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Komputerowa symulacja dynamikirozprzestrzeniania się wirusów

Wawer A., Nielek R., Kotowski R.

Zeszyty Naukowe Wyższej Szkoły Informatyki

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2006

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Vol. 5, Nr 1

115-122

PL

W pracy zaprezentowano model rozprzestrzeniania się wirusów łączący w sobie opis systemów wieloagentowych, analizę sieci społecznych i teorie zarażania się. Zbadano możliwość zastosowania prezentowanego podejścia do modelowania epidemii chorób.Typowa sieć społeczna została uzupełniona o socjologiczne mechanizmy komunikacji, systemową teorię komunikacji i o opis przepływu zasobów. Podjęto próbę uwzględnienia realistycznego opisu modelowania czasu społecznego. Sieć społeczna jest aktualizowana w cyklach rekurencyjnych na podstawie nadchodzących komunikatów: tworzą się nowe połączenia, a istniejące połączenia są mody?kowane. Inne znane modele, np. Huang et al. [2004], których autorzy wprowadzają „model małego świata wykorzystującego automaty komórkowe w celu odzwierciedlenia sieci codziennych kontaktów społecznych”, stosują statyczne struktury sieciowe. Symulacje komputerowe zostały wykonane w języku Java z wykorzystaniem Repast Toolkit. Przeprowadzono obliczenia dla kilku mechanizmów zarażania i z wieloma modelami komunikacji.

EN

A dynamic model combining multiagent systems, social network analysis andcontagion theories is presented. The possibilities of its application in epidemiological modelling are investigated. In the model, typical social network based on a directed graph was extended with sociological mechanisms of communicative behavior, systemtheory of communication and resource ?ow. The proposed approach follows realistic social time modelling. The network is updated in recurrent cycles. Network properties are modi?ed by ongoing communication, new links are established and existing ones are updated. In opposition to our approach, other known methods to simulate spreading of SARS virus, like that of Huang et al. [2004], where authors introduce the "smallworld model that makes use of cellular automata with the mirror identities of dailycontact social networks" make use of static network structure. In order to simulate virus spreading the computer software in Java based on Repast Toolkit was developed and used with several contagion mechanisms and multiple communication models.

2

Kinetic Isotope Effect in Hydrogen Isotope Exchange Between Hydrogen Sulphide or Thiol and Alcohol in Gas and Solution

Wawer A., Szydłowski J.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 1

117-121

EN

The kinetic parameters of the tritium exchange between H2 * S(D2 * S) or MeSH*(MeSD*) and MeOH(MeOD) vapours on PTFE and glass surface were measured. The *HH/*DD kinetic isotope effects are significantly lower than those for the reaction of phosphines with methanol. The kinetics of deuterium exchange between ButSH and EtOD in solutions of C6D12 and CD3CN had been studied and HH/DD isotope effect was evaluated. It appeared to be smaller than that in the vapours. These results suggest that contrary to the exchange reactions in phosphine, the elementary reaction of HH-transfer in four center transition state is not the rate limiting step and H-bond formation as well as diffusion controlled processes should be taken into account.

3

Deuterium isotope fractionation between ortho-alkyl substituted phenols and t-butylthiol in oxygen bases

Wawer A., Jelińska-Kazimierczuk M., Szydłowski J.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 3

618-626

EN

Equilibrium isotope effect in the exchange reaction of deuterium between phenol (P), 2-isopropylphenol (IPP), 2,6-diisopropylphenol (DIPP), 2,6-ditertbutyl phenol (DTBP) and tertbutylthiol (TBT) has been studied at 298 K. The fractionation factors (alpha) have been measured in cyclohexane and carbon tetrachloride solution and in a few oxygen bases: acetone, 1,4-dioxane, ethyl formate, ethyl ether, tetrahydrofurane, N,N-dimethylformamide, dimethylsulphoxide and hexamethylphosphoramide. Using chemical shifts of phenol OH protons, the thermodynamic parameters of complex formation with the oxygen bases have been determined. The experimental data show that ln alpha correlates with the formation enthalpy of the phenol-oxygen base complex in DIPP-TBT-base system but there is no simple correlation in IPP-TBT-base system. Futhermore it was found that in DTBT-TBT-base system ln alpha depends linearly on the basicity of the (solvent DN parameters). On the other hand, ln alpha correlates with acidic parameters of the solvents (AN) in IPP-TBT-base and P-TBT-base systems. All above correlations are explained by taking into account two competition processes: selfassociation of phenol molecules and their solvation by oxygen bases.