Interest in research and development as well as utilization of Cellulose NanoFiber (CNF) has increased drastically over last decades. Therefore, surface chemical modification and improvement of CNF properties can open up new applications with giving new property while keeping its inherent properties. In this research, in order to enhance THERMAL STABILITY of CNF cyanoethylation was carried out by acrylonitrile grafting at 60°C under alkaline condition. Degree of Substitution (DS) of cyanoethylated samples was calculated after determination of nitrogen content by Kjeldahl method. Moreover, the chemical structure of modified CNF was characterized with FT-IR spectroscopy and X-Ray Diffraction (XRD) pattern analyses. THERMAL STABILITY of modified CNF was then assessed by ThermoGravimetric Analysis (TGA) at three heating rate of 10oC/min, 15oC/min, and 20oC/min under nitrogen atmosphere. Differential ThermoGravimetry (DTG) curves were plotted using TGA data and activation energies were calculated from experimental data. Results of nitrogen content measurements demonstrated DS=0.87 achievement. In addition, cyanoethylation of CNF was confirmed by FT-IR spectra analyses in comparison with control samples and detection of absorption band at 2250 cm-1 which is attributed to nitrile groups. Decrease in CNF crystalinity due to cyanoethylation was demonstrated by XRD analyses. Results of TGA also indicated high THERMAL STABILITY of cyanoethylated CNF in comparison with unmodified CNF. Moreover, THERMAL decomposition of both untreated and cyanoethylated CNF occurred in one stage and increased with increasing heating rate. Also low activation energy was observed in cyanoethylated CNF than unmodified CNF. It seems that grafting of acrylonitrile to CNF can increase its utilization in special applications due to improving THERMAL STABILITY and giving thermoplasticity because of playing role as internal plasticizer.

The THERMAL degradation behavior and service lifetime of poly (p-phenylenbenzobisoxazole) (PBO) fibers, prepared by our group, were investigated. The THERMAL degradation processes of the PBO fibres were studied using TG-DTG at heating rates of 5.0, 10.0, 15.0, 20.0 K.min-1 under atmospheric air and at heating rate of 10.0 K.min-1 under nitrogen atmosphere, respectively. The THERMAL decomposition process of PBO fibre occurs in a single step in the air, being especially prominent between 900 K and 960 K. The THERMAL degradation kinetics of the PBO polymer under the non-isoTHERMAL condition, gave values for activation energy E and the pre-exponential factor A as 142.51±10 kJ.mol-1 and 2.43×107±105 min-1, respectively. Under nitrogen condition, the THERMAL degradation has started above 907 K. The THERMAL STABILITY of PBO in the nitrogen atmosphere was 80 K higher than that in the air atmosphere. Moreover, the oxygen played an important role in the degradation, which initiated the degradation of PBO. The decomposition gases of the PBO were analyzed by TG- FTIR. It was found that CO, CO2 and H2O were the main compounds during the PBO degradation in the air. PBO fibre is transformed into charred material which is stable enough and has no aromatic species. The PBO fibre can be used for long time as the temperature is less than 300ºC in air. The service lifetime of the PBO fibres was estimated by the kinetics of THERMAL degradation, and the lifetime equation at weight-loss of 5% was deduced from the equation In t = -19.954 + 17141 / T.

Earth-Sheltered Architecture is an architectural concept extensively used in traditional Persian architecture of hot arid climates. It is now gaining popularity as a means for energy saving in buildings. This paper explains diverse typologies of subterranean and semi-subterranean buildings. Key advantages of this construction include its energy efficiency, improved building protection, lower maintenance costs and increased privacy. Its main disadvantages include increased excavation and soil solidification costs, drainage and waterproofing problems, claustrophobic spaces and ventilation problems. By presenting scientific data and some case studies showing the impact of depth on the THERMAL STABILITY of the subterranean spaces, recommendations are made for promotion of this architectural typology in contemporary Iranian situation.

Fe5C2 is a recently attentioned iron carbide with high saturation magnetization and suitable chemical inertness that is known to have applications in different fields of engineering and medicine. One of the most important challenges in usage, is THERMAL STABILITY of iron carbide nanoparticles. In this research, Fe5C2 nanoparticles were synthesized through a wet chemical route. XRD and TEM techniques were used to characterize chemical and morphological features of the sample at room temperature, respectively. TEM micrograph demonstrated the spherical morphology and the average size of the nanoparticles to be 30 nm. Thermogravimetric analysis (TGA) was performed to study the THERMAL behavior of this magnetic carbide. The activation energy of the phase decomposition was evaluated to be 139. 51 kJ utilizing Ozawa method. After heating, XRD test was repeated to investigate phase changes at high temperature. Finally, X-ray diffraction pattern proved the conversion of Hagg iron carbide to iron and magnetite after heat treatment.

Background: Fatty acids are one of the most important compounds in edible oils. Oils STABILITY depends on the composition of fatty acids. The purpose of this study was to investigate the relationship between fatty acid compositions on the THERMAL STABILITY in extra virgin olive oils.Methods: Eight samples of olive oil were tested in this study.Oils were heated at 120 ° C for 4 h to evaluate the THERMAL STABILITY, were sampled every 2 hours. Fatty acid composition, Peroxide value, Anisidine value, Totox value, was conducted in accordance with Iranian national standards.Results: Results showed that oleic acid, the major fatty acid in olive oil, its value is between 69 to 74 percent. Between Palmitoleic acid and Totox index in second time (r=0.786) and Fourth Time (r=0.762), and between linoleic and Totox index in second time (r=0.643) and Fourth Time (r=0.786) there was a significant relationship. But between oleic acid and Totox index in Fourth Time (r=-0.833) is a significant inverse relationship.Conclusion: Interpretation of the results suggests that linoleic acid and palmitoleic in extra virgin olive oil are decrease in THERMAL STABILITY. But, Oleic acid increases the STABILITY of the oils in during heat treatment process.

Background: Heating at high temperatures creates a large change in the chemical properties of oils. Further research is necessary to choose the type and quality of the oil is due to its effects on health. Extra virgin olive oil is considered one of the best due to the beneficial effects of dietary oils. The aim of this study was to compare the THERMAL STABILITY of extra virgin olive oil, Iranian and foreign.Methods: Eight samples of olive oil were tested in this study.Oils were heated at 120oC for 4 h to evaluate the THERMAL STABILITY, were sampled every 2 hours. Fatty acid composition, acid value, peroxide value, anisidine value, totox value, oxidative STABILITY Rancimat, was conducted in accordance with Iranian national standards.Results: Results showed that oleic acid, the major fatty acid in olive oil, its value is between 69 to 74 percent. There was a significant relationship between time and acid value (P=0.013), peroxide value (P≤0.001), anisidine value (P≤0.001), totox value (P≤0.001). There is no significant relationship between changes in oil and acid value, peroxide value, anisidinevalue, But with totox value (P=0.003) a significant relationship was observed.Conclusion: Interpretation of the data suggests that the THERMAL process is changing the index of acidity, peroxide, anisidine and totox. The changes will further increase with time. The results will be receiving extra virgin olive oil external to the Iranian type features are better and are more resistant to heat.

Yttria stabilized zirconia (7YSZ) is widely used as standard THERMAL Barrier Coatings (TBCs). However, for temperature higher than 1200˚ c tetragonal phase may be transformed to the monoclinic phase, which results in the formation of cracks in the coating and accelerates the spallation failure of TBCs. In this study, nanostructured scandia-ceria doped zirconia (ScCeSZ) were synthesized via polymerized sol-gel method and the effect of different amounts of scandia and ceria stabilizers on the THERMAL phase STABILITY at the temputre of 1400˚ c were investigated by slow scan XRD. By comparing the amounts of monoclinic, non-transformable tetragonal (t') and cubic phases, the amount of tetragonality was calculated and eventually the optimum combination in terms of THERMAL performance was determined (4. 78ScCeSZ). Nanostructured 4. 78ScCeSZ was deposited by atmospheric plasma spraying (APS) on NiCoCrAlYcoated Inconel 738 substrates and THERMAL phase STABILITY of the coating was investigated after THERMAL shock test in 1000˚ c. With respect to enhancing THERMAL STABILITY of nanostructured 4. 78ScCeSZ, it could be suggested that nanostructured 4. 78ScCeSZ are promising substitutes for conventional YSZ in gas turbine engine.

Biodegradable polymer blends are prepared by solution casting method by mixing Sodium alginate (SA) and Lignosulphonic acid (LS) biodegradable polymers. In order to investigate for controlled drug delivery the THERMAL STABILITY of polymer blends are the primary requirements because they should be stable in aqueous medium. The polymer blends are studied using thermogravimetric analysis. The TGA data are used to analyze degradation temperature and energy of activation using ‘Horowitz and Metzger’ an approximate integral method. The energy of activation reveals that blends are stable as compared to their polymers.