Modeling compartment models

FIRAC is a computer code designed to estimate radioactive and chemical source-terms as.sociaied with a fire and predict fire-induced flows and thermal and material transport within facilities, especially transport through a ventilation system. It includes a fire compartment module based on the FIRIN computer code, which calculates fuel mass loss rates and energy generation rates within the fire compartment. A second fire module, FIRAC2, based on the CFAST computer code, is in the code to model fire growth and smoke transport in multicompartment stmetures. 

It is user friendly and possesses a graphical user interface for developing the flow paths, ventilation system, and initial conditions. The FIRIN and CFAST modules can be bypassed and temperature, pressure, gas, release energy, mass functions of time specified. FIRAC i.s applicable to any facility (i.e., buildings, tanks, multiple rooms, etc,) with and without ventilation systems. It is applicable to multi species gas mixing or transport problems, as well as aerosol transport problems, FIRAC includes source term models for fires and limitless flow paths, except the FlRlN fire compartment limit of to no more than three... 

GASFLOW models geometrically complex containments, buildings, and ventilation systems with multiple compartments and internal structures. It calculates gas and aerosol behavior of low-speed buoyancy driven flows, diffusion-dominated flows, and turbulent flows dunng deflagrations. It models condensation in the bulk fluid regions heat transfer to wall and internal stmetures by convection, radiation, and condensation chemical kinetics of combustion of hydrogen or hydrocarbon.s fluid turbulence and the transport, deposition, and entrainment of discrete particles. 

MAKEFIRE models the growth, steady state, and decay phases of the each fuel element in the compartment. It consists of routines that create and edit fire files that specify the fire heat release rate and fuel pyrolysis rate as a function of time. 

Chung, G., N. Siu, and G, Apostolakis, 1985, Improvements in Compartment Fire Modeling and Simulation of Experiments, Nuclear Technology, 69, p. 14. 

Ito, V., N. SiLi, G. Apostolakis, 1985, COMPBRN III-A Computer Code for Modelling Compartment Fires, UCLA Report - ENG-8524, November. 

Jones, W. W., 1994, Modeling Smoke Movement Through Compartmented Structures Journal of Fire Sciences. 

Siu, N. 1983, COMPBRN - A Computer Code for Modeling Compartment Fires, NUREG/ CR3239, UCLA - ENG-8257... 

Siu, N., 1980, Probabilistic Models for the Behavior of Compartment Fires, UCLA-ENG-8090,... 

For most situations and conditions in daily life, the human can be represented adequately by a simple model that is helpful for understanding human thermal regulation. The model has two thermal compartments (Fig 5.1). The... 

Absorption, distribution, biotransformation, and excretion of chemical compounds have been discussed as separate phenomena. In reality all these processes occur simultaneously, and are integrated processes, i.e., they all affect each other. In order to understand the movements of chemicals in the body, and for the delineation of the duration of action of a chemical m the organism, it is important to be able to quantify these toxicokinetic phases. For this purpose various models are used, of which the most widely utilized are the one-compartment, two-compartment, and various physiologically based pharmacokinetic models. These models resemble models used in ventilation engineering to characterize air exchange. 

In a two-compartment model, /3 is equivalent to k in the one-compartment model. Therefore, the terminal half-life for the elimination of a chemical compound following two-compartment model elimination can be calculated from the equation (i = 0.693/ti/i ... 

Physiologically based toxicokinetic models are nowadays used increasingly for toxicological risk assessment. These models are based on human physiology, and thus take into consideration the actual toxicokinetic processes more accurately than the one- or two-compartment models. In these models, all of the relevant information regarding absorption, distribution, biotransformarion, and elimination of a compound is utilized. The principles of physiologically based pharmaco/ toxicokinetic models are depicted in Fig. 5.41a and h. The... 

Figure 8.31 Network of compartments in the Imbhle column reaction engineering model after Rigopoulos and Jones, 2001)...

Drug elimination may not be first order at high doses due to saturation of the capacity of the elimination processes. When this occurs, a reduction in the slope of the elimination curve is observed since elimination is governed by the relationship Vmax/(Km- -[conc]), where Vmax is the maximal rate of elimination, Km is the concentration at which the process runs at half maximal speed, and [cone] is the concentration of the drug. However, once the concentration falls below saturating levels first-order kinetics prevail. Once the saturating levels of drugs fall to ones eliminated via first-order kinetics, the half time can be measured from the linear portion of the In pt versus time relationship. Most elimination processes can be estimated by a one compartment model. This compartment can... 

Fig. A.3. Light meter used by the author (Model 8020, Pelagic Electronics). For total light measurements, the signals are integrated with capacitors. Milliammeter reading is automatically reset at full-scale position, and the number of resets is digitally indicated below the meter. The box at the right contains a photomultiplier and sample compartment.

The IIEC model was also used to study the importance of various design parameters. Variations in gas flow rates and channeling in the bed are not the important variables in a set of first-order kinetics. The location of the catalytic bed from the exhaust manifold is a very important variable when the bed is moved from the exhaust manifold location to a position below the passenger compartment, the CO emission averaged over the cycle rose from 0.14% to 0.29% while the maximum temperature encountered dropped from 1350 to 808°F. The other important variables discovered are the activation energy of the reactions, the density and heat... 

The limited efficacy of classical anticancer diugs can be explained in part by the compartment model of dividing (growth fraction, compartment A) and nondividing (compartment B) cells. The majority of antineoplastic diugs acts upon cycling cells and will hit, therefore, compartment A only. 

These models are too simple to reflect realistic dynamic properties of the carbon budget. Even so, they depend on data that are poorly measured or lacking. Many potentially important compartments are missing or assumed to be unimportant. For example, no model considers carbon transported from terrestrial systems to the oceans through rivers and streams. While the amount is very small, it is continuous and cumulative (25)... 

Eriksson, E. (1971). Compartment models and reservoir theory. Ann. Rev. Ecol. Syst. 2, 67-84. 

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