No abstract

Fossil fuel combustion produces around 98% of coal emissions. Therefore, liquid and gaseous biofuels have become more attractive due to their environmental benefits. The biodiesel production process requires measurements that help to control and supervise the variables involved in the process. The measurements provide valuable information about the operation conditions and give estimations about the critical variables of the process. The information from measurements is essential for monitoring the state of a process and verifying if it has an optimal performance. The objective of this study was the conception of a virtual sensor based on the Extended Kalman Filter (EKF) and the model of a batch biodiesel reactor for estimating concentrations of triglycerides (TG), diglycerides (DG), monoglycerides (MG), methyl ester (E), alcohol (A), and glycerol (GL) in real-time through measurement of the temperature and pH. Estimation of the TG, DG, MG, E, A, and Gl through this method eliminates the need for additional sensors and allows the use of different types of control. For the performance analysis of the virtual sensor, the data obtained from the EKF are compared with experimental data reported in the literature, with the mean square error of the estimate then being calculated. In addition, the results of this approach can be implemented in a real system, since it only uses measurements available in a reactor such as temperature and pH.

Abstract:The genus Crotalaria comprises about 600 species that are distributed throughout the tropics and subtropical regions of the world; they are antagonistic to nematodes in sustainable crop production systems, and have also shown antimicrobial capacity. Chipilín (C. longirostrata), which belongs to this genus, is a wild plant that grows in the state of Chiapas (Mexico) and is traditionally is used as food. Its leaves also have medicinal properties and are used as hypnotics and narcotics; however, the plant has received little research attention to date. In the experimental part of this study, dried leaves were macerated by ethanol. The extract obtained was fractionated with ethyl ether, dichloromethane, ethyl acetate, 2-propanone, and water. The extracts were evaluated against three bacteria-namely, Escherichia coli (Ec), Citrobacter freundii (Cf), and Staphylococcus epidermidis (Se)-and three fungi-Fusarium oxysporum A. comiteca (FoC), Fusarium oxysporum A. tequilana (FoT), and Fusarium solani A. comiteca (FSC). During this preliminary study, a statistical analysis of the data showed that there is a significant difference between the control ciprofloxacin (antibacterial), the antifungal activity experiments (water was used as a negative control), and the fractions used. The aqueous fraction (WF) was the most active against FoC, FsC, and FoT (30.65, 20.61,and 27.36% at 96 h, respectively) and the ethyl ether fraction (EEF) was the most active against Se (26.62% at 48 h).