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Expressing Power Cycle Performance
Published in Neil Petchers, Combined Heating, Cooling & Power Handbook: Technologies & Applications, 2020
Thermal energy is associated with atomic and molecular vibration. It is considered a basic energy form because all other energy forms can be completely converted into thermal energy. But the second law of thermodynamics limits conversion of thermal energy into other forms.
Theoretical Considerations
Published in Patricia B. Coleman, Practical Sampling Techniques for INFRARED ANALYSIS, 2020
Two types of molecular vibrations correspond to the normal mode of the molecule: stretching and bending. Stretching is rhythmical movement along the bond axis and can be symmetric or antisymmetric. Two balls attached by a spring can move simultaneously away from the center of the spring or they can move in towards the center. Either of these motions is termed a symmetric stretch. Two balls attached by the spring could move simultaneously to the right or to the left. Either of these motions is termed an antisymmetric stretch. Bending vibrations arise from a change in bond angle between two atoms or movement of a group of atoms, relative to the remainder of the molecule. The terms scissoring, wagging, rocking, and twisting are often used to describe these motions. Stretching and bending vibrations are shown in Figure 4.
Physicochemical Properties of Coal
Published in Vivek Ranade, Sanjay Mahajani, Ganesh Samdani, Computational Modeling of Underground Coal Gasification, 2019
Vivek Ranade, Sanjay Mahajani, Ganesh Samdani
FTIR is a powerful tool for probing the functional groups in coal and chars. As a nondestructive analytical tool, it identifies molecular vibration – both stretching and bending – due to the absorption of infrared radiation. A sample which is processed into a pellet after mixing with potassium bromide is exposed to continuously changing wavelengths of infrared radiation. It absorbs light when the incident radiation corresponds to the energy of a particular molecular vibration. The energies of the stretching vibrations correspond to infrared radiation with wave numbers between 1200 and 4000 cm–1, while the bending vibration is in the range of 500–1200 cm–1. This part of the infrared spectrum is particularly useful for the detection of the different functional groups, because these groups have characteristic and invariant absorption peaks at these wavelengths. The important functional groups include the aromatic and aliphatic structure and oxygenates in addition to the presence of minerals. The knowledge of chemical functional groups and the resulting internal atomic arrangements and structural properties of coal are important for chemical reactivity (Haenel, 1992; Saikia et al., 2007). The performance of various utilization methods like UCG is affected by the reactivity of coal. It has been observed that the different ranks of coals represent different internal structures due to the difference in their age. For lignite and bituminous coals, the structure may vary depending on the environment in which it evolves and becomes coalified. These differences in the internal atomic structures of coal can potentially affect their reactivity, and techniques like FTIR will become important tools for process development in years to come. The technique has been extensively used for understanding the chemical structure of coal, and the same can be extended to understanding their impact on reactivity and can be the scope of future studies.
The application of structural analysis in the investigation of solvent extraction mechanism
Published in Journal of Coordination Chemistry, 2022
Shan Zhu, Huiping Hu, Song Li, Chengyong Wang
Molecular vibration spectra are generated by transitions between molecular vibration energy levels, including infrared absorption spectra (FT-IR) and Raman scattering spectra (Raman), which could be employed into the investigation of structure of samples in any form (solid, liquid and gas). It is a simple and reliable method for structural analysis of some coordination functional groups. Molecular vibrational spectra can infer the possible structure between extractant and metal ions by analyzing and comparing the changes of vibrational energy levels of functional groups in extractant before and after extraction, but the structural information of extracted species cannot be obtained intuitively [1]. According to the results obtained by infrared spectra of the extractant 2-ethylhexyl phosphoric acid (D2EHPA) and extracted complex of zirconium, Biswas [27] concluded that the extracted complex obtained by the solvent extraction of Zr(IV) with D2EHPA from hydrochloric acid medium was a tetramer. D2EHPA located in the second coordination layer, which combined with the coordinated water molecules of zirconium and no direct interactions were observed.
Synthesis of cracked Mahua oil using coal ash catalyst for diesel engine application
Published in International Journal of Ambient Energy, 2020
N. Muthukumaran, S. Prasanna Raj Yadav, C. G. Saravanan, T. Sekar
In this FTIR spectrometry has been used in the analysis of cracked Mahua oil. In this IR is radiated through the analyzing samples and transmission associated with molecular absorbance is recorded. The molecular absorbance can occur only when the frequency of the radiation exactly matches the vibration frequency of the molecule. Molecular vibration can be either stretching or bonding. Stretching vibration involves continuous changes in the inner atomic distance between two atoms, while bending vibration is a change in the angle between two bonds. The y-axis commonly shows linear in transmission, but a modern computer based spectrometry can produce spectra that linear to absorbance. The IR region includes near IR (wave number: 12,800–4000 cm−1), mid IR (wave number 4000–500 cm−1), and far IR (wave number: 200–10 cm−1). Cracked Mahua oil is characterised by FTIR and compared with neat diesel using SHIMADZU model and detector in the range 500–4000 cm−1 and the resolution is 1 cm−1and 20 scans.
Proposing a new infrared index quantifying the aging extent of SBS-modified asphalt
Published in Road Materials and Pavement Design, 2018
Chuanqi Yan, Weidong Huang, Feipeng Xiao, Lianfang Wang, Yanwei Li
Infrared spectroscopy is a result of the fundamental molecular vibration (Mccann, Hammouri, Wilson, Belton, & Roberts, 1992). Upon an interaction of the infrared radiation with an oscillating dipole moment associated with a vibrating bond, the absorption of the radiation corresponds to a change of the dipole moment. Generally, different functional groups correspond to different parts (peaks) of the infrared spectra; therefore, the characteristic peak on infrared spectra could be used for structural analysis and chemical composition quantification.