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Fuels and other energy sources
Published in Allan Bonnick, Automotive Powertrain Science and Technology, 2020
The principle of the bomb calorimeter is that the heat released by the combustion of the fuel sample is the heat gained by the water and the calorimeter. As Figure 9.1 shows, there are two main parts of the apparatus. Part (a) shows the pressure vessel that is called the bomb. The ends of the bomb unscrew to permit the sample of fuel to be placed in the crucible. The amount of fuel is approximately 1 gram, the ignition fuse wire is also inserted at this stage and the bomb is reassembled. After reassembly the bomb is charged with oxygen at about 30 bar.
Cold Fusion and Gravitational Energy
Published in Sergio C. Capareda, Introduction to Renewable Energy Conversions, 2019
In all of the above examples, complete energy and mass balances must be established and the system ‘closed’ on where the input energy is coming from and output energy produced from the chemical reactions. Bomb calorimeters are known as devices that measure the heating value of solid and liquid chemicals.
Thermoanalytical Instrumentation and Applications
Published in Grinberg Nelu, Rodriguez Sonia, Ewing’s Analytical Instrumentation Handbook, Fourth Edition, 2019
Kenneth S. Alexander, Alan T. Riga, Peter J. Haines
DTA must be regarded as being a qualitative technique in the sense that the response, through lack of calibration or because it does not respond in a quantitative manner, cannot be interpreted in terms of enthalpy change. The temperature at which changes are observed to take place should, however, be an accurate response. Once properly calibrated as a calorimeter, the equipment is termed a differential scanning calorimeter.
A unified semi-empirical model for estimating the higher heating value of coals based on proximate analysis
Published in Combustion Science and Technology, 2018
Alchris Woo Go, Angelique Trugillo Conag
Coal remains to be one of the most widely used energy source in the world. Coal energy contributes 30.03% of the world energy consumption at the end of 2014, second to that of crude oil (32.57%) (B.P., 2015). The use of coal in thermal and electrical energy generation requires knowledge of its heating value (Vargas-Moreno et al., 2012). Heating value is the amount of energy released by a given amount of fuel. Heating values may be expressed either as higher heating value (HHV) or lower heating value (LHV). Higher heating value also known as the gross calorific value is the total amount of energy released in the complete combustion of a unit fuel, while LHV or net calorific value (NCV) accounts for the heat loss due to the vaporization of water during combustion. The determination of heating value requires the use of bomb calorimeters (adiabatic or isothermal) based on the recommended procedure outlined in ASTM D5865-10. Although the use of a bomb calorimeter is relatively simple with a good accuracy, its accessibility to researchers and engineers are often times limited (Tan et al., 2015; Yin, 2011). This has led to the development of various empirical correlations relating the HHV to its elemental (ultimate) analysis and/or proximate analysis (Ghugare and Tambe, 2016; Mesroghli et al., 2009; Patel et al., 2007; Vargas-Moreno et al., 2012).
NMR T1–T2 correlation analysis of molecular absorption inside a hardened cement paste containing silanised silica fume
Published in Molecular Physics, 2018
Calin Cadar, Andrea Cretu, Marioara Moldovan, Carlos Mattea, Siegfried Stapf, Ioan Ardelean
Differential scanning calorimetry (DSC) represents a thermo-analytical technique for measuring the specific heat capacity of materials as a function of temperature, being used mainly for determining the energy changes of thermally induced phase transitions [11]. The differential scanning calorimeter measures the differential heat flow between the sample of interest and a reference cell. During the experiment, the temperature is increased linearly and the value of the energy is provided by the time integral of the measured differential heat flow. An application of the method is to obtain the pore size distribution of porous samples saturated with different fluids. DSC thermoporometry relies on the melting point depression of liquids confined inside the porous system, which is strongly correlated to the pore size. The phase transition can be observed as an endothermic or exothermic peak in the DSC thermogram obtained by plotting the excess specific heat against temperature [11].
Use of native agave fructans as stabilizers on physicochemical properties of spray-dried pineapple juice
Published in Drying Technology, 2020
Darvin Ervey Jimenez-Sánchez, Montserrat Calderón-Santoyo, Erasmo Herman-Lara, Cristina Gaston-Peña, Guadalupe Luna-Solano, Juan Arturo Ragazzo-Sánchez
The viscosity of the fruit juices can make the process of spray drying difficult in terms of low yield, equipment wear, and operational problems because the powders adhere to the walls of the equipment.[7] The sugar content of the fruit juice, such as sucrose, fructose, and glucose, contributes to the viscosity of the fruit juice powder.[5] The presence of these sugars causes a lower glass transition temperature (Tg). The stickiness of the powders is therefore related to the Tg.[8] With the end of reducing stickiness, the Tg of the pineapple juice powder can be increased with the addition of stabilizers.[9] The Tg of the spray-dried pineapple juice powders can be determined by differential scanning calorimetry (DSC). The Tg of an amorphous or semicrystalline polymer is inferior to its melting point, and it is important to differentiate between these two temperatures that describe a phase change. The Tg is observed as a change in heat flow or heat capacity. The advantage of DSC is the ease and speed with which it can be used to analyze transitions in materials. The underlying basic principle of this technique is that, when the sample experiments a physical transformation such as a phase transition, more heat should flow in it than in the reference in order to maintain both at the same temperature. This is due to heat absorption on behalf of the sample as it experiences an endothermic phase transition. Observing the difference in heat flow between the sample and the reference, differential scanning calorimeters are able to measure the Tg during such transitions and are reflected in the curves as deviations from the baseline.