Static procedure

Equilibrium moisture content of a hygroscopic material may be determined in a number of ways, the only requirement being a source of constant-temperature and constant-humidity air. Determination may be made under static or dynamic conditions, although the latter case is preferred. A simple static procedure is to place a number of samples in ordinaiy laboratoiy desiccators containing sulfuric acid solutions of known concentrations which produce atmospheres of known relative humidity. The sample in each desiccator is weighed periodically until a constant weight is obtained. Moisture content at this final weight represents the equilibrium moisture content for the particular conditions. 

For the very heavy elements which are not available in micro-or nanogram quantities or which are synthesized one atom at a time , partition methods are the only practical way of determining complexing constants. When the half-life of an element is short, dynamic rather than static procedures are used since they give the most rapid experimental results (12). 

For laboratory-scale modification, distinction has to be made between static and dynamic adsorption procedures. In a static procedure, the substrate is contacted with a known volume of gas at a well-defined pressure. The modifying gas may be stationary or circulating in a closed loop. Modification in a static gas adsorption apparatus allows the careful control of all reaction parameters. Temperature and pressure can be controlled and easily measured. Adsorption kinetics may be determined by following the pressure as a function of the reaction time. Figure 8.13 displays a volumetric adsorption apparatus, in which mercury is used, as a means to change the internal volume and for pressure measurement. 

SIS (1991) Determination of acute lethal toxicity of chemical substances and effluents to Nitocra spinipes Boeck- Static procedure. Swedish standard SS 02 81 06, Stockholm, Sweden. 

Acute tests can be further divided with respect to flow regime typically either static or static-renewal. During the static procedure, test organisms are exposed to the environmental sample in relatively nontoxic and nonreactive cups, glass beakers, or aquaria... 

From the standpoint of physicochemical measurements, family and isothermal plots are useful for the determination of vapor pressures (and, in addition, recalling Equations 13 and 16, heats of vaporization as well) from the retention data obtained from just a few chromatographic runs (33). Furthermore, the GC technique is ideally suited to instances in which the solutes are available only in minute quantities or are substantially impure, where each of these constraints ordinarily precludes bulk vapor-pressure measurements by conventional static procedures. For example, Heath and Tumlinson (34) employed log(retention) plots to determine the vapor pressures of trace acetate ingredients used in pheromone formulations. An important aspect of their work was that family correlations were obtained with a chiral-nematic stationary phase, cholesteryl p-chlorocinnamate. 

Practical Aspects of Osmometry In static osmometers, the heights of liquid in capillary tubes attached to the solvent and solution compartments (Fig. 4.3) are measured. At equilibrium, the hydrostatic pressure corresponding to the difference in liquid heights is the osmotic pressure. The main disadvantage of this static procedure is the length of time required for attainment of equilibrium. 

We will now describe some static procedures, in which the temperature is kept constant and the pressure is observed. 

An increase of the extraction yield can be obtained by the simultaneous application of a microwave field to the extraction chamber. The resulting procedure is known as microwave-assisted solvent extraction (MASE). Only static procedures are necessary. Atrazine, simazine, terbumeton, terbuthylazine, terbutryn, molinate, and bromacil were extracted from soils by using MASE with methanol, resulting in recoveries >80% for the 5-200 ng per g... 

The ordinate scale in specific terms should be identified, if possible. Increases in expansion, elongation or extension (in the static procedure) and torsional displacement should be plotted upwards and increased penetration or deformation in flexure should be plotted downwards. 

An alternative nonlinear static procedure was proposed by Aydinoglu (2003). The procedure, called Incremental Response Spectrum Analysis (IRSA) does not properly belong to the pushover methods. The procedure is displacement-based, it uses the equal displacement rule and the structure nonlinear behavior is modeled as piece-wise linear. The initial modes are computed and the elastic response spectrum for the initial structure is carried out. In the first stop the spectral ordinates are scaled to the formation of the first plastic hinge, which corresponds in the piece-wise linear capacity curve, to the first change of stiffness. The updated modal quantities are computed and additional spectral ordinates are computed up to the formation of the second plastic hinge. The procedure continues until the entire spectral ordinates are applied. The method does not require any transformation to an equivalent SDOE system. 

In order to address these issues, researchers have incorporated convection into the process of cell seeding, suppressing some of the mass transfer limitations encountered in the static procedure. Spinner flask bioreactors (Figure 44.2b) have been implemented to create convection and, thereby, hydrodynamic forces that could help increase mass transport. Poly(glycolic acid) (PGA) scaffolds were threaded onto needles and chondrocytes suspensions with a total number of cells between 2 x 10 and 10 x 10 were used. A yield of 60% was obtained after 2 h of seeding. A more uniform distribution of the cells in the scaffold was seen (compared to the static seeding) nonetheless, the concentration of cells in the outer layer of the construct was 60 to 70% higher than that in the bulk [24]. This behavior maybe due to the poor... 

While the account of kinetics in the first two chapters is sufficient for static procedures, it is insufficient if we are to consider dynamic procedures which give directly the rate of a chemical reaction. Accordingly, the rest of this chapter will cover the kinetics of tubular and continuous flow reactors, followed by a study of modern experimental methods for measuring the rate of fast reactions, completed in less than about one minute. The reader will find the description of the classical experimental procedures in the detailed texts listed at the end of the book. 

Analytic Fragility and Limit States [P(EDPI IM)] Nonlinear Static Procedures... 

Fragility analysis Fragility curve Limit state Nonlinear static procedure Pushover analysis SDOF model Seismic demand Target displacement Uncertainty... 

Analytic Fragility and Limit States [P(EDP IM)] Nonlinear Static Procedures, Fig. 1 A view of the investigated four-story building and the reinforcement in selected columns and beams... 

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