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Inorganic Chemistry
Published in Steven L. Hoenig, Basic Chemical Concepts and Tables, 2019
Writing correct chemical equations requires that you know how to predict products of reactions. Even with limited experience, one can use a few guidelines to accomplish this. Seven frequently used elements naturally occur as diatomic molecules: H2, O2, N2, F2, Cl2, Br2, I2. This is how they should always be written in a chemical equation. States of matter should be indicated by (s), (l), or (g) and ions in aqueous solution as (aq).
Light Sources, Detectors, and Recording Media
Published in Rajpal S. Sirohi, Mahendra P. Kothiyal, Optical Components, Systems, and Measurement Techniques, 2017
Rajpal S. Sirohi, Mahendra P. Kothiyal
Since N2 is added to CO2 for enhancing the power output, we consider the N2 molecule also. It is a homomnuclear diatomic molecule with no permanent dipole moment. It cannot decay radiatively from the v = 1 to the v = 0 level of electronic ground state.
Antioxidant and cytoprotective effects of sequentially extracted Terminalia prunioides pods
Published in Egyptian Journal of Basic and Applied Sciences, 2023
Phazha Baeti, Keagile Bati, Kabo Masisi, Goabaone Gaobotse, Tebogo Kwape
The body has antioxidants as an adaptation response to the prevention, and to lessen the adverse consequences of oxidative stress. When present in small amounts, antioxidants, which are chemicals and proteins that significantly slow down or stop oxidative damage, can protect cells from oxidants [8,9]. Endogenous antioxidants, such as non-enzymatic reduced glutathione (GSH), enzymatic superoxide dismutase (SOD), and enzymatic catalase (CAT), serve as the body’s first line of defense [10,11]. In many circumstances, the physiologically necessary quantities of endogenous antioxidants alone are insufficient to properly protect cells [12]. Considering this, exogenous antioxidant supplements are necessary to augment the endogenous antioxidant system. Superoxide anion is reduced by SOD into diatomic oxygen and hydrogen peroxide [13]. Hydrogen peroxide is converted by catalase (CAT) into water and, occasionally, hydroxyl anion through the Fenton reaction [14]. Hydroxyl radical is reduced by GSH to water [15]. GSH is reduced to GSSG (oxidized GSH) as a result of the hydroxyl radical reaction [16]. In order to convert back GSSH into GSH, it needs either electron and/or hydrogen atom donors. Exogenous antioxidants from medications and plants have been demonstrated in studies to convert GSSH to GSH by electron and hydrogen reduction [17]. It has been discovered that bioactive compounds extracted from plants are efficient free radical reducing agents through several mechanisms such as hydrogen atom transfer (HAT) and single electron transfer (SET) [18].
The effects of fuel injection pressure on combustion and emission characteristics of a diesel engine using frying oil methyl ester
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Krishnamani Selvaraj, Mohanraj Thangavel
The nitrogen present in the cylinder exists at a lower temperature as a diatomic molecule (stable condition), but at the higher temperature, the nitrogen molecule separates into a monoatomic molecule (unstable condition). These molecules react with the surrounding oxygen to form NOX emission by Zeldovich mechanism (Mueller, Boehman, and Martin 2009). The influence of fuel injection pressure on NOX emission at various load conditions is shown in Figure 11. It is observed from the graph that the NOX emissions of FOME at the fuel injection pressure of 260 bar is slightly higher than that of the diesel fuel at all load conditions because NOX formation is largely determined by the cylinder temperature, concentration of O2 and the reaction rate. At the rated brake power, the NOX emissions of diesel and biodiesel with fuel injection pressures of 220 bar, 240 bar and 260 bar are 5.951 gm/kW-hr, 3.859 gm/kW-hr, 4.45 gm/kW-hr and 6.35 gm/kW-hr respectively. The NOX emission for biodiesel increases with fuel injection pressure because at a higher injection pressure, the fuel droplet diameter decreased, and it vaporized more quickly, resulting in rapid combustion during the premixed period. Thus the emissions of NOX of increases with fuel injection pressure due to its higher gas temperature. The results are in good relation with the studies reported by other researchers. (Gumus, Sayin, and Canakci 2012; Jaichandar and Annamalai 2013; Sayeed et al. 2015; Bragadeshwaran et al. 2018).
Eigenvalues and thermal properties of the A1Σ u + state of sodium dimers
Published in Molecular Physics, 2022
Ridha Horchani, Nidhal Sulaiman, Safa Al Shafii
The Sun potential function is equivalent to the improved Tietz potential function for diatomic molecules using parameters such as the energy of dissociation and bond length of the molecule at equilibrium [18]. Tang et al [19] solved the Schrödinger equation with the improved Tietz empirical potential energy model. The rotation vibrational energy spectra and the un-normalised radial wave functions have been obtained. Khordad et al [20] studied the Schrodinger equation with the improved Tietz potential for six different gaseous molecules: hydrogen chloride (HCl), hydrogen fluoride (HF), deuterium fluoride (DF), boron monobromide (BBr), carbon monoxide (CO) and nitrogen monoxide (NO). The authors used the improved Tietz potential to obtain the vibrational partition function and the thermodynamically related functions for different gaseous substances by the Poisson summation function. Jia and his collaborators [21] studied the entropy of different diatomic molecules and gaseous substances, including carbon monoxide (CO), hydrogen chloride (HCl), hydrogen fluoride (HF), deuterium fluoride (DF), boron monobromide (BBr) and nitrogen monoxide (NO), using the improved Tietz potential. Jiang, Jia et al. described the internal vibration of different gases (CO, HCl, and BF) using the vibrational partition function of the improved Tietz oscillator [22]. They also obtained the vibrational enthalpy.