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Nanobiotechnology toward the Next Generation Antimicrobial Materials
Published in Poushpi Dwivedi, Shahid S. Narvi, Ravi Prakash Tewari, Dhanesh Tiwary, Nanobiotechnology for Safe Bioactive Nanobiomaterials, 2023
Poushpi Dwivedi, Shahid S. Narvi, Ravi Prakash Tewari, Dhanesh Tiwary
Thermal analysis (TGA, DTA and DSC) basically measures, as a function of temperature, the physical and chemical aspects of materials. (1) Thermogravimetric analysis (TGA) records the weight change of a test sample as a function of temperature or even time; (2) the differential thermal analysis (DTA) measures the temperature difference (T), between the test sample and any inert reference, as a function of temperature, detecting change in the heat content and (3) differential scanning calorimetry (DSC) quantitatively measures the enthalpy changes (ΔH), occurring in the test sample as a function of temperature or time. DSC is a helpful tool for understanding the thermal properties of polymer nanocomposites. DSC helps to observe the glass transition temperature (Tg) of both polymers and polymer nanocomposites. It also shows the variation in the values of (Tg), which represents particles in the polymer matrix. Photographs of SHIMADZU TGA-50 thermo-gravimetric analyzer and SHIMADZU DSC-60 Plus differential scanning calorimeter are shown in Figures 1.9 and 1.10, respectively.
Cementitious Composites for Civil Construction Made with Marble and Granite Waste
Published in R.A. Ilyas, S.M. Sapuan, Emin Bayraktar, Recycling of Plastics, Metals, and Their Composites, 2021
M.G.A. Ranieri, P. Capellato, M.A. de B. Martins, V.C. dos Santos, P.C. Gonçalves, L.R. Roque-Silva, M.L.M. Melo, A. da S. Mello
Thermal analysis techniques are widely used to determine the behavior and composition of natural and synthetic products. Differential thermal analysis (DTA) is applied to study the thermal behavior of materials such as silicates, ferrites, oxides, clays and so forth. This type of analysis provides information on fusion points, dehydration, oxidation, reduction, adsorption and solid-state reactions. Figure 21.4 shows the thermogravimetric curves for the MGR processing residue. Between 100°C and 350°C, there was a 1% loss in mass for N2, while there was a 1.5% loss in mass with O2, corresponding to the free water loss and water adsorption. Between 350°C and 600°C, the loss was 2% for N2, while O2 maintained a 1.5% loss. From 600°C to 750°C, the N2 loss was 3.5%, while O2 loss increased to 5%. This may be related to the decomposition of magnesium carbonate. From 750°C to 900°C, the changes are due to the decomposition of calcium carbonate, seeing that they do not decompose at the same temperature.
Differential Scanning Calorimetry (DSC)
Published in Ernő Pungor, A Practical Guide to Instrumental Analysis, 2020
The instruments used for DSC measurements can be divided into two groups, according to their basic principle of operation. The temperatures of the sample and of the reference material are kept at an identical value, while the temperature of the reference material is increased according to a program. The recorder records the increase in electric power necessary to attain this identity of temperatures, as a function of time. The integral of the curve recorded in the course of a transition gives the heat of transition. An apparatus working along this principle is manufactured by the firm Perkin-Elmer.The difference in the temperatures of the sample and the reference material are recorded (DTA principle) while the heat transport is controlled. Instruments of this type are manufactured by Du Pont (U.S.), Mettler (Switzerland), and Linseis (BRD).
Economic geology and genesis of kaolin resources in the East African Rift system: the case of Alemtena kaolin deposit, Ethiopia
Published in Applied Earth Science, 2020
Getnet Gezahegn, Worash Getaneh
Petrographical, mineralogical, geochemical, and physical tests are the main laboratory methods used for the current study. Five kaolin samples were analysed using X-Ray Diffraction (XRD) method to determine the type and amount of minerals present in the deposit. Samples were dried, milled and sieved to different size classes. Kaolin samples of 30 grams of less than 2-μm size fractions were sent to the Geological Survey of Japan for quantitative and qualitative mineralogical analysis. Quantitative mineralogical determination of kaolin is done based on TG-DTA methods. This method operates based on the change in the physical properties of a substance subjected to a controlled temperature. Thermo Gravimeter (TG) is used to measure a variation in mass by either gain or loss at controlled environment. Differential Thermal Analysis (DTA) is a technique used for measuring the difference in temperature between a sample and a reference material. Kaolinite contents were calculated based on 13.9% of crystal water (weight loss between 450°C and 650°C). Moreover, five thin sections of parent rocks were prepared for petrographic examination.
Synthesis and characterization of [BaO-(10-x)ZrO2-TiO2-SiO2-xCrO3] type glass and glass ceramics
Published in Journal of Asian Ceramic Societies, 2020
Zaireen Fatima, Ajaz Hussain, Chandkiram Gautam, Prakash Singh, Afroz Ahmed, Gulab Singh, Manoj Kumar Singh
DTA is a technique used to determine the glass transition temperature, Tg and crystallization temperature, TC. It operates to record the temperature difference between a substance and a reference material against time or temperature as the two samples are subjected to identical temperature regimes in an environment heated or cooled at a controlled heating rate. Glass samples were crushed to form the sugar like particles of about 50 mg. The DTA measurements were performed for the glass samples using a “Perkin Elmer Thermal Analysis” from RT to 1200°C heating @ 10°C/min. Sintered kaolin was used as a reference material. In addition to the crystallization temperature, the glass transition temperature was also determined using DTA results. Therefore, based on the DTA results, the glasses were converted into glass ceramics by given an optimized heat treatment schedule.
Hydration and characteristics of metakaolin pozzolanic cement pastes
Published in HBRC Journal, 2018
Hamdy El-Diadamony, Ahmed A. Amer, Tarek M. Sokkary, Samir El-Hoseny
The most widely used thermal method of analysis is differential thermal analysis (DTA). Fig. 7 illustrates the DTA/DTG thermograms of the hydrated OPC paste after curing up to 90 days. The DTA thermograms show the occurrence of four endothermic peaks at 100, 150, 420–450, 700–750 °C. The endothermic peaks located below 200 °C are mainly due to the dehydration of interlayer water of CSH and CAH or CASH, whereas the endothermic peak appeared at 420–450 °C is due to the decomposition of Ca(OH)2 [25]. The last endothermic peak located at 700–750 °C is due to the decomposition of CaCO3 [26]. It is clear that the intensities of the endothermic peaks characteristic for Ca(OH)2 and CaCO3 increase with the increase of curing time up to 90 days due to progress of hydration of OPC pastes. Also, the endothermic peaks of CSH and CASH increase with curing time due to progress of hydration.