Records Added in November 2020
Records added in November 2020
Change year: 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024
Change month: January | February | March | April | May | June | July | August | September | October | November | December
Showing records 1 to 25 of 92. [First] Page: 1 2 3 4 Last
LAPSE Stakeholder Report 2020
LAPSE Interessenter Rapport 2020
Thomas A Adams II
November 30, 2020 (v1)
Subject: Other
Keywords: LAPSE, Stakeholder Report
This is the LAPSE stakeholder report for 2020, including news, interesting statistics, new features, and the plan for the next year.
Dette er det LAPSE interessenter rapport for 2020, inkludert nyheter, interessant statistikk, nye funksjoner, og planen for neste år.
Cooling Performance Analysis of the Lab-Scale Hybrid Oyster Refrigeration System
Xuejun Qian, Yulai Yang, Seong W. Lee, Marc J. L. Caballes, Oludayo S. Alamu
November 24, 2020 (v1)
Keywords: air circulation, cabinet, compartment, cooling performance, cooling process, hybrid, oyster, refrigeration system, temperature distribution
Compared with the waste-to-heat and electricity-based hybrid refrigeration system, the innovative lab-scale refrigeration system integrated with the DC and AC cooling units that able to use solar and electricity as energy resources. Previous studies found that temperature control and uniform temperature distribution in refrigeration systems are both critical factors reducing vibrio growth on raw oysters and saving energy consumption. Therefore, this refrigeration system also equipped a specially designed divider and was used to test various air circulation strategies to achieve uniform temperature distribution in six individual compartments. The objective is to investigate and evaluate the effects of air circulation strategies and operating conditions on the cooling performance, including temperature distribution, standard deviation of compartment temperatures, and cooling time using a factorial design method. Results indicated the maximum temperature difference between the compartment... [more]
Intensive Multiple Sequential Batch Simultaneous Saccharification and Cultivation of Kluyveromyces marxianus SS106 Thermotolerant Yeast Strain for Single-Step Ethanol Fermentation from Raw Cassava Starch
Kwanruthai Malairuang, Morakot Krajang, Rapeepong Rotsattarat, Saethawat Chamsart
November 24, 2020 (v1)
Keywords: ethanol production, intensive multiple sequential batch cultivation, Kluyveromyces marxianus, simultaneous saccharification and cultivation (SSC), thermotolerant yeast
We developed the intensive multiple sequential batch simultaneous saccharification and cultivation of the selected thermotolerant yeast strain for single-step ethanol production. The selection and high-cell-density inoculum production of thermotolerant yeast able to produce ethanol under the optimal conditions for single-step ethanol fermentation has become a necessity. In this study, the newly isolated Kluyveromyces marxianus SS106 could tolerate high temperatures (35−45 °C) and grow under a wide range of pH values (3.0−5.5), which are the optimum conditions of raw cassava starch hydrolyzing enzyme used in single-step ethanol fermentation. The high-cell-density concentration of K. marxianus SS106 was produced by a single batch and an intensive multiple sequential batch process in a 5-L stirred tank bioreactor using the simultaneous saccharification and cultivation (SSC) method. The single SSC process yielded the yeast cell biomass at a concentration of 39.30 g/L with a productivity of... [more]
Preparation of Long-Term Antibacterial SiO2-Cinnamaldehyde Microcapsule via Sol-Gel Approach as a Functional Additive for PBAT Film
Yangfan Xu, Chongxing Huang, Xiujie Dang, Muhammad Rafiullah Khan, Haohe Huang, Yuan Zhao, Shuangfei Wang
November 24, 2020 (v1)
Subject: Materials
Keywords: antibacterial materials, cinnamaldehyde, composite film, PBAT
The mesoporous silica wall materials can achieve controlled load and sustained-release of active agents. An antimicrobial nanoscale silica microcapsule containing cinnamaldehyde (CA) was prepared by the sol-gel method and applied in poly (butyleneadipate-co-terephthalate) (PBAT) film. The surface morphology, physical and chemical properties, and antibacterial properties of microcapsules and films were studied. The effects of different temperatures and humidities on the release behavior of microcapsules were also evaluated. Results showed that CA was successfully encapsulated in silica microcapsule which had a diameter of 450−700 nm. The antibacterial CA agent had a long-lasting release time under lower temperature and relative humidity (RH) environment. At low temperature (4 °C), the microcapsules released CA 32.35% in the first 18 h, and then slowly released to 56.08% in 216 h; however, the microcapsules released more than 70% in 18 h at 40 °C. At low humidity (50%RH), the release rat... [more]
Contact Time of Double-Droplet Impacting Superhydrophobic Surfaces with Different Macrotextures
Dian-Ji Lin, Ling-Zhe Zhang, Meng-Chao Yi, Xin Wang, Shu-Rong Gao, Yan-Ru Yang, Shao-Fei Zheng, Xiao-Dong Wang
November 24, 2020 (v1)
Subject: Other
Keywords: contact time, double-droplet, impact, macrotexture, superhydrophobic surface
The contact time of droplets on superhydrophobic surfaces is an especially important parameter in many applications, such as self-cleaning, anti-icing, and spray cooling. In this study, we investigate the contact time of two identical droplets simultaneously impacting superhydrophobic surfaces decorated with three different macrotextures, i.e., bathtub-like groove (S1), vertical wall (S2), and rectangular ridge (S3), via lattice Boltzmann method (LBM) simulations. We explore influences of the geometrical parameters of the macrotextures, as well as the center-to-center distance of the two droplets, on the contact time. We found a new rebounding regime with significantly reduced contact times. We demonstrate that, as compared with impacting a smooth superhydrophobic surface, the contact time can be decreased by 41% for macrotexture S1 because of the asymmetric spreading and retraction of droplets motivated by the macrotexture. We also demonstrate that the new regime depends on the center... [more]
Decoupling Adaptive Smith Prediction Model of Flatness Closed-Loop Control and Its Application
Mingming Song, Hongmin Liu, Yanghuan Xu, Dongcheng Wang, Yangyang Huang
November 24, 2020 (v1)
Keywords: adaptive Smith, cold rolling, dynamic decoupling, flatness control, pure time-delay
Flatness control system is characterized by multi-parameters, strong coupling, pure time delay, which complicate the establishment of an accurate mathematical model. Therefore, a control scheme that combines dynamic decoupling, PI (Proportion and Integral) control and adaptive Smith predictive compensation is proposed. To this end, a dynamic matrix is used to decouple the control system. A multivariable coupled pure time-delay system is transformed into several independent generalized single-loop pure time-delay systems. Then, a PI-adaptive Smith predictive controller is constructed for the decoupled generalized single-loop pure time-delay system. Simulations show that the scheme has a simple and feasible structure, and good control performance. When the mathematical model of the control system is inaccurate, the control performance of adaptive Smith control method is evidently better than that of the ordinary Smith control method. The model is successfully applied to the cold rolling... [more]
Quantum Chemical Study on the Influence of Dodecyl Trimethyl Ammonium Bromide on the CH4 Adsorption of Coal
Shuo Liu, Jiaxing Gao, Yibo Tang, Junfeng Wang, Shaocheng Ge
November 24, 2020 (v1)
Keywords: adsorption energies, CH4 adsorption, density functional theory, quantum chemistry
The adsorption of dodecyl trimethyl ammonium bromide (DTAB) on coal can affect the wettability of coal and change the water absorption of coal. After DTAB treatment, the change in the CH4 adsorption capacity of coal is worth further study. To reveal the microscopic mechanism of the influence of DTAB on the CH4 adsorption capacity of coal, we employed the density functional theory (DFT) with the 6-311 G (d, p) basis set. DFT-based computations interpreted the adsorption process of CH4 and DTAB on coal molecules and determined the stable structure, adsorption distance, Mulliken overlapping populations, and adsorption energies of the two adsorption configurations. The results showed that the adsorption energies of CH4 and DTAB on the molecular model of coal were 2.15 and 42.69 kJ/mol and the adsorption stability distances were 0.261 and 0.238 nm, respectively. The DTAB−coal configuration was more stable than the CH4−coal configuration. When there was competitive adsorption between DTAB an... [more]
Effects of Mercury II on Cupriavidus metallidurans Strain MSR33 during Mercury Bioremediation under Aerobic and Anaerobic Conditions
Guillermo Bravo, Paulina Vega-Celedón, Juan Carlos Gentina, Michael Seeger
November 24, 2020 (v1)
Subject: Biosystems
Keywords: aerobic, anaerobic, bioremediation, Cupriavidus metallidurans, mercury
Mercury is a toxic element that harms organisms and disturbs biogeochemical cycles. Mercury bioremediation is based on the reduction of Hg (II) to Hg (0) by mercury-resistant bacteria. Cupriavidus metallidurans MSR33 possesses a broad-spectrum mercury resistance. This study aims to establish the effects of mercury on growth, oxygen uptake, and mercury removal parameters by C. metallidurans MSR33 in aqueous solution during aerobic and anaerobic mercury bioremediation. A new culture medium (GBC) was designed. The effects of mercury (II) (20 ppm) on growth parameters, oxygen uptake, and mercury removal were evaluated in GBC medium in a bioreactor (3 L) under aerobiosis. The anaerobic kinetics of mercury removal was evaluated by nitrogen replacement during mercury bioremediation in a bioreactor. Strain MSR33 reached a growth rate of µ = 0.43 h−1 in the bioreactor. Mercury inhibited oxygen uptake and bacterial growth; however, this inhibition was reversed after 5 h. Strain MSR33 was able to... [more]
Research on the Optimal Configuration of Regional Integrated Energy System Based on Production Simulation
Tao Shi, Ruan-Ming Huang, Cang-Bi Ding
November 24, 2020 (v1)
Keywords: integrated energy system, optimal configuration, production simulation, scene clustering
This paper is focused mainly on the production simulation method of a regional integrated energy system under random scenarios for optimal configuration. First, the cooling, heating, and electric load demand of the regional integrated energy system is described quantitatively in the form of time series, as well as the power characteristics of renewable energy, such as wind power and photovoltaic power generation. Then, a typical scenario set of regional integrated energy system configurations considering the random probability characteristics is established through scene clustering. Second, considering the power output characteristics and cost factors of different types of distributed energy, the corresponding technical and economic quantitative model is established. Third, a multi-objective production simulation model of a regional integrated energy system considering configuration constraints and operation constraints is proposed with economic and environmental protection as the main... [more]
Design, Fundamental Principles of Fabrication and Applications of Microreactors
Adama A. Bojang, Ho-Shing Wu
November 24, 2020 (v1)
Keywords: construction, fabrication, laminar flow, microreactor, pharmaceutical
This study highlights the development of small-scale reactors, in the form of microstructures with microchannel networking. Microreactors have achieved an impressive reputation, regarding chemical synthesis ability and their applications in the engineering, pharmaceutical, and biological fields. This review elaborates on the fabrication, construction, and schematic fundamentals in the design of the microreactors and microchannels. The materials used in the fabrication or construction of the microreactors include silicon, polymer, and glass. A general review of the application of microreactors in medical, biological, and engineering fields is carried out and significant improvements in these areas are reported. Finally, we highlight the flow patterns, mixing, and scaling-up of multiphase microreactor developments, with emphasis on the more significant industrial applications.
Data-driven Spatial Branch-and-bound Algorithm for Box-constrained Simulation-based Optimization
Jianyuan Zhai, Fani Boukouvala
November 14, 2020 (v1)
Subject: Optimization
Keywords: Black-box Optimization, Branch-and-bound, Simulation-based Optimization
The ability to use complex computer simulations in quantitative analysis and decision-making is highly desired in science and engineering at the same rate as computation capabilities and first-principle knowledge advance. Due to the complexity of simulation models, direct embedding of equation-based optimization solvers may be impractical and data-driven optimization techniques are often needed. In this work, we present a novel data-driven spatial branch-and-bound algorithm for simulation-based optimization problems with box constraints, aiming for consistent globally convergent solutions. The main contribution of this paper is the introduction of the concept data-driven convex underestimators of data and surrogate functions, which are employed within a spatial branch-and-bound algorithm. The algorithm is showcased by an illustrative example and is then extensively studied via computational experiments on a large set of benchmark problems.
Classification and Comparison of Dividing Walls for Distillation Columns
Zewei Chen, Rakesh Agrawal
November 11, 2020 (v1)
Keywords: dividing wall column, multicomponent distillation, Process Intensification
A classification method is proposed to classify dividing walls into 5 types. Each type of dividing wall has its unique structural characteristics which impact its total vapor duty, construction complexity and controllability. Based on this classification, a comprehensive guideline to draw optimal dividing wall columns for any n-component distillation is provided.
Impact of Dual Substrate Limitation on Biodenitrification Modeling in Porous Media
Mostafa Abaali, Jérôme Harmand, Zoubida Mghazli
November 11, 2020 (v1)
Keywords: biodenitrification, convection-diffusion-reaction equations, finite element method, Modelling
In this work, we consider a model of the biodenitrification process taking place in a spatially-distributed bioreactor, and we take into account the limitation of the kinetics by both the carbon source and the oxidized nitrogen. This model concerns a single type of bacteria growing on nitrate, which splits into adherent bacteria or free bacteria in the liquid, taking all interactions into account. The system obtained consists of four diffusion-convection-reaction equations for which we show the existence and uniqueness of a global solution. The system is approximated by a standard finite element method that satisfies an optimal a priori error estimate. We compare the results obtained for three forms of the growth function: single substrate limiting, “multiplicative” form, and “minimum” form. We highlight the limitation of the ‘ single substrate limiting model”, where the dependency of the bacterial growth on the nitrate is neglected, and find that the “minimum” model gives numerical re... [more]
Encapsulation of Active Ingredients in Food Industry by Spray-Drying and Nano Spray-Drying Technologies
Claudia I. Piñón-Balderrama, César Leyva-Porras, Yolanda Terán-Figueroa, Vicente Espinosa-Solís, Claudia Álvarez-Salas, María Z. Saavedra-Leos
November 11, 2020 (v1)
Keywords: conventional spray drying, food active ingredients, microencapsulation, nano spray drying
Since its invention in 1872 by Samuel Percy, the spray drying of food products has been widely used, whether in products consumed by babies in milk formulations, powdered sweets and cocoa soluble in milk for children, or food supplements rich in proteins, vitamins, and minerals for adults. All of these products were first formulated in solution and then converted into powders to facilitate the transport and preservation of the properties during storage. In recent years, novel technologies such as nano spray drying have emerged for the development of food formulations with high-cost active ingredients. The aim of the present work is to present a review of the literature reported in the last 10 years related to these technologies. The basis of the spray-drying technologies i.e., conventional and nano, are described and compared, emphasizing the instrumental processing conditions for achieving a desired product. Examples of some unwanted reactions presented during the encapsulation of act... [more]
Not Just Numbers: Mathematical Modelling and Its Contribution to Anaerobic Digestion Processes
Matthew J. Wade
November 11, 2020 (v1)
Subject: Biosystems
Keywords: anaerobic digestion, data-driven models, hybrid modelling, mathematical analysis, mathematical modelling, mechanistic models, thermodynamics
Mathematical modelling of bioprocesses has a long and notable history, with eminent contributions from fields including microbiology, ecology, biophysics, chemistry, statistics, control theory and mathematical theory. This richness of ideas and breadth of concepts provide great motivation for inquisitive engineers and intrepid scientists to try their hand at modelling, and this collaboration of disciplines has also delivered significant milestones in the quality and application of models for both theoretical and practical interrogation of engineered biological systems. The focus of this review is the anaerobic digestion process, which, as a technology that has come in and out of fashion, remains a fundamental process for addressing the global climate emergency. Whether with conventional anaerobic digestion systems, biorefineries, or other anaerobic technologies, mathematical models are important tools that are used to design, monitor, control and optimise the process. Both highly struc... [more]
Evaluation of Osmotic Dehydration Process in Plant Tissue with Low-Field Magnetic Resonance Imaging Enhanced with Paramagnetic Ions
Mateusz Suchanek, Zbigniew Olejniczak
November 11, 2020 (v1)
Keywords: courgette, low-field MRI, osmotic dehydration, paramagnetic contrast agent, zucchini
A novel, non-invasive low-field Magnetic Resonance Imaging (MRI) technique for studying the osmotic dehydration process in fruits and vegetables is proposed. A saturated solution of paramagnetic salt is used as both the osmotic substance and the contrast agent for MRI. Using courgette as an example, it is demonstrated that the results obtained by the new method are consistent with the standard mass transport analysis, but additional information about the spatial distribution of osmotic substance within the sample and its evolution in time is provided. The MRI method is much more efficient in terms of experiment time and the amount of biological material needed. Possible extensions of the technique to improve its accuracy are discussed.
Acid Hydrolysis of Olive Tree Leaves: Preliminary Study towards Biochemical Conversion
Soledad Mateo, Pilar Mateo, Marco Barbanera, Cinzia Buratti, Alberto J. Moya
November 11, 2020 (v1)
Keywords: characterization, hemicellulose, hydrolysis, olive tree leaves
Olive tree leaves, an abundant agricultural by-product without enough industrial market outlets, are presented in this study as a relevant resource of available carbohydrates to be chemically treated for monomeric sugar production. Characterization of two main granulometric fractions is the starting point for testing the specific effect and the relevance of three main factors (time, temperature, and sulfuric acid concentration) on diluted acid hydrolysis with respect to oligosaccharides, simple sugars, and fermentation inhibitory compounds production. The selected conditions (100 ∘ C, 90 min, and 6% w/w H 2 SO 4 ) to perform the small scale hydrolytic process, considering response surface methodology (2 3 factorial design with center points), implied production of acetic acid and hydroxymethylfurfural in concentrations not exceeding 1.10 kg m − 3 and 0.25 kg m − 3 , respectively. Thus, these experimental conditions were the reference fra... [more]
A Novel Cysteine-Functionalized MxOy Material as Support for Laccase Immobilization and a Potential Application in Decolorization of Alizarin Red S
Agnieszka Kołodziejczak-Radzimska, Teofil Jesionowski
November 11, 2020 (v1)
Subject: Biosystems
Keywords: Catalysis, decolorization, kinetic, l-cysteine, laccase, SiO2, ZrO2
Immobilization process improves the enzyme properties, like stability, activity, selectivity or specificity. In the study, a novel cysteine-functionalized MxOy (ZrO2, SiO2) material was used as a support for the immobilization of laccase from Trametes versicolor. The proposed matrix was prepared using a simple sol-gel method. The cysteine was introduced during the synthesis of a sample. Additionally, the obtained supports were modified with glutaraldehyde. The basic properties of the prepared cysteine functionalized ZrO2 and SiO2 were determined using spectroscopic, thermal, porous, electrostatic and elemental analysis. Furthermore, the obtained biocatalytic systems were used as catalysts in the oxidation of sulfonic acid. Catalytic and kinetic parameters were determined based on the proposed model reaction. Next, laccase immobilized on ZrO2- and SiO2-based materials were, for the first time, utilized in the decolorization of Alizarin Red S. In that process, the influence of duration,... [more]
A Simplified and Optimized Chemical Mechanism for Combustion of n-Pentane at Atmospheric Pressure
Zhiqun Meng, Jinggang Wang, Jiawen Qi, Chuchao Xiong, Liquan Hou, Jinghui Luo
November 11, 2020 (v1)
Keywords: atmospheric pressure, combustion, n-pentane, optimized mechanism, simplified mechanism
In the present study, the detailed mechanism of n-pentane combustion, including 697 species and 3214 reactions, is first simplified to a mechanism with only 26 species and 134 reactions, which is suitable for the pressure of 1 atm, temperatures of 1000−1600 K, and equivalent ratios of 0.5−1.6. However, when the equivalence ratio is 1.0, in the temperature range of 1000−1100 K, compared with the detailed mechanism, the maximum error of the ignition delay time predicted by the simplified mechanism exceeds 20%. Therefore, based on the method of temperature sensitivity analysis, the simplified mechanism is further utilized through reducing the A-factor of 2HO2 = H2O2 + O2 (−1) and 2HO2 = H2O2 + O2 (−2) by 10 times. By comparing with the detailed mechanism and predicting the ignition delay time, laminar flame speed, species profile, and extinction residence time, it is found that the optimized mechanism has good accuracy in the applicable range, and is fully capable of simulating the combus... [more]
Performance and Kinetics of Bioaugmentation, Biostimulation, and Natural Attenuation Processes for Bioremediation of Crude Oil-Contaminated Soils
Cevat Yaman
November 11, 2020 (v1)
Subject: Biosystems
Keywords: bioaugmentation, bioremediation, biostimulation, crude oil, first-order reaction rate model, Monod model, natural attenuation
Bioremediation of contaminated sites is usually limited due to the inadequate availability of nutrients and microorganisms. This study was conducted to assess the impact of bioaugmentation (BA) and biostimulation (BS) on petroleum hydrocarbon degradation efficiency. In addition, treatment performance and kinetics of different remediation processes were investigated. For this purpose, four tanks containing oil-contaminated soils were tested. Tank 1 was operated as the natural attenuation process. Then, a microbial inoculum and nutrients were added to tank 2 to promote BA and BS. In tank 3, only the BA process was adopted, whereas in tank 4, only the BS process was adopted. After 63 days of operation, the total petroleum hydrocarbon (TPH) in tank 2 was reduced from 1674 to 430 mg/kg, with 74% reduction. Tank 1, tank 3, and tank 4 indicated TPH reductions of 35%, 41%, and 66%, respectively. Microbiological analysis of the inoculum indicated that Alcanivorax was the dominant bacterium. The... [more]
Energy Management Strategy for Fuel Cell and Battery Hybrid Vehicle Based on Fuzzy Logic
Dongxu Li, Bing Xu, Jie Tian, Zheshu Ma
November 11, 2020 (v1)
Keywords: energy management strategy, FCHV, fuzzy logic control, powertrain system, secondary development
In order to improve fuel economy and enhance operating efficiency of fuel cell hybrid vehicles (FCHVs), fuzzy logic control (FLC) strategies are available and suggested for adoption. In this paper, the powertrain of a fuel cell hybrid vehicle is designed and the parameters of the motor, battery, and fuel cell are calculated. The FLC strategy and the power following control (PFC) strategy are designed for the studied FCHV. A secondary development for Advanced Vehicle Simulator (ADVISOR) is implemented based on the standard driving cycles, and a Chinese typical city driving cycle is imported. Simulation results demonstrate that the proposed FLC strategy is more valid and reasonable than the traditional PFC strategy. The proposed FLC strategy affects the vehicle characteristics significantly and contributes to better performance in four aspects: fuel economy, efficiency of battery and fuel cell system, battery state of charge (SOC), and battery life. Hence, the FLC strategy is more suitab... [more]
Lattice Boltzmann Simulation of Ferrofluids Film Boiling
Mohammad Yaghoub Abdollahzadeh Jamalabadi
November 11, 2020 (v1)
Keywords: boiling, ferrofluids, Lattice Boltzmann method, numerical simulation
In the present investigation, two phase film boiling of ferrofluids under an external field delivered around a two-dimensional square cross-section heater was investigated using the lattice Boltzmann technique. The purpose of this work is to find the effect of magnetic field magnitude and direction on the Nusselt number in single and double heater geometry. The improving thermal efficiency in the horizontal and vertical placement of heaters is also presented. The governing equations of mass conservation, momentum conservation, and energy conservation are solved by using a central-moments-based Lattice Boltzmann scheme. The air pocket generated around heater raised incorporating magnetic effects. The heat transfer through this advancement has been explored quantitatively and abstractly. The results shows that with the development in the volumetric applied force at the bubble-fluid interface, the bubble boundary layer thickness around the square heater lessened which cause the Nusselt nu... [more]
A Process-Based Modeling Method for Describing Production Processes of Ship Block Assembly Planning
Dongsu Jeong, Dohyun Kim, Taihun Choi, Yoonho Seo
November 9, 2020 (v1)
Keywords: block assembly planning, process-based modeling, production process, ship production, shipbuilding manufacturing
Ship block assembly planning is very complex due to the various activities and characteristics of ship production. Therefore, competitiveness in the shipbuilding industry depends on how well a company operates its ship block assembly plan. Many shipbuilders are implementing various studies to improve their competitiveness in ship block assembly planning, specifically regarding technology usage, such as modeling and simulation (M&S) and Cyber-Physical Systems (CPS). Although these technologies are successfully applied in some production planning systems, it is difficult to tailor ship production planning systems with flexibility due to unexpected situations. Providing a flexible plan for these production planning systems requires a way to describe and review the organic relationships of ship production processes. In this research, a process-based modeling (PBM) method proposes a novel approach to describing the production process of ship block assembly planning by redefining production... [more]
Green Method Synthesised Graphene-Silver Electrochemical Nanobiosensors for Ethambutol and Pyrazinamide
Rachel Fanelwa AjayI, Siphokazi Tshoko, Yonela Mgwili, Siphamandla Nqunqa, Takalani Mulaudzi, Noluthando Mayedwa, Emmanuel Iwuoha
November 9, 2020 (v1)
Subject: Biosystems
Keywords: cytochrome P450-2D6, Ethambutol, graphene oxide, pyrazinamide, silver nanoparticles, TB drug
A novel nanobiosensor was constructed with graphene oxide (GO) sheets coupled to pear extract-based green-synthesised silver nanoparticles (Ag-NPs) to which cytochrome P450-2D6 (CYP2D6) enzyme was attached. The biosensor was applied in the electrochemical detection of the tuberculosis (TB) treatment drugs, ethambutol (EMB) and pyrazinamide (PZA). The surface morphology of the green-synthesised nanocomposites was studied by performing High-Resolution Transmission Electron Microscopy (HR-TEM) and High-Resolution Scanning Electron Microscopy (HR-SEM). Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy were used for structural analysis, while Ultraviolet Visible (UV-Vis) Spectroscopy was used in the optical characterisation of the nanocomposite material. Electrochemical studies on glassy carbon electrode (GCE), which were done by Cyclic Voltammetry (CV), showed that the GO|Ag-NPs||GCE electrode was highly conductive, and thereby indicating its suitability as a platform f... [more]
CFD and Experimental Characterization of a Bioreactor: Analysis via Power Curve, Flow Patterns and k L a
Luis A. Ramírez, Edwar L. Pérez, Cesar García Díaz, Dumar Andrés Camacho Luengas, Nicolas Ratkovich, Luis H. Reyes
November 9, 2020 (v1)
Subject: Biosystems
Keywords: bioreactors, Computational Fluid Dynamics, impellers, mass transfer, oxygen diffusion, stirred tank
Mixing operations in biological processes is of utmost importance due to its effect on scaling-up and heat and mass transfer. This paper presents the characterization of a bench-top bioreactor with different impeller configurations, agitation and oxygen transfer rates, using CFD simulations and experimental procedures. Here, it is demonstrated that factors such as the type of impeller and the flow regime can drastically vary the operation as in the preparation of cultures. It was observed that the bioreactor equipped with a Rushton generates a k L a of 0.0056 s−1 for an agitation velocity and airflow rate of 250 RPM and 5 L/min, respectively. It is suitable result for the dissolved oxygen (DO) but requires a considerable amount of power consumption. It is here where the importance of the agitator’s diameter can be observed, since, in the case of the two propeller types studied, lower energy consumption can be achieved with a smaller diameter, as well as a much smaller shear c... [more]
Showing records 1 to 25 of 92. [First] Page: 1 2 3 4 Last
Change year: 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024
Change month: January | February | March | April | May | June | July | August | September | October | November | December