Plugging point

The characteristics of diesel fuel taken into account in this area are the cloud point, the pour point, and the cold filter plugging point (CFPP). 

The cold filter plugging point (CFPP) is the minimum temperature at which a given volume of diesel fuel passes through a well defined filter in a limited time interval (NF M 07-042 and EN 116 standards). For conventional diesel fuels in winter, the CFPP is usually between —15 and —25°C. 

Additives acting on the pour point also modify the crystal size and, in addition, decrease the cohesive forces between crystals, allowing flow at lower temperatures. These additives are also copolymers containing vinyl esters, alkyl acrylates, or alkyl fumarates. In addition, formulations containing surfactants, such as the amides or fatty acid salts and long-chain dialkyl-amines, have an effect both on the cold filter plugging point and the pour point. 

Cold filter plugging point EN 116 (NF M 07-042) Vacuum filtration through a calibrated filter... 

Some additives have the ability to lower the pour point without lowering the cloud point. A number of laboratory scale flow tests have been developed to provide a better prediction of cold temperature operability. They include the cold filter plugging point (CFPP), used primarily in Europe, and the low temperature flow test (LTFT), used primarily in the United States. Both tests measure flow through filter materials under controlled conditions of temperature, pressure, etc, and are better predictors of cold temperature performance than either cloud or pour point for addithed fuels. 

For a component to be generic, you must provide ways that your clients designers can specialize it to their needs. The techniques include parameters passed when a function is called tables read by the component configuration or deployment options on the component plug-points—a place where the component can be plugged into a variety of other components and frameworks, such as a workflow system, into which a variety of components can be plugged. 

Components can be designed to plug in to each other and in to frameworks. The plug-points are defined with action specifications (see Sections 1.9.2 and 1.9.3). 

Two components fit together if their plug-points conform. Document them with refinements. 

There are two specifications at a plug-point the services offered advertisement of one component and the required of the other. We must ensure that one matches the other. 

Reuse comes in many flavors, from cut-and-paste to building libraries of low-level utility routines and classes to creating skeletons of entire applications with plug-points that can be customized. The latter requires a particular mind-set to extract commonality while deferring only those aspects that are variable. 

But there is a difficulty. If alterations are not allowed, a component can be useful in many contexts only if it is designed with a good set of parameters and plug-points. It must follow the well-known Open-Closed Principle ... 

Every 00 language provides some form of plug-ins. The most common form is the use of framework classes the superclasses implement the skeleton of an application—implementing methods that call operations that must be defined in the subclasses—and a set of subclasses serves to specialize the application. The plug-points are the subclasses and their overriding methods. In C++, a template List class can be instantiated to provide lists of numbers, lists of elephants, or lists of whatever class the client needs the plug-point is a simple template parameter. 

BoundingBox box = innerBox() II plug-point deferred to subclass Point location = locationQ // plug-point deferred to subclass... 

The actual rendering and computation of the inner box and location must be deferred to the subclasses plug-points. However, if a subclass provides the appropriate bits as plugins, it can inherit and use the same implementation of display. Thus, we are imposing a consistent skeletal behavior on all subclasses but permitting each one to flesh out that skeleton in its own ways. 

Define an interface representing demands that the reusable skeleton framework makes on the applications—the plug-points for extension. Application contains newer code however, the existing (base) code calls newer code to delegate specialized bits. 

The relation between these plug-points is analogous to refinement. 

Each of the model frameworks in Figure 11.10 could come with a default implementation framework. Our design, at the level of framework-sized components, would look like Figure 11.11. Each of the framework components has its plug-points suitably filled by implementation units from this problem domain. Thus, the instructor allocator has Instructor and Session as plug-ins for Resource and Job and the trend monitor has Session and Topic plugged in for Indication and Product. 

There are several implementation mechanisms for achieving the effect of plug-points and plug-ins. This section discusses the main ones, emphasizing the value of black-box composition over white-box inheritance for large-grained reuse. 

For every interface, define a default implementation with inheritance plug-points ... 

The LoanFactory may be a supertype, with different implementations providing different policies in different Libraries. See Pattern 16.18, Plug-Points and Plug-Ins. 

Simulated filter plugging point (SFPP) Proposed European standard... 

COLD FiLTER PLUGGING POINT (CFPP) REDUCTION... 

The cloud point and the cold filter plugging point temperatures for fuel which does not contain a wax crystal modifier can often be the same. Typically, untreated cloud point and CFPP values will be within 2°F to 4°F (about 1°C to 2°C) of each other. If the temperature difference between an untreated fuel s cloud point and CFPP differ by 10°F (5.6°C) or more, the fuel probably contains a wax crystal modifier. 

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