create beneficial airflow within the work space and promote drying of the repair pipe segments. Crews also convey water as needed to points of discharge and construct temporary weirs to control continuously flowing nuisance water. 

General work activities associated with the PCCP-strengthening-system installation that occur outside of the pipe include the preparation and mixing of the epoxy system and the saturation of glass- and carbon-fabric sheets prior to mobilizing the saturated sheets into the pipe for technician installation. General work activities associated with the CFRP system installation that wUl occur inside of the pipe include joint preparation, surface preparation of the inner core, installation of the CFRP system, and installation of flie end terminations. Details for each procedure are provided in the following sections. 

This subsection wUl include an overview of installation methods with particular focus on wet lay-up and the various components that lead to successful CFRP system installations. Wet lay-up is the procedure considered best practice as an installation method. As detailed below, this includes the saturation of the fiber system through a mechanical saturator. Other installation methods, such as dry lay-up, may lead to inadequate fiber saturation and delamination of the CFRP system. Dry lay-up is the application of dry fiber sheet and in situ application of the epoxy to the fiber at the point of application. This is deemed to be an uiueliable installation method. Detailed steps of the wet lay-up process follow. 

Surface preparation is one of the most important aspects of the CFRP installation process. Concrete surfaces are to be prepared to an ICRI profile of CSP-3 or greater to create an open-pore stmeture and to remove aU protrusions, sharp edges, and surface contaminants. Surface residue resulting from surface preparation is to be collected from within the constmetion area and removed from the pipe. 

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Operators select methods of repair for damaged bonded structure depending on the cause of the damage, size of the damage, type of bonded assembly and even the length of time until the next major overhaul of the aircraft. 

The second method of repair is much more time consuming and tedious if it can be accomplished at all. It presupposes that the conserv-... 

Lamination Shop. This shop has four restorers who keep an Arbee machine in constant use, laminating material that does not lend itself to other methods of repair. Polyethylene film and Japanese tissue are used to make a sandwich for the damaged artifact in a process that uses application of heat, then pressure with metal rollers, to complete the cycle. 

The jobs that will be lost in the manufacture of throwaway items will be counterbalanced by an increased number of jobs in maintenance and repair. Many items are discarded today because it is cheaper to buy a new one than to repair the old one. This calls for research on new automated methods of repair as well as on new designs that make repair simple. Increasing the cost of disposal may also help. (See Chap. 17 for more on environmental economics and Chap. 18 for greening of consumers.)... 

Heretofore, the most commonly used method of repairing cracks in concrete was by injection of a cement slurry grout. It is obvious that such a grout, based on a cementitious composition, would shrink and not fill the void completely. it is also highly likely that such a grout, after curing, v/ould crack again at the same stress points. 

For this reason, in the third part of the research project, a comprehensive fatigue inspection evaluation and rehabilitation study will be carried out in order to describe the fatigue-life reserve level of the old railroad bridges and to develop the most feasible method of repair or rehabilitation to increase the fatigue life to meet the new needs. 

It should be pointed out that none of these methods of repair is an ideal solution to damage in load carrying structures. These methods are temporary solutions to extend the service time of the material, and each of these repair strategies requires monitoring of the damage and manual intervention to enact the repair. Also, all these repair methods require an interruption to the service. This is unacceptable for some structures, such as aircraft during flight, where... 

Gravity fill is also used when cracking is random or patterned. The material normally used is gravity polymer covered with hard and durable sand. Epoxy resin-based materials instead of elastomer/plastomer-based materials are preferred when a longer-lasting surface skid resistance is required. However, this method of repair can be very expensive. 

The repair of damaged glass linings is a specialized subject, but many repairs can be readily carried out by skilled tradesmen at a fraction of the cost of reglassing with relatively little interruption to production. There are four main methods of repairing ... 

Congenital heart disease (CHD) occurs in approximately 25 000 births per year in the United States. An atrial septal defect (ASD) is a spedfic form of CHD and is the third most common type of defect. Many people suffer from this disorder and in many cases it is only detected when the patient reaches middle age. Effective and efficient methods of repair are therefore needed to minimize the risks associated with traditional methods of ASD repair. In recent years, transcatheter closure methods for secundum type ASD have been developed. Currently the Amplatzer Septal Occluder, the Gore Helex Septal Occluder and the NMT Medical CardioSEAL-STARFiex Septal Occlusion systems have received FDA approval for ASD repair, the first of these only in 2001. This indicates that the use of these devices is still in its infancy. It can therefore be assumed that much more can be done to develop improved and more effective closure devices. It is the purpose of this chapter to describe ASDs and to outline the available technology with regard to transcatheter ASD repair devices. Hie discussion will centre around their construction and functioning, with special reference to their textile component. 

Gunning. The placing of a refractory powder or slurry by means of a cement gun most commonly, gunning is practised as a method of repairing furnace linings without the need to cool them to room temperature. 

This is a rapid method of repair that removes the existing lead pipe from service and replaces it with a non-lead pipe lateral such as copper or plastic. 

This is a method of repair that creates a lining after abrasively cleaning an existing lead pipe. 

It has often been said that concrete is destined to crack.The purpose of proper design and the objective of the design engineer are to minimize cracking without the expectation of eliminating it. When cracking does develop, it is important to determine the basic causes, as well as its extent, before deciding on the method of repair. 

Although the code recommends taking out of service defective sections of the pipeline, it accepts that this is not always possible. It does, therefore, allow for certain methods of repair while the pipeline is in service, such as the use of mechanically split sleeves, hot tapping, encirclement of welds, etc. The engineer should, however, be aware that these methods may not apply to rubber, polyurethane, or HDPE-lined steel pipes as they would damage the internal lining by heat. 

Kelly CH (1998) Extrophy and epispadias Kelly s method of repair. In O Neill JA (ed) Pediatric surgery, 5th edn. Mosby, St Louis, pp 1732-1759 Lizscano-Gil LA, Garcia-Cruz D, Sanchez-Corona J (1995) Omphalocele-exstrophy-imperforate anus-spina bifida complex in a male prenatally exposed to diazepam. Arch Med Res 26 95-96... 

ABSTRACT Technological advancements in area of sensor-based online maintenance systems have made the possibility of repairing some failed safety support systems of Nuclear Power Plants (NPP) such as electrical supply, I C systems, ventilation systems. However, the possibility of repair during accident situation is yet to be included into PSA level-1. Therefore, this paper presents a scheme of PSA level-1 by implementing an integrated method of Repairable Event Tree (RET) and Repairable Fault Tree (RET) analysis. The Core Damage Frequency (CDF) is calculated from consequence probabilities of the RET. An initiating event of Decay Heat Removal (DHR) systems of ASTRID reactor is analyzed. The proportionate CDFs estimated with repair and without repair have been compared and found that the recoveries can reduce CDF. In sum, this paper attempts to deal with the possibility of repair of some safety systems in PSA and its impacts on CDF of the NPP. 

Dermabond (2-OCA by Ethicon, a Johnson Johnson Company), the latest in CA technology, has less toxicity and almost four times the strength of N-butyl-2-cyanoacrylate. Special plasticizers have been added to the formula to provide flexibility. It is marketed to replace sutures that are 5-0 or smaller in diameter for incision or laceration repair. Patients, especially children, readily accept the idea of being glued over traditional methods of repair." " This adhesive reaches maximum bonding strength within... 

A well accepted method of repair involving an external fixture is the utilization of mechanical clamps (also known as sleeves) to encase the damaged region. These can be applied for both leak containment and strengthening (Coley and Caraballo, 2011). The clamps arc typically metallic and consist of two-piece flanged shells with oversized annuli that fit over the pipe, with perimeter elastomeric seals for fluid containment. The clamps are fixed together via a series of bolts on the flanges. For underwater applications, they are normally fitted with aluminium anode blocks for cathodic protection. 

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