The Experts below are selected from a list of 85971 Experts worldwide ranked by ideXlab platform
A Boller - One of the best experts on this subject based on the ideXlab platform.
-
Mathematical Description of differential scanning calorimetry based on periodic temperature modulation
Thermochimica Acta, 1994Co-Authors: Bernhard Wunderlich, Yimin Jin, A BollerAbstract:Abstract The changes needed in the Mathematical Description of differential scanning calorimetry caused by periodical modulation of temperature are presented. Calibration procedures and possible extensions of the method are suggested, all based on the model of scanning calorimetry without temperature gradient within the sample. The basic differential equation for heat flow under modulation conditions is solved and the steady state identified. The main advantage of modulated differential thermal analysis is the elimination of nonperiodic heat losses and gains. It is suggested that the precision of heat capacity measurement may be increased by a factor of 10 using proper calibration. The thermal analysis in transition regions is discussed.
Strzałkowski Jarosław - One of the best experts on this subject based on the ideXlab platform.
-
Mathematical Description of Sorption Isotherms of Autoclaved Aerated Concrete
Energy Procedia, 2015Co-Authors: Siwińska Agata, Strzałkowski JarosławAbstract:Abstract The article presents the results of measurements and developed on their basis sorption isotherms with Mathematical Description of the graphs obtained. The research was conducted on samples of three kinds of autoclaved aerated concretes with similar bulk density of approximately 600 kg/m 3 , but provided by different manufacturers. The tested concretes were also different by composition of raw materials. One of the examined concretes had fly ash in its composition. The moisture sorption studies were conducted at temperature 25 o C and at six relative humidity levels φ ≈ 11, 33, 53, 75, 84, 97%. The levels of temperature and relative humidity conditions correspond to a typical temperature/humidity conditions in which in practice commonly used autoclaved aerated concretes can be found. The moisture sorption content was obtained after several months of measurements at the equilibrium state. This data was then used to prepare sorption isotherms of the tested materials. The experimentally obtained data were then applied to calculate Mathematical Description of graphs. For this purpose three commonly known and used equations were applied: equation of Chen Y. and Chen Z., equation of Jovanovic’s for multi-layer adsorption, and Huttig's equation. Using statistical methods the compliance of the adsorption isotherm equations was compared with experimental data. For that purpose the STATISTICA programme was used. To estimate the coefficients of the equations the authors used one of the programme modules, i.e. the non-linear estimation. To assess how well the data fit a statistical model the coefficient of determination R 2 was used.
Jorge Chirife - One of the best experts on this subject based on the ideXlab platform.
-
an alternative to the guggenheim anderson and de boer model for the Mathematical Description of moisture sorption isotherms of foods
Food Research International, 1995Co-Authors: Hector A Iglesias, Jorge ChirifeAbstract:Abstract The fitting abilities of an isotherm equation originally developed by Ferro Fontan et al. ( J. Food Sci. , 47 , 1590–4, 1982) (FF) was compared with the well-known GAB model. For this purpose literature data of 156 food isotherms (comprising 92 different food products) were examined with both models. The results of the evaluation indicated that the FF equation is an accurate tool for the Mathematical Description of food isotherms. The FF equation represents accurately the sorption isotherm of 92 different food products (proteins, starchy, cereals and oilseeds, meats, vegetables, miscellaneous) in the range of water activity 0.10–0.90 with only 2–4% average error in the predicted moisture content. In fact, the average error for the 156 isotherms examined was only 3.3%. The FF equation only has three parameters that need determining (as has the GAB model); thus it is proposed as an alternative equation to the widely used GAB model.
Bernhard Wunderlich - One of the best experts on this subject based on the ideXlab platform.
-
Mathematical Description of differential scanning calorimetry based on periodic temperature modulation
Thermochimica Acta, 1994Co-Authors: Bernhard Wunderlich, Yimin Jin, A BollerAbstract:Abstract The changes needed in the Mathematical Description of differential scanning calorimetry caused by periodical modulation of temperature are presented. Calibration procedures and possible extensions of the method are suggested, all based on the model of scanning calorimetry without temperature gradient within the sample. The basic differential equation for heat flow under modulation conditions is solved and the steady state identified. The main advantage of modulated differential thermal analysis is the elimination of nonperiodic heat losses and gains. It is suggested that the precision of heat capacity measurement may be increased by a factor of 10 using proper calibration. The thermal analysis in transition regions is discussed.
Siwińska Agata - One of the best experts on this subject based on the ideXlab platform.
-
Mathematical Description of Sorption Isotherms of Autoclaved Aerated Concrete
Energy Procedia, 2015Co-Authors: Siwińska Agata, Strzałkowski JarosławAbstract:Abstract The article presents the results of measurements and developed on their basis sorption isotherms with Mathematical Description of the graphs obtained. The research was conducted on samples of three kinds of autoclaved aerated concretes with similar bulk density of approximately 600 kg/m 3 , but provided by different manufacturers. The tested concretes were also different by composition of raw materials. One of the examined concretes had fly ash in its composition. The moisture sorption studies were conducted at temperature 25 o C and at six relative humidity levels φ ≈ 11, 33, 53, 75, 84, 97%. The levels of temperature and relative humidity conditions correspond to a typical temperature/humidity conditions in which in practice commonly used autoclaved aerated concretes can be found. The moisture sorption content was obtained after several months of measurements at the equilibrium state. This data was then used to prepare sorption isotherms of the tested materials. The experimentally obtained data were then applied to calculate Mathematical Description of graphs. For this purpose three commonly known and used equations were applied: equation of Chen Y. and Chen Z., equation of Jovanovic’s for multi-layer adsorption, and Huttig's equation. Using statistical methods the compliance of the adsorption isotherm equations was compared with experimental data. For that purpose the STATISTICA programme was used. To estimate the coefficients of the equations the authors used one of the programme modules, i.e. the non-linear estimation. To assess how well the data fit a statistical model the coefficient of determination R 2 was used.
