Papers by Keyword: Differential Scanning Calorimeter (DSC)

Abstract: In this study, carbon-based materials prepared using an isoperibol oxygen bomb calorimeter of varying oxygen pressure were added to water to form carbon-based suspensions (CBSs). The thermal conductivity, viscosity, density, and contact angle of CBSs were measured by appropriate instruments to understand the fundamental characteristics of CBSs. A differential scanning calorimeter (DSC) was used to measure and analyze the phase change characteristics of CBSs to evaluate the feasibility of employing CBSs as phase change materials (PCMs) in ice-storage air-conditioning systems. The experimental results revealed that the thermal conductivity, viscosity, and density of CBSs did not significantly change but a significant reduction in the contact angle of sample’s droplets occurred compared with that of water. The CBS of S5 had the lowest melting temperature and subcooling degree (SD) and highest freezing temperature in the DSC experiments; thus, S5 was determined to be the most suitable CBS for use as a PCM in this study.

Abstract: Now a day biodiesel becomes best alternative for diesel fuel. Thermogravimetry technique has great acceptance in the field of fossil fuel. The thermal and kinetics properties of diesel and Jatropha biodiesel are analyzed by using popular technique of thermogravimetry. The aim is to study the behavior of diesel, biodiesel and their blends in Nitrogen gas atmosphere at the heating rate of 5K/min, 10K/min and 15K/min from 30°C to 600°C. From study it is found that as heating rate increases peak is shifting toward higher value which shows that there is less uniform heating. The study clearly shows biodiesel is more stable than diesel indicating that transesterification make sample less stable. The Arrehenius Kinetic model is applied to study the activation energy. As percentage of biodiesel increases, stability of sample increases and hence increases in activation energy

Abstract: Current trend for manufacturers associated to MIM industry try to enhance the feedstock in term of its characteristics, since it is the most crucial part of the MIM process. This paper covered the characterization and rheological studies on a ready-made feedstock of stainless steel 316L which is vital to determine the availability and suit the needs of many advanced applications. There are three different experiments involved which are Scanning Electron Microscope (SEM), Differential Scanning Calorimeter (DSC), Thermogravimetric (TGA) and Capillary Rheometer. Observation through SEM gives an insight of the bonding microstructure matrices of the feedstock and also determines the homogeneity of the feedstock. DSC testing defines the melting temperature of the 3 binders used which are 62.07°C for surfactant, 178.72°C for filler and 236.61°C for backbone binder. From TGA result, it showed that the total weight loss of feedstock was 39%. Throughout the capillary rheometer testing, the feedstocks viscosity was decreasing as the shear rate increasing. The feedstock exhibits pseudoplastic behaviour since its flow behaviour index was less than 1. It is founded that at the temperature of 190°C, the feedstock exhibits the best characteristics for injection.

Abstract: In this paper, high resolution transmission electron microscopy (HRTEM) has been used to observe a Zr_41.25Ti_13.75Ni₁₀Cu_12.5Be_22.5 (at. %) bulk metallic glass (BMG) prepared from different methods, i.e. ion milling and electropolishing. The ion thinning brings out the white bulb pattern on the specimen surface and induces localized temperature increasing. The electropolishing does not influence microstructure of the amorphous phase. A new preparation technique of grinding method is introduced. For BMG, the electropolishing and grinding are the better method for TEM specimen preparation as compared with the ion thinning.

Abstract: Polypropylene/organo montmorillonite nanocomposites modified with 0.001-0.1 wt% calcium pimelate, a β-nucleating agent, were prepared using twin screw extruder. The effects of calcium pimelate content on crystallization behavior were investigated using differential scanning calorimeter (DSC). The crystallization kinetics were studied using both nonisothermal and isothermal methods. The development of relative crystallinity with the crystallization time was analyzed by the Avrami equation. For nonisothermal studies, the Kissingers theory was employed and the crystallization activation energy was calculated. The results showed that the crystallization temperature shifted to a higher temperature range when calcium pimelate was added. The alpha crystal form of polypropylene nanocomposite was suppressed, by the additions of calcium pimelate, while beta crystallization reaction was accelerated.

Abstract: The first-order diffusionless structural phase transition in Cu_67.64Zn_16.71Al_15.65 is characterized by jerky propagation of phase front related to the appearance of avalanches. In this work we describe a full analysis of this avalanche behaviour using calorimetric heat-flux measurements and the results are compared with acoustic emission (AE) measurements.

Abstract: The phase transformation of high Cr ferritic heat-resistant steel has been investigated by using differential scanning calorimeter and predicted by Thermo-calc calculation. The steel specimens were hot rolled and followed by air cooling, and then heated from room temperature up to different austenitization temperature as 800°C, 900°C, 1000°C and 1100°C. The DSC curves during heating process showed that the magnetic transition temperature and the Ac1 temperature are 744.9°C and 850.9°C, respectively. The austenitization range was about 58°C. The onset and offset temperature of martensite transformation both increase with the increase of austenitization temperature. The experimental results and the Thermo-calc calculated results both displayed that M23C6 carbides precipitated at around 950°C, and δ-ferrite started to form at about 1020°C.

Abstract: Directly mixing the PCM to asphalt mixture may adversely affect mixture performance. By the experiment of SEM, the diffusion-absorption circle testing and the DSC, the micro-morphology and the adsorption characteristics to PCM of four carriers and the thermal properties of the composite shape-stabilized phase change materials (CSPCM) were analyzed. The results showed that the activated carbon, the floating bead and the white carbon black have more developed porous structure. The white carbon black has the best effect on the adsorption of PCM. The shape-stabilized PCM prepared by the physical adsorption method has the leakage problem. The CSPCM with the white carbon black carrier has the best heat storage capacity. The white carbon black is the best carrier of PCM for asphalt mixture.

Abstract: Green thermosetting resins are were prepared using Epoxidizided palm oil (EPO) and epoxy based petroleum. The polymer resins were cured through amine system with the addition of various percentage of imidazole catalyst (5, 10, 25 and 30%). The evaluation for thermal due to high cross link densities blend samples toward heat. All the blend samples presented thermoset characteristics that was dependent upon the quantity of catalyst. As expected, the Tg decreased as the amount of imidazole increased.

Abstract: Most applications expose the materials to wide range of temperatures, which may influence on thermal behavior of materials. Thermal degradation of wood polymer composites (WPCs) is a crucial aspect for application and manufacturing process of these products. In this research, wood polymer composites with different nanoclay contents were prepared by melts compounding method. The amount of wood flour and coupling agent were fixed at 40% and 10% wt% (total weight), respectively, and the different levels of nanoclay include 0, 3 and 5% wt% were used in preparing the composites. Thermal properties of nanocomposites were characterized by Differential Scanning Calorimeter (DSC) and thermal gravimetric analysis (TGA). The DSC analyses show that the crystallization temperature (Tc), enthalpy ΔHm, and the degree of crystallinity (Xc) of the nanocomposites were increased by addition of nanoclay. The TGA results indicate that by increasing the nanoclay percentage the degradation temperatures and thermal stability was enhanced.