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Records Added in February 2021
Records added in February 2021
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Showing records 1 to 25 of 79. [First] Page: 1 2 3 4 Last
CFD-DEM Simulation of a Coating Process in a Fluidized Bed Rotor Granulator
Philipp Grohn, Marius Lawall, Tobias Oesau, Stefan Heinrich, Sergiy Antonyuk
February 22, 2021 (v1)
Keywords: capillary force, CFD-DEM simulation, coating model, drying process, fluidized bed rotor granulator, viscous force, wet particle
Coating of particles is a widely used technique in order to obtain the desired surface modification of the final product, e.g., specific color or taste. Especially in the pharmaceutical industry, rotor granulators are used to produce round, coated pellets. In this work, the coating process in a rotor granulator is investigated numerically using computational fluid dynamics (CFD) coupled with the discrete element method (DEM). The droplets are generated as a second particulate phase in DEM. A liquid bridge model is implemented in the DEM model to take the capillary and viscous forces during the wet contact of the particles into account. A coating model is developed, where the drying of the liquid layer on the particles, as well as the particle growth, is considered. The simulation results of the dry process compared to the simulations with liquid injection show an important influence of the liquid on the particle dynamics. The formation of liquid bridges and the viscous forces in the li... [more]
Resource Allocation in Two-Patch Epidemic Model with State-Dependent Dispersal Behaviors Using Optimal Control
Sunmi Lee, Okbun Baek, Luis Melara
February 22, 2021 (v1)
Keywords: final epidemic size, optimal control interventions, the basic reproduction number, two-patch model with virtual dispersal
A two-patch epidemic model is considered in order to assess the impact of virtual dispersal on disease transmission dynamics. The two-patch system models the movement of individuals between the two-patches using a residence-time matrix P, where P depends on both residence times and state variables (infected classes). In this work, we employ this approach to a general two-patch SIR model in order to investigate the effect of state dependent dispersal behaviors on the disease dynamics. Furthermore, optimal control theory is employed to identify and evaluate patch-specific control measures aimed at reducing disease prevalence at a minimal cost. Optimal policies are computed under various dispersal scenarios (depending on the different residence-time matrix configurations). Our results suggest there is a reduction of the outbreak and the proportion of time spent by individuals in a patch exhibits less fluctuations in the presence of patch-specific optimal controls. Furthermore, the optimal... [more]
Single and Binary Equilibrium Studies for Ni2+ and Zn2+ Biosorption onto Lemna gibba from Aqueous Solutions
Liliana Morales-Barrera, César Mateo Flores-Ortiz, Eliseo Cristiani-Urbina
February 22, 2021 (v1)
Subject: Biosystems
Keywords: competitive biosorption, divalent nickel, divalent zinc, Lemna gibba, pH and metal concentration effect, single and binary metal biosorption isotherm
The biosorption ability of Lemna gibba for removing Ni2+ and Zn2+ ions in aqueous batch systems, both individually and simultaneously, was examined. The influences of solution pH and initial single and binary metal concentrations on equilibrium Ni2+ and Zn2+ biosorption was explored. The optimal solution pH for Ni2+ and Zn2+ biosorption was 6.0, for both the single and binary metal systems. Ni2+ and Zn2+ biosorption capacities increased with increasing initial metal concentrations. The presence of Zn2+ ions more adversely affected the biosorption of Ni2+ ions in the binary metal systems than vice versa. The single and binary biosorption isotherms of Ni2+ and Zn2+ revealed that L. gibba’s affinity for Zn2+ ions was higher than that for Ni2+ ions. The Redlich−Peterson and Freundlich isotherm models fit well to the experimental equilibrium data of Ni2+ ions, whereas Redlich−Peterson and Langmuir models better described the equilibrium data of Zn2+ ions in single metal systems. The modifie... [more]
Digital Twins in Pharmaceutical and Biopharmaceutical Manufacturing: A Literature Review
Yingjie Chen, Ou Yang, Chaitanya Sampat, Pooja Bhalode, Rohit Ramachandran, Marianthi Ierapetritou
February 22, 2021 (v1)
Keywords: biopharmaceutical manufacturing, digital twin, Industry 4.0, pharmaceutical manufacturing, process modeling
The development and application of emerging technologies of Industry 4.0 enable the realization of digital twins (DT), which facilitates the transformation of the manufacturing sector to a more agile and intelligent one. DTs are virtual constructs of physical systems that mirror the behavior and dynamics of such physical systems. A fully developed DT consists of physical components, virtual components, and information communications between the two. Integrated DTs are being applied in various processes and product industries. Although the pharmaceutical industry has evolved recently to adopt Quality-by-Design (QbD) initiatives and is undergoing a paradigm shift of digitalization to embrace Industry 4.0, there has not been a full DT application in pharmaceutical manufacturing. Therefore, there is a critical need to examine the progress of the pharmaceutical industry towards implementing DT solutions. The aim of this narrative literature review is to give an overview of the current statu... [more]
Optimal Energy Management for Microgrids Considering Uncertainties in Renewable Energy Generation and Load Demand
Haotian Wu, Hang Li, Xueping Gu
February 22, 2021 (v1)
Keywords: ant colony optimization, energy management, microgrids, Optimization, pattern search optimization, Renewable and Sustainable Energy, uncertainty, wind power
This paper proposes an efficient power management approach for the 24 h-ahead optimal maneuver of Mega−scale grid−connected microgrids containing a huge penetration of wind power, dispatchable distributed generation (diesel generator), energy storage system and local loads. The proposed energy management optimization objective aims to minimize the microgrid expenditure for fuel, operation and maintenance and main grid power import. It also aims to maximize the microgrid revenue by exporting energy to the upstream utility grid. The optimization model considers the uncertainties of the wind energy and power consumptions in the microgrids, and appropriate forecasting techniques are implemented to handle the uncertainties. The optimization model is formulated for a day-ahead optimization timeline with one-hour time steps, and it is solved using the ant colony optimization (ACO)-based metaheuristic approach. Actual data and parameters obtained from a practical microgrid platform in Atlanta,... [more]
In Vitro Bioadsorption of Cd2+ Ions: Adsorption Isotherms, Mechanism, and an Insight to Mycoremediation
Raman Kumar, Priyanka Sharma, Ahmad Umar, Rajeev Kumar, Namita Singh, P. K. Joshi, Fahad A. Alharthi, Abdulaziz Ali Alghamdi, Nabil Al-Zaqri
February 22, 2021 (v1)
Keywords: bioadsorption, bioadsorption mechanism, cadmium, heavy metals, isotherms, mycoremediation, T. fasciculatum, T. longibrachiatum
The objective of this paper is to establish the significance of the mycoremediation of contaminants such as Cd2+ to achieve sustainable and eco-friendly remediation methods. Industries such as electroplating, paint, leather tanning, etc. release an enormous amount of Cd2+ in wastewater, which can drastically affect our flora and fauna. Herein, we report on the in vitro bioadsorption of Cd2+ ions using fungal isolates obtained from different contaminated industrial sites. The detailed studies revealed that two fungal species, i.e., Trichoderma fasciculatum and Trichoderma longibrachiatum, were found to be most effective against the removal of Cd2+ when screened for Cd2+ tolerance on potato dextrose agar (PDA) in different concentrations. Detailed adsorption studies were conducted by exploring various experimental factors such as incubation time, temperature, pH, inoculum size, and Cd2+ salt concentrations. Based on optimum experimental conditions, T. fasciculatum exhibited approximately... [more]
Degradation Status Recognition of Axial Piston Pumps under Variable Conditions Based on Improved Information Entropy and Gaussian Mixture Models
Chuanqi Lu, Zhi Zheng, Shaoping Wang
February 22, 2021 (v1)
Keywords: axial piston pump, degradation identification, energy moment entropy, Gaussian mixture model, waveform matching extrema mirror extension EMD
Axial piston pumps are crucial for the safe operation of hydraulic systems and usually work under variable operating conditions. However, deterioration status recognition for such pumps under variable conditions has rarely been reported until now. Therefore, it is valuable to develop effective methods suitable for processing variable conditions. Firstly, considering that information entropy has strong robustness to variable conditions and empirical mode decomposition (EMD) has the advantages of processing nonlinear and nonstationary signals, a new degradation feature parameter, named local instantaneous energy moment entropy, which combines information entropy theory and EMD, is proposed in this paper. To obtain more accurate degradation feature, a waveform matching extrema mirror extension EMD, which is used to suppress the end effects of EMD decomposition, was employed to decompose the original pump’s outlet pressure signals, taking the quasi-periodic characteristics of the signals i... [more]
Quartz Sand Filter Media with Special Wettability for Continuous and Efficient Oil/Water Separation and Dye Adsorption
Bigui Wei, Xuying Luo, Xiaosan Song, Hanyue Guo, Liang Dai, Hongwei Zhang, Gang Wang
February 22, 2021 (v1)
Subject: Materials
Keywords: continuous filtration, dye adsorption, oil/water separation, quartz sand, underoil highly hydrophobic, underwater superoleophobic
For continuous and efficient oil/water separation and adsorption of dyes, coconut shell powder was grafted onto the surface of quartz sand by dip-coating method to make coconut shell powder-covered quartz sand filter media (CSQS) with superhydrophilic and underwater superoleophobic properties and superoleophilic and underoil highly hydrophobic properties. The contact angles of the underwater oil and underoil water with CSQS were more than 151.2° and 134.2°, respectively. A continuous oil/water separation device was designed. The separation device filled with CSQS can separate oil/water mixture (whether heavy or light oil) into water and oil at the same time with a separation efficiency of above 99.92%. The filter layer can be recovered through reverse extrusion even after lyophobic liquid penetrated the filter layer; hence, the separation efficiency of the filter layer was still above 99.99% for diesel and water mixture. Simultaneously, CSQS can effectively adsorb methylene blue with t... [more]
A Multi-Scale Approach to Modeling the Interfacial Reaction Kinetics of Lipases with Emphasis on Enzyme Adsorption at Water-Oil Interfaces
Sherly Rusli, Janna Grabowski, Anja Drews, Matthias Kraume
February 22, 2021 (v1)
Keywords: enzymatic hydrolysis, interfacial kinetics modeling, lipases, protein adsorption
The enzymatic hydrolysis of triglycerides with lipases (EC 3.1.1.3.) involves substrates from both water and oil phases, with the enzyme molecules adsorbed at the water-oil (w/o) interface. The reaction rate depends on lipase concentration at the interface and the available interfacial area in the emulsion. In emulsions with large drops, the reaction rate is limited by the surface area. This effect must be taken into account while modelling the reaction. However, determination of the interfacial saturation is not a trivial matter, as enzyme molecules have the tendency to unfold on the interface, and form multi-layer, rendering many enzyme molecules unavailable for the reaction. A multi-scale approach is needed to determine the saturation concentration with specific interfacial area so that it can be extrapolated to droplet swarms. This work explicitly highlights the correlation between interfacial adsorption and reaction kinetics, by integration of the adsorption kinetics into the enzy... [more]
Impact of Fermentation Processes on the Bioactive Profile and Health-Promoting Properties of Bee Bread, Mead and Honey Vinegar
Rodica Mărgăoan, Mihaiela Cornea-Cipcigan, Erkan Topal, Mustafa Kösoğlu
February 22, 2021 (v1)
Keywords: bee bread, Fermentation, health benefits, honey vinegar, lactic acid bacteria, mead, volatile compounds
Recently, an increasing interest is paid to bee products obtained as a result of the fermentation process. Some of them can be consumed directly (bee-collected pollen, honey, bee bread etc.), while others are the result of lactic and/or acid fermentation (honey vinegar and honey wine). Bee bread is the result of pollens’ lactic fermentation, whereas mead is obtained by honeys’ lactic fermentation. Moreover, as a result of honey acetic acid fermentation, honey vinegar is obtained. Sensory characteristics and aroma composition have been scarcely studied, which may depend on the starter culture and fermentation process. Along with the medicinal properties they are a vital resource for future researches as they are of particular importance in the food market. In this review, we discuss the aroma-active compounds, taste, and sensorial characteristics of fermented bee products along with the approaches that can be developed for the flavor improvement based on existing technologies. Furthermo... [more]
Combined Response Surface Method and Modified Differential Evolution for Parameter Optimization of Friction Stir Welding
Thanatkij Srichok, Rapeepan Pitakaso, Kanchana Sethanan, Worapot Sirirak, Parama Kwangmuang
February 22, 2021 (v1)
Keywords: friction stir welding, modified differential evolution, response surface method, ultimate tensile strength
In this study, we constructed a new algorithm to determine the optimal parameters for friction stir welding including rotational speed, welding speed, axial force, tool pin profile, and tool material. The objective of welding is to maximize the ultimate tensile strength of the welded aluminum. The proposed method combines the response surface method and the modified differential evolution algorithm (RSM-MDE). RSM-MDE is a method that involves both experimental and simulation procedures. It is composed of four steps: (1) finding the number of parameters and their levels that affect the efficiency of the friction stir welding, (2) using RSM to formulate the regression model, (3) using the MDE algorithm to find the optimal parameter of the regression model obtained from (2), and (4) verifying the results obtained from step (3). The optimal parameters generated by the RSM-MDE method were a rotation speed of 1417.68 rpm, a welding speed of 60.21 mm/min, an axial force of 8.44 kN, a hexagon-... [more]
Temporal-Spatial Neighborhood Enhanced Sparse Autoencoder for Nonlinear Dynamic Process Monitoring
Nanxi Li, Hongbo Shi, Bing Song, Yang Tao
February 22, 2021 (v1)
Keywords: Bayesian, dynamic process, Fault Detection, sparse autoencoder, temporal-spatial neighborhood
Data-based process monitoring methods have received tremendous attention in recent years, and modern industrial process data often exhibit dynamic and nonlinear characteristics. Traditional autoencoders, such as stacked denoising autoencoders (SDAEs), have excellent nonlinear feature extraction capabilities, but they ignore the dynamic correlation between sample data. Feature extraction based on manifold learning using spatial or temporal neighbors has been widely used in dynamic process monitoring in recent years, but most of them use linear features and do not take into account the complex nonlinearities of industrial processes. Therefore, a fault detection scheme based on temporal-spatial neighborhood enhanced sparse autoencoder is proposed in this paper. Firstly, it selects the temporal neighborhood and spatial neighborhood of the sample at the current time within the time window with a certain length, the spatial similarity and time serial correlation are used for weighted reconst... [more]
Nanotechnology in Enhanced Oil Recovery
Goshtasp Cheraghian, Sara Rostami, Masoud Afrand
February 22, 2021 (v1)
Subject: Materials
Keywords: EOR, interfacial tension, nanofluids, nanotechnology, NPs, wettability
Nanoparticles (NPs) are known as important nanomaterials for a broad range of commercial and research applications owing to their physical characteristics and properties. Currently, the demand for NPs for use in enhanced oil recovery (EOR) is very high. The use of NPs can drastically benefit EOR by changing the wettability of the rock, improving the mobility of the oil drop and decreasing the interfacial tension (IFT) between oil/water. This paper focuses on a review of the application of NPs in the flooding process, the effect of NPs on wettability and the IFT. The study also presents a review of several investigations about the most common NPs, their physical and mechanical properties and benefits in EOR.
Effect of Heat Treatment and Light Exposure on the Antioxidant Activity of Flavonoids
Irina Ioannou, Leila Chekir, Mohamed Ghoul
February 22, 2021 (v1)
Subject: Biosystems
Keywords: bioactivities, degradation products, flavonoids, heat process, light exposure, TEAC
The application of food processes can lead to a modification of both the structure and the activities of flavonoids. In this article, the effect of heat treatment and exposure to light on the antioxidant activity of 6 model flavonoid solutions (rutin, naringin, eriodictyol, mesquitol, luteolin, and luteolin 7-O-glucoside) was studied. The evolution of the antioxidant activity measured after heat treatment of 130 °C at 2 h and an exposure to visible light for 2 weeks is measured by the ABTS (2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) method and represented by a new parameter called ΔTEAC. The model solution of Mesquitol showed the highest increase in ΔTEAC after a heat treatment, a value of 200 mM was obtained. The increase in ΔTEAC is always greater with thermal treatment than with light exposure. Thus, temperature and light lead to different degradation pathways of the flavonoid. In vivo measurements were carried out with solutions of naringin, erodictyol,... [more]
Optimal Cooling System Design for Increasing the Crystal Growth Rate of Single-Crystal Silicon Ingots in the Czochralski Process Using the Crystal Growth Simulation
Hye Jun Jeon, Hyeonwook Park, Ganesh Koyyada, Salh Alhammadi, Jae Hak Jung
February 22, 2021 (v1)
Keywords: cooling system design, crystal growth rate, crystal growth simulation, Czochralski process, pulling speed, single crystal silicon
Here, we report a successfully modified Czochralski process system by introducing the cooling system and subsequent examination of the results using crystal growth simulation analysis. Two types of cooling system models have been designed, i.e., long type and double type cooling design (LTCD and DTCD) and their production quality of monocrystalline silicon ingot was compared with that of the basic type cooling design (BTCD) system. The designed cooling system improved the uniformity of the temperature gradient in the crystal and resulted in the significant decrease of the thermal stress. Moreover, the silicon monocrystalline ingot growth rate has been enhanced to 18% by using BTCD system. The detailed simulation results have been discussed in the manuscript. The present research demonstrates that the proposed cooling system would stand as a promising technique to be applied in CZ-Si crystal growth with a large size/high pulling rate.
Batch Syngas Fermentation by Clostridium carboxidivorans for Production of Acids and Alcohols
Fabiana Lanzillo, Giacomo Ruggiero, Francesca Raganati, Maria Elena Russo, Antonio Marzocchella
February 22, 2021 (v1)
Keywords: Butanol, Clostridium carboxidivorans, Ethanol, growth kinetics, Syngas
Syngas (CO, CO2, and H2) has attracted special attention due to the double benefit of syngas fermentation for carbon sequestration (pollution reduction), while generating energy. Syngas can be either produced by gasification of biomasses or as a by-product of industrial processes. Only few microorganisms, mainly clostridia, were identified as capable of using syngas as a substrate to produce medium chain acids, or alcohols (such as butyric acid, butanol, hexanoic acid, and hexanol). Since CO plays a critical role in the availability of reducing equivalents and carbon conversion, this work assessed the effects of constant CO partial pressure (PCO), ranging from 0.5 to 2.5 atm, on cell growth, acid production, and solvent production, using Clostridium carboxidivorans. Moreover, this work focused on the effect of the liquid to gas volume ratio (VL/VG) on fermentation performances; in particular, two VL/VG were considered (0.28 and 0.92). The main results included—(a) PCO affected the grow... [more]
Experimental and Numerical Study on Hydraulic Performance of Chevron Brazed Plate Heat Exchanger at Low Reynolds Number
Yi Zhong, Kai Deng, Shenglang Zhao, Jinlin Hu, Yingjie Zhong, Qingyong Li, Zenan Wu, Zhiming Lu, Qing Wen
February 22, 2021 (v1)
Keywords: analysis, brazed plate heat exchanger, Computational Fluid Dynamics, corrugated, Darcy friction factor, low Reynolds number, pressure drop
Few experiments have been performed to investigate the hydraulic performance in a chevron brazed plate heat exchanger (BPHE) with the narrow channel at lower Reynolds number. The hydraulic characteristics of seven types of chevron BPHEs were investigated experimentally and numerical simulation revealed the effects of structural parameters on hydraulic performances. The correlations between friction factor f and Re were fitted out based on more than 500 sets of pressure drop data. The research results show that there is a power-law between f and Re; which has a similar trend but a different amplitude for different plates, and the exponent of the power-law could be approximate to a constant. Numerical results show that the pressure drop Δp is positively correlated with the corrugated angle and spacing, however, negatively correlated with the corrugated height. Research on the hydraulic performance is significant for the optimal design of BPHE.
Tensile Behavior of a Glass FRCM System after Different Environmental Exposures
Jacopo Donnini, Francesca Bompadre, Valeria Corinaldesi
February 22, 2021 (v1)
Subject: Materials
Keywords: durability, environmental exposure, Fabric-Reinforced Cementitious Matrix (FRCM), glass fibers
The use of Fabric-Reinforced Cementitious Matrix (FRCM) systems as externally bonded reinforcement for concrete or masonry structures is, nowadays, a common practice in civil engineering. However, FRCM durability against aggressive environmental conditions is still an open issue. In this paper, the mechanical behavior of a glass FRCM system, after being subjected to saline, alkaline and freeze−thaw cycles, has been investigated. The experimental campaign includes tensile tests on the fabric yarns, compression and flexural tests on the matrix and tensile tests (according to AC434) on FRCM prismatic coupons. The effects of the different environmental exposures on the mechanical properties of both the constituent materials and the composite system have been investigated and discussed. Ion chromatography analysis has also been performed to better understand the damage mechanisms induced by environmental exposures and to evaluate the ions’ penetration within the inorganic matrix. Alkaline e... [more]
Scale-Up Cultivation of Phaeodactylum tricornutum to Produce Biocrude by Hydrothermal Liquefaction
Irene Megía-Hervás, Alejandra Sánchez-Bayo, Luis Fernando Bautista, Victoria Morales, Federico G. Witt-Sousa, María Segura-Fornieles, Gemma Vicente
February 22, 2021 (v1)
Keywords: biocrude, culture, hydrothermal liquefaction, microalgae, Phaeodactylum tricornutum, scale-up
Phaeodactylum tricornutum is an interesting source of biomass to produce biocrude by hydrothermal liquefaction (HTL). Its biochemical composition, along with its biomass productivity, can be modulated according to this specific application by varying the photoperiod, the addition of CO2 or the variation of the initial nitrate concentration. The lab-scale culture allowed the production of a P. tricornutum biomass with high biomass and lipid productivities using a 18:6 h light:dark photoperiod and a specific CO2 injection. An initial concentration of nitrates (11.8 mM) in the culture was also essential for the growth of this species at the lab scale. The biomass generated in the scale-up photoreactor had acceptable biomass and lipid productivities, although the values were higher in the biomass cultivated at the lab scale because of the difficulty for the light to reach all cells, making the cells unable to develop and hindering their growth. The biocrudes from a 90-L cultivated microalg... [more]
Machine Learning for the Classification of Alzheimer’s Disease and Its Prodromal Stage Using Brain Diffusion Tensor Imaging Data: A Systematic Review
Lucia Billeci, Asia Badolato, Lorenzo Bachi, Alessandro Tonacci
February 22, 2021 (v1)
Keywords: Alzheimer’s disease, diffusion tensor imaging, Machine Learning, magnetic resonance imaging, mild cognitive impairment, support vector machine
Alzheimer’s disease is notoriously the most common cause of dementia in the elderly, affecting an increasing number of people. Although widespread, its causes and progression modalities are complex and still not fully understood. Through neuroimaging techniques, such as diffusion Magnetic Resonance (MR), more sophisticated and specific studies of the disease can be performed, offering a valuable tool for both its diagnosis and early detection. However, processing large quantities of medical images is not an easy task, and researchers have turned their attention towards machine learning, a set of computer algorithms that automatically adapt their output towards the intended goal. In this paper, a systematic review of recent machine learning applications on diffusion tensor imaging studies of Alzheimer’s disease is presented, highlighting the fundamental aspects of each work and reporting their performance score. A few examined studies also include mild cognitive impairment in the classi... [more]
Thermostable α-Glucan Phosphorylase-Catalyzed Enzymatic Copolymerization to Produce Partially 2-Deoxygenated Amyloses
Jun-ichi Kadokawa, Shota Nakamura, Kazuya Yamamoto
February 22, 2021 (v1)
Keywords: 2-deoxyamylose, d-glucal, enzymatic copolymerization, heteropolysaccharide, α-glucan phosphorylase
α-Glucan phosphorylase catalyzes the enzymatic polymerization of α-d-glucose 1-phosphate (Glc-1-P) monomers from a maltooligosaccharide primer to produce α(1→4)-glucan—i.e., amylose. In this study, by exploiting the weak specificity for the substrate recognition of a thermostable α-glucan phosphorylase (from Aquifex aeolicus VF5), we investigated the enzymatic copolymerization of 2-deoxy-α-d-glucose 1-phosphate (dGlc-1-P), which was produced in situ from d-glucal, with Glc-1-P to obtain non-natural heteropolysaccharides composed of α(1→4)-linked dGlc/Glc units—i.e., partially 2-deoxygenated amylose. The reactions were carried out at different monomer feed ratios using a maltotriose primer at 40 °C for 24 h. The products were precipitated from the reaction medium, isolated by centrifugation, and subjected to 1H NMR spectroscopic and powder X-ray diffraction measurements to evaluate their chemical and crystalline structures, respectively. Owing to its amorphous nature, the partially 2-de... [more]
Self-Humidifying Proton Exchange Membranes for Fuel Cell Applications: Advances and Challenges
Seyed Hesam Mirfarsi, Mohammad Javad Parnian, Soosan Rowshanzamir
February 22, 2021 (v1)
Keywords: gas cross-over, nanocomposite membranes, polymer electrolyte fuel cells, proton exchange membranes, self-humidifying membranes, ultra-thin membranes
Polymer electrolyte fuel cells (PEFCs) provide efficient and carbon-free power by converting the hydrogen chemical energy. The PEFCs can reach their greatest performance in humidified condition, as proton exchange membranes (PEMs) should be humidified for their proton transportation function. Thus, external humidifiers are commonly employed to increase the water content of reactants. However, being burdened with external humidifiers can make the control of PEFCs complicated and costly, in particular for transportation application. To overcome this issue, self-humidifying PEMs have been introduced, with which PEFC can be fed by dry reactants. In fact, internal humidification is accomplished by produced water from the recombination of permeated hydrogen and oxygen gases on the incorporated platinum catalysts within the PEM. While the water production agent remains constant, there is a broad range of additives that are utilized to retain the generated water and facilitate the proton condu... [more]
Quality Prediction and Yield Improvement in Process Manufacturing Based on Data Analytics
Ji-hye Jun, Tai-Woo Chang, Sungbum Jun
February 22, 2021 (v1)
Keywords: classification, process manufacturing, semi-supervised learning, time-series analysis, yield improvement
Quality management is important for maximizing yield in continuous-flow manufacturing. However, it is more difficult to manage quality in continuous-flow manufacturing than in discrete manufacturing because partial defects can significantly affect the quality of an entire lot of final product. In this paper, a comprehensive framework that consists of three steps is proposed to predict defects and improve yield by using semi-supervised learning, time-series analysis, and classification model. In Step 1, semi-supervised learning using both labeled and unlabeled data is applied to generate quality values. In addition, feature values are predicted in time-series analysis in Step 2. Finally, in Step 3, we predict quality values based on the data obtained in Step 1 and Step 2 and calculate yield values with the use of the predicted value. Compared to a conventional production plan, the suggested plan increases yield by up to 8.7%. The production plan proposed in this study is expected to con... [more]
Microfluidics for Two-Dimensional Nanosheets: A Mini Review
Chang-Ho Choi, Yeongwon Kwak, Rajiv Malhotra, Chih-Hung Chang
February 22, 2021 (v1)
Subject: Materials
Keywords: 2D materials, liquid exfoliation, microfluidics
Since the discovery of graphene, there has been increasing interest in two-dimensional (2D) materials. To realize practical applications of 2D materials, it is essential to isolate mono- or few-layered 2D nanosheets from unexfoliated counterparts. Liquid phase exfoliation (LPE) is the most common technique to produce atomically thin-layered 2D nanosheets. However, low production yield and prolonged process time remain key challenges. Recently, novel exfoliation processes based on microfluidics have been developed to achieve rapid and high yield production of few-layer 2D nanosheets. We review the primary types of microfluidic-based exfoliation techniques in terms of the underlying process mechanisms and the applications of the 2D nanosheets thus produced. The key challenges and future directions are discussed in the above context to delineate future research directions in this exciting area of materials processing.
Identification of Fungi in the Debitterizing Water of Apricot Kernels and Their Preliminary Evaluation on Degrading Amygdalin
Ning Zhang, Qing-An Zhang, Jian-Li Yao, Juan Francisco García-Martín
February 22, 2021 (v1)
Keywords: amygdalin, degradation, ITS, microorganisms, β-glucosidase
Debitterizing water contains a great amount of amygdalin, a potential toxic compound, so it is mandatory the degradation of amygdalin to reduce the water’s toxicity and environmental pollution. In this paper, the suspended mycelia in debitterizing water were firstly investigated by digital microscope, cold field emission scanning electron microscope, and internal transcribed spacers (ITS) high-throughput sequencing. Thereafter, the degradation of commercial amygdalin by the identified species was assessed by determining the changes of amygdalin content and the β-glucosidase activity. The results indicate that the mycelia matched with genus of lower fungi, mainly including Irpex, Trichoderma and white rot fungus. Among them, Irpex lacteus had a definite promoting effect on the degradation of amygdalin, which was not caused by producing β-glucosidase, and the suitable degrading colony numbers ranged from 6.4 × 106 CFU/mL to 6.4 × 107 CFU/mL. In conclusion, this research might provide a p... [more]
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