Revista Mexicana de Ingeniería Química <div class="_4wyf">The Mexican Journal of Chemical Engineering &nbsp;(ISSN 1665-2738,&nbsp; issn-e: 2395-8472) 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) Fri, 08 Jan 2021 00:00:00 +0000 OJS 60 Evaluation of the hydroconversion reactions of Jatropha curcas L. oil on hydrodesulfuration catalysts <p><em>This work evaluated the activity of two commercial catalysts Ni-Mo/Al<sub>2</sub>O<sub>3</sub> and Co-Mo/Al<sub>2</sub>O<sub>3</sub> for the hydrodesulfurization process (HDS) developed by the Mexican Petroleum Institute (IMP). The process is performed on Jatropha curcas oil, due to its excellent flow properties at room temperature, allowing its mixing with commercial hydrocarbon cuts. Catalysts have the characteristic of the hydrodeoxygenation reactions of fatty acids present in J. curcas vegetable oil for the generation of chemically similar hydrocarbons to those of fossil origin. </em></p> <p><em>The following conditions were evaluated: pressure of 145 -400 psia, temperature from 300 to 390 °C and residence times of 0.5 and 2.0 min (WHSH -60 h<sup>-1</sup> and 30 h<sup>-1</sup>). HDS process activity with pure J. curcas oil and 20% mixture with n-hexadecano as a model molecule of HDS hydrocarbons. The Ni-Mo/Al<sub>2</sub>O<sub>3</sub>-type catalyst showed increased conversion of triglycerides and fatty acids to linear-chain hydrocarbons, being greater than 85%, compared to the Co-Mo/Al<sub>2</sub>O<sub>3</sub>-based catalyst, which had a conversion of close to 82%. Catalytic activity was also observed to be very temperature-dependent.</em></p> <p>&nbsp;</p> J. García-Dávila, E. Ortega-Sánchez, F.S. Sandoval-Sosa, J. Dinorín-Tellez, L. Sánchez-Minutti, A.L. Martinez-Ayala ##submission.copyrightStatement## Fri, 31 Jul 2020 22:54:08 +0000 Partial recovery of MRJP1 protein expressed in Pichia pastoris using chromatographic techniques <p>Major Royal Jelly Protein 1 (MRJP1) is the main protein component of the bee-produced complex mixture royal jelly, which is the only nutrient source for queen bees promoting increased lifespan, body size and fertility. Recombinant production of MRJP1 represents an alternative to direct extraction from royal jelly. Production in <em>Pichia pastoris</em> results in high density biomass, with a supernatant containing high amount of impurities. Various methods have been applied to recover and/or purify MRJP1. Here, exploiting the physicochemical properties of MRJP1, reverse phase chromatography (RPC), size exclusion chromatography (SEC) and ion-exchange chromatography (IEX) were investigated as alternative methods to recover MRJP1 directly from supernatant. All techniques showed a 57-kDa band in SDS-PAGE analysis, corresponding to the size of recombinant MRJP1, with contaminants attributed to culture media. However, SEC coupled to IEX evidenced a single peak in the chromatogram corresponding to MRJP1 which suggest it may be a good protocol to recover recombinant MRJP1 from <em>P. pastoris</em> supernatant. This approach serves as a procedure to identify MRJP1 in fermentation culture of <em>P. pastoris</em>. This is the first report about characterization of IEX-based recovery of recombinant <em>Apis mellifera</em> MRJP1 produced in <em>Pichia pastoris </em>without the use of histidine tags.</p> A. Robles-Zamora, D. Enriquez-Ochoa, M. Ureña-Herrera, J.M. Aguilar-Yañez, M.E.G. Brunck, K. Mayolo-Deloisa ##submission.copyrightStatement## Mon, 03 Aug 2020 21:18:42 +0000 Comparative and combinatorial study of Biogenic Bismuth nanoparticles with Silver Nanoparticles and Doxycycline against Multidrug Resistant Staphylococcus aureus BTCB02 and Salmonella typhi BTCB06 <p>At the present time world is facing a turmoil due to emergence of diseases caused by antibiotic resistant pathogens. The current need is to find alternative ways of curing diseases led by these pathogens. In this context the current study was steered towards finding the potential of extracellularly synthesized biogenic bismuth nanoparticles BiNPs in combination with biogenic silver nanoparticles AgNPs and doxycycline hydrochloride against multidrug resistant pathogens. MIC value for BiNPs was 6 and 10mg/l and for biogenic AgNPs it was 16 and 18ug/l against <em>Salmonella typhi</em> BTCB06 and <em>Staphylococcus aureus</em> BTCB02, respectively. Whereas combination of BiNPs and doxycycline MIC was 3 and 5mg/l and for BiNPs and AgNPs it was 8 and 9ug/l for <em>S. typhi</em> and <em>S. aureus, </em>respectively. FICI value for the combination of BiNPs and Doxycycline was 0.75 against <em>Salmonella typhi</em> and <em>Staphylococcus aureus</em>, respectively. However the combination of AgNPs and BiNPs had FICI value 1 against both the test strains. Bismuth nanoparticles and doxycycline showed synergistic effect against both pathogens. BiNPs and AgNPs showed additive effect against both pathogens. Conclusively, biogenic BiNPs can be used as an excellent alternative alone or in combination in combating diseases caused by resistant pathogens.</p> S. Iftikhar, M. Iqtedar, H. Saeed, M. Aftab, R. Abdullah, A. Kaleem, F. Aslam ##submission.copyrightStatement## Thu, 01 Oct 2020 05:10:46 +0000 Effect of Vitreoscilla hemoglobin on recombinant protein expression and energy and redox state of CHO cells <p><em>Vitreoscilla</em> hemoglobin (VHb) expression confers considerable improvements to microbial cell factories. However, the effect of VHb on animal cells has been scarcely studied. To gain insight about the impact of VHb on aerobic energy metabolism and recombinant protein expression, CHO-K1 cells stably expressing the green fluorescent protein (GFP) were obtained and transfected for VHb expression. GFP expression slightly increased, whereas cell viability and the mitochondrial membrane potential were not affected by VHb expression. In contrast, the NAD<sup>+</sup>/NADH ratio and ATP cell content tended to decrease, while the NADP<sup>+</sup>/NADPH ratio increased as a consequence of VHb presence. These results suggest that VHb can improve recombinant protein expression in CHO cells by altering the energy metabolism. This can be useful for the design of robust cell factories for industrial applications.</p> M. Juárez, C.H. González de la Rosa, J.C. Sigala Alanis, A.R. Lara-Rodríguez ##submission.copyrightStatement## Tue, 06 Oct 2020 03:27:30 +0000 Biodegradation of cocoa shell by phytopatogenic fungi for Pleurotus ostreatus production <p>Three treatments based on spores <em>Colletotrichum gloeosporioides</em> (B1), spores <em>Rhizopus stolonifer</em> (B2) and a mixture of spores <em>Colletotrichum gloeosporioides</em> + <em>Rhizopus stolonifer</em> (B3) to increase the degradation of the cocoa shell. Using the treatment (B1) was obtained the highest degradation of the cocoa shell being of 57.18%, and the leachates production was of 84 mL with pH of 4.10. <em>Pleurotus ostreatus </em>strain (UE01) was cultivated using a mixture of wheat straw with cocoa shell degraded (without or with the 3 treatments), and the productivity and chemical composition of the mushrooms were determined. <em>Pleurotus ostreatus</em> strain (UE01) cultivated on the mixture of wheat straw with cocoa shell degraded with the treatment (B2) showed the highest biological efficiency (124.15 %) and the highest production rate (2.71 %), while the fruit bodies obtained in this mixture exhibited the highest protein content being of 27.84%, and lowest carbohydrate content being of 63.83%. The solutions with <em>Colletotrichum gloeosporioides</em> and <em>Rhizopus stolonifer</em> can be used for the farmers to improve the degradation of cocoa shell and increase the production of <em>Pleurotus ostreatus</em> mushrooms with highest protein content.</p> J.D. Valenzuela-Cobos, R. Lazo-Sulca, D. Noriega-Verdugo, M. Garcés, A. Grijalva-Endara ##submission.copyrightStatement## Sun, 08 Nov 2020 19:12:59 +0000 Integral valorization from industrial Persian lime processing wastes (Citrus latifolia Tanaka): simultaneous recovery of oils and antioxidants <p>Mexico´s Persian lime production in 2019 was close to 1.3 million of tons, inferring an approximately 390,000 tons of peel residues during its processing. This residues presents an interesting opportunity for obtaining value-added products, mainly due to its composition, formed principally by water, soluble sugars, fiber, organic acids, fatty acids, minerals, essential oils, flavonoids, and vitamins. Despite this, the valorisation of this residual biomass has been almost completely ignored. In this paper, the residual peel was analyzed in order to determine its biotechnological potential, for this, different oil extraction methods were compared, the fatty acids profile was determined, also characterization and the antioxidant potential of the defatted residues were evaluated. The results showed that the principal fatty acids present in the oil extracted were Palmitic, Oleic and Linoleic, which allows its use for food and bioenergy purposes, moreover, the defatted residual biomass characterization presents a chemical composition which allows the use for as livestock, biogas production or agronomy. To our knowledge, this is the first report of antioxidant activity from defatted Persian lime residual biomass, wherein, the residues generated by steam distillation showed the bigger amount of phenolic compounds, but the obtained from hexane extraction presents a higher antioxidant activity.</p> D.L. Ambriz-Pérez, I.Y. Palomares-Ruíz, F.J. Gómez-Córdoba, N.Y. Mejias-Brizuela, N. Araiza-Lizarde, D.U. Santos-Ballardo ##submission.copyrightStatement## Mon, 09 Nov 2020 06:25:19 +0000 Agave salmiana syrup improves the production of recombinant human interleukin-2 in Escherichia coli <p>The expression of heterologous proteins in <em>Escherichia coli </em>is strongly affected by the type of carbon source used. In this work, the expression of a synthetic codon-optimized gene of human interleukin-2 in <em>E. coli</em> BL21-SI, carrying plasmid pET12a-hIL2 is presented. Glucose, fructose or Agave syrup from <em>Agave salmiana,</em> were used as carbon sources for production of recombinant human IL-2 (rhIL-2) in 1.5-L bioreactor aerobic cultures using mineral medium. Codon optimization of the native <em>hIL-2</em> gene eliminated the presence of 35 rare codons for <em>E. coli</em>, and improved the codon usage up to 76% compared with the native gene sequence. Cultures using 10 g/L glucose showed the lowest production of rhIL-2, and in contrast, cultures using fructose improved the production of rhIL-2 1.9-times. The utilization of fructose from Agave syrup enhanced the rhIL-2 production 3.9-times, reaching 103.42±6.61 mg<sub>IL-2</sub>/L. The specific rhIL-2 production rate (5.52±0.33 mg<sub>IL-2</sub>/g<sub>DCW</sub>·h) using Agave syrup was also the highest. These results indicate that Agave syrup stimulates the production of rhIL-2 and it is an inexpensive alternative carbon source. This research abilities the potential use the Agaves to produce alternative and valuable biotechnological products instead the alcoholic beverages.</p> V.E. Balderas-Hernández, E. Medina-Rivero, A.P. Barba-De la Rosa, Dr., A. De León-Rodríguez ##submission.copyrightStatement## Thu, 19 Nov 2020 05:56:10 +0000 Removal of heterocyclic compound carbazole using cell immobilization of Thalassospira profundimaris strain M02 <p>Cell immobilization offers promising potential to maximize microbial biodegradation activity and overcome limitations involved in bioremediation. <em>Thalassospira profundimaris</em> strain M02 was used to determine the effectiveness of cell immobilization for carbazole biodegradation. Effects of different matrices, effective diffusivity, mechanical strength, matrix concentration, cell mass load and reusability were investigated in this study. Results revealed that calcium alginate (Ca-Al) was better compared to gellan gum as higher carbazole biodegradation rate was observed. Diffusion analysis and mechanical strength analyses also revealed that Ca-Al possessed superior characteristics as immobilization matrix for carbazole biodegradation compared to gellan gum. Ca-Al works best at 4% (w/v) with 1.25 g of cell mass loading. In addition, immobilized strain M02 retained carbazole biodegradation activity after 6 cycles of usage.</p> I.M. Maliki, N.H. Abdul-Manas, S.A. Ahmad, H. Fuse, N. Ramírez-Moreno, A. Zulkharnain ##submission.copyrightStatement## Wed, 02 Dec 2020 04:12:25 +0000 Molecular docking of oxidases from Pleurotus ostreatus and the activity of those produced by ARS 3526 strain grown in both, submerged and solid-state fermentations <p><em>Pleurotus ostreatus </em>is a basidiomycete fungus capable of producing oxidases involved in the degradation of lignin, such as laccase (Lac), manganese peroxidase (MnP), versatile peroxidase (VP), veratryl alcohol oxidase (VAO) and dye-decolorizing peroxidase (DyP). In this research, the molecular docking showed that the interaction between Mn-ion, ABTS or DMP ligand with the respective oxidases studied were strongly supported by exposed GLU and ASP charged residues H-bonded or hydrophobic-bonded, in most of the complexes, mainly GLU and ASP played a very important role in the union, especially in the presence of the Mn-ion. On the other hand, the growth and activity of such enzymes of <em>Pleurotus ostreatus</em> ARS 3526 grown in both, submerged fermentation (SmF) and solid-state fermentation (SSF) were evaluated. The specific growth rate in SSF was 2.5 times higher than in SmF. The values of activity of Lac, VP and DyP were higher in the SSF, of the VAO activity was similar in both fermentation systems and SmF had the higher MnP activity value in comparison with SSF. This study provides evidence of the enzymatic potential of this fungus and shows the similarities in charged amino acids when used in their catalytic interactions, and the intimate relationship between the enzyme and its substrate.</p> L.D. Herrera-Zúñiga, M. González-Palma, G. Díaz-Godínez, D. Martínez-Carrera, C. Sánchez, R. Díaz ##submission.copyrightStatement## Sun, 13 Dec 2020 00:00:00 +0000 Kinetic parameters of Lactobacillus plantarum and Saccharomyces boulardii growing in a beet molasses culture media <p>Regular consumption of probiotic microorganisms as part of the diet can contribute to improving health and mitigating the effects of metabolic syndrome diseases. Then, it is essential to design production processes for this type of microorganisms, which are optimal from the point of view of production time and cost. This paper presents a study of the effect of using a low-cost culture medium, formulated with beet molasses, which manages to enhance the growth of two types of probiotic microorganisms, <em>Saccharomyces boulardii,</em> and <em>Lactobacillus plantarum</em>. In addition to its effect on cellular biomass growth, a kinetic model for both strains growth is also presented. This model includes factors such as the <em>S. boulardii</em> capability to hydrolyze saccharose into their respective monosaccharides and the inhibition effect of lactic acid production on <em>L. plantarum</em> growth. Finally, a mixed culture production scheme is proposed for both microorganisms, in order to take advantage of the yeast's capability to hydrolyze saccharose, in order not to require the addition of extra glucose to the culture medium.</p> C. González-Figueredo, O.A. Rojas-Rejón, A. Martínez-Vera-Negrete, A.E. Carranza-Volquarts, F.J. Estrada-Girón, J.C. Peña-Partida ##submission.copyrightStatement## Wed, 23 Dec 2020 06:41:19 +0000 Flavonoids activity determination of ginkgo sample using electrochemical method <p>The determination of flavonoids activity is very important for drug effect evaluation. In this work, we proposed an advanced hydrogel based electrochemical approach for the quick determination flavonoids activity in plant extract. Zinc ions and chitosan have been used as raw materials for hydrogel synthesis. Then, the presence of the hydroxy radicals can initiate the depolymerization process. The presence of the flavonoids can delay the depolymerization and consequently used for determining their activity. We used ginkgo leaf extract as an example, demonstrated the successful preparation of the hydrogel platform and showed potential application in flavonoids activity determination.</p> P. Zheng, B. Wang, Y. Huang, H. Huang ##submission.copyrightStatement## Thu, 30 Apr 2020 00:00:00 +0000 Biofunctional characterization of red, black and white ginseng (Panax ginseng Meyer) root extracts <p>An organized biofunctional characterization of red, black, and white ginseng root extracts and fractions was performed. To assess antioxidant, antiglycation, enzyme inhibitory, antiamnestic, cytotoxic, thrombolytic, antibiofilm potentials in roots of three <em>Panax ginseng</em> preparations (red, black, white), powdered material was extracted and fractionated into different solvents. Antioxidant activity, phenolic and flavonoids contents were assessed by using free radical scavenging, Folin–Ciocalteu reagent and aluminum chloride colorimetric assays. Antiglycation and enzyme (alpha amylase, alpha glucosidase and acetylcholinesterse) inhibition activities were tested by prescribed methods along with cytotoxic (antihemolytic profile), thrombolytic activity, and biofilm growth inhibition assays. Red and black ginseng indicated maximum phenolic contents (37.26 ± 1.563 g GAE) and flavonoid contents (149.4 ± 2.032 g CE) respectively. The DPPH scavenging ability (62.84%) of red ginseng was higher than black and white ginseng. Significant antidiabetic activities were exhibited by black and white ginseng. The highest antihemolytic (71.2%) and thrombolytic (87%) actions were shown by black and red ginseng respectively. Red and white ginseng maximally inhibited the growth of <em>Pasteurella multocida</em> while in the case of <em>Staphylococcus aureus</em>, red ginseng showed optimum antibiofilm activity. The present study demonstrates that all three preparations of <em>P. ginseng </em>have effective yet variable functional characteristics that warrant further exploration.</p> F. Hussain, A. Akram, J. Hafeez, M. Shahid ##submission.copyrightStatement## Wed, 12 Aug 2020 00:00:00 +0000 Isolation of autochthonous microorganisms to formulate a defined inoculum for small-scale cocoa fermentation <p>In cocoa fermentation exists a wide microbial diversity; the most important microorganisms are yeasts, lactic acid bacteria (LAB), and acetic acid bacteria (AAB). Such diversity can result that fermented cocoa quality is not always the same. The use of microbial consortia can steer the process, allowing the production of fermented cocoa beans with homogeneous quality and safety. For that reason, it was proposed to use indigenous microorganisms to formulate defined inoculums to conduct the small- fermentation of Mexican cocoa. A total of 54 strains were isolated from the spontaneous fermentation of cocoa. These included yeasts (<em>Candida</em>, <em>Rhodotorula</em>, <em>Saccharomyces</em> and <em>Yarrowia</em>), LAB (<em>Lactobacillus</em> and <em>Lactococcus</em>), and AAB (<em>Acetobacter</em> and <em>Gluconobacte</em>r). The cocoa fermentations were inoculated with an inoculum composed of lipolytic <em>Yarrowia</em>, <em>Lactococcus lactis</em>, and <em>Acetobacter aceti</em>, only varying the form of inoculation (mixed or microbial succession) and were compared with spontaneous fermentation. It was observed that fermentation conducted by succession inoculation form showed similar behavior to the spontaneous process, obtaining well-fermented cocoa beans with homogeneous quality and safety.</p> <p>&nbsp;</p> J.A. Huerta-Conde, S. Schorr-Galindo, C. Figueroa-Hernández, Z.J. Hernández-Estrada, M.L. Suárez-Quiroz, O. González-Ríos ##submission.copyrightStatement## Tue, 15 Sep 2020 00:00:00 +0000 Growth kinetic model, antioxidant and hypoglycemic effects at different temperatures of potential probiotic Lactobacillus spp <p>The effect of fermentation temperature (32, 37 and 42 °C) on the growth and <em>in vitro</em> antioxidant and hypoglycemic activity of <em>Lactobacillus plantarum, L. pentosus and L. acidipiscis </em>isolated from Chiapas cheese previously characterized as potential probiotics, were evaluated in the present research. The Unified-Gompertz method was used to model the bacterial growth of the strains (R&gt;0.987). Similar biomass production was obtained at the end of 32 °C and 37°C. The maximum absolute growth rate was 0.526 h<sup>-1</sup> for <em>L. acidipiscis </em>at 37°C. The antioxidant activity resulted maximum in DPPH at 32°C and 14 h in <em>L. pentosus </em>(7402.62 ± 318.52 μM Trolox/mL<em>) </em>and in ABTS at 32 °C and 24 h in <em>L. acidipiscis (</em>1612.94 ± 56.71 μM Trolox/mL).The inhibition of α-amylase (%) and α-glucosidase (%) resulted maximum at 37 °C and 24 h for <em>L. acidipiscis </em>(97.084 ± 0.752 and 99.756 ± 0.104, respectively). These results concluded that the three strains could be considered mesophilic and with antioxidant and hypoglycemic activity. Moreover, <em>L. acidipiscis</em> gave the best results in all the experiments done. So, more research should be done with this strain to better stablish its potential health benefits</p> A. Andrade-Velasques, L. Dominguez-Cañedo, G. Melgar-Lalanne ##submission.copyrightStatement## Mon, 27 Apr 2020 16:24:45 +0000 ACE- Inhibitory and metal-binding activity produced during milk fermentation by three probiotic potential LAB strains isolated from Chiapas double cream cheese <p>Some probiotic lactic acid bacteria could generate bioactive peptides during milk fermentation. The aim of this work was to evaluate the ACE inhibitory and mineral-binding (calcium and iron) activity during milk fermentation by three probiotic LAB strains (<em>Lactobacillus plantarum</em>, <em>Lb. pentosus</em> and <em>Lb. acidipiscis</em>) as well as mixed fermentation.&nbsp; These strains were previously isolated from Chiapas double cream cheese. The fermentation that showed the highest microbial growth was performed by <em>Lb. plantarum</em>, followed by mixed fermentation and <em>Lb. acidipiscis</em>. However, the mixed fermentation had higher proteolysis. Milk fermentations performed with <em>Lb. acidispiscis</em>, <em>Lb. pentosus</em> and mixed showed high ACE-inhibitory activity (97%). The <em>Lb. plantarum</em> and mixed fermentations showed the higher iron-binding activity, 99 % and 97, respectively, whereas the <em>Lb. acidipiscis </em>and mixed fermentations had the highest calcium-binding activity. These results showed that probiotic microorganisms isolated from double cream cheese have great potential to be used in the production of functional foods.</p> H. Hern´andez-Sánchez, F.S. Fajardo-Espinoza, G.F. Gutiérrez-López, S.V. Ávila-Reyes, C. Cano-Sarmiento, C.Y. Figueroa-Hernández ##submission.copyrightStatement## Fri, 15 May 2020 15:08:16 +0000 Effect of potassium sorbate as an interface agent in biodegradable bi-layers polymers <p>Studies that are focused on the design and development of biodegradable materials with promising physicochemical properties for industrial use have been of great importance. In this research, bilayer materials were developed using TPS monolayers assembled with monolayers sheets of amorphous polylactic acid (PLA<sub>a</sub>) and polycaprolactone (PCL). Potassium sorbate was evaluated as an interfacial adhesion material. Structural properties of the laminated materials (FTIR and SEM), behaviour with water (rate of water vapour transmission, solubility in water and moisture content) and biodegradation of the materials were evaluated. Physical and chemical interactions between the studied monolayers by the addition of potassium sorbate were found. The use of monolayer sheets of PLA<sub>a</sub> and PCL overcomes the disadvantages of the materials obtained from starch. A practical alternative was developed to obtain materials with better properties. Besides, the degradation time of TPS was evaluated and compared with other polymers. These laminated materials are a great alternative to the decrease in the use of conventional plastics and are applicable as packaging in the food industry.</p> A. Díaz-Pedraza, Y. Piñeros-Castro, R. Ortega-Toro ##submission.copyrightStatement## Sat, 24 Oct 2020 17:55:13 +0000 Changes in the physicochemical, rheological, biological, and sensorial properties of habanero chili pastes affected by ripening stage, natural preservative and thermal processing <p>Physicochemical and rheological properties, total phenolic content (TPC), capsaicinoids identification and quantification, antioxidant activity (AA) and sensorial analysis were determined on two ripening stages of habanero (<em>Capsicum chinense </em>Jacq.) pepper pastes added with lemon essential oil (LEO) as natural preservative and subjected to thermal process. Rheological parameters indicated that habanero chili pastes with orange ripening stage and thermal processing presented the higher consistency coefficient, flow index, and viscoelastic (G´ and G´´) behavior values. The addition of LEO favored the increment of TPC and AA, as well as color preservation. Thermal processing potentiated total capsaicinoid content (TCC), TPC, and AA, but affected the color characteristics. The combination of LEO and thermal processing significantly affect the sensorial attributes in two of the three sensorial tests performed. These results suggested that apart from sensorial perception, the natural preservative LEO and the thermal processing improved physicochemical and rheological properties as well as biological activity of habanero pastes of the two ripening stage increasing habanero pepper quality and marketing possibilities.</p> N. Medina-Torres, J.C. Cuevas-Bernardino, T. Ayora-Talavera, J.A. Patrón-Vázquez, I. Rodríguez-Buenfil, N. Pacheco ##submission.copyrightStatement## Wed, 02 Sep 2020 00:00:00 +0000 Influence of retinyl palmitate on nucleation and growth kinetics in batch sugarcane crystallization <p>The influence of retinyl palmitate (RP) on nucleation and growth kinetics, in the sugarcane fortification process, is analyzed.&nbsp; Batch cooling crystallization experiments using natural and linear profiles were carried out adding different amounts of RP. At each experiment, sugar concentration, crystal mass and crystal size distribution were measured as a function of time. Nucleation and growth rates were determined experimentally and kinetic parameters were determined using power-law type relations. At the end of each experiment, crystals were observed in microscope and morphological changes were analyzed. The results showed that the presence of RP in the fortification process of sugar generated a decrease in both nucleation and growth rates. The decrement was bigger when the initial concentration of RP increased. Moreover, it was observed that fortified crystals suffer morphological changes into their habit.</p> P.A. Quintana-Hernández, X.M. Medina-Galván, D. Maldonado-Caraza, J.N. Reyes-Valadez ##submission.copyrightStatement## Wed, 19 Aug 2020 00:00:00 +0000 Analysis of the MK brick kiln thermal behavior <p><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">Resumen: </span></span></span></span><br><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">El horno MK2 es una alternativa reciente y relevante para la cocción artesanal de ladrillos rojos porque considera una opción ecológica. </span></span></span><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">Por lo tanto, se ha llevado a cabo una investigación del comportamiento térmico de un proceso de cocción de horno MK. </span></span></span><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">Se realizó una quema experimental de ladrillos en las condiciones que normalmente maneja el productor de ladrillos. </span></span></span><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">Se obtuvieron perfiles de temperatura, un balance de calorías y pruebas de compresión para obtener una mejor comprensión del comportamiento térmico del horno. </span></span></span><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">Los perfiles de temperatura detallan las temperaturas alcanzadas en cada zona dentro del horno y la uniformidad de la temperatura dentro de la cámara.</span></span></span><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">El balance de calor muestra la cantidad de energía requerida para elevar la temperatura de los ladrillos, las pérdidas de calor a través de las paredes y en los gases de combustión. </span></span></span><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">También se analiza la influencia de la temperatura alcanzada por los ladrillos en la resistencia a la compresión. </span></span></span><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">información requerida para determinar la cantidad de ladrillos que realmente requieren con la especificación marcada en el estándar aplicable para resistencia a la compresión. </span></span></span><span style="vertical-align: inherit;"><span style="vertical-align: inherit;"><span style="vertical-align: inherit;">Finalmente, se necesita un diseño MK-n para evaluar el número óptimo de cámaras necesarias para minimizar las pérdidas de calor.</span></span></span></span></p> J. Lara-Mireles, S. Alonso-Romero, E. Fías-Chimal, R. Zitzumbo-Guzmán, J. del Real Olvera, L. Hernández-Mena ##submission.copyrightStatement## Fri, 09 Oct 2020 22:58:12 +0000 Cd (II) and Pb (II) biosorption in aqueous solutions using agricultural residues of Phaseolus vulgaris L.: Optimization, kinetics, isotherms and desorption <p>Industrial activities are the most common cause of water contamination by heavy metals, which endanger the quality of water resources and human health, due to their bioaccumulation capacity and consequent biomagnification. For this reason, the removal of metals from effluents before their discharge into the receiving water bodies is of crucial importance. This is why, in the present investigation, the biosorption processes of Cd (II) and Pb (II) in <em>Phaseolus vulgaris L.</em> (bean) agricultural residues (stems, leaves and leaf sheaths) were optimized. The influence of pH, biosorbent doses and initial concentration levels of metallic ions was evaluated using the response surface methodology (RSM). Quadratic models were developed for the percent removal of Cd (II) and Pb (II). Optimal biosorption conditions were attained at pH = 4.3, a 7.4 g/L biosorbent dose and an initial 9.14 mg/L concentration of each metal, achieving percent removals of 87.70 and 95.58% for Cd (II) and Pb (II), respectively. The FT-IR characterization showed that the functional groups involved in adsorption would be in the range of 2300 to 2400 cm<sup>-1</sup>. The biosorption kinetics were described by the pseudo first order model and the equilibrium data was adjusted to the Freundlich isotherm. An approximate desorption of 98% of Cd (II) and Pb (II) was achieved. The <em>Phaseolus vulgaris L.</em> residue showed a great biosorption capacity of Cd (II) and Pb (II) simultaneously.</p> B.M. Salazar-Pinto, V. Zea-Linares, J.A. Villanueva-Salas, E.G. Gonzales-Condori ##submission.copyrightStatement## Wed, 14 Oct 2020 22:56:34 +0000 Comparative study of selective zinc leaching from EAFD using carboxylic agents <p>Recycling of industrial waste has become a process of highly positive impact on the environment, industry and human health. The management of the electric arc furnace dust (EAFD) is a necessary and interesting task due to the possible recovery of its elevated metallic content (Zn, Pb, Cu, etc.). This reduces the environmental pollution generated by the leachability of its heavy metals and produces new revenues for the steel industries. In this work, a hydrometallurgical route was studied to extract the zinc present in EAFD.&nbsp; The research carried out using two carboxylic acids: sodium citrate and oxalic acid at moderate concentrations (≤ 0.5 M). The effect of pH, molar concentration and stirring speed was analyzed. Under pressure and ambient temperature, after 3 h of leaching, the results showed that both agents can leach zinc from waste, reaching metal extractions of approximately 50%. The more stable franklinite (ZnFe<sub>2</sub>O<sub>4</sub>) and hematite (Fe<sub>2</sub>O<sub>3</sub>) phases were not decomposed under these mild conditions. Citrate was especially promising due to its selectivity for zinc.</p> J. Borda, R. Torres ##submission.copyrightStatement## Tue, 10 Nov 2020 17:31:01 +0000 Degradation of sucralose present in Splenda sweetener by TiO2 photocatalysis assisted with photo-Fenton <p>The pollutant legislation and its ecotoxicological dates recognize several water pollutants. However, there are others that have not yet been recognized as emerging organic pollutants because the damage that could be caused to the environment, especially in the water, is still unknown. For example, it is interesting to pay attention on Splenda because is increasingly consumed worldwide today. Splenda is one of the emerging pollutants that has not yet been formally declared as a pollutant, but there are some findings that show Splenda as a water pollutant, specifically the sucralose molecule, due to persistence in the environment. In this work, the mineralization of Splenda, in different initial concentrations (72 mg l<sup>-1</sup>, 144&nbsp;mg l<sup>-1</sup> and 288 mg l<sup>-1</sup>), was carried out by TiO<sub>2</sub> photocatalysis assisted with photo-Fenton. Splenda mineralization is less than 58% by these processes when used separately; however, Splenda was mineralized 62.8% (72 mg l<sup>-1</sup>), 83.7% (144 mg l<sup>-1</sup>) and 58.8% (288 mg l<sup>-1</sup>) by TiO<sub>2</sub> photocatalysis assisted with photo-Fenton at 2 h, 5 h and 5 h, respectively. In all cases, the mineralization followed a pseudo-first-order reaction.</p> A. Sandoval-González, A. Álvarez-Gallegos, J.A. Hernández, S. Silva-Martínez ##submission.copyrightStatement## Tue, 22 Sep 2020 00:00:00 +0000 Characterization of slug flow in heavy oil and gas mixtures <p><em>In the process of engineering, where flows in two phases are involved, one of the most recurring flow patterns is called a slug. Its characterization is essential to predict the drop pressure and liquid holdup. To analyze it &nbsp;̶&nbsp; among other experimental techniques &nbsp;̶ &nbsp;capacitive or inductive sensors are used to transform the liquid-gas fraction present in the pipeline to a voltage time-series. The method chosen for the signal processing is decisive for the correct estimation of the frequency and the fraction of the slug, among other parameters. Recently, analysis methodologies have been developed that reduce the subjectivity of signal processing, and tend to improve the quality of the results. This paper optimization to an algorithm based on probabilistic methods. The methodology proposed against the original was compared, ̶ from experimental data of upward slug flow in inclined pipes ̶ finding that with the optimization there is better performance when working at inclination angles close to the vertical; the above suggests a combined use of both methods.</em></p> C.A. Carcaño-Silvan, G. Soto-Cortés, F. Rivera-Trejo ##submission.copyrightStatement## Sat, 04 Apr 2020 19:01:42 +0000 Historical analysis of accidents in the Mexican chemical industry <p>An analysis of accidents that occurred mainly in the chemical industry within the Mexican Republic throughout the last century was made. The country's industrial growth has boosted its economic development, increasing the occurrence of high-impact accidents inside and outside chemical plants. The main purpose of this work was to create a database that contained information related to the accidents that occurred in the Mexican chemical industry. For this extensive investigation, it was necessary to obtain information from news, reports and articles related to this topic. In the database, 267 accidents were collected from 1900 until 2019. A statistical analysis showed that Petroleos Mexicanos, PEMEX, is the company with the highest accidents rate, because this company was a monopoly in the Mexican petrochemical industry until 2013. The types of accidents that occurred the most were explosions and fires, 122 and 55 of these reported accidents, respectively. The most frequently reported substances were diesel and gasoline with a 20% of the total accidents, followed by hydrocarbons and their derivatives with 18.7%. Finally, the importance of creating databases like this one is remarked, with the objective of implementing better safety measures and improving the regulations that govern the nation.</p> A. Palacios, C. Mata, C. Barraza ##submission.copyrightStatement## Thu, 21 May 2020 00:00:00 +0000 Effect of antiscalants and operating variables on the performance of desalination by direct contact membrane distillation (DCMD) <p>The effect of hydrodynamic conditions (feed and permeate flow rates) and the action of six different types of antiscalants on desalination of seawater from the Gulf of Mexico by direct contact membrane distillation (DCMD) was studied. The effect of feed temperature during the DCMD process was also evaluated on performance of two microfiltration membranes (0.5 µm) having different thickness (300 and 250 µm). Results showed more than 100 % increments on water vapor flux by raising feed temperature from 50 to 70 <sup>o</sup>C and feed flow rates up to 7 L·min<sup>-1</sup>. No significant effect on process performance was determined by raising permeate flow rates in the range tested. Choosing the type and concentration of antiscalants is critical during seawater desalination by DCMD. Performance of this process increased by up to 49.2 % during desalination of real seawater by adding the KMRO S-516 antiscalant designed to disperse iron, silica and calcium carbonate salts. During DCMD no important water vapor flux decay and no increase on conductivity of the distillate was observed by antiscalants’ dosage. In addition, scanning electron microscopy (SEM) from the membrane surface after DCMD desalination of seawater treated with the KMRO S-516 antiscalant confirmed the absence of scaling.</p> A.L. Peñaranda-López, B. Torrestiana-Sánchez ##submission.copyrightStatement## Sun, 25 Oct 2020 00:00:00 +0000 Green synthesis of silver nanoparticles using the aqueous extract of Larrea tridentate and Eucalyptus <p>In this paper, we report the synthesis of silver nanoparticles (AgNPs) using AgNO<sub>3</sub> as a precursor salt and the aqueous extracts of Eucalyptus and Larrea tridentate as reducing agents for the metal salt and stabilizing agents of the nanoparticles obtained. A solution of 25 ml of 0.1 M AgNO<sub>3</sub> was prepared to which 10 ml of the extract was added, the reaction was kept under stirring at 50 °C for 24 hours.&nbsp; The extracts obtained were analyzed by the HPLC-Ms technique, to know the compounds and families that contain the aqueous extracts and identify the functional groups responsible for the reduction of Ag<sup>+</sup> ions.&nbsp;This information was of great relevance to propose a reaction mechanism for the synthesis of nanoparticles. On the other hand, by means of DRX the obtaining of the AgNPs was confirmed because the results showed a crystalline nature in the cubic structure centered on the face corresponding to the silver, in addition to the Uv-vis spectroscopy the surface plasmon resonance was observed in the characteristic 430-450 nm range of these nanoparticles, the presence of functional groups on the surface of the nanoparticles was confirmed by infrared spectroscopy, and by SEM a quasi-spherical morphology and average sizes of 20-100 nm were observed using the extract of Eucalyptus and 20-60 nm with Larrea tridentate extract.</p> <p>&nbsp;</p> K.C. Córdova-Cisneros, A. Sáenz-Galindo, J.A. Ascacio-Valdés, R.I. Narro-Cespedes, A. Castañeda-Facio ##submission.copyrightStatement## Mon, 13 Apr 2020 00:23:20 +0000 Effect of the concentration of glycerin in the performance of chitosan membranes utilized in aqueous phase permeation <p>We have carried out the synthesis of a series of chitosan-based membranes by casting solution method. The membranes were synthesized from commercial chitosan and glycerin as a plasticizer, varying the concentration of glycerin to determine the concentration that allows the formation of membranes with the best physicochemical properties to retentate permeating test molecules. Formed membranes were cross-linked with sulfuric acid, and tested in the permeation of sodium chloride, saccharose and a whey protein. The physicochemical characteristics of the membrane were evaluated by the water swelling factor, viscous molecular weight and DSC. The passage of the tested molecules through the membrane and other characteristics were modified with glycerin content in the forming solution.</p> J.A. Galicia-Aguilar, M. López-Badillo, M.A. García-Castro, J.L. Varela-Caselis, C. Solís-Martínez, J. Ortega-Pérez ##submission.copyrightStatement## Sat, 02 May 2020 21:17:53 +0000 Cobalt and copper nanoparticles on partially reduced graphene oxide interlayer spacing carbon nanotubes or carbon black as catalysts for oxygen reduction reaction <p>In this paper, we reported the synthesis of Co and Cu nanoparticles (NPs) supported on partially reduced graphene oxide (M/rGO), with the incorporation of spacers as multi-walled carbon nanotubes (MWCNT) and carbon black (CB) among graphene interlayers to generate carbon nanocomposites. The oxygen reduction reaction (ORR) polarization curves show that the use of MWCNT as spacer improves the current density up to 6.9 times for Co NPs and up to 3.5 times for Cu NPs materials. Also, the charge transfer resistance decreases using CB: 950 times for Co NPs and 68 for Cu NPs materials. All carbon-nanocomposites present upgraded stability comparing to the commercial platinum catalyst (Pt/C).</p> Y.Y. Rivera-Lugo, C. Silva-Carrillo, B. Trujillo-Navarrete, E.A. Reynoso-Soto, T. Romero-Castañón, S.W. Lin-Ho, J.C. Calva-Yañez, F. Paraguay-Delgado, R.M. Félix-Navarro ##submission.copyrightStatement## Fri, 05 Jun 2020 00:00:00 +0000 Purification of agave fiber by a hydrothermal method <p>The bagasse of agave <em>tequilana Weber</em> is a lignocellulosic waste generated by the tequila production process. Purification of agave fiber was carried out by evaluating the effect of temperature and reaction time on the hydrothermal process. Hydrolysis was carried out in a high pressure digester, temperature 140°C, the process was standardized using 3.5 g of fiber previously dried, a solution of 0.5 M nitric acid (HNO<sub>3</sub>) in deionized water and reaction time of 6 h, the developed pressure inside the system caused the release of organic material such as hemicellulose and lignin from the cellulose microfiber grid that forms the structure of agave bagasse. Overall, a yield of 326 g/kg dry matter was obtained; equivalent to 48% of the theoretical value, this method is a promising alternative to treat this type of waste.</p> S.J. Guevara-Martínez, M.C. Chávez-Parga, J. Espino-Valencia, M. Arroyo-Albiter ##submission.copyrightStatement## Tue, 20 Oct 2020 02:06:41 +0000 Application of FESEM and FTIR for evaluation of Staphylococcus aureus biofilms grown on chitin and polycarbonate membrane <p><em>The aim of this study was to use Field Emission Scanning Electron (FESEM) and Fourier transform infrared spectroscopy (FTIR), to investigate the structure and the film-forming capacity of Staphylococcus aureus, on two different surface materials, Chitin and Polycarbonate membrane filter. Both the substrates, having diverse properties, showed varied attachments of bacterial and biofilm development. FESEM showed that higher bacterial colonization and biofilm growth was obtained in the rough surface of chitin with complex structure, compared to that of polycarbonate membrane at different time intervals. Due to its high magnification and resolution, FESEM enabled a more detailed analysis of the biofilm cells, influenced by different structural organisations and morphology.&nbsp; On the other hand, FTIR analyses revealed the chemical conformation of the substrate and its biofilm state. However, the difference in the spectra of the two substrates was not large. Prominent band absorbance at 1200-800 cm<sup>-1</sup> for polysaccharides and proteins at 1700- 1400 cm<sup>-1</sup> were observed at its biofilm states. These findings promote the prospect of using FESEM and FTIR for understanding biofilm morphology and architecture, as well as its chemical interaction with the substrate.</em></p> R. Baishya, R. Chatterjee, S. Banerjee, M.S. Hasnain ##submission.copyrightStatement## Wed, 23 Dec 2020 06:32:13 +0000 Effect of the manufacturing parameters on the quality of the ceramic thermal barrier coating after ageing by thermal treatment <p>Ceramic coatings of zirconium oxide (ZrO<sub>2</sub>) were prepared and stabilized with yttrium oxide (7-8 wt% Y<sub>2</sub>O<sub>3</sub>) by plasma-aided thermal projection (APS), at different injection distance and carrier gas flow conditions. Ageing thermal treatments were performed to know the corresponding effects on the quality and performance of the thermal barrier. Determination of layer thickness of the thermal barrier, evolution of the thermally grown oxide (TGO) layer and the evaluation of the mechanical properties through nanoindentation was carried out by the micro-structural study. Results shown out that the effect of the projection distance is not significant. However, a significant effect of the gas flow, namely, the lower the flow is, the higher the thickness of the ceramic layer. Apparently, the layers coatings micro-structure is not significantly altered (the form of the splats) due to the increase in the treatment time, but the distribution of the defects and the exogenous particles (pollutants) presented clear shifts. Consequently, a decrease for the values of the mechanical properties of the layers which produce the thermal barrier was observed; also, thickness of the TGO layer was increased because of the thermal treatment time. During undertaken studies, the TGO layer never exceed the critical limit.</p> S. Bravo, J. Torres-González, J. Morales-Hernández, E. Martínez-Franco, J.C. González-Olvera, F.E. Mercader-Trejo, A. Rodríguez-López, A. Manzano-Ramírez, A. Esparza, R. Herrera-Basurto ##submission.copyrightStatement## Tue, 15 Sep 2020 00:00:00 +0000 1-D coordination polymer with helical chirality in octacyanomolybdate (V)- and Nd(III)-based: Synthesis, structure, and Hirshfeld surface analyses <p>A new one-dimensional cyanide-based coordination polymer consisting of octacyanomolybdate(V) and Nd(III) has been synthesized and characterized through a single-crystal X-ray and elemental analysis. The compound consists of one-dimensional chains single strand chiral helix of [(Terpy)(DMF)<sub>3</sub>(MeOH)Nd-CN-Mo(CN)<sub>7</sub>] (NdMo-1) (Terpy is 2,2′:6′,2′′-terpyridine, DMF is dimethylformamide), where each Mo(CN)<sub>8 </sub>entity acts as a two-monodentate bridging ligand towards two Nd(III) ions through two of its eight cyanide groups in cis positions, respectively, in an alternating fashion. Corresponding chains are connected utilizing hydrogen bond interactions to form a three-dimensional supramolecular structure that stabilizes the whole molecule. These interactions have been validated using the Hirshfeld surface analysis.</p> M. Muddassir ##submission.copyrightStatement## Mon, 27 Apr 2020 15:59:23 +0000 Rice flour-based films: effects of type and solvent and plasticizer concentration <p>The use of rice flour as a polymer matrix for the development of biodegradable films is an economical alternative to the use of rice starch. In this work, the comparison of the type of solvent was evaluated in films made with rice flour using glycerol as a plasticizer (0.75, 1, 1.25, 1.5, 1.75 and 2 ml) and the substitution of water with 0.5N acetic acid as solvent by the casting method; For this, the response of the characteristics of thickness, solubility, water vapor permeability, FTIR, Scanning Electron Microscopy (SEM) and mechanical tests were evaluated. Noting that using acetic acid as a solvent favorably influences the characteristics of the films obtained, however, the concentration of glycerol from 50% w/w in relation to the mass of rice flour, generates a similar behavior for both solvents.</p> M.J. Quequezana-Bedregal, K.A. Castillo-Rosales, E. Medrano de Jara, Z. Vargas-Galarza, H. Lastarria-Tapia, J. Castañón-Vilca, E. García-Hernández ##submission.copyrightStatement## Wed, 21 Oct 2020 00:54:03 +0000 Application of modified vegetable oil for improvement of biodegradable materials based on thermoplastic starch and polylactic acid <p><em>Currently, it is a challenge for academia and industry to develop materials capable of replacing conventional petroleum-derived polymers. The objective of the present study was to evaluate the physicochemical and morphological properties of biodegradable materials obtained from thermoplastic yam starch (TPS), and polylactic acid (PLA) improved with the addition of epoxidized sesame oil (ESO). The blends were made by extrusion, and the films were made by compression moulding. The interaction with water, mechanical properties and structural properties were studied. As a result, the addition the ESO on the TPS / PLA polymeric matrix caused a decrease in moisture content, surface wettability and lower permeability to water vapour. Furthermore, when adding ESO at 3%, elastic modulus and the tensile strength increased approximately double and the deformation capacity for the mixtures without ESO by more than 70%. Regarding structural properties, the addition of ESO promoted the formation of a TPS / PLA interface without marked separation and smoother surfaces. The materials obtained show promising properties for the development of food packaging with low moisture content.</em></p> M. Bohórquez-Ayala, D. Rojano-Quiroz, R. González-Cuello, L. García-Zapateiro, R. Ortega-Toro ##submission.copyrightStatement## Fri, 11 Dec 2020 16:29:57 +0000 The role of alkoxysilanes functional groups for surface modification of TiO2 nanoparticles on non-isothermal crystallization of isotactic polypropylene composites <p><em>Functionalization of fillers provides advantages in non-isothermal crystallization of isotactic polypropylene (iPP); therefore, kinetic properties iPP composites filled with alkoxysilane-functionalized titanium dioxide (TiO<sub>2</sub>) were investigated to understand the role of functional groups. The surface modification of TiO<sub>2</sub> nanoparticle was carried out with three different alkoxysilanes: 3-aminopropyltrimethoxysilane (APTMS), 3-chloropropyltrimethoxysilane (CPTMS) and 3-glycidoxypropyltrimethoxysilane (GPTMS); after, composites were prepared 0.5% by weight in iPP. The results of the X-Ray Diffraction and Nuclear magnetic resonance analyses showed the characteristic signals of each chemical species that confirm the success of surface modification of the oxide with alkoxysilanes. The study by Differential scanning calorimetry at different cooling rates allowed to observe that the non-isothermal crystallization of iPP composites is described by Jeziorny’s and Mo’s equations; and that the addition of fillers of TiO<sub>2</sub>&nbsp;modified with the alkoxysilanes changed the crystallization process thanks to the functional groups and their interface interactions with the polymer matrix; for example, the presence of CPTMS and GPTMS caused recrystallization of iPP and therefore, increased the crystallization process rate. Finally, the activation energy of the composites varied depending on the alkoxysilane used, since less energy was needed for some cases; derived from better dispersion and that the particles acted as nucleation centers.</em></p> J.A. González-Calderón, M. Peña-Juárez, R. Zarraga, D. Contreras-López, J. Vallejo-Montesinos ##submission.copyrightStatement## Fri, 18 Dec 2020 18:21:29 +0000 Effect of silicon dots into coconut fibers on the nucleating capacity of β-crystals of polypropylene <p>Three concentrations of sodium hydroxide (3, 5, and 7% based on a composition by weight) and 2 reaction times (1 and 4 h) were used to treat coconut fiber. According to the results, the inclusion of treated fiber in polymer influenced the melting temperature of the composite incremented it to 165°C, which is attributable to the a-crystal melting; however, the introduction of the untreated fiber interrupts the crystallinity sequence for a-crystallinity and favors the formation of the b-crystals. The X-ray diffraction analysis confirmed that pristine coconut fiber can be an efficient β-nucleating agent when it is used with no alkaline treatment, indicating that its b-nucleating capability is related to the presence of silicon dots on the fiber surface. In terms of mechanical behavior, the untreated fiber composites presented the highest value in storage modulus (4260 MPa) compared to pure polypropylene; and the presence of a higher content of β-crystals in the polymer matrix gave an improvement of 82%. The results suggest that a high formation of β-crystals in polypropylene matrices reinforced with coconut fiber occurs when a previous alkaline treatment is not used.</p> M. del Angel-Monroy, V. Escobar-Barrios, M.G. Peña-Juarez, R. Camarena-Rangel, I. Montes-Zavala, J.A. Gonzalez-Calderon, E. Perez ##submission.copyrightStatement## Fri, 25 Dec 2020 17:57:27 +0000 Concentration estimation and fault tolerant control in a CSTR modelled as a quasi linear parameter varying system <p>A design of a product concentration estimation and a Fault Tolerant Control (FTC) strategy for compensate an&nbsp;actuator fault in a Continuous Stirred Tank Reactor (CSTR) are developed in this paper. Second and third-order&nbsp;CSTR systems are considered to validate the proposed FTC scheme. Furthermore, a comparison between nonlinear,&nbsp;linear and quasi Linear Parameter Varying (qLPV) models for both CSTR systems are presented. The results&nbsp;demonstrate that the qLPV representation reproduce the nonlinear, in the selected segment, better than the linear&nbsp;model. Then, a Proportional-IntegralObserver (PIO) is designed using the qLPV representation in order to estimate&nbsp;the states and the actuator fault presented in the process. These estimations are used by the FTC system for compute&nbsp;a new control law using a Linear Matrix Inequality (LMI) to ensure the stability of both the qLPV PIO and the&nbsp;FTC law. Thus, the main contributions of this work are four: i) to propose a new representation of the second and&nbsp;three-order CSTR nonlinear model by means of a qLPV system, preserving the nonlinear dynamics of the original&nbsp;nonlinear model, ii) to exploit the easiness to extend theoretical results that originally were conceived for linear&nbsp;systems, to qLPV systems, iii) to estimate the product concentration in order to generate a new FTC law, and iv) to&nbsp;validate in simulation the FTC scheme to reduce the effect of an actuator fault in a CSTR process.</p> G. Ortiz-Torres, J.Y. Rumbo-Morales, F.D.J. Sorcia-Vázquez, A.F. Pérez-Vidal, A. Cruz-Rojas, J.A. Brizuela-Mendoza, E. Oceguera-Contreras ##submission.copyrightStatement## Wed, 20 May 2020 00:00:00 +0000 The Multi alcohols continuous unit for biodiesel production: Design and automation <p><em>In this paper, the evaluation and implementation of a control grid for a continuous biodiesel production plant was carried out using a layout that allows the use of ethyl alcohol (C<sub>2</sub>H<sub>5</sub>OH) and methyl alcohol (CH<sub>3</sub>OH), and a capacity of 100 L/h. First, the production system was divided into 8 subsystems, in order to identify and detail all the sub-processes that happen in the plant during the production of biodiesel. Then, it was developed careful studies of the systems and identification of the processing steps that demand a greater need for automation, using applied control strategies according to the specific need of each one, such as: feedback, on-off, ratio and proportion, split rang, and cascade. Thus, utilizing PFD (Process Flow Diagram) and P&amp;ID (Piping and Instrumentation Diagram), it was possible to obtain a control loop capable of integrating the entire plant, aiming at greater stability of all process variables, which in turn result in a better functioning of the plant, as well as a final product capable of meeting the most varied quality standards, from different raw materials.</em></p> R. Pessoa-e-Silva, L. Moura-Andrade, F.A. Silva-Mota, W.F. Alencar-Borges ##submission.copyrightStatement## Fri, 25 Dec 2020 17:45:50 +0000 Using artificial neural networks in prediction of the drying process of foods that are rich in sugars <p>The production of powder which comes from dehydration sugar-rich foods (SRF), has great economic potential. However, the concentration of the different types of sugar that the SRF consist of varies, this presents problems in the drying process. drying carrying agents are used, nevertheless there isn't an exact dosage for all the SRF. Artificial Neural Networks or (ANN) recently became one of the most efficient empirical methods used to predict and model such systems, especially non-linear systems, Therefore the main objective for this work, was to develop a mathematical model of inverse propagation ANN throughout predicting the spray drying of the SRF, we took 6 input variables Mdx, F, G, S, T and OA and took 6 output as well H, Tg, °BX, HI, WA, R. The selected ANN model was (10-16-14-10) was compared with experimental data done by orthogonal regression which shows that the PMSSRF) model is an efficient model to predict the spray drying of the SRF and therefore the number the amount of experimental testing has been reduced replacing in this way the traditional, trial and error methodologies used, by using the tool development.</p> E. Figueroa-Garcia, V.S. Farias-Cervantes, M. Segura-Castruita, I. Andrade-Gonzalez, M.I. Montero-Cortés, A.M. Chávez-Rodríguez ##submission.copyrightStatement## Mon, 03 Aug 2020 00:00:00 +0000 Analysis of gasification and tar reforming with in-situ generated char and steam <p class="Els-footnote" style="margin-bottom: 12.0pt; text-align: left; text-indent: 0cm; line-height: normal;" align="left"><span lang="EN-US" style="font-size: 11.0pt;">Biomass gasification has an overwhelming potential to satisfy the world’s energy needs. However, the technology is constrained by the formation of tars and the costs associated to their eradication. However, moisture, an intrinsic part of biomass, and char, a regular product from gasification, can contribute to tar removal via steam reforming. This work presents an analysis, based on numerical simulations, to elaborate a concept where the steam and char released from gasification are used to reform the produced tars. Results indicate that when the amount of moisture in wood biomass is 8% or more, at adequate temperatures (around 1073 K) the produced steam volume meets the necessary criteria for char catalytic tar reforming. On the side of char, calculations indicate that more than double the char necessary to achieve 0.5 seconds residence time in a bed is produced during each run. Moreover, it was found that moisture in biomass leads to increases in the Lower Heating Value of the produced gas and decreases in the tar contents. Based on theoretical calculations, the concept appears promising and should be subject to experimentation.</span></p> C.A. Duarte-Ruiz, D.A. Buentello-Montoya ##submission.copyrightStatement## Tue, 15 Sep 2020 00:00:00 +0000