Revista Mexicana de Ingeniería Química <div class="_4wyf">The Mexican Journal of Chemical Engineering &nbsp;(ISSN 1665-2738) publishes original research papers with the aim of promoting a rapid share of relevant research in various disciplines of Chemical Engineering and its interfaces with other enigineering disciplines. A volume is published each year and it consists of three issues, which are published every four months.&nbsp;</div> en-US <p>By publishing your paper in our journal you are also granting it the copyright of the information that it contains.</p> (Francisco J Valdes Parada) (Francisco J. Valdés-Parada) Tue, 07 Jan 2020 00:24:28 +0000 OJS 60 Biodegradation of plantain rachis using phytopathogenic fungi for composting <p>The phytopathogenic fungi such as: <em>Colletotrichum</em> sp. and <em>Rhizopus</em> sp. were isolated of banana and tomatoes respectively, 3 biodegradators were used: with spores <em>Colletotrichum</em> sp. (B1), with spores <em>Rhizopus</em> sp. (B2) and a mixture of spores <em>Colletotrichum</em> sp. + <em>Rhizopus</em> sp. (B3). Using the biodegradator (B3) was obtained the highest degradation of the plantain rachis being of 42.91%, and the leachates production was of 80 mL with pH of 7.96 on the 30<sup>th</sup> day of the experimentation. The banana rachis degraded by the mixture of spores of <em>Colletotrichum</em> sp. + <em>Rhizopus</em> sp. (B3) showed the lowest organic carbon content being of 29.52% and the highest nitrogen content being of 2.30%, generating a Carbon/Nitrogen (C/N) ratio of 12.84%. The results evidenced that the biodegradator composed by the mixture of <em>Colletotrichum</em> sp. + <em>Rhizopus</em> sp. (B3) can be used to increase the degradation of the plantain rachis encouraging the use of this biomass in the composting process.</p> J. D. Valenzuela Cobos, R. O. Ramírez Grimón, C. Vargas Farías, A. Grijalva-EndaraE, O. A. Mercader-Camejo ##submission.copyrightStatement## Wed, 04 Sep 2019 15:45:54 +0000 Hyper production of carboxy methyl cellulase by Thermomyces dupontii utilizing physical and chemical mutagenesis <p>Utilization of cellulases as substitute of chemical process gained huge momentum in the field of biotechnology&nbsp; Now there is dire need to find out un explore reveres of fungi possessing greater potential for efficient cellulase production.&nbsp; This boosted isolation of novel thermo tolerant fungal strains capable of producing the targeted product. In this investigation 70 thermophilic cellulolytic fungal strains were isolated. All the strains were screened via submerged fermentation. The strain showing highest CMCase activity was identified by conventional method i.e. &nbsp;based on morphology and microscopic features and confirmed by 18S&nbsp;<em>rDNA</em><em>&nbsp;</em>gene sequencing, using specific ITS primers. The modified CTAB method was used for rapid extraction of DNA from thermo tolerant strain.&nbsp; The selected strain subsequently subjected to sequencing and phylogenetic analysis. The result indicates the selected strain was found to be <em>T. dupontii.</em> For strain improvement the<em> T. dupontii</em> was subjected to random mutagenesis by using (UV) irradiation and EMS treatment. Out of 40 screened mutant <em>T. dupontii</em> EMS 15 had 2.4 fold more yield (21.8 U/ml/min) as compared to parental strain. The Five fermentation media were also screened. The Medium3 gave higher titer of cellulase activity (29.3 U/ml/min) and found to be the best medium.</p> K. Nisar, R. Abdullah, A. Kaleem, M. Iqtedar, F. Saleem ##submission.copyrightStatement## Wed, 02 Oct 2019 17:58:27 +0000 Determination of metabolites involved in natural succinic acid production from glucose, glycerol and crude glycerin by HPLC methodology <p><em>Bio-succinic acid process involves complex biochemical pathways in which diverse metabolites may be cogenerated. Their identification and quantification allow an adequate monitoring and understanding of the bioprocess. In this work, a HPLC methodology for simultaneous determination of glucose, glycerol, ethanol and citric, pyruvic, succinic, lactic, formic, acetic and propionic acids was validated, presenting adequate selectivity and linearity. Matrix effect was observed for citric and lactic acids, glycerol and ethanol. The limits of detection and quantification ranged from 0.006 to 0.021 g.L<sup>-1</sup> and 0.018 to 0.065 g.L<sup>-1</sup>, respectively. Recovery values were between 89 and 109% and variation coefficients were less than 2.3%. The intermediate precision was verified with short-term stability, after one freezing and thawing cycle and analysis by a second analyst. The analysis of fermentation samples showed that Actinobacillus succinogenes’s metabolism was carbon source dependent, while Basfia succiniciproducens presented similar metabolic behavior for the carbon sources evaluated, with less variety of generated products. Succinic acid represented around 37% and 25% of products originated by fermentation of glucose and glycerol sources, respectively, using A. succinogenes. Meanwhile, maximum succinic acid production was equivalent to 50% and 80% of metabolites produced in the fermentation of glucose and glycerol sources by B. succiniciproducens.</em></p> L. Jaramillo, L.B. Pazutti, P.F. de Aguiar, V.S. Ferreira-Leitão, E.C. Sérvulo ##submission.copyrightStatement## Fri, 04 Oct 2019 00:00:00 +0000 Fed-batch cultivation and operational conditions for the production of a recombinant anti-amoebic vaccine in Pichia pastoris system. <p>It was developed a fed-batch bioprocess to produce a recombinant vaccine against <em>Entamoeba histolytica </em>under operational conditions attainable to large scale bioprocesses. We have produced this recombinant protein in shake flask and stirred tank bioreactor. Initial results in shake flask cultures under different methanol concentration of 0.5, 1.5 and 3% (v/v) produced extracellular protein at quantities of 10, 22 and 33 μg/mL, respectively. Then a scale-up process was performed from shake flask to fermenter by keeping similar volumetric power supply (P/V). The operational conditions were set up in fermenter as those used at commercial scale and supply of pure oxygen was avoided to keep the scalability of the bioprocess. After the scale-up process, the production of the recombinant protein reached 0.43 mg/mL, an improvement in production of 12 times, although the methanol and oxygen limited conditions observed. Maximum volumetric productivity of 3.75 mg/L h was achieved in fermenter cultures against 263.75 µg/L h reached in shake flask. Besides the limited conditions in methanol and oxygen, the yields obtained from the bioprocess were comparable to those observed in Mut<sup>+</sup> strains previously reported, then saturated methanol conditions are not necessary to compensate limited oxygen conditions.</p> S. L. Martínez-Hernández, M. A. Marin-Muñoz, J. Ventura-Juarez, J. Jauregui ##submission.copyrightStatement## Tue, 08 Oct 2019 00:00:00 +0000 Enzymatic cyanide detoxification by partially purified cyanide dihydratase obtained from Serratia marcescens strain AQ07. <p>The partially purified enzyme of indigenously isolated <em>Serratia marcescens</em>strain AQ07 was utilised to develop the best form of cyanide detoxification method that is eco-friendly and cost effective. The present study evaluates the feasibility of the enzyme to degrade high cyanide concentrations and the possible metabolic pathways involved, for which the protein concentration and cyanide detoxification activity were quantified. Bacterial cells grown in cyanide incorporated medium were disrupted by sonication and the resultant cell free extract were tested for metabolic pathway. The cell free extract was precipitated by ammonium sulphate precipitation and partially purified by ion exchange chromatography using DEAE cellulose. The maximum enzyme activity achieved was 2125 µM/min. The partially purified enzyme was found to be able to detoxify 82% of 2 mM KCN in 10 min of incubation and cyanide degradation (or depletion) rate showing a linear increase with increasing enzyme concentration. The effective accruing of ammonia as metabolite illustrated that the detoxification was ensued via the function of cyanide dihydratase. Additional confirmation through SDS-Page showed that the molecular weight of enzyme was assessed to be ~38 kDa, which is tandem with the reported cyanide dihydratases. Hence, the use of enzyme as a substitute to live bacterial cells in detoxification of cyanide illustrates various advantages such as the capacity to withstand and detoxify higher cyanide concentration and total reduction in the total cost of process since nutrient provision is immaterial.</p> K. I. Karamba, M. K. Sabullah, A. Zulkharnain, C. Gomez-Fuentes, S. A. Ahmad ##submission.copyrightStatement## Fri, 18 Oct 2019 00:00:00 +0000 Assessment of intermediate and long chains agave fructan fermentation on the growth of intestinal bacteria cultured in a gastrointestinal tract simulator <p>The prebiotic activities of agave fructans are well documented; however, little is known about the effects of agave fructan fractions in particular. Some reports have demonstrated that different fructan chain lengths have different effects on the growth of intestinal microbiota bacterial communities. The aim of this study was to evaluate two agave fructan fractions on the growth of probiotic and pathogenic bacteria cultured in a gastrointestinal tract simulator. The growth was carried out by plate count using media selective for each different bacterial type. In addition, the metabolites generated via fructan metabolism were analyzed by ultra-high performance liquid chromatography. These results suggest that these fructan fractions possess prebiotic activities and have beneficial effects via inhibition of intestinal pathogen growth. These effects particularly depend on the length of the selected fructan fraction administration period. This knowledge is important for enhancing the selective use of prebiotics in functional foods.</p> R. García-Gamboa, M. S. Gradilla-Hernández., R. I. Ortiz-Basurto, R. A. García-Reyes, M. González-Avila ##submission.copyrightStatement## Fri, 01 Nov 2019 00:00:00 +0000 Antagonistic microorganisms efficiency to suppress damage caused by Colletotrichum gloeosporioides in papaya crop: Perspectives and challenges <p>Papaya (<em>Carica papaya</em> L.) is one of the most valued tropical fruits worldwide due to its nutritional content. Its production is drastically affected by <em>Colletotrichum gloeosporioides</em>, one of the main pathogens responsible for anthracnose disease. Several techniques as an alternative of conventional chemical treatments for disease control have been studied. Among these techniques, the use of antagonist microorganism has emerged as a promising, eco-friendly alternative for postharvest disease control. This review is focused on the inhibition of <em>Colletotrichum </em><em>gloeosporioides</em> in papaya applying microbial antagonists. Furthermore, the main purpose of this study is to provide the results of <em>in vivo</em> and <em>in vitro</em> assays, that addressed the use of microorganisms and their activity as biocontrol agents in papaya, considering its application to diminish crop losses and suggesting possible future researches addressed to their attractive usage. We believe that a specific compilation is helpful for groups that are in research of pre- and postharvest fruits management, providing useful information to create new perspectives and/or alternative in emerging technologies.</p> J.M. Silva-Jara, R. López-Cruz, J.A. Ragazzo-Sánchez, M. Calderón-Santoyo ##submission.copyrightStatement## Wed, 30 Oct 2019 00:00:00 +0000 Production of bacterial cellulose by Komagataeibacter xylinus using mango waste as alternative culture medium <p>Bacterial cellulose (BC) is a high value-added nano-structured biopolymer with important biomedical applications.&nbsp; Its biosynthesis from waste carbon sources might modify BC structure and properties, thus Mango pulp waste (MPW) was evaluated as an alternative culture medium for its production by the bacteria <em>Komagataeibacter xylinus</em>. The use of MPW could also decrease BC cost since the use pure sugars for its obtaining is expensive. The effect of different nitrogen sources and buffer addition to MPW-medium on the polymer yield was also investigated. Using MPW and yeast extract as a nitrogen source, a production of 6.32 g/L of BC was obtained after 16 days of static culture. &nbsp;BC was characterized by SEM, XRD, TGA, FTIR and Water holding capacity (WHC). Chemical structure and thermal degradation of BC produced from MPW were similar to those of BC obtained with pure sugars (350°C). Crystallinity index of BC produced in mango-based medium was lower (62.7 % vs. 77.2 %); WHC was higher (108.7 % vs.&nbsp; 88.7 %); and fiber diameter was smaller (98.8 nm vs. 50.6 nm).</p> M. E. García-Sánchez, J. R. Robledo-Ortiz, I. Jiménez-Palomar, O. González-Reynoso, Y. González-García ##submission.copyrightStatement## Wed, 06 Nov 2019 00:00:00 +0000 Optimization of the byosynthesis of gold nanoparticles using Hypericum perforatum and evaluation of their antimicrobial activity <p>The functionality of metal nanoparticles is reported mainly in the pharmaceutical and biomedical areas. Gold nanoparticles (AuNPs) have shown numerous activities among these the microbicidal capacity, as transporters of therapeutic drugs and in the treatment of genetic diseases. The AuNPs are synthesized by physical, chemical and biological methods; the green synthesis is a eco-friendly method based on biological principles that have functional groups serving as reducing agents and stabilizers in the reaction. The objective of this work was the optimization in the conditions for AuNPs synthesis using Hypericum perforatum and assess the antimicrobial activity of optimal treatments obtained. The AuNPs were synthesized by the combination of biological and physical methods, characterized by FTIR, spectrophotometry, TEM and DLS; and the antimicrobial effect of the optimized AuNPs was evaluated. The smallest particle size obtained was 20 nm, however not all AuNPs showed antimicrobial activity, the minimum inhibitory and minimum bactericidal concentrations were 0.42 and 0.84 μg AuNPs/mL, respectively. The information obtained presents a method of AuNPs synthesis in a fast and free of pollutants for the environment, providing an alternative to obtain antimicrobial compounds with no microbial resistance</p> J. C. Serrano-Niño, J. R. Solis-Pacheco, A. Cavazos-Garduño ##submission.copyrightStatement## Mon, 11 Nov 2019 00:00:00 +0000 Application of response surface methodology for statistical optimization of carboxymethylcellulase by Thermomyces dupontii TK-19 using submerged fermentation <p>In present work, optimization of nutritional parameters for carboxy methyl cellulase production was studied through experimental design. A central composite design, with 8 axial points, 16 factorial points and 6 center points were used for optimizing and predicting four independent variables such as Lactose, peptone, ammonium sulphate and Tween 80. By means of ANOVA significance of four independent variables and their possible interactions was tested with 95% of confidence level. A good agreement was obtained between predicted and experimental model. The predicted response 71.3 U/ml/min from the model showed close agreement with 72 U/ml/min of the experimental data which validates the effectiveness of the model while reducing the required number of experiments.</p> K. Nisar, R. Abdullah, A. Kaleem, M. Iqtedar ##submission.copyrightStatement## Sat, 09 Nov 2019 00:00:00 +0000 Optimization of process variables for hyper-production of lovastatin from wild type Aspergillus terreus and its efficacy studies <p>The objective of this study was the investigation of optimum conditions for lovastatin production from Aspergillus terreusthrough response surface methodology (RSM) with central composite design (CCD). The efficacy of produced and purified statinwas thenevaluated by using induced hypercholesterolemic rats. A. terreus was used to synthesize statin by using solid state fermentation on lignocellulose substrate, w</p> <p>En este trabajo se investigaron las condiciones óptimas para la producción de lovastatina a partir de&nbsp;<em>Aspergillus terreus&nbsp;</em>usando una metodología de superficie de respuesta (RSM) con un diseño central compuesto (CCD). La eficacia de la estatina producida y purificada se evaluó en ratas en ratas con hipercolesterolemia inducida. Se empleó&nbsp;<em>A. terreus</em>&nbsp;para sintetizar la estatina mediante fermentación en estado sólido usando un sustrato lignocelulósico (paja de trigo).&nbsp;&nbsp;Se realizaron un total de 30 experimentos por triplicado para los cuatro parámetros físicos en cinco niveles y como variable de respuesta se midió la producción de estatina por&nbsp;<em>A. terreus</em>. La producción máxima de estatina (60 mg/g) se logró a una temperature de 30 °C, pH 7.37, tamaño de inóculo de 4.5 mL tiempo de fermentación de 192 h. Lla hipercolesterolemia se indujo en las ratas de los grupos I, II and III, alimentándolas con una dieta alta en colesterol durante 30 días. El grupo III (grupo de tratamiento) fue dado la estatina producida por&nbsp;<em>A. terreus&nbsp;</em>de los días 15-30, encontrándose que al dí 30 había ocurrido una reducción significativa en el colesterol sérico (Incrementando el significativamente el nivel del colesterol de alta densidad (HDL) y disminuyendo significativamente el colesterol de baja densidad (LDL).</p> <p>heat straw. Total 30 experiments were conducted in triplicate for four physical parameters, each at five levels and response (statin production) from A. terreus was measured. Maximum statin formation (60mg/g) obtained from A. terreus at temperature 30oC, pH 7.37, Inoculum size 4.5 mL and fermentation time 192 h. Hypercholesterolemia was induced in rats by feeding a high cholesterol diet in group I,II and group III from 0 to 30 days. From days 15-30, Group III (treatment group) was given statin extracted from A. terreus. Significant reduction in serum cholesterol level in group III rats treated with purified statin were observed at 30th day with significant increase in serum HDL levels along with significant reduction of serum LDL levels.</p> T. Bashir, M. Asgher, F. Hussain, H. N. Bhatti ##submission.copyrightStatement## Sat, 16 Nov 2019 00:00:00 +0000 Physico-mechanical, barrier and antimicrobial properties of linseed mucilague films incorporated with H. virginiana extract <p>Increased interest in providing safe food with excellent quality and shelf-life has resulted in increased efforts toward developing new bio-based packaging materials. The objectives of this study were to develop and characterize films based on linseed mucilage (LM) at concentrations of 2.0%, 2.5%, and 3.0% and the further development of antimicrobial films (AFs) incorporating <em>Hamamelis virginiana</em> (Hv) extract. The films with the greatest LM concentration was selected as the best formulation based on its mechanical properties, water vapor permeability and moisture sensitivity. Moreover, the antimicrobial activities of Hv extract against foodborne pathogens were evaluated. Minimum inhibitory concentrations were 1.18 mg mL<sup>-1</sup> for <em>L. monocytogenes</em> and 2.37 mg mL<sup>-1</sup> for <em>S. typhi, S. aureus, </em>and <em>E. coli</em>. Finally, AFs were developed by incorporating Hv extract at 2.37 mg mL<sup>-1</sup> into a base of 3.0% LM, increasing elongation at break, antioxidant activity to 80.56%, moisture sensitivity, and antimicrobial activity (increasing inhibition zones to 19.50 – 22.50 mm). It also decreased tensile strength, maximum force, and water vapor permeability. These results suggest that AFs based on LM with Hv extract have sufficient properties for a potential packaging material.</p> M. Z. Treviño-Garza, S. A. Yañez-Echeverría, S. García, A. E. Mora-Zúñiga, K. Arévalo-Niño ##submission.copyrightStatement## Mon, 16 Dec 2019 00:00:00 +0000 Microencapsulation of phenolic compounds: technologies and novel polymers <p>In the last years, the interest and use of bioactive phenolic compounds has increased in food and pharmaceutical fields, this mainly because of the benefits reported by many researchers i.e. antioxidant activity and their potential use as nutraceuticals. Unfortunately, all these benefits are linked generally with their stability, which may be weak depending on the environment conditions. In this tenor, microencapsulation could be a technological option to preserve those molecules and provide them the desired stability. Furthermore, it may permit a better managing and masking of the astringent taste that most of phenolic compounds have. In this review encapsulation techniques such as spray drying, extrusion, molecular inclusion in cyclodextrins, electrospray and liposomes are discussed, also the&nbsp;different wall materials, including polysaccharides, proteins, whey protein, different mucilages, inulin, zein and FucoPol are described.</p> E. Macías-Cortés, J. A. Gallegos-Infante, N. E. Rocha-Guzmán, M. R. Moreno-Jiménez, L. Medina-Torres, R. F. González-Laredo ##submission.copyrightStatement## Sat, 07 Sep 2019 03:39:05 +0000 Obtaining of Crataegus mexicana leaflets using an indirect solar dryer <p>Drying behavior for ripe and unripe <em>Crataegus mexicana </em>was studied for an indirect solar dryer in order to obtain the effective diffusion coefficients . The behavior of the drying process was examined, observing a significant effect related to the ripeness degree of the fruit. The effective diffusion coefficients were 5.698 x10<sup>-10</sup> m<sup>2</sup>/s and 5.993 x10<sup>-10</sup> m<sup>2</sup>/s, for unripe and ripe <em>Crataegus mexicana</em>, respectively. Solar drying is a viable alternative for adding value to the production of this fruit in central México.</p> A. Tlatelpa-Becerro, R. Rico-Martínez, G. Urquiza-Beltrán, M. Calderón-Ramírez ##submission.copyrightStatement## Tue, 15 Oct 2019 00:00:00 +0000 Heat transfer simulation in corn kernel during nixtamalization process <p>Maize nixtamalization is an alkaline cooking process that yields several food products. One of the critical parameters which are traditionally monitored in the process is temperature; however, to date the measurement of this variable has not been carried out inside the corn kernel itself. In this study, heat transfer inside a corn kernel during the nixtamalization process was simulated by means of finite element analysis (FEA) in a tridimensional (3D) model. In addition, thermophysical properties of corn kernel [thermal conductivity (<em>k</em>), specific heat capacity (<em>C<sub>p</sub></em>) and bulk density (<em>ρ<sub>b</sub></em>)] were determined as a function of temperature (25, 50 and 75 °C). The magnitudes of the thermophysical properties increased with temperature and the convective heat transfer coefficient (<em>h</em>) was computed as 2143 ± 407 W/m<sup>2</sup>·K (<em>N<sub>Bi</sub></em> =0.0094). Also, the simulation model was good (<em>R<sup>2</sup><sub>adj</sub></em> &gt; 0.99) and predictions showed that the corn kernel’s surface was rapidly heated and the alkaline solution’s temperature (85 °C) at corn kernel’s center was achieved at 80 s of heating. Furthermore, some predictions in the anatomical parts of the corn kernel were performed. This study contributes to the understanding and improvement of the optimal conditions of the nixtamalization process which allows saving energy, having economic rewards and obtaining high quality nixtamalized products.</p> E. García-Armenta, J. J. Caro-Corrales, K. Cronin, C. Reyes-Moreno, R. Gutiérrez-Dorado ##submission.copyrightStatement## Fri, 18 Oct 2019 00:00:00 +0000 Bioactive compounds from mango peel (Mangifera indica l. var. Tommy atkins) obtained by supercritical fluids and pressurized liquids extraction <p>Currently, large quantities of by-products of mango are generated due to the high consumption of this fruit worldwide. In order to give it an added value, two "clean" technologies: supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE) were evaluated for obtaining their analytes. Results indicated that although higher yields were obtained by PLE, in general a higher concentration of compounds (gallotannins, flavonoids, xanthones, gallic acid, etc.) was obtained by SFE, except for Gallic acid due to its high solubility in pressurized water. The best results for SFE were obtained at 50 °C, 20 MPa and co-solvent flow rate corresponding to 20 % of the CO<sub>2</sub> flow; while for PLE the best condition was at 6.67 g.min<sup>-1</sup> Milli-Q water, 40 °C and 10 MPa. This work provides additional information on the phytochemical composition of Brazilian Tommy Atkins mango peel and its possible use as a functional ingredient.</p> N. Sánchez-Mesa, J.U. Sepúlveda-Valencia, H.J. Ciro-Velásquez, M.A. Meireles ##submission.copyrightStatement## Fri, 18 Oct 2019 00:00:00 +0000 α-Zein nanoparticles as delivery systems for hydrophobic compounds: Effect of assembly parameters <p>In this study, protein nanoparticles were assembled from a-zein using liquid antisolvent-precipitation methodology. The nanoparticles were loaded with krill oil, which is an important nutraceutical. The nanoparticles displayed different physicochemical characteristics depending on the assembly parameters chosen during their preparation. The fabrication process involved the use of biopolymer coatings (the protein b-lactoglobulin and the carbohydrate chitosan). Non-coated nanoparticles showed a particle size between 340-400 nm and surface charge of around -40 mV (pH 8.0). The protein copolymer b-lactoglobulin allowed the fabrication of smaller (<em>d</em> » 200 nm; z-potential » -60 mV) and more stable nanoparticles against pH changes (from 3.0 to 7.0). Chitosan was the best biopolymer coating for improving the antioxidant activity of the particles. The apparent pI for the different nanoparticles was modified after krill oil nanoencapsulation. These results support the idea that controlling the solvent system is a means to control physicochemical characteristics of a-zein nanoparticles.</p> C. Sánchez-Juárez, D. Reyes-Duarte, M. Hernández-Guerrero, M. Morales-Ibarría, J. Campos-Terán, I. J. Arroyo-Maya ##submission.copyrightStatement## Mon, 28 Oct 2019 00:00:00 +0000 An electroanalytical method for brewing vinegar authentic identification <p>An electrochemical fingerprint-based methodology is described here for vinegar authentic identification. The commercial three-electrode system can be directly inserted into vinegar for voltammetric profile recording without the addition of electrolyte. The free amino acids and aroma compounds produced from the fermentation process can be oxidized during the differential pulse voltammetric scan. The fingerprint pattern of vinegar varies between the different brand due to the different raw ingredients and fermentation process. The DPV profiles can be converted into 2D scatter patterns for identifying twelve different vinegar in this work. In addition, clustering analysis confirmed the feasibility of the proposed method for vinegar authentic identification. We believe the proposed methodology can be further extended for other food quality screening application.</p> L. Fu, H.Y. Zhang, Y.H. Zheng, H.W. Zhang, Q.H. Liu ##submission.copyrightStatement## Mon, 28 Oct 2019 00:00:00 +0000 Kinetics of solid-liquid extraction of anthocyanins obtained from Hibiscus rosa-sinensis <p>In this study the effect of temperature (25, 40 and 60 °C), solvent polarity using water (H<sub>2</sub>O)-ethanol (EtaOH) solvent with 100, 90:10 and 80:20 (H<sub>2</sub>O:EtaOH % v/v), and solvent-to-solid ratio (40/1, 60/1 and 80/1 mL/g) on the extraction yield of anthocyanins from <em>Hibiscus rosa-sinensis</em> was analyzed. The experimental data were fitted to Spiro and Siddique model with a good accuracy () and the specific extraction rate constant was perfectly related to the apparent diffusivity using the lumped parameter model. The major percentage of the anthocyanin extraction yield was 63.81±1.33, 68.95 ±1.53, and 83.09±3.14 when the used solvent was H<sub>2</sub>O, H<sub>2</sub>O-EtaOH (90:10), and H<sub>2</sub>O-EtaOH (80:20), respectively.&nbsp; The diffusivity was affected mainly by temperature, tending to be more temperature sensitive as the solvent polarity decreased. Activation energy values (), in range from 19.64 to 29.28 kJ mol<sup>-1</sup>, allow to infer that the extraction of anthocyanins is favored when using an ethanolic aqueous solution as a solvent. Response surface methodology was successfully applied to the anthocyanin extraction yield, confirming that the process parameters (solvent polarity, solid-to-solvent ratio and temperature) affected the extraction yields.</p> J.P. Pérez-Orozco, L.M. Sánchez-Herrera, E. Barrios-Salgado, M.T. Sumaya-Martínez ##submission.copyrightStatement## Tue, 29 Oct 2019 00:00:00 +0000 Influence of ethyl cellulose in a multicomponent mixture (sorbitan monopalmitate-vegetable oils) on physicochemical properties of organogels <p>The modification of vegetable oils from liquid to solid state gel type is achieved by organogelation, the first phenomenon experienced is nucleation that can be spectrophotometrically evaluated and obtain thermodynamic properties. The objective of the work was to evaluate the solid formation from nucleation to macroscopic properties of the mixture: sorbitan monopalmitate and ethyl cellulose in canola, olive and coconut vegetable oils. Nucleation kinetics, solid growth analysis, oscillatory rheology characterization, thermal properties by differential scanning calorimetry and microstructural formation by optical microscopy were evaluated. Non-isothermal nucleation kinetics indicated short induction times for canola and prolonged in coconut, the inclusion of ethyl cellulose involved a more compact solid formation in the systems, without modifying the growth parameters, the coconut organogel was more sensitive to thermal changes. Non-isothermal nucleation kinetics are useful for determining the thermodynamic properties of organogels and the closest to thermodynamic equilibrium, the inclusion of ethyl cellulose being decisive; same that does not influence formation speed and solid growth. The multicomponent gels obtained showed that the structural differences depend on the concentration of the mixture that includes ethyl cellulose, presenting more compact structures and thereby more resistant gels.</p> <p><em>Keywords</em>: nucleation, organogelation, ethyl cellulose, vegetable oils.</p> M. García-Andrade, R. F. González-Laredo, N. E. Rocha-Guzmán, W. Rosas-Flores, M. R. Moreno-Jimenez, E.A. Peña-Ramos, J. A. Gallegos-Infante ##submission.copyrightStatement## Fri, 06 Dec 2019 00:00:00 +0000 Kinetics and statistical approach for 2,5-dichlorophenol degradation in short reaction time by solar TiO2/glass photocatalysis <p>Aqueous 2,5-dichlorophenol (2,5-DCP) degradation was studied. Degradation was performed by solar photolysis and heterogeneous photocatalysis on TiO<sub>2</sub> synthesized by sol-gel method. A thin film solar reactor of 1 m<sup>2</sup> surface area was used. Solution was recirculated for 30 min under a laminar regime, with 20° and 26° surface slopes, under different temperatures and radiation. Samples were taken every 5 min to determine chemical oxygen demand (COD) and absorbance at λ= 280 nm. A 2<sup>3</sup> factorial with covariates and repeated measures experimental design was used to determine degradation kinetics of 2,5-DCP in short reaction times, having two response variables: COD and concentration of 2,5-DCP, determined at 280 nm.&nbsp; The factors were: reactor inclination angles (20° and 26°), flow (355 L/h and 407 L/h) and process (photolysis and photocatalysis); and covariates: solar radiation, temperature, evaporation and initial concentration of 2,5-DCP. By comparing the kinetic constants of both processes using Student-t statistic, significant differences (p &lt;0.05) between them were found. Degradation reaction of 2,5-DCP in short times by solar photocatalysis, clearly showed a reaction order n = 1, reaching degradation of 75% (20 min), 83% (25 min) and up to 95% (30 min).</p> M. M. Morones-Esquivel, C. M. Núñez-Núñez, L. A. González-Burciaga, J. L. Hernández-Mendoza, G. I. Osorio-Revilla, J. B. Proal-Nájera ##submission.copyrightStatement## Mon, 02 Sep 2019 22:40:42 +0000 Rheokinetic and efectiveness during the phenol removal in mescal vinasses with a rotary disks photocatalytic reactor (RDPR) <p>This research shows rheokinetic removal of phenol in mescal distillery residues in a RDPR, using titanium dioxide as semiconductor, with a residence time of 72 h. The highest phenol removal was 82.39% at 55 rpm and 60% (v/v) diluted vinasses; the optimum values were obtained by canonical analysis. Rheological analysis was carried out with a stirrer and Peltier temperature control, and RheoPlus software. Vinasses showed a satisfactory adjustment to Herschel-Bulkley model, rheological index values (n&gt;1) meaning dilatant flow. Temperature dependence models Arrhenius and Poiseuille were carried out. The kinetic analysis was fitted to Langmuir- Hinshelwood. High shear rates at the disks surface and the dilatancy increased vinasses viscosity, promoting the full contact to the semiconductor, increasing the removal efficiency. The effectiveness factor obtained (0.9981) explained that all the reaction is carried out at the catalyst surface. There was rheokinetic correlation found between the initial yield stress and removed concentration.</p> R. S. Gines-Palestino, E. Oropeza- De la Rosa, C. Montalvo-Romero, D. Cantú-Lozano ##submission.copyrightStatement## Fri, 04 Oct 2019 00:00:00 +0000 Obtaining kinetic parameters of polyamide imide reaction <p>The influence in addition order of monomers for the polymerization reaction of polyamide imide (PAI), at a 1:1 molar ratio of TMA:MDI in NMP as a solvent was studied thoroughly. In the first instance, the chemical structure of the PAI was obtained using FTIR, <sup>1</sup>H-NMR and Elemental analysis. On the other hand, the reaction kinetic followed by viscosimetry (measuring the instantaneous intrinsic viscosities at different times), was carried out on three synthesis routes proposed at 140 ℃ for 24 h of reaction: a) MDI / NMP solution to later add TMA, b) MDI / TMA solution in NMP and c) TMA / NMP solution to later add MDI, in order to determine some parameters such as reaction order and rate constant. The kinetic data analysis methods applied were the integral, the differential and Powell's, which showed that the reaction order was 2 and the velocity constant of <em>k</em> = 0.0006 M<sup>-1</sup>·s<sup>-1</sup>.</p> M López-Badillo, M.A. Velasco-Hernández, M.A. García-Castro, R.J. Aranda-García, J.A. Galicia-Aguilar, M.D. Guevara-Espinosa, V.E. Carreón-Rodríguez ##submission.copyrightStatement## Fri, 25 Oct 2019 00:00:00 +0000 PPO activity of two varieties of pears. Control of enzymatic browning for temperature effect, presence of inhibitors and complexation with b-cyclodextrin <p>Polyphenoloxidase (PPO) is an enzyme that produces enzymatic browning, which causes numerous losses in the industry. For this reason, the characterization and inhibition of PPO are very important. In this work were characterized PPOs from two types of pears (<em>Pyrus communis L</em>): White of Aranjuez (<sub>A</sub>PPO) and Williams (<sub>W</sub>PPO), since this comparison has not been done before. The optimum pH and temperature for enzyme activity were determined (<sub>A</sub>PPO: 7 and 30ºC; <sub>W</sub>PPO: 7.5 and 24.5ºC). Both enzymes are heat-labile enzymes and exhibited similar behaviour against temperature. The enzymes analysed showed a higher affinity for 4-methylcatechol than for catechol. The inhibition of PPOs through ascorbic acids, 4-hexylresorcinol, sodium isoascorbate and citric acid was determined. Additionally, the inhibitory effect of b-Cyclodextrin, which results in the prevention of fruit oxidation because it forms an inclusion complex with the substrates, was evaluated. The value of the constant of the complex formed was 16888 M<sup>-1</sup>.</p> G. M. Melo, M. A. Filippa, J. A. Ragazzo Sanchez, E. I. Gasull ##submission.copyrightStatement## Sat, 09 Nov 2019 00:00:00 +0000 Kinetics and microbial structure of nitrogen cycle bacteria contained in the rhizosphere of natural wetland polluted with chromium <p>Wetlands have been considered a feasible technology for wastewater treatment in the last decades; however, information on the kinetics and microbial structure of nitrogen cycle bacteria involved on the rhizosphere activity of natural wetlands polluted with chromium is still scarce. The goal was to evaluate the kinetic behavior of nitrification, denitrification, and ANAMMOX on rhizosphere sludge, with and without chromium, through batch cultures, as well as the microbial structure using Next Generation Sequencing (NGS). The microbial sludge was able to nitrify (3.8 ± 0.2 mg NO<sub>3</sub><sup>-</sup>-N/gVSS-h) and carry out the ANAMMOX (0.67 ± 0.05 mg NH<sub>4</sub><sup>+</sup>-N/gVSS-h), however, denitrifying activity was not observed. Chromium inhibited the nitrifying process, and the IC<sub>50 </sub>obtained for the nitrifying activity was of 7.9 mg Cr<sup>VI</sup>/L. ANAMMOX activity was stopped in the presence of chromium, even to the lowest chromium concentration tested. Recovery cultures showed that ANAMMOX bacteria suffered some damage by chromium presence since they required more than 5 days to recover the activity. Microbial results indicated that <em>Xanthomonadaceae</em> (17.17%), <em>Ignavibacteriaceae </em>(16.52%), <em>Trueperaceae</em> (10.66%) and <em>Chitinophagaceae</em> (10.06%) dominated in the microbial sludge, whereas <em>Nitrosomonas</em> and <em>Planctomycetaceae </em>were in lesser proportion. This research improves the understanding of bacteria behavior on natural wetlands polluted with metals.</p> G. González Blanco, V. Pérez Pérez, J. Orozco Villafuerte, J. Aguirre Garrido, R. Beristain Cardoso, L. Buendía González ##submission.copyrightStatement## Mon, 02 Sep 2019 22:48:30 +0000 Treatment of wastewater from the petrochemical industry by a chemical Fenton process <p>Advanced oxidation processes aid in the degradation of contaminating organic matter, as they can form easily degradable compounds by biologic processes or break organic matter down to its minerals. In this study, it was tested the Fenton process of chemical oxidation for organic matter degradation of petrochemical wastewater with chemical oxygen demand (COD) higher than 20 g/L. In batch testing, it was used the statistical factorial experiments design, confirmed by verification tests utilizing various concentrations in water and subsequently in continuous flow in a pilot plant by oxidation under the Fenton process. Variables’ effects on contaminant degradation in water follow an order: pH &gt; relation Fe<sup>2+</sup>/H<sub>2</sub>O<sub>2</sub> &gt; time &gt; [H<sub>2</sub>O<sub>2</sub>]. The Fenton process removes more than 50% of contaminants in COD testing and more than 70% in continuous testing. Easily oxidated organic matter consumes H<sub>2</sub>O<sub>2</sub> at the beginning of the process, whereas organic matter that was more difficult to degrade was oxidized with a hydroxyl radical (OH•).</p> <p><strong>&nbsp;</strong></p> R. Contreras-Bustos, J. Cardenas-Mijangos, A. Dector-Espinoza, A. Rodriguez-García, L. Montoya-Herrera, J. Jiménez-Becerril ##submission.copyrightStatement## Sat, 07 Sep 2019 03:20:56 +0000 Comparative study of the use of starch from agroindustrial materials in the coagulation-floculation process <p>Coagulation-flocculation is a process that takes place in the water treatment industries with the aim of reducing the repulsive potential of the double electric layer of colloids using the addition of coagulants. This study evaluated the use of cassava (<em>Manihot esculenta</em>), yam (<em>Dioscorea alata</em>) and plantain (<em>Musa paradisiaca</em>) starch, post-harvest residual, in the coagulation-flocculation process for the removal of turbidity in a synthetic water sample. The extraction of the starches was carried out by two methods: alkaline with NaOH and with deionized water. The starches obtained were characterized by physical analysis (color, state and pH), quantifying the nitrogen and carbon content. The effect of the coagulant concentration and the stirring rate on the coagulation-flocculation capacity of the starches under study were assessed as well. It was found that the plantain starch, obtained by both methods, reached the best percentages of turbidity reduction up to 94.6%, becoming an alternative to synthetic coagulants. The results presented in this basic study can be of great value for the scaling of starch production from these residues at an industrial level in the department of Bolívar, Colombia</p> A. Villabona-Ortíz, C. Tejada-Tovar, R. Ortega Toro ##submission.copyrightStatement## Wed, 02 Oct 2019 01:13:30 +0000 Synthesis of TiO2-Au nanoparticles as sensors of 3-mercaptopropionic acid <p>3-Mercaptopropionic acid (3MPA) is an essential organic compound in aquatic environments given that has a fundamental role in the biogeochemistry of sulfur (S), is generated during the degradation of amino acids containing S, such as methionine in some plants and sequential demethylation of dimethylsulfoniopropionate (DMSP). The level of concentration of the 3MPA in aquatic environments is from nanomolar to micromolar. Also, 3MPA is toxic at certain concentrations and is used in experimentation to cause seizures in mice for scientific advances on epilepsy. Therefore, in this work, we report the developed of a novel portable, selective, and fast response sensor; based on an Au-TiO<sub>2</sub> electrode for the quantification of 3MPA. The electrochemical technique of cyclic voltammetry was used to obtain the calibration curve of the sensor, with a limit of detection (LOD) of 50 nM in a linear range of 0 to 80 μM.</p> K. Montoya-Villegas, R. M. Félix-Navarro, L. Rejón-García, C. Silva-Carrillo, B. Trujillo-Navarrete, S. W. Lin-Ho, E. A. Reynoso-Soto ##submission.copyrightStatement## Sat, 16 Nov 2019 00:00:00 +0000 Effects of agitation rates over metastable zone width (MSZW) of concentration for cane sugar crystallization <p>The aim of this work is the experimental measurement of metastable zone width (MSZW) of concentration for sugar cane solutions by means of the polythermal method coupled with an image acquisition system, taking into account the effects of agitation rate and temperature, which represents a key novelty, since this is the first work that considers both variables experimentally. A split plot experimental design was followed with two factors, temperature with four levels (40, 50, 60 and 70 °C), and agitation rate with 3 levels (150, 250 and 350 rpm); the response variables were density (as a measure of concentration) and crystal size distribution. The results allow to demonstrate that agitation rate does not exhibit a statistical effect on the MSZW for the crystallization of cane sugar, attributing the formation of nuclei and their growth to effects by changes in the temperature. This contributes to better understanding of the phenomenological behavior occurring in sugar cane crystallization.</p> K.B. Sánchez-Sánchez, E. Bolaños-Reynoso, J.M. Méndez-Contreras, R. Cerecero-Enriquez ##submission.copyrightStatement## Tue, 15 Oct 2019 00:00:00 +0000 Effect of spray-drying conditions on moisture content and particle size of coffee extract in a prototype dryer <p>In this study the effect of spray drying conditions on moisture content and particle size of coffee extract was researched. The factors investigated were the inlet temperature (150 to 220 °C), air flow (537 to 691 kg·h), and the frequency of the rotary atomizer (60 to 90 Hz). Analysis of variance revealed that the independent variables had significant effects (p&lt;0.10) on the response variables. An increase in frequency of the rotary atomizer from 60 Hz to 90 Hz produced an increase in outlet temperature; and therefore, a decrease in product moisture content. The luminosity of the powders increased as the inlet temperature and air flow increase from 145 °C to 220 °C and from 537 kg·h<sup>-1</sup> to 691 kg·h<sup>-1</sup>, respectively; therefore, the powder coffee turned brighter. A decrease in hysteresis was observed with an increase in the air flow rate from 537 to 691 kg·h.</p> J. Villegas-Santiago, F. Gómez-Navarro, A. Dominguez-Niño, M. A. García-Alvarado, M. A. Salgado-Cervantes, G. Luna-Solano ##submission.copyrightStatement## Thu, 24 Oct 2019 00:00:00 +0000 Room temperature biosynthesis of gold nanoparticles with Lycoris aurea leaf extract for the electrochemical determination of aspirin <p>Nanoparticle synthesis using plants is an alternative to conventional physical and chemical methods. In this paper, we demonstrate the synthesis of AuNPs using Lycoris aurea leaf extract. The prepared AuNPs show an average size of 24.1 nm based on TEM characterization. The biosynthesized AuNPs were then applied for electrode surface modification. The modified electrode was successfully used for the electrochemical determination of aspirin. The modified electrode could linearly detect aspirin from 100 μM to 2.6 mM with a limit of detection of 11.3 μM.</p> J. Ying, Y. Zheng, H. Zhang, L. Fu ##submission.copyrightStatement## Wed, 11 Sep 2019 04:23:11 +0000 Study of the corrosion inhibition of copper in synthetic seawater by Equisetum arvense as green corrosion inhibitor <p>Extract of the stems of <em>Equisetum arvense</em> was studied as a natural corrosion inhibitor (NCI) in synthetic seawater exposing samples of copper. To determine the protection of the metal by the NCI, electrochemical tests using potentiodynamic polarization curves, electrochemical impedance spectroscopy and linear polarization resistance were performed at room temperature. The morphological characterization of the material with and without NCI was carried out by scanning electron microscopy. The chemical composition of the NCI was determined by Fourier transform-infrared spectroscopy (FTIR) and gas chromatography coupled to mass spectrometry (GC-MS). The results showed that <em>Equisetum arvense</em> acts as a mixed-type NCI, achieving an inhibition efficiency of 53.78% when using 1000 ppm of NCI. From EIS the charge transfer resistance increased in the first 21 h, obtaining an inhibition efficiency of 87.5%. LPR results showed similar behavior than EIS at the same concentration. FTIR revealed that the chemical structure of the compounds of methanol extract of <em>Equisetum arvense</em> have functional groups such as: -OH, C-H, C=O and C-O, whereas GC-MS showed that eight compounds are present in the NCI.</p> A. Esquivel-López, C. Cuevas-Arteaga, M. G. Valladares-Cisneros ##submission.copyrightStatement## Wed, 02 Oct 2019 00:32:32 +0000 Composite material elaborated from conducting biopolymer cassava starch and polyaniline <p>This paper presents the preparation of a composite material synthesized from a conducting biopolymer of cassava starch and polyaniline. The composite material was made from the addition of aniline to the synthetic mixture of a conducting biopolymer of cassava starch with plasticizers (glycerol, glutaraldehyde and polyethylene glycol) and lithium perchlorate. The resulting composite material was a dark colored film with flexible and stable consistency. FTIR-ATR spectroscopy showed that there is a possible interaction by hydrogen bonds between the structures of the origin polymers, established between the OH groups of the starch and the NH group of the polyaniline. On the other hand, the electrochemical response of the composite material presented redox activity, with oxidation and reduction process well marked and intense in its signals. Additionally, the electrochemical signals of the composite material were stable when recording 50 consecutive cycles.</p> A.A. Arrieta-Almario, J. M. Mendoza-Fandiño, M. S. Palencia-Luna ##submission.copyrightStatement## Fri, 11 Oct 2019 00:00:00 +0000 Swirling fluidized bed plasma reactor for the preparation of supported nanoparticles <p>A swirling fluidized bed reactor design for the preparation of supported nanoparticles is reported. It uses a DC plasma torch that decomposes and vaporizes salt precursors; the cationic part condenses as metal nanoparticles on a powder support. Any fluidizable granular material can be used as support, as long as it withstands the temperatures of the plasma torch. The torch is located at the center of the reactor axis and the powder is fluidized using a cyclonic action (swirl) to minimize the space where the grains could come into direct contact with the plasma zone. The reactor was tested for silver nanoparticles (AgNPs) supported on silica-alumina, using silver nitrate as precursor. The results show large grains decorated with nano-sized metal particles. Depending on the load of silver nitrate, the size of the nanoparticles can range from 3 to 50 nm, as measured using transmission electron microscopy. They are in a non-oxidized state, as revealed with x-ray photoelectron spectroscopy. The AgNPs/SiO2–Al2O3 composite was tested as a catalyst in the hydrodesulphurization of dibenzothiophene. This method can be scaled up to produce large quantities of supported metallic particles. Its inherent simplicity, high processing speed and the low operating cost are its main advantages.</p> G. Soto, E. Pahuamba, F. Ramírez, J. Cruz-Reyes, M. del Valle, H. Tiznado ##submission.copyrightStatement## Wed, 06 Nov 2019 00:00:00 +0000 Improving platinum dispersion on SBA-15 by titania addition. <p>Pt (1 and 1.5 wt%) was impregnated on SBA-15 and corresponding Ti-modified composites at different TiO<sub>2</sub> contents (3, 5, 10 and 20 wt%). Materials were characterized by N<sub>2</sub> physisorption, X-ray diffraction, Fourier transformed infrared spectroscopy, scanning electron microscopy and transmission electron microscopy. SBA-15 had surface area greater than 800 m²/g that progressively decreased with increasing TiO<sub>2</sub> content in binary materials. Very different hydrolysis rate of Ti and Si alkoxides could provoke encapsulation of segregated titania domains in SBA-15 structure. Highly reactive titanium butoxide hydrolysis-condensation could take place before reactions corresponding to tetraethyl orthosilicate. Pt dispersion clearly augmented with Ti concentration in composites where numerous tiny noble metal particles were observed on titania domains surface. Also, corresponding pore size maxima shifted to lower diameters (as to that of non-impregnated supports) after platinum loading suggested metallic crystals inside pores of Ti-modified carriers. However, some large cubic platinum crystals were also observed suggesting &nbsp;sintering (during calcining at 500 °C) of metallic particles weakly interacting with SBA-15 component. After materials annealing under air metallic platinum was evidenced (by XRD) pointing out to noble metal reduction during decomposition of organics from Ti and Si alkoxides used during carriers synthesis which presence was ascertained by FTIR.</p> G. Morales-Hernández, J. G. Pacheco-Sosa, J. Escobar-Aguilar, J. G. Torres-Torres, H. Pérez-Vidal, M. A. Lunagómez-Rocha, D. De la Cruz-Romero, P. del Angel-Vicente ##submission.copyrightStatement## Wed, 18 Dec 2019 00:00:00 +0000 Potato starch-based films: Effects of glycerol and montmorillonite nanoclay concentration <p>The films can be obtained from renewable resources such as polysaccharides, proteins, and lipids. Potato starch is a polysaccharide found in abundance, low cost, biodegradable, edible, and can be obtained from agro-industrial waste. In the present study, biodegradable films were obtained from potato starch mixed with montmorillonite nanoclay (MMT) as crosslinking agent and glycerin as a plasticizer; and thus characterize properties such as: permeability to water vapor, solubility, thickness, functional groups by FTIR,&nbsp; analysis of the morphology by scanning electron microscopy (SEM), and mechanical properties. 9 mixtures combining different proportions of glycerol (1, 1.5 and 2 ml) with montmorillonite nanoclay (MMT) (0, 0.03 and 0.05 g) were prepared.</p> E. Medrano de Jara, E. García-Hernández, M.J. Quequezana-Bedregal, C.D. Arrieta-González, R. Salgado-Delgado, H. Lastarria-Tapia, J.A. Castañón-Vilca ##submission.copyrightStatement## Fri, 04 Oct 2019 03:26:35 +0000 Non-competitive L2/D control applied to continuous concentric tubes heat exchanges <p>L2/D proportional integral (PI) control was applied to continuous concentric tubes heat exchangers as example of space distributed parameter systems, both in SISO and MIMO structures. Dynamic model was expressed in continuous space state and leaded to demonstrate that L2/D control is a class of parametric geometric control. Results show that proposed control applied in heat exchangers, gives similar performance and robustness with less parameters than previous geometric controls reported in literature in SISO structures. The proposed L2/D PI control was easily extended to MIMO structure.</p> R. González-González, J. A. Flores-Márquez, E. López-Sanchez, G. C. Rodríguez-Jimenes, J. Carrillo-Ahumada, M. A Garcia-Alvarado ##submission.copyrightStatement## Wed, 11 Sep 2019 02:26:53 +0000 Sequential synthesis of PID controllers based on LQR method <p>The linear quadratic regulator (LQR) method is generalized to allow synthesis of PID controllers in MIMO processes. The proposed method is sequentially applied to produce proportional, integral and derivative actions. Three major usages are conceived for the proposed methodology: (i) &lt;&lt;de novo&gt;&gt; design of PID controllers, (ii) addition of derivative action to existing PI controllers and (iii) diagonalization of PID gain matrices. The two last procedures can be applied to controllers designed with different methodologies. The developed method was applied to the &lt;&lt;de novo&gt;&gt; design of a centralized PID controller for a three input-three output distillation column as well as the addition of derivative action to existing both centralized and multiloop PI controllers for a nonlinear CSTR. Proposed LQR method allowed the synthesis of centralized and multiloop PID controllers with better characteristics for set-point tracking, disturbance rejection, limited use of control signal and insensitivity to plant model uncertainty than those reported by other authors.</p> M. A. Hernández-Osorio, C. E. Ochoa-Velasco, M. A. García-Alvarado, A. Escobedo-Morales, I. I. Ruiz-López ##submission.copyrightStatement## Thu, 14 Nov 2019 00:00:00 +0000 Thermal study of a solar distiller using computational fluid dynamics (CFD) <p>Este estudio presenta el diseño, el modelado y el comportamiento de un destilador solar utilizando Computational Fluid Dynamics (CFD). Los parámetros medidos son: 1) el comportamiento de la temperatura interna, 2) la cantidad de cobertura y volumen generada después del proceso de destilación solar, 3) los coeficientes de transferencia obtenidos durante los meses de operación. Los principales resultados indican que el mes de mayo tiene la temperatura promedio más alta del agua en el interior con 44ºC y la mayor producción de agua destilada con un promedio de 1000 ml por día. El mismo mes tuvo un promedio de radiación global incidente por día de 5,8 kWh / m<sup>2</sup>, que es el más alto entre los meses de operación. Se aplica el modelo de Kumar y Tiwari para estudiar el comportamiento térmico del destilador solar. Para determinar la capacidad de beber del agua destilada, se realizaron los análisis de laboratorio y se encontró que el agua cumple con la norma NOM-127-SSA1-1994. Por lo tanto, el agua limpia se obtuvo al mismo tiempo del sistema diseñado en condiciones climáticas reales.</p> R.J. García-Chávez, A.U. Chávez-Ramirez, H.I. Villafán-Vidales, J.B. Velázquez-Fernández, I.P. Hernández Rosales ##submission.copyrightStatement## Tue, 08 Oct 2019 00:00:00 +0000 Effect of the sulfonated catalyst in obtaining biodiesel when used in a diesel engine with controlled tests . <p>The experimentally obtained biodiesel from used vegetable oil is used as an alternative energy source that has been synthesized from reactions directed by a solid acid catalyst. The solid acid catalyst was prepared by sulfonating rubber from rubber for used tires. For the realization and analysis of biodiesel tests in the internal combustion engine, an experimental design was applied in which the type of biofuel feed was used as the main control, namely pure commercial diesel (DIEP), a mixture of 50/50% biodiesel-diesel (MEBD) and pure biodiesel (BIOP). The performance values ​​and the emission and combustion characteristics of the fuel feed were investigated and compared under the same experimental conditions. During gas combustion, a considerable reduction of CO, unburned hydrocarbon and NOx emissions was achieved by using BIOP obtained in the laboratory compared to DIEP.</p> L. A. Sánchez-Olmos, M. Sánchez-Cárdenas, K. Sathish-Kumar, D. N. Tirado-González, V. A. Maldonado-Ruelas, R. A. Ortiz-Medina ##submission.copyrightStatement## Tue, 03 Dec 2019 00:00:00 +0000