Calculation of PSA

The most significant differences between TPSA and 3D PSA were observed for large macrocycles containing many polar substituents These substituents are usually buried in the center of the ring and are therefore not accessible to solvent. Fragment-based TPSA provided larger values than 3D PSA in such cases. 

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A numerical calculation of PSA operation were performed with the Stop Go method and results were compared with the experimental results. 

The Seismic Safety Margins Research Program developed a computer code called SMACS (Seismic Methodology Analysis Chain with Statistics) for calculating the seismic responses of structures, systems, and components. This code links the seismic input as ensembles of acceleration time histories with the calculations of the soil-structure interactions, the responses of major structures, and the responses of subsystems. Since uses a multi-support approach to perform the time-history response calculations for piping subsystems, the correlations between component responses can be handled explicitly. SMACS is an example of the codes that are available for calculating seismic response for PSA purposes. 

Even, limited PSAs use and contain much information. This information may come as memos and process reports and flow sheets, equipment layout, system descriptions, toxic inventory, hazardous chemical reactions, test, maintenance and operating descriptions. From this, data and analyses are prepared regarding release quantities, doses, equipment reliability, probability of exposure, and the risk to workers, public, and environment. An executive summary analysis is detailed, and recommendations made for risk reduction. Thus the information will be text, calculations of envelope fracture stresses, temperatures, fire propagation, air dispersion, doses, and failure probabilities - primarily in tabular form. 

PSA. Hence, we only mention here that the definition of PSA is similar to that of Na and N. Thus, PSA possesses the same disadvantages when compared to thermodynamic H-bond descriptors. In fact, it has been estimated that there is a strong linear relationship between the calculated static PSA and the calculated dynamic polar surface [32, 33]. A further possible simplification using only the number of H-bond forming atoms and PLS statistics was proposed [35]. Excellent correlahons of PSA with the number of H-bond donors and acceptors were published [35, 36]. 

Calculation of the percentage of free PSA compared with the total PSA ... 

Calculation of the serum PSA concentration per unit volume of prostate gland (PSA density) ... 

Kelder et al. [25] also explored the role of PSA as a determinant for the transport of drugs through the BBB. Initially, they calculated and correlated the PSA of 45 drug molecules with their known brain-penetration data. A linear relationship was obtained between brain penetration and dynamic polar surface area (DPSA) as shown in Eq. 34 ... 

Osterberg and Norinder [35] analyzed the improvement in the prediction of drug transport processes by the combination of the hydrogen-bonding descriptors and calculated log P. Two data sets were used. The calculated static PSA and the experimental log BB values for 70 compounds (data set 1) were taken from the work of Clark. The calculated dynamic PSA and the experimental log... 

When this kind of PSA study is developed, wherein top event quantification, sensitivity analysis and dynamic management of the proposed systems are required, the complexity of data processing and calculations requires the use of appropriate software, such as the processing PSA package Saphire 6.0, developed by Idaho National Laboratory for the Nuclear Regulatory Commission of the United States and which is used in this work (Smith, 2005). 

These two functions are not truly independent parameters, since both correlate with the compound s log P value. Indeed, Log BB has also been calculated using PSA alone, as well as several other solvation and free energy methods. - " After Young showed that experimental Log P values could be correlated with experimental Log BB data algorithms were developed to calculate Log BB based on tPSA and c Log P (c Log P is a computed Log P value, based on a calculation of the contributions of the individual atoms and fragments in a molecule to its overall partition coefficient). ... 

The lipophilicity of PSA polymers, which is markedly affected by chemical composition, may influence drug solubility (Table 5). In general, acrylic copolymers have medium lipophilicity compared with other PSA polymers, and have the most excellent drug solubility. A suitable lipophilicity of copolymers can be obtained by changing the compositional content of comonomers. The lipophilicity of acrylic copolymers can be roughly estimated by the theoretical calculation of the hydrophobic parameters of copolymers according to the hydrophobic fragments of each comonomer, or the calculation of the octanol-water partition coefficients (log PC). ... 

Figure 10.19. Comparison of model calculations of H2 purity and recovery with experimental data for two H2 PSA processes (a) ROG feed and (b) SMROG feed.

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