Records Added in 2020
Records added in 2020
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Showing records 101 to 125 of 1263. [First] Page: 1 2 3 4 5 6 7 8 9 Last
Synthesis and Characterization of CoxOy−MnCO3 and CoxOy−Mn2O3 Catalysts: A Comparative Catalytic Assessment Towards the Aerial Oxidation of Various Kinds of Alcohols
Osamah Alduhaish, Syed Farooq Adil, Mohamed E. Assal, Mohammed Rafi Shaik, Mufsir Kuniyil, Khalid M. Manqari, Doumbia Sekou, Mujeeb Khan, Aslam Khan, Ahmed Z. Dewidar, Abdulrahman Al-Warthan, Mohammed Rafiq H. Siddiqui
December 17, 2020 (v1)
Keywords: alcohols, catalyst, cobalt oxide, manganese carbonate, oxidation, oxygen
CoxOy−manganese carbonate (X%)(CoxOy−MnCO3 catalysts (X = 1−7)) were synthesized via a straightforward co-precipitation strategy followed by calcination at 300 °C. Upon calcination at 500 °C, these were transformed to CoxOy−dimanganese trioxide i.e., (X%)CoxOy−Mn2O3. A relative catalytic evaluation was conducted to compare the catalytic efficiency of the two prepared catalysts for aerial oxidation of benzyl alcohol (BzOH) to benzaldehyde (BzH) using O2 molecule as a clean oxidant without utilizing any additives or alkalis. Amongst the different percentages of doping with CoxOy (0−7% wt./wt.) on MnCO3 support, the (1%)CoxOy−MnCO3 catalyst exhibited the highest catalytic activity. The influence of catalyst loading, calcination temperature, reaction time, and temperature and catalyst dosage was thoroughly assessed to find the optimum conditions of oxidation of benzyl alcohol (BzOH) for getting the highest catalytic efficiency. The (1%)CoxOy−MnCO3 catalyst which calcined at 300 °C displaye... [more]
Scale-Up of Mixing Equipment for Suspensions
Tomáš Jirout, František Rieger, Dorin Ceres
December 17, 2020 (v1)
Keywords: axial agitator, Mixing, scale-up, suspension
This paper deals with the scale-up of equipment for the mixing of suspensions. The measurement of just-suspended agitator speeds was carried out with standard, pitched, four-blade turbines and folded, four-blade turbines in three vessels (290 mm, 600 mm, and 800 mm in diameter) for several particle sizes and concentrations. The results of measurements confirmed that scale-up based on dimensionless Froude number dependence, on the relative particle size and concentration, can be used. On the basis of the results, a scale-up rule for agitator speeds in a given suspension and equipment geometry was recommended, and various conclusions reported by different investigators were discussed.
Detection of E. coli O157:H7 in Food Using Automated Immunomagnetic Separation Combined with Real-Time PCR
Ji Young Park, Min-Cheol Lim, Kisang Park, Gyeongsik Ok, Hyun-Joo Chang, Nari Lee, Tae Jung Park, Sung-Wook Choi
December 17, 2020 (v1)
Keywords: automation, foodborne pathogen, immunomagnetic separation, pretreatment, real-time PCR
In this study, we describe the development of an automated immunomagnetic separation device combined with real-time polymerase chain reaction (PCR) for detecting foodborne bacteria. Immunomagnetic separation (IMS) is a well-known method for the separation and concentration of target bacteria from a large volume of food samples. Magnetic beads functionalized with an antibody provide selectivity for target bacteria such as Escherichia coli O157:H7. Moreover, compared to conventional methods, real-time PCR enables high-sensitivity detection of target bacteria. The method proposed in this study involves three steps: (1) pre-enrichment, (2) automated IMS and concentration of target bacteria, and (3) detection of target bacteria by real-time PCR. Using food samples with a working sample volume as large as 250 mL, the whole process only requires 3 h. As a result, target bacteria in the range of 101−102 colony-forming units per mg or g of sample can be detected in food samples, such as milk, g... [more]
A Novel Geometric Error Compensation Method for Gantry-Moving CNC Machine Regarding Dominant Errors
Hong Lu, Qian Cheng, Xinbao Zhang, Qi Liu, Yu Qiao, Yongquan Zhang
December 17, 2020 (v1)
Keywords: compensation method, gantry-type CNC machine, geometric error, multi-body system, VLGSA
Gantry-type computer numerical control (CNC) machines are widely used in the manufacturing industry. A novel structure with moveable gantry is proposed to improve the traditional gantry-type machine structure’s disadvantage of taking up too much space. Geometric errors have direct impacts on the actual position of the tool, which significantly reduces the accuracy of machines. Errors of different components are always coupled and have uncertain effects on the total geometric error. Thus, it is essential to find an effective way to identify the dominant errors and do targeted compensation. First, a novel identification method using value leaded global sensitivity analysis (VLGSA) is proposed to find the dominant errors. In VLGSA, weighting factors which show the influence of the error range are used to modify the multi-body system (MBS) error model. Results show that the dominant errors in three directions respectively contribute 80%, 86% and 85% of the total error in their directions.... [more]
Comprehensive Improvement of Mixed-Flow Pump Impeller Based on Multi-Objective Optimization
Mengcheng Wang, Yanjun Li, Jianpin Yuan, Fan Meng, Desmond Appiah, Jiaqi Chen
December 17, 2020 (v1)
Keywords: 3D inverse design, circulation, Computational Fluid Dynamics, mixed-flow pump, multi-objective optimization
The spanwise distribution of impeller exit circulation (SDIEC) has a significant effect on the impeller performance, therefore, there is a need for its consideration in the optimization design of mixed-flow pumps. In this study, a combination optimization system, including a 3D inverse design method (IDM), computational fluid dynamics (CFD), Latin hypercube sampling (LHS) method, response surface model (RSM), and non-dominated sorting genetic algorithm (NSGA-Ⅱ) was used to improve the performance of the mixed-flow pump after considering the effect of SDIEC on the performance of the impeller. The CFD results confirm the accuracy and credibility of the optimization results because of the good agreement the CFD results established with the experimental measurements. Compared with the original impeller, the pump efficiency of the preferred impeller at 0.8Qdes, 1.0Qdes, and 1.2Qdes improved by 0.63%, 3.39%, and 3.77% respectively. The low-pressure region on the blade surface reduced by 96.9... [more]
Techno-Economic Evaluation of Biorefineries Based on Low-Value Feedstocks Using the BioSTEAM Software: A Case Study for Animal Bedding
Miguel Sanchis-Sebastiá, Joaquín Gomis-Fons, Mats Galbe, Ola Wallberg
December 17, 2020 (v1)
Keywords: animal bedding, bioethanol, biorefinery, BioSTEAM, techno-economics
Biofuels are still too costly to compete in the energy market and it has been suggested that low-value feedstocks could provide an opportunity for the production of low-cost biofuels; however, the lower quality of these feedstocks requires the introduction of a conditioning step in the biorefinery process. The aim of this study was to evaluate whether feedstock savings cover the cost of conditioning in the case of animal bedding. The BioSTEAM software was used to simulate a wheat straw biorefinery and an animal bedding biorefinery, whose economic performance was compared. The wheat straw biorefinery could deliver ethanol at a minimum selling price of USD 0.61 per liter, which is similar to prices in the literature. The cost of producing ethanol in the animal bedding biorefinery without water recycling was almost 40% higher, increasing the minimum selling price to USD 1.1 per liter of ethanol. After introducing water recycling in the conditioning step, the animal bedding biorefinery cou... [more]
Numerical Analysis of the Flow around Two Square Cylinders in a Tandem Arrangement with Different Spacing Ratios Based on POD and DMD Methods
Feng Wang, Xiaodong Zheng, Jianming Hao, Hua Bai
December 17, 2020 (v1)
Keywords: dynamic mode decomposition, flow characteristics, numerical analysis, proper orthogonal decomposition, two square cylinders
To more clearly understand the changes in flow characteristics around two square cylinders with different spacing ratios, the main mode of the flow field was extracted by using the Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) methods. The changes in the main mode of the flow field at different spacing ratios and the difference of the time series were analyzed and compared. This processing can separate the mixed information in the flow field and obtain the dominant modes in the flow field. These main modes can clearly reflect the dominant flow characteristics in the flow field. The analysis results show that when L/D = 2, the flow field structure is consistent with the flow field around a single square cylinder. When L/D = 2.5−3.5, the vortex shedding from upstream cylinders combines with the vortex near the downstream cylinders. This mutual coupling causes a significant change in the drag coefficient value of the downstream cylinder. When L/D = 4, the main... [more]
Potential Cultivation of Lactobacillus pentosus from Human Breastmilk with Rapid Monitoring through the Spectrophotometer Method
Toan Nguyen-Sy, Guo Yong Yew, Kit Wayne Chew, Thi Dong Phuong Nguyen, Thi Ngoc Thu Tran, Thi Dieu Huong Le, Chau Tuan Vo, Hoang Kim Pham Tran, Muhammad Mubashir, Pau Loke Show
December 17, 2020 (v1)
Subject: Biosystems
Keywords: bacteria sequencing, breast milk, Lactobacillus isolation, lag phase
The present study focused on the development of a new method to determine the lag phase of Lactobacillus in breast milk which was attained during the 1st, 3rd, and 6th month (M1, M3, and M6). The colonies’ phylogenetic analysis, derived from the 16S rRNA gene sequences, was evaluated with genus Lactobacillus pentosus and achieved a similarity value of 99%. Raman spectroscopy in optical densities of 600 nm (OD600) were used for six consecutive days to observe the changes of the cell growth rate. The values of OD600 were well fitted with the regression model. From this work, M1 was found to be the longest lag phase in 18 h, and it was 17% to 27% longer compared to M3 and M6, respectively. However, the samples of M3 and M6 showed the shortest duration in reaching 0.5 of OD600 nm (16 h) which was enhanced by 80% and 96% compared to M1, respectively. These studies will be of significance when applied in determining the bacteria growth curve and in assessing the growth behavior for the strai... [more]
Seawater Desalination: A Review of Forward Osmosis Technique, Its Challenges, and Future Prospects
Aondohemba Aende, Jabbar Gardy, Ali Hassanpour
December 17, 2020 (v1)
Keywords: desalination technologies, draw solutions, forward osmosis, membrane fouling, water desalination, water scarcity
Currently over 845 million people are believed to be living under severe water scarcity, and an estimated 2.8 billion people across the globe are projected to come under serious water scarcity by the year 2025, according to a United Nations (UN) report. Seawater desalination has gained more traction as the solution with the most potential for increasing global freshwater supplies amongst other solutions. However, the economic and energy costs associated with the major desalination technologies are considered intrinsically prohibitive largely due to their humongous energy requirements alongside the requirements of complex equipment and their maintenance in most cases. Whilst forward osmosis (FO) is being touted as a potentially more energy efficient and cost-effective alternative desalination technique, its efficiency is challenged by draw solutes and the draw solutes recovery step in FO applications alongside other challenges. This paper looks at the present situation of global water s... [more]
The Influence of the Porous Structure of Activated Coke for the Treatment of Gases from Coal Combustion on Its Mechanical Strength
Zhongjie Hu, Heng Zhou, Weili Zhang, Shengli Wu
December 17, 2020 (v1)
Subject: Materials
Keywords: abrasive resistance, activated coke, circular sorbent, compression strength, gas cleaning, pore diameter distribution, porosity characteristics
This study investigated influences of the open/close states of pores and porosity distribution of activated coke on the mechanical strength of common activated coke for the purification of coal-fired flue gas by analyzing pore structure, abrasive resistance, and compression strengths of 9 types of desulfurization and denitration activated cokes. Research conclusions are conducive to disclosing the influences of porosity characteristics of activated coke for the purification of coal-fired flue gas on mechanical strength, decreasing the physical consumption of activated coke in the recycling of flue gas purification systems, and lowering the purification cost of coal-fired flue gas. According to research results, pores in the ranges of 0−2 nm and 2−500 nm of activated coke are further developed after recycling using the coal-fired flue gas purification system, and the average compression strength of activated coke is about 70% of the added fresh activated coke. However, the abrasive resi... [more]
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]
Showing records 101 to 125 of 1263. [First] Page: 1 2 3 4 5 6 7 8 9 Last
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