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Cellular Level Water Distribution and Its Investigation Techniques
Published in M. Azharul Karim, Chung-Lim Law, Intermittent and Nonstationary Drying Technologies, 2017
Chung-Lim Law, Md. Imran H. Khan, R. Mark Wellard, Md. Mahiuddin, M. Azharul Karim
Dilatometry (DIL) is a thermo-analytical technique that can be used for measuring bound water, based on thermal expansion or contraction of material while subjected to a controlled temperature. This method is based on the fact that when water freezes it expands about 9% in volume. In this procedure, the sample and a non-freezing (at the temperatures employed) indicator fluid are entered into the dilatometer as shown in Figure 9.7. The change in the level of the meniscus of the indicator fluid indicates the change in volume of the freezing sample. Moreover, if a sample of material of known water content is immersed in a liquid with a low freezing point which is immiscible with water and enclosed in a system in which small changes in volume can be measured, the expansion accompanying freezing can be measured and the amount of water which froze can be calculated. From this the amount of unfrozen or bound water can be calculated.
Sintering Process Variables and Techniques
Published in Mohamed N. Rahaman, Ceramic Processing, 2017
Most sintering furnaces are equipped with a temperature controller to take the system through the required heating cycle. In many cases, it is also necessary to have fairly precise control of the sintering atmosphere around the powder compact or to use a sintering atmosphere that is not compatible with the furnace element. For laboratory-scale experiments, a tube furnace can often provide the desired temperature and atmosphere control. Silica tubes can be used up to ~1100°C, whereas high-purity Al2O3 tubes can be used up to 1600°C–1800°C. However, the low thermal shock resistance of Al2O3 limits its maximum heating or cooling rate to 10°C/min–20°C/min, depending on the thickness of the tube. A dilatometer is useful in research and development because it allows the shrinkage of a powder compact to be measured continuously as a function of time or temperature in a single experiment.
Thermal buckling of flax fibre reinforced epoxy laminated composite plate using finite element analysis
Published in International Journal for Computational Methods in Engineering Science and Mechanics, 2022
Guru Anandan, Venkatachalam Gopalan, Senthilnathan Natarajan
The dilatometer is used to measure the thermal expansion coefficient. The sample is cut in a warp and weft directions from the fabricated composite plate. The required sample of size 40 mm × 10 mm × 3 mm is tested following ASTM E228 [38] standard. The sample is placed inside the dilatometer in the required position. The push rod is adjusted to touch the specimen and to maintain zero tolerance. The temperature is increased gradually to 120 °C from room temperature and pressure is applied on the push rod. The corresponding thermal strain is measured. From the strain data, thermal expansion coefficient is determined in terms of temperature. The properties of flax/epoxy laminate are highlighted in Table 1.
Equation of State: Manhattan Project Developments and Beyond
Published in Nuclear Technology, 2021
Scott D. Crockett, Franz J. Freibert
A modern EOS model is built by leveraging data collected over experimental conditions ranging from ambient, static compression, and shock regimes, and by developing an integrated theoretical approach to ensure data set inclusion. These modern models cover compressions of 0 to 106 volumetric strains and temperatures from 0 to 109 kelvins. Once optimized across multiple data sets, the model forms naturally extend to known thermodynamic limits. We start, however, with ambient data along the 1-atm isobar. The EOS-relevant thermophysical properties data include information for the reference density, thermal expansion, specific heat, and bulk moduli. X-ray diffraction measures the initial crystal structure and density. Dilatometry measures the thermal expansion. Resonant ultrasound spectroscopy is used to measure the adiabatic bulk modulus. Calorimetry is a measurement of the enthalpy and specific heat. Experimental methods also provide the temperatures of phase transitions (solid-solid, solid-liquid, liquid-gas, solid-gas). These isobaric data provide constraints to the thermal components of an EOS model. Then theoretical calculations are used for constraining our models in regions where data are often absent. For that we rely on DFT, quantum molecular dynamics, and quantum Monte Carlo calculations. These methods are computationally intensive, but better match experimental results for most materials describable by a multiphase EOS (Ref. 24). Such a modern multiphase EOS generated at LANL for aluminum is shown in Fig. 2. Other modern EOS models include that of the Lawrence Livermore National Laboratory PURGATORIO, a novel implementation of the INFERNO EOS physical model.50
A Critical Review of the Experimentally Known Properties of U-Pu-Zr Alloys. Part 1: Phases and Phase Diagrams
Published in Nuclear Technology, 2019
Dawn E. Janney, Steven L. Hayes, Cynthia A. Adkins
Liquidus temperatures have been reported for eight U-Pu-Zr alloys, all of which have at least 50 at. % U (Sec. III). If it is assumed that there is a consistent relationship between liquidus temperatures and alloy compositions, large errors in reported temperatures seem likely. Measurements using DSC were near the upper temperature limits of the instruments and used calibration standards that were not identified or were significantly below the data values. Measurements using dilatometry were complicated by partial melting of the sample. It is not clear which (if any) of the existing measurements are accurate, and new measurements of liquidus temperatures are needed for all compositions.