Static variables

In C++, the static variables and operations of a class can be thought of as forming a class object but with limited features. There is no metaclass to which class-object classes belong and no dynamic definition of new classes. 

The frequency matrix Qy and the memory function matrix Ty, in the relaxation equation are equivalent to the Liouville operator matrix Ly and the Uy matrix, respectively. The later two matrices were introduced by Kadanoff and Swift [37] (see Section V). Thus the frequency matrix can be identified with the static variables (the wavenumber-dependent thermodynamic quantities) associated with the nondissipative part, and the memory kernel matrix can be identified with the transport coefficients associated with the dissipative part. 

At the beginning of the EntityDictionaryDao, it defines a series of constants the size and the name of each entity dictionary. Using these constants, the code allocates the Java Collection objects so that the sizes of these Collection objects do not need to expand at runtime, which causes extra CPU cycles to be wasted. Following the sizes are String constants names that are used to look up each entity dictionary. The class also defines SQL statements that are used to query the entity dictionary as static variables and initialize them in a static block ... 

The class first declares a set of static variables for holding the entity dictionaries. Its private constructor and the static getlnstance() method make it a Singleton. Its load...() methods call EntityDictinaryDao to load the entity dictionaries from the data source. Let us again use personnel dictionary as an example. The code snippet of the loadPersonnel() method is as follows ... 

Static variables are similar to boolean variables, with the semantic difference that their values are retained across procedural invocations. Since static variables have state information, they are always implemented as registers in the resulting hardware. Static variables may be optionally initialized to a pre-specified value upon system reset. The registers implementing static variables can be explicitly loaded by using the load assignment statement. For example. 

Let V be a static variable and reg be its implementing register. We identify three possible scenarios in which the value of a variable needs to be explicitly loaded into its implementing register. Even though the load statement may be omitted in a HardwareC description in the following cases, it is implied and therefore the corresponding statement will take one control state to execute. 

We consider only static variables because (1) int variables are always resolved at compde-time, and (2) boolean variables are either converted to static variables during behavioral optimizations, or they satisfy the single assignment requirement and are always implemented as wires. 

At the end of its defining block. We stated earlier that a static variable needs to retain its last assigned value for the next invocation of the model. If the final value of v is different firom its register value, then we need to load this final value into the register reg. Consider the defining block of V below. 

The loop body is traversed with the (exit = 0) entry as the top of stack. Upon completion, the two entries for each variable are examined. If the entries are identical, then they are popped off and the new top of stack is updated to this value. Oth wise, the variable has been modified in the loop, in which case it is stored into a register, or equivalently, it is classified as a static variable. The register first loads the value of the (exit = 1) entry before ent ng the loop. Each time the loop is repeated, it loads the value of the (exit = 0) entry. For this case, the new top of stack is updated with the variable itself. 

Sonochemistry is strongly affected by a variety of external variables, including acoustic frequency, acoustic intensity, bulk temperature, static pressure, ambient gas, and solvent (47). These are the important parameters which need consideration in the effective appHcation of ultrasound to chemical reactions. The origin of these influences is easily understood in terms of the hot-spot mechanism of sonochemistry. 

Knoop developed an accepted method of measuring abrasive hardness using a diamond indenter of pyramidal shape and forcing it into the material to be evaluated with a fixed, often 100-g, load. The depth of penetration is then determined from the length and width of the indentation produced. Unlike WoodeU s method, Knoop values are static and primarily measure resistance to plastic flow and surface deformation. Variables such as load, temperature, and environment, which affect determination of hardness by the Knoop procedure, have been examined in detail (9). 

Time is a critical variable because the magnetite settles if the mixture is held too long in a static condition. Use of hydrocyclones makes possible the separation in a fraction of a minute (21). These devices impart centrifugal force to the system, thereby permitting a separation to be made at a specific gravity less than that required in static, heavy-Hquid separations. 

Solubility. Sohd—Hquid equihbrium, or the solubiHty of a chemical compound in a solvent, refers to the amount of solute that can be dissolved at constant temperature, pressure, and system composition in other words, the maximum concentration of the solute in the solvent at static conditions. In a system consisting of a solute and a solvent, specifying system temperature and pressure fixes ah. other intensive variables. In particular, the composition of each of the two phases is fixed, and solubiHty diagrams of the type shown for a hypothetical mixture of R and S in Figure 2 can be constmcted. Such a system is said to form an eutectic, ie, there is a condition at which both R and S crystallize into a soHd phase at a fixed ratio that is identical to their ratio in solution. Consequently, there is no change in the composition of residual Hquor as a result of crystallization. 

Distillation columns are controlled by hand or automatically. The parameters that must be controlled are (/) the overall mass balance, (2) the overall enthalpy balance, and (J) the column operating pressure. Modem control systems are designed to control both the static and dynamic column and system variables. For an in-depth discussion, see References 101—104. 

Variable voltage (fixed frequency) static control Figure 6.40 Energy conservation through static control... 

There is special coverage of fluid couplings for soft starting and speed control, A comparison between static drives and variable-speed fluid couplings is inade. 

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