Determination Of Thermal Behavior Research Articles

Determination of Thermal Behavior from Core Flux Density with Image Processing Technique for Distribution Transformers

Determination of Thermal Behavior from Core Flux Density with Image Processing Technique for Distribution Transformers

Effect of Grain Size upon the Thermal Behavior of Copper and Diamond Powders using Differential Scanning Calorimetry (DSC)

Objectives: In this study, the heat capacity and heat flow of varied grain size of copper and diamond powders were investigated. Methods: Heat capacity and heat flow of varied grain size of copper (1 μm-70 μm) and diamond powders (2 μm-300 μm) were measured using differential scanning calorimetry (DSC). The thermal properties of copper and diamond powders were determined in a temperature range of 0-500oC, with a heating rate of 5k/min in a nitrogen environment. Findings: Heat capacity and heat flow of copper and diamond powders increases with grain size and it is consistent with earlier researchers. Heat capacity of copper and diamond powders also increases with grain size. The heat capacity and heat flow was 1.4 J/gk and 0.24 mW/mg respectively for 60-70μm grain size of copper powder, whereas the values of the same were found to be 0.9 J/gk and 0.4 mW/mg for diamond powder of grain size in the range of 270 to 300 μm is determined. This study reveals that the diamond powders show better thermal performance over copper powder. Application/Improvements: Determination of thermal behavior is critical in determining the amount of heat transferred in micro electronics and solar thermal based applications.

Compatibility and decomposition kinetics studies of prednicarbate alone and associated with glyceryl stearate

In this work, TG/DTG and DSC techniques were used to the determination of thermal behavior of prednicarbate alone and associated with glyceryl stearate excipient (1:1 physical mixture). TG/DTG curves obtained for the binary mixture showed a reduction of approximately 37 °C to the thermal stability of drug (\( T_{{{\text{d}}m/{\text{d}}t = 0\,{\text{DTG}}}}^{\text{Max}} \)). The disappearance of stretching band at 1280 cm−1 (νas C–O, carbonate group) and the presence of streching band with less intensity at 1750 cm−1 (νs C–O, ester group) in IR spectrum obtained to the binary mixture submitted at 220 °C, when compared with IR spectrum of drug submitted to the same temperature, confirmed the chemical interaction between these substances due to heating. Kinetics parameters of decomposition reaction of prednicarbate were obtained using isothermal (Arrhenius equation) and non-isothermal (Ozawa) methods. The reduction of approximately 45% of activation energy value (Ea) to the first step of thermal decomposition reaction of drug in the 1:1 (mass/mass) physical mixture was observed by both kinetics methods.

The effects of opioid and FMRF-amide peptides on thermal behavior in the snail

Administration of methionine-enkephalin, beta-endorphin or, as previously shown, the opiate agonist, morphine sulfate (0.10–10.0 μg per snail), resulted in significant dose-dependent increases in the latency of thermal (40°C hot plate) avoidance behavior of the terrestrial snail, Cepaea nemoralis. The analgesic effects could be blocked by the opiate antagonist, naloxone, as well as by the non-opioid peptides, FMRF-amide and YGG-FMRF-amide. When administered by themselves the FMRF-amide peptides had significant bimodal effects either decreasing (0.10 and 10.0 μg) or increasing (1.0 μg) the latency of the response to the thermal stimulus. These results indicate that opioid and FMRE-amide peptides may be involved in the determination of thermal behavior in the snail. They also suggest that FMRF-amide peptides may function as endogenous modulators of opioid activity.