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Parametric Analysis of a Mechanical Draft Cooling Tower using Two Mathematical Models

Journal of engineering Science and Technology Review 2021年第3期14卷 42-50页

作者： Obregon-Quiñones, Luis Guillermo Aristizábal-González, Cristian Alexis Caro-Candenazo, Miguel Antonio Research Group on Sustainable Chemical and Biochemical Processes Chemical Engineering Program Universidad del Atlántico Carrera 30 # 8-49 Puerto ColombiaAtlantico Colombia Department of Mathematics Universidad del Atlántico Carrera 30 # 8-49 Puerto ColombiaAtlantico Colombia

that determines the effect of the column cross-sectional area on multiple operating variables such as air humidity, air and water outlet temperature, among others. The computer code uses the Merkel's model and the CDAWC (Continuous Differential Air-Water Contactor) model for later comparison. It was observed a decrease in the outlet water temperature by approximately 14% when the tower's cross-sectional area increased from 1 to 2 m2. It increases the air outlet temperature by about 17% due to increased air-water contact. A negative convective heat transfer in the air was obtained in the cooling toweŕs bottom due to the large amount of energy required for the heat transfer by vaporization, which was much larger than the convective heat. The evaporative heat transfer is over 80% of the total heat transferred © 2021 School of Science, IHU. All rights reserved

关键词： Mass transfer

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Matlab-Based program for the Parametric Study of Piping Systems

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Journal of engineering Science and Technology Review 2023年第6期16卷 161-169页

作者： Carvajal, Diego Alexander Obregón, Luis Guillermo Candezano, M.A.C. Research Group on Sustainable Chemical and Biochemical Processes Chemical Engineering Program Universidad del Atlántico Carrera 30 # 8-49 Puerto Colombia Atlántico Colombia Department of Mathematics Universidad del Atlántico Carrera 30 # 8-49 Puerto Colombia Atlántico Colombia

Educative computational tools for education in chemical engineering has been increasing in the last decade due to the advance in technology. This branch of engineering has many subjects that make it difficult to have only one robust software that contains all the main subjects. It involves the creation of special programs dedicated to specific areas of study. One of the main subjects in chemical engineering programs is fluid mechanics. This study presents the application of a graphical user interface developed in Matlab for the study of piping systems where the flow rate, pump power, and pressure drops are determined as a function of the material, diameter, length, and elevation of the pipe, as well as the number and type of pipe couplings. The software is based on an algorithm that allows the solution of piping systems with elevation using energy balances, specific equations of fluid mechanics, and specific geometric parameters. Three relevant case studies were developed, showing the behavior of the energy expenses of the pumps. It was found an increase in the pump power from 91.4% to 3713.4% when a pipe diameter of 2 1/2 inches is increased from 20% to 60%. It was observed that the effect of the length of the pipe on the energy consumption of the pump is not significant for flows lower than 8 L/s. When the flow rate in the pipeline is 15 L/s and a change of pipeline is made from a 2-inch pipe - PVC schedule 40 to one of PVC schedule 80 of the same size, a 26.5% increase in pump power is needed. For steel pipes with schedule 40 and schedule 80, a rise of 30% and 67.8% was required, respectively. © 2023 School of Science, IHU. All rights reserved.

关键词： Polyvinyl chlorides

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Sensory profile estimation of yacon (Smallanthus sonchifolius) juice acidified with lactobionic acid: Combination of flash profile, E-nose and sensometrics: E-nose and Flash Profile Correlating Sensometrics of Yacon Juice

Food Chemistry Advances

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Food Chemistry Advances 2024年 4卷

作者： Marques, Caroline Toazza, Carlos Eduardo Bortolan Bona, Evandro Mitterer-Daltoé, Marina Leite Masson, Maria Lucia Department of Chemical Engineering Graduate Program in Food Engineering (PPGEAL) Federal University of Paraná Av. Francisco Heráclito dos Santos n. 100 PR Curitiba 81531-980 Brazil Department of Food Engineering Graduate Program in Food Technology (PPGTA) Federal University of Technology-Paraná Via Rosalina Maria dos Santos n. 1233 PR Campo Mourão 87301-899 Brazil Department of Chemistry Graduate Program in Chemical and Biochemical Technology Processes (PPGTP) Federal University of Technology-Paraná Km 01 PR Pato Branco 85503-390 Brazil

Yacon juice is a worthy alternative of a product able to keep all the benefits of the yacon roots. Lactobionic acid has been studied as a food functional acidifier, although still without permission to be applied in foods, cannot be sensory evaluated. Thus, the only approach to estimate a sensory profile of a lactobionic acid-added product is correlating sensory data with chemometric assessments. Sensory evaluation of yacon juice was performed with flash profile and its results were correlated with E-nose ones. Sensometrics showed a high similarity between yacon juice with lactobionic acid and tartaric acid regarding the volatile signals, and both raised the descriptors: Astringency, yellow color pearl-like, herbal, soy, cereal and leaf flavor, acid and bitter residual flavors. This study showed not just the potential of yacon juice as a new product, but also the suitability of combining flash profile and sensometrics to access a potential ingredient. © 2023 The Authors

关键词： Chemometrics Functional food GPA Lactobionic acid Product development

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Mixing of powders inside a cyclic shear mixing device: A parametric analysis

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Journal of engineering Science and Technology Review 2019年第4期12卷 1-6页

作者： Obregón, Luis Guillermo Valencia, Guillermo Eliecer Forero, Jorge Duarte Research Group on Sustainable Chemical and Biochemical Processes Chemical Engineering Program Universidad del Atlántico Barranquilla Colombia Efficient Energy Management Research Group Mechanical Engineering Program Universidad del Atlántico Barranquilla Colombia

Although the mixture of powders in recent years has been studied with great progress, there are still a lot of parameters to consider that make it difficult to have a complete understanding. In this work, powder mixing was studied inside a simple shear mixing device consisting of a small container with two moving walls and three static walls. The aim is to obtain a basic knowledge of the internal behavior of granular materials in the surface and the height direction of the device as a function of the particle size, filling level and disturbance of the wall velocity. Results reveal that on the surface of the cavity when velocities of the moving wall are about 9 cm/s two zones are created, a high-speed zone and a low-speed zone. The width of the high-speed zone of flow is approximately 9 to 11 times the average particle size. A difference in density of 0.1 g/cm3 has no significant effect on the movement of the particles from the bottom to the top. Reasons point out to the high shear stress applied by the moving walls. © 2019 School of Science, IHU.

关键词： Particle size

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Metabolic engineering of Yarrowia lipolytica for Enhanced Production of Naringenin-Derived Flavonoids: Apigenin and Acacetin

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Journal of agricultural and food chemistry 2025年第23期73卷 2025 May 29页

作者： Nahye Park Yangsub Ham Seungwoo Cha Byeongseon Jang Gyeongmin Kim Seung-Ho Baek Ji-Sook Hahn Interdisciplinary Program for Biochemical Engineering and Biotechnology Seoul National University 1 Gwanak-ro Gwanak-gu Seoul 08826 Republic of Korea. Department of Chemical and Biological Engineering Institute of Chemical Processes Seoul National University 1 Gwanak-ro Gwanak-gu Seoul 08826 Republic of Korea. Center for Bio-Based Chemistry Korea Research Institute of Chemical Technology (KRICT) Ulsan 44429 Republic of Korea.

Apigenin and acacetin are flavonoids with potent antioxidant, anti-inflammatory, and anticancer activities, making them attractive for pharmaceutical and nutraceutical applications. However, their low natural abundance presents a challenge to large-scale production. In this study, we engineered for the biosynthesis of apigenin and acacetin from naringenin. To enhance naringenin production from l-tyrosine, we introduced four heterologous genes, optimized the flux through the l-tyrosine pathway, and eliminated the competing homogentisate pathway. Malonyl-CoA availability was increased by downregulating (fatty acid synthase 1), while erythrose-4-phosphate levels were elevated through overexpression of (transketolase 1). Additionally, genes encoding flavone synthase and flavonoid 4'-O-methyltransferase were integrated to convert naringenin into apigenin, and subsequently apigenin into acacetin. Under fed-batch fermentation with an optimized carbon-to-nitrogen ratio, acacetin production reached 1.10 g/L─the highest titer reported to date in a microbial system. These results highlight as a promising chassis for scalable flavonoid biosynthesis.

关键词： Yarrowia lipolytica acacetin apigenin flavonoids naringenin

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Phenomenological modeling of polyols, citric acid and bio-oil concurrent production by Yarrowia lipolytica from glycerol

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Cleaner chemical engineering 2023年 5卷

作者： Ana Luiza B.M.A. Campos Felipe V. do Nascimento Argimiro R. Secchi Maria Alice Z. Coelho Chemical and Biochemical Process Engineering Program EPQB/EQ Universidade Federal do Rio de Janeiro PO Box 68502 ZIP 21941-972 Rio de Janeiro Brazil Biochemical Processes Technology Department Chemistry Institute Universidade do Estado do Rio de Janeiro Rio de Janeiro Brazil

biochemical routes have shown to be an interesting alternative for the reuse of glycerol, largely generated as a co-product in biodiesel production reaction. Previous works from the research group have demonstrated that glycerol can be efficiently assimilated by Yarrowia lipolytica to produce erythritol, mannitol, citric acid and bio-oil. To better understand the metabolic pathways involved, this work proposes a mathematical model to describe the observed phenomenon. This is the first computational work to model polyol's production and to address the simultaneous formation of four products by Yarrowia lipolytica . Particle Swarm Optimization and Interior Point Optimization were employed together to find the global optima. The developed model proved to be significantly promising and capable of satisfactorily predict the system's behavior in more than one experimental condition. Not only products’ concurrent formation was accurately described, but also polyols’ modeling was successfully performed, reaching R² values greater than 0.93.

关键词： Yarrowia lipolytica Erythritol Mannitol Biodiesel Particle swarm optimization Interior point optimization

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Forcing mass transfer approach in multicomponent miscible mixtures using the lattice Boltzmann method

arXiv

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arXiv 2025年

作者： Lourenço, Ramon G.C. Constantino, Pedro H. Tavares, Frederico W. Chemical Engineering Program PEQ/COPPE Federal University of Rio de Janeiro PO Box 68502 RJ Rio de Janeiro21941-972 Brazil Federal University of Rio de Janeiro P.O. Box 68542 RJ Rio de Janeiro21941-909 Brazil Program in Engineering of Chemical and Biochemical Processes EPQB Federal University of Rio de Janeiro P.O. Box 68542 RJ Rio de Janeiro21941-909 Brazil

While the lattice Boltzmann method (LBM) has proven robust in areas like general fluid dynamics, heat transfer, and multiphase modeling, its application to mass transfer has been limited. Current modeling strategies often oversimplify the complexities required for accurate and realistic mass transfer simulations in multicomponent miscible mixtures involving external forces. We propose a forcing approach within the explicit velocity-difference LBM framework to address these limitations. Our approach recovers the macroscopic mass conservation equations, the Navier-Stokes equation with external forcing term, and the full Maxwell-Stefan equation for ideal mixtures at low Knudsen numbers. A novel boundary scheme for impermeable solid walls is also suggested to ensure proper mass conservation while effectively managing the spatial interpolations required for multicomponent mixtures with varying molecular masses. We demonstrated the physical consistency and accuracy of the proposed forcing approach through simulations of the ultracentrifuge separation of uranium isotopes and the Loschmidt tube with gravitational effects. Our approach encompasses advanced modeling of species dynamics influenced by force fields, such as those encountered in geological CO$_2$ sequestration in aquifers and oil reservoirs under gravitational fields. © 2025, CC BY-NC-ND.

关键词： Petroleum reservoir evaluation

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Efficient ( S )-acetoin production in Saccharomyces cerevisiae by modulating α-acetolactate decarboxylase stereospecificity

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Bioresource Technology 2025年 434卷

作者： Seungwoo Cha Byeongseon Jang Daeyeol Lee Injae Cho Wooyoung Park Youngmin Lee Hyesoo Shin Minyoung Kim Changmin Sung Ji-Sook Hahn Department of Chemical and Biological Engineering Institute of Chemical Processes Seoul National University 1 Gwanak-ro Gwanak-gu Seoul 08826 Republic of Korea Doping Control Center Korean Institute of Science and Technology 5 Hwarang-ro 14-gil Seongbuk-gu Seoul 02792 Republic of Korea Interdisciplinary Program for Biochemical Engineering and Biotechnology Seoul National University 1 Gwanak-ro Gwanak-gu Seoul 08826 Republic of Korea

Acetoin, a four-carbon α-hydroxyketone with a chiral center, exists as two stereoisomers—( R )- and ( S )-acetoin—both of which hold potential pharmaceutical applications. While microbial production of ( R )-acetoin has been well studied, fermentative production of ( S )-acetoin remains limited due to its reliance on non-enzymatic spontaneous decarboxylation of unstable intermediates. As a result, costly precursors like diacetyl or 2,3-butanediol are often used, posing challenges for economic scale-up. In this study, we engineered Saccharomyces cerevisiae to produce stereospecific ( S )-acetoin directly from glucose, a low-cost and abundant carbon source. The native racemic acetoin pathway was eliminated by disrupting pyruvate decarboxylase (PDC) activity, and the stereospecificity of Bacillus subtilis α-acetolactate decarboxylase (ALDC), which naturally favors ( R )-acetoin, was engineered to preferentially produce ( S )-acetoin. Oxygen uptake was genetically enhanced to support efficient conversion of intermediates and suppress byproducts. This work established a novel, enzyme-driven pathway for ( S )-acetoin biosynthesis with over 90% enantiomeric purity, without the addition of chemical compounds.

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Trends in Membrane Distillation for Wastewater Treatment

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Journal of Environmental Protection 2021年第2期12卷 106-124页

作者： Graziela Salvan Cerveira Jorge Lima de Magalhães Adelaide Maria de S. Antunes Program of Engineering of Chemical and Biochemical Processes School of Chemistry Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil Instituto Nacional da Propriedade Industrial (INPI) Rio de Janeiro Brazil Professional Postgraduation Program in Management Research and Development in the Pharmaceutical Industry Centre for Technological Innovation/NIT-FAR Oswaldo Cruz Foundation/FIOCRUZ Ministry of Health Rio de Janeiro Brazil Global Health and Tropical Medicine (GHTM) Instituto de Higiene e Medicina Tropical (IHMT) University NOVA of Lisbon (UNL) Rua da Junqueira Lisbon Portugal

Membrane distillation (MD) is a promising technology that enables the treatment of high-salinity wastewater. To monitor the state and trends of MD technology for wastewater treatment, the patent filings from the last nine years were analyzed. A total of 72 documents with a special focus either on the membrane itself or on the equipment and process were found. China, United States and Japan play a leading role in the development of these technologies. Most of the inventions concentrating on the membrane apply polymers as the material. Inventions describing the equipment and process are mainly related to system and module design, but also cover the combination of MD with other technologies, the treatment customization to a specific type of wastewater, fouling control and cleaning, and energy recovery. Finally, enhancements in water flux and energy efficiency are found to be key factors to broaden the application of MD technology in wastewater treatment.

关键词： Membrane Distillation Patents Trends Wastewater

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Comparative study of mixing liquids and powders in a continuous medium using CFD

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Journal of engineering Science and Technology Review 2018年第5期11卷 134-138页

作者： Enamorado, Alberto Mario Fuentes Betancourt, Juan Bernardo Restrepo Obregon, Luis Guillermo Research Group in Process Simulation and Coal Transformation Chemical Engineering Program Universidad del Atlántico Barranquilla Colombia Research Group on Sustainable Chemical and Biochemical Processes Chemical Engineering Program Universidad del Atlántico Barranquilla Colombia

Prediction of flow and mixing of powders is a difficult challenge that has not been solved yet. Different numerical methods have been used to find the solution to the mathematical models proposed, but there are no experiments to compare and validate the results. The method with the best approximation is the discrete element method (DEM). However, this method requires a high computational power. In this article, it was made a comparison between the experimental results obtained when mixing two powders in an oscillatory low shear mixing device, and the 3D simulation of the same equipment using liquids with the help of a commercial software of computational fluids dynamics, CFD. Experiments at different wall velocities and wall displacements were run. Results reveal that the mixing in solids and liquids present lots of similarities when working at low velocity. This velocity lets solids to stay in frictional regime and liquids in the laminar regime. A zone of no mixing at the bottom of the mixing cavity is presented in liquids which is similar to the triangular pattern of no mixing found in solids. The height of the no mixing zone depends on the time of mixing, and the displacement and velocity of the walls. Under laminar regime conditions, the Navier Stokes equations can be applied to the powders because the velocity profiles obtained are similar. © 2018 Eastern Macedonia and Thrace Institute of Technology.

关键词： Shear stress

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