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Flexible and Stretchable Actuators
Published in Muhammad Mustafa Hussain, Nazek El-Atab, Handbook of Flexible and Stretchable Electronics, 2019
Thermoresponsive materials respond, i.e., expand or contract when exposed to heat. The volume of most of the materials increases when their temperature elevates and vice versa. The expansion of these materials can be utilized as force to displace the materials. There might be other ways to heat up the materials; which include the direct thermal radiation, laser-induced heat, photo-thermal effects, and electro-thermal effects [54]. Thermal driven actuators (TDAs) show relatively large output force AC compared to that of EAPs. Amjadi et al. demonstrated a powerful actuation of the multiresponsive paper actuator, which they stimulated by increasing the temperature also. They used a bilayer that contains a copy paper and PPy film. Since the PPy has a large thermal expansion coefficient, the actuator showed a bending of about 360° upon heating [55]. Likewise, Zhang et al. reported a programmable composite of CNT-hydrogel polymer, which demonstrated the actuation when heated up to ~48°. Same actuators were also acted as ODAs, when subjected to ultrafast near-infrared light [56]. Likewise, Tokudome et al. studied a hydrogel actuation on bilayer materials, where they did mimic the wrinkles in nature and that these wrinkles exhibited large deformations [57].
Force-System Resultants and Equilibrium
Published in Richard C. Dorf, The Engineering Handbook, 2018
Volume (V) refers to a space occupied in three dimensions. It is generally measured in cubic meters m3, cubic centimeters cm3, cubic inches (in. 3, or cubic feet ft3. Volume may also be measured in units of liters (L) or gallons (gal).
Introduction
Published in Ronald L. Fournier, Basic Transport Phenomena in Biomedical Engineering, 2017
Volume refers to the amount of space that an object occupies and depends on the mass of the object. The mass density is the mass of an object divided by the volume of space that it occupies. Specific volume is the volume of an object divided by its mass. Specific volume is, therefore, just the inverse of the mass density. For solids and liquids, the volume of an object of a given mass is not strongly dependent on the temperature or the pressure. For solids and liquids, the volume is then the mass multiplied by the specific volume or the mass divided by the density of the object. For gases, the volume of a gas is also strongly dependent on both the temperature and the pressure. For gases, we need to use an equation of state to properly relate the volume of the gas to the temperature, pressure, and moles (mass divided by molecular weight).
Development of a High Heat Flux Electric Joule Heating System for Testing a One-Side Heated Cooling Channel
Published in Fusion Science and Technology, 2022
Donkoan Hwang, Minkyu Park, Hoongyo Oh, Ji Hwan Lim, Moo Hwan Kim, Kil-Byoung Chai, HangJin Jo
The properties considered in the selection of heater material are electrical resistivity (), melting temperature (Tmelting), thermal expansion coefficient (), thermal conductivity (k), oxidation, and manufacturing feasibility. In particular, , Tmelting, and are the most important properties to consider when selecting a heater material. Electrical resistivity determines the amount of current flowing in a heater circuit under the given voltage. The electrical resistivity of a material is proportional to its electric resistance. Voltage and current are determined by the electric resistance based on Ohm’s law. As the melting point is the limitation of failure of the heater material, the heater material temperature should be lower than the melting point. The temperature of the heater is reduced as the heater thickness decreases under the given power condition by the law of heat conduction (Fourier’s law). Consequently, the melting point is associated with the thickness of the heater. The volume expansion as temperature changes is proportional to the temperature rise and the thermal expansion coefficient of each material. As an electric joule heating system consists of various materials, this property must be considered for bonding different materials.
A review on the production and physicochemical properties of renewable diesel and its comparison with biodiesel
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Rashi Koul, Naveen Kumar, R.C Singh
Density is a quantity that matches the amount of matter an object has to its volume. The density of any substance is the ratio of the mass of a fluid to its volume. The density of a substance is dependent on temperature. The density of the diesel is usually measured at 15°C (Bezergianni and Dimitriadis 2013; Das et al. 2009) and in some papers at 40°C (Koul 2015; Šimáček et al. 2010). Density is intensely correlated with some of the fuel factors, mainly cetane number, arene structure, viscosity, the boiling point, and the volatile nature (Bezergianni and Dimitriadis 2013). Whenever there is an increase in the temperature of the substance, except for a few, the density falls and volume rises (Ramírez-Verduzco et al. 2011). The density for the biodiesel made from varying resources like jatropha oil, palm oil, mahua oil, rapeseed oil, etc. ranges between 880 and 890 kg/m3 (Balat 2011). The density for RD ranges between 775 and 816 kg/m3 (Prokopowicz et al. 2015; Singh, Subramanian, and Garg 2017). As per the EN590, the density of RD is less than diesel fuel and biodiesel. This leads to an increase in the pour speed, which is at around 4–5% more than diesel and biodiesel (Sonthalia and Kumar 2017). The same thing was explained by Crepeau et al. (2018) in his paper using the Bernoullis equation, stating that flow rate is inversely proportional to the square root of the density of the fluid (Crepeau, Gaillard, and Schaberg 2018; Sonthalia and Kumar 2017). If the same quantity of BD and RD fuel is injected into the CI engine, the volume will be less in case of RD due to the less density (Khair and Jääskeläinen 2019). Therefore, it also indicates that the RD will have less energy content, which leads to less power and less torque. If in case a constant volume injection system is taken up for conducting the experiments, then there will be variants in the fuel density which in turn can affect the variation of the energy content (Hartikka, Kuronen, and Kiiski 2018). The measure of the energy possessed by the fuel is relative to the mass of the fuel that is infused into the cylinder (Bezergianni and Dimitriadis 2013). To compensate for this loss, one has to increase the fuel quantity, which is approximately 3–6% more than the diesel, which means more fuel consumption (Kuronen and Mikkonen 2018; Nylund et al. 2011).