Synthesis of Bio-additive for Low Sulphur Diesel: Transesterification of Soybean Oil and Ethylene Glycol using K2CO3 Catalyst

The desulphurization process of diesel fuel is carried out to reduce the amount of SO2 emissions that can cause acid rain. However, the desulphurization process in diesel fuel not only removes the sulfur compounds but polyaromatic and polar compounds are also eliminated during this process. The loss of these two compounds can reduce the lubricity properties of diesel fuel. Therefore, it is necessary to add an additive compound that can increase the lubricity properties. In this research, 2-hydroxyethyl ester (HEE) was synthesized as an additive to increase the lubricity of diesel fuel. This compound was synthesized through the transesterification reaction of soybean oil and ethylene glycol with K2CO3 as the base catalyst. The composition of the synthesized additives was analyzed using the Gas Chromatography-Mass Spectrometry (GC-MS). Based on the results of GC-MS spectrum analysis, it is known that the 2-hydroxyethyl ester compound has been formed with a yield of 66.5% (relative to the area of the chromatogram peak). The HEE compound obtained is a mixture of 2 hydroxyethyl palmitate, 2 hydroxyethyl linoleate, 2 hydroxyethyl stearate, 2 hydroxyethyl arachidonate, 2 hydroxyethyl nervate, and 2 hydroxyethyl behenate.

Production of ROS by Gallic Acid Activates KDM2A to Reduce rRNA Transcription

Metformin, which is suggested to have anti-cancer effects, activates KDM2A to reduce rRNA transcription and proliferation of cancer cells. Thus, the specific activation of KDM2A may be applicable to the treatment of cancers. In this study, we screened a food-additive compound library to identify compounds that control cell proliferation. We found that gallic acid activated KDM2A to reduce rRNA transcription and cell proliferation in breast cancer MCF-7 cells. Gallic acid accelerated ROS production and activated AMPK. When ROS production or AMPK activity was inhibited, gallic acid did not activate KDM2A. These results suggest that both ROS production and AMPK activation are required for activation of KDM2A by gallic acid. Gallic acid did not reduce the succinate level, which was required for KDM2A activation by metformin. Metformin did not elevate ROS production. These results suggest that the activation of KDM2A by gallic acid includes mechanisms distinct from those by metformin. Therefore, signals from multiple intracellular conditions converge in KDM2A to control rRNA transcription. Gallic acid did not induce KDM2A-dependent anti-proliferation activity in non-tumorigenic MCF10A cells. These results suggest that the mechanism of KDM2A activation by gallic acid may be applicable to the treatment of breast cancers.

Exergetic, Economic and Exergo-Environmental Analysis of Bottoming Power Cycles Operating with CO2-Based Binary Mixture

This study focused on investigating the bottoming power cycles operating with CO2-based binary mixture, taking into account exergetic, economic and exergo-environmental impact indices. The main intent is to assess the benefits of employing a CO2-based mixture working fluid in closed Brayton bottoming power cycles in comparison with pure CO2 working fluid. Firstly, selection criteria for the choice of suitable additive compound for CO2-based binary mixture is delineated and the composition of the binary mixture is decided based on required cycle minimum temperature. The decided CO2-C7H8 binary mixture with a 0.9 mole fraction of CO2 is analyzed in two cycle configurations: Simple regenerative cycle (SRC) and Partial heating cycle (PHC). Comparative analysis among two configurations with selected working fluid are carried out. Thermodynamic analyses at varying cycle pressure ratio shows that cycle with CO2-C7H8 mixture shows maximum power output and exergy efficiency at rather higher cycle pressure ratio compared to pure CO2 power cycles. PHC with CO2-C7H8 mixture shows 28.68% increment in exergy efficiency with the levelized cost of electricity (LCOE) 21.62% higher than pure CO2 PHC. Whereas, SRC with CO2-C7H8 mixture shows 25.17% increment in exergy efficiency with LCOE 57.14% higher than pure CO2 SRC. Besides showing lower economic value, cycles with a CO2-C7H8 mixture saves larger CO2 emissions and also shows greater exergo-environmental impact improvement and plant sustainability index.

A Mathematical Study of a Generalized SEIR Model of COVID-19

In this work (Part I), we reinvestigate the study of the stability of the Covid-19 mathematical model constructed by Shah et al. (2020) [1]. In their paper, the transmission of the virus under different control strategies is modeled thanks to a generalized SEIR model. This model is characterized by a five dimensional nonlinear dynamical system, where the basic reproduction number can be established by using the next generation matrix method. In this work (Part I), it is established that the disease free equilibrium point is locally as well as globally asymptotically stable when . When , the local and global asymptotic stability of the equilibrium are determined employing the second additive compound matrix approach and the Li-Wang’s (1998) stability criterion for real matrices [2]. In the second paper (Part II), some control parameters with uncertainties will be added to stabilize the five-dimensional Covid-19 system studied here, in order to force the trajectories to go to the equilibria. The stability of the Covid-19 system with these new parameters will also be assessed in Intissar (2020) [3] applying the Li-Wang criterion and compound matrices theory. All sophisticated technical calculations including those in part I will be provided in appendices of the part II.

Preparation and Characterization of DOPO-ITA Modified Ethyl Cellulose and Its Application in Phenolic Foams

In order to improve the performance of phenolic foam, an additive compound of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and Itaconic acid (ITA) were attached on the backbone of ethyl cellulose (EC) and obtained DOPO-ITA modified EC (DIMEC), which was used to modify phenolic resin and composite phenolic foams (CPFs). The structures of DOPO-ITA were verified by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (1H NMR). The molecular structure and microstructure were characterized by FT-IR spectra and SEM, respectively. Compared with EC, the crystallinity of DIMEC was dramatically decreased, and the diffraction peak positions were basically unchanged. Additionally, thermal stability was decreased and Ti decreased by 24 °C. The residual carbon (600 °C) was increased by 25.7%. With the dosage of DIMEC/P increased, the Ea values of DIMEC composite phenolic resins were increased gradually. The reaction orders were all non-integers. Compared with PF, the mechanical properties, flame retardancy, and the residual carbon (800 °C) of CPFs were increased. The cell size of CPFs was less and the cell distribution was relatively regular. By comprehensive analysis, the suitable dosage of DIMEC/P was no more than 15%.

Global Dynamics of an Avian Influenza A(H7N9) Epidemic Model with Latent Period and Nonlinear Recovery Rate

An SEIR type of compartmental model with nonlinear incidence and recovery rates was formulated to study the combined impacts of psychological effect and available resources of public health system especially the number of hospital beds on the transmission and control of A(H7N9) virus. Global stability of the disease-free and endemic equilibria is determined by the basic reproduction number as a threshold parameter and is obtained by constructing Lyapunov function and second additive compound matrix. The results obtained reveal that psychological effect and available resources do not change the stability of the steady states but can indeed diminish the peak and the final sizes of the infected. Our studies have practical implications for the transmission and control of A(H7N9) virus.

PENGARUH WAKTU REAKSI DAN RASIO MOL ASAM LINOLEAT DENGAN ISOPROPANOL PADA SINTESA PLASTISIZER ISOPROPIL LINOLEAT

Diversity of palm oil product in Indonesia is still limited, therefore it is needed to take an advantage of the development of downstream product of crude palm oil by esterification reaction. Esterification reaction is a reaction between carboxylic acid and alcohol to form ester. One of the emerging downstream product fatty acid alkyl ester is plasticizer. Plasticizer is an additive compound added to polymer to improve flexibility and workability. The purpose of this research was conducted to study the effect of reaction time and mole ratio and identify product of plasticizers isopropyl linoleic. In this research, plasticizer was synthesized by esterification of linoleic acid and isopropanol, using activated natural zeolite catalyst. The process was done with a variation of reaction time (4, 6, and 8 hours) and mole ratio (1: 6, 1: 9, and 1:12), with reaction temperature at 80 °C, stirring speed at 200 rpm and 15% of composition of linoleic acid based catalyst as fixed variables. From the analysis of the results showed that the esterification reaction time and mole ratio affect the product conversion. The best operating condition obtained in this research was 4 hours of reaction time and 1:12 of mole ratio which resulted the conversion of reaction was 67.09%. Characteristics of plasticizer produced from this research were viscosity (at 20 °C) 2.405 to 2.803 mPa.s and Specific Gravity (at 20 °C) from 0.863 to 0.872.

The Lifetime Model of the One-Unit-System with Two Kinds of Wear-Out

A system at inception is endowed with a random amount of resource, the process of the lapse of system life can be viewed as that of the depletion of random resource caused by the wear-out effect. This thesis considers the wear-out process of the system as the sum of an additive compound nonhomogeneous poisson shock wear-out and a continuous routine wear-out in time t. With the introduction of the concept of random resource, a wear-out model is built. Moreover, the aging properties of the system lifetime are studied in this model.