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Temperature Relationship (temperature + relationship)
Selected AbstractsModelling thermal degradation of composite materialsFIRE AND MATERIALS, Issue 2 2007Javier Trelles Abstract A one,dimensional, transient thermal degradation heat transfer model for the response of composite materials when exposed to fire is presented. The model can handle layers of different materials. Material properties are functions of temperature. The reaction can be specified using Arrhenius-type parameters or by inputting a density,temperature relationship determined by any experimental technique such as thermogravimetric analysis. The model is validated against the experimental data presented in Boyer's 1984 dissertation. Overall, the model provides excellent agreement with the experimental data. It is shown that very little difference is found between results arrived at by Arrhenius kinetics and results obtained by specifying the easier to measure density,temperature relationship. From this it is concluded that this technique is a viable alternative to Arrhenius-type models. Copyright © 2006 John Wiley & Sons, Ltd. [source] Steady and dynamic shear rheology of glutinous rice flour dispersionsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 6 2006Byoungseung Yoo Summary The steady and dynamic shear rheological properties of Korean glutinous rice flour dispersions were evaluated at different concentrations (4, 5, 6, 7 and 8%). Glutinous rice flour dispersions at 25 °C showed a shear-thinning behaviour (n = 0.487,0.522) with low magnitudes of Casson yield stresses (,oc = 0.056,0.339 Pa). The magnitudes of ,oc, consistency index (K) and apparent viscosity (,a,100) increased with the increase in concentration. The power law model was found to be more suitable than the exponential model in expressing the relationship between concentration and apparent viscosity. The apparent viscosity over the temperature range of 25,70 °C obeyed the Arrhenius temperature relationship, with high determination coefficients (R2 = 0.982,0.998), indicating that the magnitudes of activation energies (Ea) were in the range of 9.05,11.89 kJ mol,1. A single equation, combining the effects of temperature and concentration on ,a,100, was used to describe the flow behaviour of glutinous rice flour dispersions. Magnitudes of storage (G,) and loss (G,,) moduli increased with the increase in concentration and frequency. Magnitudes of G, were higher than those of G,, over most of the frequency range. [source] RHEOLOGICAL PROPERTIES OF HOT PEPPER-SOYBEAN PASTEJOURNAL OF TEXTURE STUDIES, Issue 4 2001B. YOO Rheological properties of fermented hot pepper-soybean paste (HPSP) were evaluated at different total solid contents (TS, 43.6-54.7%) and temperatures (10-40C). HPSP samples at 20C are highly shear thinning fluids (n=0.25-0.33) with large magnitudes of Casson yield stresses (106-573 Pa). Consistency index (K) and apparent viscosity (,a,20) increased with increase in TS. Apparent viscosity of HPSP obeyed the Arrhenius temperature relationship. The magnitudes of activation energy (7.6-20.4 kJ/mole) for HPSP increased with increase in TS. A single equation, combining the effects of temperature and concentration on ,a,20, was used to describe flow behavior of HPSP. The time-dependent model of Weltman was found to be most applicable (R2= 0.97-0.99) for HPSP. Storage (G') and loss (G") moduli increased with increase in TS, while complex viscosity (,*) decreased. Magnitudes of G'were higher than those of G" over the entire range of frequencies (,). [source] Decorating Polypyrrole Nanotubes with Au Nanoparticles by an In Situ Reduction ProcessMACROMOLECULAR RAPID COMMUNICATIONS, Issue 11 2009Jingjing Xu Abstract Au nanoparticle-decorated polypyrrole nanotubes (defined as PPy/Au nanocomposites) are prepared by an in situ reduction process. Polypyrrole (PPy) nanotubes are prepared by a self-degraded template method, and Au nanoparticles are deposited in situ by the reduction of HAuCl4. The size and uniformity of the Au nanoparticles that decorate the PPy nanotubes can be controlled by adjusting the experimental conditions, such as the stabilizers used and the reaction temperature. The morphologies and optical properties of the nanocomposites have been characterized by scanning electron microscopy, transmission electron microscopy, UV-vis, and FT-IR spectroscopy. Conductivity measurements show that the conductivities of the nanocomposites decrease with a decrease of temperature, and the conductivity,temperature relationship obeys the quasi-one dimensional variable range hopping model. [source] | ||||||||||