An experimental and theoretical analysis of the water vapor adsorption in several types of porous building materials is presented. For the measurement of adsorption isotherms, a DVS-Advantage water sorption device is used. The experimental data is analyzed using theoretical formulas based on the BET, BSB, BDDT, and FHH isotherms, assuming a monoas well as multi-layer water vapor adsorption. The BSB equation is found to provide a good approximation for the relative humidities below 0.6-0.7, whereas the FHH equation shows a sufficient accuracy for the relative humidities above 0.4-0.5. Based on a combination of BSB and FHH isotherms, a semi-empirical formula is proposed that allows one to obtain a very accurate approximation of experimental data for all analyzed materials and all values of the relative humidity.Keywords Water vapor adsorption · Porous building materials · Theoretical adsorption isotherms · Experimental measurements Abbreviations c BET constant (-) C s Surface concentration (mol m −3 ) C sat s saturation surface concentration (mol m −3 ) D Fractal dimension (-) H a Molar heat of adsorption (J mol −1 K −1 ) H c Molar heat of condensation/vaporization (

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We consider three microscopic model molecular systems, each containing an equimolar mixture of a chiral molecule and its nonsuperimposable mirror image. The molecules in each model are assumed to lie on a thin film in such a way that they occupy the sites of a honeycomb lattice. Although neither enantiomorph is externally favored at low temperatures, we prove that for one range of interactions, chiral segregation into ordered phases containing a single enantiomorph occurs for two of the models and, in a second range of interactions, ordered racemic phases (containing equal numbers of each enantiomorph) occur for the two models. For a third range of interactions, each of the two models has an infinite number of ground-state configurations and, moreover, an associated residual entropy. In all three ranges of interactions considered, the third model has an infinite number of ground-state configurations and a residual entropy.

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