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Water Content
Published in Alan J. Lutenegger, Laboratory Manual for Geotechnical Characterization of Fine-Grained Soils, 2023
Each Speedy should be calibrated individually so that any differences in manufacturing can be accounted for using a specific calibration chart. How repeatable are the values obtained from the Speedy? Are results less reliable than either convection oven method or microwave oven method values of Water Content? Table 1.4 shows results obtained using large patches of soil prepared to different Water Contents. Twenty tests were performed with the convection oven, microwave oven, and Speedy methods at two different Water Contents (a total of 120 tests). The results show that in every case, the coefficient of variation is less than 5%, which is very good for soil tests, considering the possibility of natural variations in the soil.
On the Estimation of Shrinkage and Thermal Strains during Composite Cure
Published in Golam M. Newaz, Ronald F. Gibson, Proceedings of the Eighth Japan-U.S. Conference on Composite Materials, 2019
Composites measuring 6 in by 6 in were laid up in the prescribed configurations and strain gages bonded to the surface plies and/or embedded at selected ply interfaces in the 0° or 90° directions. In all cases the gage element was located at least 0.5 in from a free edge. While the strain gage itself is encapsulated, the gage leads were insulated from the conductive reinforcing carbon fibers with Kapton (polyimide) tape. The stack of prepreg was then vacuum bagged and the composite initially cured, under vacuum, in a forced-convection oven. Subsequent cures were conducted in an autoclave, using the setup described in the sketch in Figure 1, in accordance with the manufacturers’ recommended cure cycles. By using a gage from the same production lot, bonded to an ultra-low CTE titanium silicate block, as part of the Wheatstone half-bridge, the output of the active gage was compensated for temperature and pressure variations in the autoclave to yield the strain arising solely from composite cure.
Compaction of soils
Published in Alan J. Lutenegger, Soils and Geotechnology in Construction, 2019
Determination of compacted water-content is required, along with the total density, in order to calculate compacted dry-density. Several traditional methods are available for determining field-compacted water-content, including: Convection Oven DeterminationMicrowave Oven DeterminationCarbide Gas “Speedy” MethodDirect-Heating MethodNuclear Moisture Meter
Evaluation of storage stability of dried cranberry powders based on the moisture sorption isotherms and glass transition temperatures
Published in Drying Technology, 2022
Izabela Staniszewska, Łukasz Dzadz, Hong-Wei Xiao, Magdalena Zielinska
Cranberries were subjected to hot air convective drying (HACD) and microwave-vacuum drying (MWVD) according to the procedure described by Zielinska and Zielinska.[1] HACD was conducted in a forced convection oven (FED53 127 Binder, Bohemia, NY, USA) at the temperature of 80 °C. The heating oven was ventilated by fan-assisted, forced-air circulation. The rate of ventilation was measured according to the standard[45] and the air change rate was 59·h−1. The load of material was 5 kg·m−2. The mass losses were monitored at 5 min intervals during drying and the process was stopped when no mass loss was recorded for three consecutive measurements. Microwave drying was conducted under reduced pressure of 4 ÷ 6 kPa and microwave power of 150 W in a specially designed drying chamber (Promis Tech, Wroclaw, Poland). Drying chamber rotated with a speed of 6 rpm to prevent material from overheating. The microwave-vacuum dryer was equipped with a pyrometer to measure the surface temperature of fruits. MWVD was stopped when the surface temperature of fruits increased sharply up to 80 °C. All of the HACD and MWVD drying experiments were conducted in triplicate.
Prediction of self-heating in detergent powders for application to spray dryer wall accumulations
Published in Drying Technology, 2020
Lewis Maxfield, Luis Martindejuan, Andrew E. Bayly
In this method, a basket of powder with a number of type K thermocouples embedded in the powder is heated in a Memmert UF75 forced convection oven. Of these thermocouples, one is placed at the geometric center, and at least one more thermocouple is radially offset from this. For a set ambient temperature, the basket is heated and the temperature is recorded at the center and offset point for the duration of the experiment. From this, the cross-point temperature and heating rate at the basket center, , is noted. Repeating this for a range of ambient temperatures and plotting the cross-point temperature and values for each test in accordance with Equation (5) allows the zero-order kinetics to be estimated. Unlike the steady-state approach, every test performed using this method yields a data point. In this investigation, equi-cylindrical baskets of diameter 50 and 60 mm were used with an array of three thermocouples spaced at distances of 0, 6, and 12 mm from the basket center, and at basket half-height, as shown in Figure 2. These thermocouples are connected to a Pico Technology USB TC-08 data logger and sampled at a rate of 1 measurement per second. These baskets were heated at oven temperatures ranging from 222 to 235 °C.
Nonwoven membranes for tissue engineering: an overview of cartilage, epithelium, and bone regeneration
Published in Journal of Biomaterials Science, Polymer Edition, 2019
Thalles Canton Trevisol, Rayane Kunert Langbehn, Suellen Battiston, Ana Paula Serafini Immich
As already mentioned, the development of a scaffold coated with an apatite for bone tissue engineering is being extensively studied. The bioactive ceramic particles must be placed on the surface of the composite to function effectively. However, it has been difficult to expose the hydrophilic ceramic particles to the surface of the hydrophobic polymers since they are heavier than the polymers. To overcome this problem, Kim and Rhee [77] have developed a biodegradable PCL nonwoven fabric with a partially embedded apatite surface designed for scaffold application. The PCL nonwoven fabric was produced by the electrospinning technique. The apatite crystals were partially or fully incorporated into the PCL fibers by controlling the degree of the fiber surface melting in a forced convection oven. Melted PCL got into the gaps between the apatite crystals and fixed just into their lower layers while the upper surface remained untouched. The scaffold with a partially embedded apatite surface showed good water absorption, cell penetrability, higher apatite adhesion strength and higher tensile strength compared to the control nonwoven fabric (PCL coated with apatite, without the heat treatment).