Recent Submissions
New records verified within the last 30 days
Real Wastewater Treatment Using a Moving Bed and Wastewater-Borne Algal−Bacterial Consortia with a Short Hydraulic Retention Time
Donghan Kang, Keugtae Kim
January 24, 2022 (v1)
Keywords: bacterial community, microalgae, moving media, photobioreactor
Algal−bacterial consortium is a promising technology, combined with wastewater treatment plants, because algae produce molecular oxygen for nitrification and organic removal and reduce carbon dioxide emissions. However, algal−bacterial consortia based on suspended growth require a relatively long hydraulic retention time (HRT) of 4 d to 6 d for removal of organic matter and nutrients. For the algal−bacterial consortia in a photobioreactor (PBR) containing a moving bed, the organic matter and nutrient removal and the community structure of algal−bacterial consortia were investigated to determine the performance under a relatively short HRT of 2.5 d. Moving media containing algal−bacterial consortia enhanced the photosynthetic oxygen concentration (0.2 mg dissolved oxygen (DO)·L−1 to 5.9 mg DO·L−1), biochemical oxygen demand removal (88.0% to 97.2%), ammoniacal nitrogen removal (33.8% to 95.3%), total nitrogen removal (61.6% to 87.7%), total phosphate removal (66.4% to 88.7%), algal grow... [more]
Bioactive Compounds Produced by the Accompanying Microflora in Bulgarian Yoghurt
Ivan Ivanov, Kaloyan Petrov, Valentin Lozanov, Iassen Hristov, Zhengjun Wu, Zhenmin Liu, Penka Petrova
January 24, 2022 (v1)
Keywords: Bulgarian yoghurt, cyclic peptides, IPA, Lactobacillus bulgaricus, metagenomics, MLST, PFGE, RAPD, Streptococcus thermophilus
Bulgarian yoghurt is associated with health benefits and longevity of consumers. The specific microflora producing bioactive metabolites is responsible for this effect. The present study examines the biodiversity in four homemade yoghurts from regions containing endemic microflora. Metagenome sequencing indicated Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus were predominant in all samples. In addition, yoghurts contained accompanying lactic acid bacteria (LAB) including Lacticaseibacillus paracasei, Lb. helveticus, Limosilactobacillus fermentum, Lb. rhamnosus, Lactococcus lactis, Pediococcus acidilactici, Leuconostoc mesenteroides, and Leuc. pseudomesenteroides. A negligible amount of pollutant strains was found. Twenty-four LAB strains were isolated from the yoghurts and identified. Lb. delbrueckii subsp. bulgaricus strains were genotyped by randomly amplified polymorphic DNA−PCR (RAPD), multi-locus sequence typing (MLST), and pulse field gel electrophore... [more]
Morphology and Structure Controls of Single-Atom Fe−N−C Catalysts Synthesized Using FePc Powders as the Precursor
Ning Yan, Fan Liu, Xu Meng, Meng Qin, Guangqi Zhu, Luxia Bu, Zigeng Liu, Wei Wang
January 24, 2022 (v1)
Keywords: Fe–N–C, morphology, ORR
Understanding the origin of the high electrocatalytic activity of Fe−N−C electrocatalysts for oxygen reduction reaction is critical but still challenging for developing efficient sustainable nonprecious metal catalysts used in fuel cells. Although there are plenty of papers concerning the morphology on the surface Fe−N−C catalysts, there is very little work discussing how temperature and pressure control the growth of nanoparticles. In our lab, a unique organic vapor deposition technology was developed to investigate the effect of the temperature and pressure on catalysts. The results indicated that synthesized catalysts exhibited three kinds of morphology—nanorods, nanofibers, and nanogranules—corresponding to different synthesis processes. The growth of the crystal is the root cause of the difference in the surface morphology of the catalyst, which can reasonably explain the effect of the temperature and pressure. The oxygen reduction reaction current densities of the different catal... [more]
Rapid and Green Preparation of Multi-Branched Gold Nanoparticles Using Surfactant-Free, Combined Ultrasound-Assisted Method
Phat Trong Huynh, Giang Dang Nguyen, Khanh Thi Le Tran, Thu Minh Ho, Vinh Quang Lam, Thanh Vo Ke Ngo
January 24, 2022 (v1)
Subject: Materials
Keywords: chitosan, green synthesis, hydroquinone, multi-branched gold nanoparticles, ultrasound
The conventional seed-mediated preparation of multi-branched gold nanoparticles uses either cetyltrimethylammonium bromide or sodium dodecyl sulfate. However, both surfactants are toxic to cells so they have to be removed before the multi-branched gold nanoparticles can be used in biomedical applications. This study describes a green and facile method for the preparation of multi-branched gold nanoparticles using hydroquinone as a reducing agent and chitosan as a stabilizer, through ultrasound irradiation to improve the multi-branched shape and stability. The influence of pH, mass concentration of chitosan, hydroquinone concentration, as well as sonication conditions such as amplitude and time of US on the growth of multi-branched gold nanoparticles, were also investigated. The spectra showed a broad band from 500 to over 1100 nm, an indication of the effects of both aggregation and contribution of multi-branches to the surface plasmon resonance signal. Transmission electron microscopy... [more]
Optimisation of the Geometric Parameters of Longitudinally Finned Air Cooler Tubes Operating in Mixed Convection Conditions
Piotr Kopeć, Beata Niezgoda-Żelasko
January 24, 2022 (v1)
Keywords: heat pump evaporator, longitudinal finned tubes, mixed convection, optimisation of geometric parameters
The results of optimisation calculations presented in the article are related to longitudinally finned tubes of a heat pump evaporator operating under natural wind-induced flow of outdoor air conditions. The finned surface is characterised by an unusual, wavy fin shape. The article presents the methodology applied to seeking optimal geometric parameters of the finned tube in which thermal calculations were performed by modelling a mixed convection process on the finned surface using the finite volume method. In the case of maximising the heat flow with the minimum mass of the fins, the optimal solution was dominated by the minimum mass of the fins and thus geometric parameters correspond to the number of fins n = 6, fin height h = 0.065 and fin thickness s = 0.0015 m. Optimisation calculations made for maximum efficiency of the exchanger at constant mass indicated that the tube with ten fins (n = 10) with a height of h = 0.11 m and a thickness of s = 0.0018 m allowed maximum heat flow... [more]
Influence of Surface Waviness of Journal and Bearing Bush on the Static Characteristics of Hydrodynamic Bearing
Minghui Yang, Hong Lu, Xinbao Zhang, Meng Duan, Liu Bao, Bowen Wang, Wan Wu
January 24, 2022 (v1)
Keywords: finite difference method, hydrodynamic journal bearing, static characteristics, surface waviness
An investigation on the surface waviness of both the journal and the bearing bush and their impact on the static characteristics of the hydrodynamic journal bearing is presented in this paper. The finite difference method is introduced to solve a Reynolds equation and obtain the unknown pressure field. The static characteristics, including the load carrying capacity, attitude angle, end leakage flow rate and frictional coefficient are studied under different waviness parameters. The numerically simulated results indicate that the waviness of the bearing bush may deteriorate or enhance the bearing system, depending on the phase angle. The waviness of the journal causes periodic changes in bearing behavior, owing to the alteration in the phase angle. The profile of the journal and bearing surfaces near the attitude angle determines the performance of the bearing system.
Investigation of Electrochemical Processes in Solid Oxide Fuel Cells by Modified Levenberg−Marquardt Algorithm: A New Automatic Update Limit Strategy
Mark Žic, Iztok Fajfar, Vanja Subotić, Sergei Pereverzyev, Matevž Kunaver
January 24, 2022 (v1)
Keywords: automatic limit strategy, CNLS, LMA, off-limits, processes
Identification of ongoing processes in solid oxide fuel cells (SOFC) enables both optimizing the operating environment and prolonging the lifetime of SOFC. The Levenberg−Marquardt algorithm (LMA) is commonly used in the characterization of unknown electrochemical processes within SOFC by extracting equivalent electrical circuit (EEC) parameter values from electrochemical impedance spectroscopy (EIS) data. LMA is an iteration optimization algorithm regularly applied to solve complex nonlinear least square (CNLS) problems. The LMA convergence can be boosted by the application of an ordinary limit strategy, which avoids the occurrence of off-limit values during the fit. However, to additionally improve LMA descent properties and to discard the problem of a poor initial parameters choice, it is necessary to modify the ordinary limit strategy. In this work, we designed a new automatic update (i.e., adaptive) limit strategy whose purpose is to reduce the impact of a poor initial parameter ch... [more]
Identifying Shared Risk Genes between Nonalcoholic Fatty Liver Disease and Metabolic Traits by Cross-Trait Association Analysis
Hongping Guo, Zuguo Yu
January 24, 2022 (v1)
Subject: Biosystems
Keywords: metabolic trait, nonalcoholic fatty liver disease, shared gene
Nonalcoholic fatty liver disease (NAFLD) generally co-occurs with metabolic disorders, but it is unclear which genes have a pleiotripic effect on NAFLD and metabolic traits. We performed a large-scale cross-trait association analysis to identify the overlapping genes between NAFLD and nine metabolic traits. Among all the metabolic traits, we found that obesity and type II diabetes are associated with NAFLD. Then, a multitrait association analysis among NAFLD, obesity and type II diabetes was conducted to improve the overall statistical power. We identified 792 significant variants by a cross-trait meta-analysis involving 100 pleiotripic genes. Moreover, we detected another two common genes by a genome-wide gene test. The results from the pathway enrichment analysis show that the 102 shared risk genes are enriched in cancer, diabetes, insulin secretion, and other related pathways. This study can help us understand the molecular mechanisms underlying comorbid NAFLD and metabolic disorder... [more]
Case Study of Anaerobic Digestion Process Stability Detected by Dissolved Hydrogen Concentration
Daniela Platošová, Jiří Rusín, Jan Platoš, Kateřina Smutná, Roman Buryjan
January 24, 2022 (v1)
Keywords: amperometric sensor, anaerobic digestion, dissolved hydrogen, Fermentation, rotary bioreactor
The paper presents the results of a laboratory experiment of mesophilic single-stage anaerobic digestion performed to verify the possibility of early detection of process instability and reactor overload by evaluating the course of dissolved hydrogen concentration of the main intermediate. The digestion process was run in a Terrafors IS rotary drum bioreactor for 230 days. The substrate dosed on weekdays was food leftovers from the university canteen. At an average temperature of 37 °C, an organic loading of volatiles of 0.858 kg m−3 day−1 and a theoretical retention time of 259 days, biogas production of 0.617 Nm3 kg VS−1 was achieved with a CH4 content of 51.7 vol. %. The values of the established FOS/TAC stability indicator ranged from 0.26 to 11.4. The highest value was reached when the reactor was overloaded. The dissolved hydrogen concentration measured by the amperometric microsensor ranged from 0.039−0.425 mg dm−3. Data were statistically processed using Pearson’s correlation c... [more]
Batch Mode Reactor for 3,5-Dinitrosalicylic Acid Degradation by Phanerochaete chrysosporium
Rafał Madaj, Witold Sroczyński, Michał Sójka, Tomasz P. Olejnik, Elżbieta Sobiecka
January 24, 2022 (v1)
Keywords: batch reactor, biodegradation, Phanerochaete chrysosporium, the 3,5-dinitrosalicylic acid
A new batch mode reactor was constructed to conduct continuous biodegradation of 3,5-dinitrosalicylic acid. Various types of matrices with immobilized Phanerochaete chrysosporium were immersed in a solution containing pollutant and mineral nutrients. Three parameters were chosen to optimize the process. The nitrate and nitrite ions concentrations and HPLC analysis were used to prove the biodegradation of 3,5-dinitrosalicylic acid, and the mixed effects model using one-factor ANOVA was used for statistical calculations. The results showed the correlation between the initial pH, a medium composition, and the process time. In pH = 6.5, the degradation effectiveness was estimated at 99% decrease in the substrate within 14 days, while an 80% decrease of acid concentration was indicated in pH = 3.5 after 28 days of the process duration.
Investigation on the Performance Enhancement and Emission Reduction of a Biodiesel Fueled Diesel Engine Based on an Improved Entire Diesel Engine Simulation Model
Weigang Yu, Zhiqing Zhang, Bo Liu
January 24, 2022 (v1)
Keywords: biodiesel fuel, comprehensive performance, diesel engine, fuel injection rate, fuel injection system
In order to improve the efficiency of the diesel engine and reduce emissions, an improved heat transfer model was developed in an AVL-BOOST environment which is a powerful and user-friendly software for engine steady-state and transient performance analysis. The improved heat transfer model considers the advantages of the Woschni1978 heat transfer model and Honhenberg heat transfer model. In addition, a five-component biodiesel skeletal mechanism containing 475 reactions and 134 species was developed to simulate the fuel spray process and combustion process since it contained methyl linolenate, methyl linoleate, methyl oleate, methyl stearate, and methyl palmitate, which are a majority component in most biodiesel. Finally, the propulsion and load characteristics of a diesel engine fueled with biodiesel fuel were investigated by the improved heat transfer model in term of power, brake specific fuel consumption (BSFC), soot and NOx emissions. Similarly, the effects of the fuel injection... [more]
Chitosan Plasma Chemical Processing in Beam-Plasma Reactors as a Way of Environmentally Friendly Phytostimulants Production
Tatiana Vasilieva, Oscar Goñi, Patrick Quille, Shane O’Connell, Dmitry Kosyakov, Semen Shestakov, Nikolay Ul’yanovskii, Michael Vasiliev
January 24, 2022 (v1)
Keywords: chitooligosaccharides, electron-beam plasma, plant biostimulants, plasma chemical processing
A novel technique of phytoactive water-soluble chitooligosaccharide (COS) production in low-temperature plasma is described. Design, operation, and control of plasma chemical reactors used to produce COS from the powder of high molecular weight chitosan are presented. The electron beam plasma is strongly non-equilibrium and chemically active; plasma was excited by injecting the scanning electron beam into reaction volume filled with aerosol, containing oxygen and chitosan powder. Plasma chemical processes, responsible for the raw chitosan destruction and techniques of these processes to obtain control of products of optimal molecular weight, are considered. COS, in amounts sufficient for laboratory tests with some plants, were produced. Tests showed that the addition of COS into the liquid growing medium at 0.25 and 1 mg/mL stimulates root growth in Arabidopsis thaliana seedlings (Col-0) by up to 40%, with respect to control plants. Foliar application of these COS formulations at 0.25... [more]
Algorithmic Approaches to Inventory Management Optimization
Hector D. Perez, Christian D. Hubbs, Can Li, Ignacio E. Grossmann
January 24, 2022 (v1)
Keywords: inventory management, multi-echelon, reinforcement learning, stochastic programming, Supply Chain
An inventory management problem is addressed for a make-to-order supply chain that has inventory holding and/or manufacturing locations at each node. The lead times between nodes and production capacity limits are heterogeneous across the network. This study focuses on a single product, a multi-period centralized system in which a retailer is subject to an uncertain stationary consumer demand at each time period. Two sales scenarios are considered for any unfulfilled demand: backlogging or lost sales. The daily inventory replenishment requests from immediate suppliers throughout the network are modeled and optimized using three different approaches: (1) deterministic linear programming, (2) multi-stage stochastic linear programming, and (3) reinforcement learning. The performance of the three methods is compared and contrasted in terms of profit (reward), service level, and inventory profiles throughout the supply chain. The proposed optimization strategies are tested in a stochastic s... [more]
Optimal Production and Inventory Policy in a Multiproduct Bakery Unit
Belmiro P. M. Duarte, André M. M. Gonçalves, Lino O. Santos
January 24, 2022 (v1)
Keywords: food processing unit, inventory policy, multiproduct plant, optimal production policy
The problem of finding optimal production and inventory policies is crucial for companies of the food industry, especially those processing multiple products. Since companies are required to adopt the most efficient solutions to prosper, the operation at these optimal conditions can have an extensive impact on profit, resource allocation and product quality. We address the problem of finding the optimal production and inventory policy in a multiproduct bakery unit for two contexts: (i) deterministic consumption without inventory control; and (ii) stochastic consumption combined with delayed inventory control. A formulation is proposed for each of these two setups. The restrictions considered in the model framework are related to workforce availability, and the cost structure includes four components: (i) production cost; (ii) inventory cost; (iii) setup cost; and (iv) the cost due to the degradation of perceived quality. The problem is formulated as a Mixed Integer Linear Programming o... [more]
Advances in Biomass Co-Combustion with Fossil Fuels in the European Context: A Review
Miroslav Variny, Augustín Varga, Miroslav Rimár, Ján Janošovský, Ján Kizek, Ladislav Lukáč, Gustáv Jablonský, Otto Mierka
January 24, 2022 (v1)
Subject: Energy Policy
Keywords: ash, biomass pretreatment, co-combustion, Fossil Fuel, greenhouse gases, oxy-combustion, reburning, synergy
Co-combustion of biomass-based fuels and fossil fuels in power plant boilers, utility boilers, and process furnaces is a widely acknowledged means of efficient heat and power production, offering higher power production than comparable systems with sole biomass combustion. This, in combination with CO2 and other greenhouse gases abatement and low specific cost of system retrofit to co-combustion, counts among the tangible advantages of co-combustion application. Technical and operational issues regarding the accelerated fouling, slagging, and corrosion risk, as well as optimal combustion air distribution impact on produced greenhouse gases emissions and ash properties, belong to intensely researched topics nowadays in parallel with the combustion aggregates design optimization, the advanced feed pretreatment techniques, and the co-combustion life cycle assessment. This review addresses the said topics in a systematic manner, starting with feed availability, its pretreatment, fuel prope... [more]
Cold Plasma Deposition of Polymeric Nanoprotrusion, Nanoparticles, and Nanofilm Structures on a Slide Glass Surface
Sun-Woo Yi, In-Keun Yu, Woon-Jung Kim, Seong-Ho Choi
January 24, 2022 (v1)
Subject: Materials
Keywords: methyl methacrylate (MMA), nanofilm structure, nanoparticles structure, nanoprotrusion structure, plasma process, super hydrophobic properties, trifluoro methylmethacrylate (TFMA), trimethylsilyl methyl methacrylate (TSMA)
In this study, we coated the surface of glass slides with nanoprotrusion, nanoparticles, and nanofilm structures by one-step plasma deposition of three vinyl monomers. Three functional vinyl monomers with symmetrical polarity sites were used: methyl methacrylate (MMA), trifluoro methylmethacrylate (TFMA), and trimethylsilyl methyl methacrylate (TSMA). The TSMA/MMA (80/20, mol-%) nanoprotrusion-coated surface of slide glass was superhydrophobic, with a 153° contact angle. We also evaluated the transmittance (%) of the slide glass with nanoprotrusions in the infrared (IR) (940 nm), ultraviolet (365 nm) and visible light (380−700 nm) regions. The obtained nanoprotrusion structure surface of slide glass created by plasma deposition transmits more than 90% of visible light.
Population-Based Parameter Identification for Dynamical Models of Biological Networks with an Application to Saccharomyces cerevisiae
Ewelina Weglarz-Tomczak, Jakub M. Tomczak, Agoston E. Eiben, Stanley Brul
January 24, 2022 (v1)
Keywords: derivative-free optimization, dynamic models, evolutionary computing, glycolysis, metabolism, yeast
One of the central elements in systems biology is the interaction between mathematical modeling and measured quantities. Typically, biological phenomena are represented as dynamical systems, and they are further analyzed and comprehended by identifying model parameters using experimental data. However, all model parameters cannot be found by gradient-based optimization methods by fitting the model to the experimental data due to the non-differentiable character of the problem. Here, we present POPI4SB, a Python-based framework for population-based parameter identification of dynamic models in systems biology. The code is built on top of PySCeS that provides an engine to run dynamic simulations. The idea behind the methodology is to provide a set of derivative-free optimization methods that utilize a population of candidate solutions to find a better solution iteratively. Additionally, we propose two surrogate-assisted population-based methods, namely, a combination of a k-nearest-neigh... [more]
Centrifugal Microfluidic Integration of 4-Plex ddPCR Demonstrated by the Quantification of Cancer-Associated Point Mutations
Franziska Schlenker, Elena Kipf, Nadine Borst, Nils Paust, Roland Zengerle, Felix von Stetten, Peter Juelg, Tobias Hutzenlaub
January 24, 2022 (v1)
Subject: Biosystems
Keywords: centrifugal step emulsification, digital droplet polymerase chain reaction (ddPCR), droplet fluorescence evaluation, droplet stability, microfluidics, multiplexing
We present the centrifugal microfluidic implementation of a four-plex digital droplet polymerase chain reaction (ddPCR). The platform features 12 identical ddPCR units on a LabDisk cartridge, each capable of generating droplets with a diameter of 82.7 ± 9 µm. By investigating different oil−surfactant concentrations, we identified a robust process for droplet generation and stabilization. We observed high droplet stability during thermocycling and endpoint fluorescence imaging, as is required for ddPCRs. Furthermore, we introduce an automated process for four-color fluorescence imaging using a commercial cell analysis microscope, including a customized software pipeline for ddPCR image evaluation. The applicability of ddPCRs is demonstrated by the quantification of three cancer-associated KRAS point mutations (G12D, G12V and G12A) in a diagnostically relevant wild type DNA background. The four-plex assay showed high sensitivity (3.5−35 mutant DNA copies in 15,000 wild type DNA copies) a... [more]
Development of Carbonization and a Relatively High-Temperature Halogenation Process for the Removal of Radionuclides from Spent Ion Exchange Resins
Hee-Chul Yang, Hyeon-Oh Park, Kyu-Tae Park, Sung-Jun Kim, Hyung-Ju Kim, Hee-Chul Eun, Keunyoung Lee
January 24, 2022 (v1)
Keywords: carbonization, halogenation, kinetic analysis, numerical optimization, spent resin, thermodynamic analysis
This study investigated a two-step thermochemical treatment process consisting of carbonization and halogenation for the removal of radionuclides from spent cation-exchange resin (CER). Based on a thermal analysis of cation-exchange resins, we propose a two-step thermochemical treatment process involving the conversion of spent CER into pyrocarbon and then the removal of radioactive elements from the carbonized CER by converting them volatile halides at very high temperatures. The proposed process mainly consists of a carbonization and halogenation reactor, a UHC (unburned hydrocarbon) combustor, and wet scrubber. A step-by-step experimental and numerical optimization study was conducted with the carbonization and halogenation reactor and the UHC combustor. The optimum operating conditions could be established based on the results of a thermal analysis of the CER, a nonisothermal kinetic analysis, a numerical modeling study of a plug flow reactor (PFR)-type combustor, and a thermodynam... [more]
Learn Aspen Plus in 24 Hours 2nd Edition Solution Files
Thomas A. Adams II
January 6, 2022 (v1)
Keywords: Aspen Plus, Education, Learn Aspen Plus in 24 Hours, Simulation
These Aspen Plus v12 simulations are the solution or demonstration files for the book Learn Aspen Plus in 24 Hours, 2nd Edition, by Thomas A. Adams II. They are given as-is with no warranty or guarantee of accuracy or correctness. They are for educational purposes only.

The files list contains a large .zip of all files, or otherwise you can download them independently.

Files correspond to these tutorials:

Tutorial 2 Physical Property Modelling - Selecting physical properties. Understanding the database.
Tutorial 3 Problem Solving Tools - Design Specs and Sensitivity Analyses
Tutorial 4 Heat Exchangers - HEATER, HEATX
Tutorial 5 Equilibrium-based Distillation Models - RadFrac (in equilibrium mode)
Tutorial 6 Advanced Problem Solving Tools - Utilities, GHG Emissions, Optimization
Tutorial 7 Chemical Reactor Models - RSTOIC, REQUIL, RYIELD, RGIBBS, RCSTR, RPFR
Tutorial 8 Rate-based Distillation Models - RadFrac (in rate-based mode)
Tutorial 9 Custom Models and External Con... [more]
Dynamic Lifecycle Assessment of Solid Oxide Fuel Cell System Considering Long-Term Degradation Effects
Mina Naeini, James S. Cotton, Thomas A. Adams II
December 15, 2021 (v1)
Keywords: Environmental impacts, Life Cycle Analysis, Performance degradation, SOFC
The submission includes SimaPro project for LCA of SOFCs with 10-year replacement plan, a text file explaining how to run the SimaPro file, and SOFC inventory tables provided in an Excel file.