A new criterion for the determination of the start of combustion (SOC) from the diesel engine in-cylinder pressure diagram was developed. It is defined as the maximum of the third order derivative of the cylinder pressure with respect the crank angle. This criterion declares SOC more precisely than other previously published criterions based on pressure diagnostics. This fact was proven analytically and was discernable from the analysis of the experimental data. Beside its accuracy it is also robust enough to allow automatic evaluation of the SOC during processing of the pressure data for a large number of cycles. Analysis of the first law of thermodynamics applied to the engine cylinder showed that the third order derivative of the cylinder pressure with respect to the crank angle is the most suitable criterion for determination of the SOC from the cylinder pressure diagram. Subsequently the criterion was validated through experimental data analysis of the cylinder pressure diagrams for various engine speeds and loads. Cylinder pressure diagrams were processed with a computer code based on the first law of thermodynamics to evaluate the rate of heat release (ROHR), which formed the base for experimental validation. The cylinder pressure was measured with an advanced piezoelectric sensor at the resolution 0.1 deg. CA. Top dead center was determined with the capacitive top dead center sensor. Due to the analytic foundation of the developed method and its validation through highly accurate experimental data it can be concluded that new criterion is credible for the determination of the SOC.
A new criterion for the determination of the start of combustion (SOC) from the diesel engine in-cylinder pressure diagram was developed. It is defined as the maximum of the third-order derivative of the cylinder pressure with respect to the crank angle. This criterion declares SOC more precisely than other previously published criteria based on pressure diagnostics. This fact was proven analytically and was discernable from the analysis of the experimental data. Besides its accuracy it is also robust enough to allow automatic evaluation of the SOC during processing of the pressure data for a large number of cycles. By applying the first law of thermodynamics analysis to the engine cylinder it was discovered that the third-order derivative of the in-cylinder pressure with respect to the crank angle is the most suitable criterion for determination of the SOC from the in-cylinder pressure diagram. Subsequently, the criterion was validated through experimental data analysis of the in-cylinder pressure diagrams for various engine speeds and loads. In order to evaluate the rate of heat release (ROHR), which formed the base for the experimental validation, in-cylinder pressure diagrams were processed with a computer code based on the first law of thermodynamics. The cylinder pressure was measured with an advanced piezoelectric sensor at the resolution 0.1 deg CA. Top dead center was determined with the capacitive top dead center sensor. Due to the analytic foundation of the developed method and its validation through highly accurate experimental data it can be concluded that new criterion is credible for the determination of the SOC.
Abstract
In this study, a low cost carbon adsorbent was prepared from date seeds. Their surface was modified with potassium hydroxide for use as an adsorbent for the removal of synthetic dye (methyl orange (MO)) from aqueous solutions. The effects of initial MO concentration, adsorbent dosage and temperature were studied. A two-cubed (23) factorial design was carried out on the experimental data, with two replications for the process optimization. The results showed that all three factors and their interactions up to the third order were significant for the removal efficiency of MO. Maximum equilibrium adsorption capacity was 66.26 mg/g at 318 K.
The linearity of Junctionless nanowire transistors operating in the linear regime has been evaluated through experimental data and numerical simulations. The influences of the fin width, the gate bias, the temperature, the doping concentration and the geometry on the overall linearity have been evaluated. The increase of the series resistance associated both to the variation of the physical parameters and the incomplete ionization effect has shown to improve the second order distortion and degrade the third order one.
The perturbative configuration interaction using strictly localized molecular orbitals, called the modified PCILO method has been applied in this communication for the calculations of the energy terms of 15 small molecules up to the third order of the perturbation theory. For this method the use of the Rayleigh-Schrodinger many-body perturbation theory with the Moller-Plesset type of the Hamiltonian partitioning is characteristic. On the CNDO/2 and INDO level of approximations the strictly localized molecular orbitals have been constructed by solving the modified 2 x 2 Roothaan's equations. From the zeroth order ground-state wave function the charge distributions, dipole moments and carbon 13-proton nuclear spin-spin coupling constants have been calculated. Results show that the chemical formula, represented with the zeroth order of the perturbation theory, is a good order of the approximation for the study of the molecule. For diatomic molecules the equilibrium interatomic distances and harmonic force constants have been calculated up to the third order of the perturbation theory. The second order of the perturbation theory provides results which are very near to the MO-LCAO-SCF calculations. The main advantage of the PCILO method lies in much saving of the computing time.
In this present paper, the recurrence equations of an Ising model with three coupling constants on a third-order Cayley tree are obtained. Paramagnetic and ferromagnetic phases associated with the Ising model are characterized. Types of phases and partition functions corresponding to the model are rigorously studied. Exact solutions of the mentioned model are compared with the numerical results given in Ganikhodjaev et al. [J. Concr. Appl. Math., 2011, 9, No. 1, 26-34].
Surface modification of date seeds (Phoenix dactylifera) using potassium hydroxide for wastewater treatment to remove azo dye