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Records Added in July 2021
Records added in July 2021
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Showing records 1 to 25 of 104. [First] Page: 1 2 3 4 5 Last
Prototype of the Runway Monitoring Process at Smaller Airports: Edvard Rusjan Airport Maribor
Boštjan Kovačič, Damjan Želodec, Damjan Doler
July 29, 2021 (v1)
Keywords: airport, deformations, FWD, geo-information model, geodesy, measurements, monitoring, vertical deviations
The last 20-year announcement predicts a 3.5% increase in the number of yearly passengers which will result in the doubling of the number of passengers in air transport by 2037. Such anticipation indicates the need for efficient monitoring of airport infrastructure as the support of opportune and efficient maintenance works. The novelties of this article are a process model of maintenance and monitoring, suitable for smaller and less burdened airports, and the methodology of monitoring of runways by implementation of the geodetic and geomechanics falling weight deflectometer (FWD) method. In addition, the results confirm the assumption that a specific environment such as an airport allows for sufficiently reliable determination of deformation areas or areas of vertical deviations of runways in a relative short time period available for measurements by using geodetic methods only or by combining other methods; our research model includes the FWD method. With the research, we have also s... [more]
Mixing of Particles in a Rotating Drum with Inclined Axis of Rotation
Parag Widhate, Haiping Zhu, Qinghua Zeng, Kejun Dong
July 29, 2021 (v1)
Keywords: discrete element method, Mixing, rotating drum
Various experimental and numerical studies have been carried out to study the mixing processes inside rotating drums with a horizontal axis of rotation in the past, but little effort has been made to investigate the rotating drums with an inclined axis of rotation, though such inclined drums exist in industrial waste management, food processing, power and pharmaceutical industries. To fill this gap, in this work, the discrete element method was used to study the mixing phenomena of a rotating drum for different angles of inclination from 0° to 15°. It was found that for inclined rotating drums, the whole bed Lacey mixing index is higher than that for the horizontal drum by 7.2% when the angle of inclination is 10°. The mixing index is related to the area ratio of the active region to the whole bed and volumetric fill. Increase in volumetric fill would lead to the decrease of the mixing index. The mixing index and area ratio exhibit similar patterns along the length of the drum for diff... [more]
Comparative Study on CFD Turbulence Models for the Flow Field in Air Cooled Radiator
Chao Yu, Xiangyao Xue, Kui Shi, Mingzhen Shao, Yang Liu
July 29, 2021 (v1)
Keywords: Computational Fluid Dynamics, engine compartment, heat transfer, turbulent model, vortex
This paper compares the performances of three Computational Fluid Dynamics (CFD) turbulence models, Reynolds Average Navier-Stokes (RANS), Detached Eddy Simulation (DES), and Large Eddy Simulation (LES), for simulating the flow field of a wheel loader engine compartment. The distributions of pressure fields, velocity fields, and vortex structures in a hybrid-grided engine compartment model are analyzed. The result reveals that the LES and DES can capture the detachment and breakage of the trailing edge more abundantly and meticulously than RANS. Additionally, by comparing the relevant calculation time, the feasibility of the DES model is proved to simulate the three-dimensional unsteady flow of engine compartment efficiently and accurately. This paper aims to provide a guiding idea for simulating the transient flow field in the engine compartment, which could serve as a theoretical basis for optimizing and improving the layout of the components of the engine compartment.
Subspace Based Model Identification for an Industrial Bioreactor: Handling Infrequent Sampling Using Missing Data Algorithms
Nikesh Patel, Brandon Corbett, Johan Trygg, Chris McCready, Prashant Mhaskar
July 29, 2021 (v1)
Keywords: data driven model identification, missing data, subspace identification
This manuscript addresses the problem of modeling an industrial (Sartorius) bioreactor using process data. In the context of the Sartorius Bioreactor, it is important to appropriately address the problem of dealing with a large number of variables, which are not always measured or are measured at different sampling rates, without taking recourse to simpler interpolation- or imputation-based approaches. To this end, a dynamic model for the Sartorius Bioreactor is developed via appropriately adapting a recently presented subspace model identification technique, which in turn uses nonlinear iterative partial least squares (NIPALS) algorithms to gracefully handle the missing data. The other key contribution is evaluating the ability of the identification approach to provide insight into the process by computing interpretable variables such as metabolite rates. The results demonstrate the ability of the proposed approach to model data from the Sartorius Bioreactor.
Characterization of a Wireless Vacuum Sensor Prototype Based on the SAW-Pirani Principle
Sofia Toto, Mazin Jouda, Jan G. Korvink, Suparna Sundarayyan, Achim Voigt, Hossein Davoodi, Juergen J. Brandner
July 29, 2021 (v1)
Keywords: compact, Pirani, SAW, sensing, vacuum, wireless
A prototype of a wireless vacuum microsensor combining the Pirani principle and surface acoustic waves (SAW) with extended range and sensitivity was designed, modelled, manufactured and characterised under different conditions. The main components of the prototype are a sensing SAW chip, a heating coil and an interrogation antenna. All the components were assembled on a 15 mm × 11 mm × 3 mm printed circuit board (PCB). The behaviour of the PCB was characterised under ambient conditions and in vacuum. The quality of the SAW interrogation signal, the frequency shift and the received current of the coil were measured for different configurations. Pressures between 0.9 and 100,000 Pa were detected with sensitivities between 2.8 GHz/Pa at 0.9 Pa and 1 Hz/Pa close to atmospheric pressure. This experiment allowed us to determine the optimal operating conditions of the sensor and the integration conditions inside a vacuum chamber in addition to obtaining a pressure-dependent signal.
Flow and Diffusion Characteristics of Typical Halon Extinguishing Agent Substitute under Different Release Pressures
Jiaming Jin, Renming Pan, Ruiyu Chen, Xiaokang Xu, Quanwei Li
July 29, 2021 (v1)
Subject: Other
Keywords: aircraft weight reduction, diffusion, flow, Halon candidate substitute, HFC-125, release pressure
To provide guidance towards reducing the weight of the HFC-125 storage vessel by reducing the release pressure and to reveal the effects of release pressure on the extinguishing efficiency of HFC-125, we investigated the flow and diffusion characteristics of HFC-125 under six release pressures in the present study. The influence of release pressure on the degree of superheat, injection duration, pressure loss, jet angle, and concentration distribution were analyzed. Results show that the degree of superheat and the injection duration both decreased with the release pressure. The bubble expansion in the HFC-125 could slow down the pressure decrease in the storage vessel. The flow process in the pipeline can be divided into three phases: pipeline filling, stable flow, and mixed gases release. Both of the maximum and mean values of the pipeline pressure loss increased with the release pressure. The maximum concentration value decreased with the increase of the distance from the nozzle. Th... [more]
Iron-Based Catalytically Active Complexes in Preparation of Functional Materials
Katarzyna Rydel-Ciszek, Tomasz Pacześniak, Izabela Zaborniak, Paweł Błoniarz, Karolina Surmacz, Andrzej Sobkowiak, Paweł Chmielarz
July 29, 2021 (v1)
Keywords: “green” oxidants, controlled radical polymerization, heterogeneous catalysis, homogeneous catalysis, iron-based catalysts, oxidation processes
Iron complexes are particularly interesting as catalyst systems over the other transition metals (including noble metals) due to iron’s high natural abundance and mediation in important biological processes, therefore making them non-toxic, cost-effective, and biocompatible. Both homogeneous and heterogeneous catalysis mediated by iron as a transition metal have found applications in many industries, including oxidation, C-C bond formation, hydrocarboxylation and dehydration, hydrogenation and reduction reactions of low molecular weight molecules. These processes provided substrates for industrial-scale use, e.g., switchable materials, sustainable and scalable energy storage technologies, drugs for the treatment of cancer, and high molecular weight polymer materials with a predetermined structure through controlled radical polymerization techniques. This review provides a detailed statement of the utilization of homogeneous and heterogeneous iron-based catalysts for the synthesis of bo... [more]
An Integrated Approach to the Design of Centralized and Decentralized Biorefineries with Environmental, Safety, and Economic Objectives
Antioco López-Molina, Debalina Sengupta, Claire Shi, Eman Aldamigh, Maha Alandejani, Mahmoud M. El-Halwagi
July 29, 2021 (v1)
Keywords: biorefining, CAPEX correlation, centralized facilities, distributed manufacturing, integration, sustainable design
Biorefineries provide economic, environmental, and social benefits towards sustainable development. Because of the relatively small size of typical biorefineries compared to oil and gas processes, it is necessary to evaluate the options of decentralized (or distributed) plants that are constructed near the biomass resources and product markets versus centralized (or consolidated) facilities that collect biomass from different regions and distribute the products to the markets, benefiting from the economy of scale but suffering from the additional transportation costs. The problem is further compounded when, in addition to the economic factors, environmental and safety aspects are considered. This work presents an integrated approach to the design of biorefining facilities while considering the centralized and decentralized options and the economic, environmental, and safety objectives. A superstructure representation is constructed to embed the various options of interest. A mathematic... [more]
The Effects of Biofertilizers on Growth, Soil Fertility, and Nutrients Uptake of Oil Palm (Elaeis Guineensis) under Greenhouse Conditions
Aaronn Avit Ajeng, Rosazlin Abdullah, Marlinda Abdul Malek, Kit Wayne Chew, Yeek-Chia Ho, Tau Chuan Ling, Beng Fye Lau, Pau Loke Show
July 29, 2021 (v1)
Keywords: biofertilizers, chemical fertilizer, oil palm seedlings nursery, plant growth promoting rhizobacteria
The full dependency on chemical fertilizers in oil palm plantation poses an enormous threat to the ecosystem through the degradation of soil and water quality through leaching to the groundwater and contaminating the river. A greenhouse study was conducted to test the effect of combinations of biofertilizers with chemical fertilizer focusing on the soil fertility, nutrient uptake, and the growth performance of oil palms seedlings. Soils used were histosol, spodosol, oxisol, and ultisol. The three treatments were T1: 100% chemical fertilizer (NPK 12:12:17), T2: 70% chemical fertilizer + 30% biofertilizer A (CF + BFA), and T3: 70% + 30% biofertilizer B (CF + BFB). T2 and T3, respectively increased the growth of oil palm seedlings and soil nutrient status but seedlings in oxisol and ultisol under T3 had the highest in almost all parameters due to the abundance of more efficient PGPR. The height of seedlings in ultisol under T3 was 22% and 17% more than T2 and T1 respectively, with enhance... [more]
Ultrasonically Induced Polymerization and Polymer Grafting in the Presence of Carbonaceous Nanoparticles
Sarah Cohen, Evgeni Zelikman, Ran Yosef Suckeveriene
July 29, 2021 (v1)
Subject: Materials
Keywords: grafting, nanoparticles, polymerization, sonochemistry
Nanotechnology refers to technologies using at least one nanometric dimension. Most advances have been in the field of nanomaterials used in research and industry. The vast potential of polymeric nanocomposites for advanced materials and applications such as hybrid nanocomposites with customized electrical conductivity, anti-bacterial, anti-viral, and anti-fog properties have attracted considerable attention. The number of studies on the preparation of nanocomposites in the presence of carbon materials, i.e., carbon nanotubes (CNTs) and graphene, has intensified over the last decade with the growing interest in their outstanding synergic properties. However, the functionality of such nanocomposites depends on overcoming three key challenges: (a) the breakdown of nanoparticle agglomerates; (b) the attachment of functional materials to the nanoparticle surfaces; and (c) the fine dispersion of functional nanoparticles within the polymeric matrices. Ultrasonic polymerization and grafting i... [more]
Experimental Study on Ramp Shock Wave Control in Ma3 Supersonic Flow Using Two-Electrode SparkJet Actuator
Wei Xie, Zhenbing Luo, Yan Zhou, Lin Wang, Wenqiang Peng, Tianxiang Gao
July 29, 2021 (v1)
Keywords: dynamic pressure measurement, schlieren images, shock wave control, SparkJet actuator, supersonic flow
The control of a shock wave produced by a ramp (ramp shock) in Ma3 supersonic flow using a two-electrode SparkJet (SPJ) actuator in a single-pulse mode is studied experimentally. Except for schlieren images of the interaction process of SPJ with the flow field, a dynamic pressure measurement method is also used in the analysis of shock wave control. In a typical experimental case, under the control of single-pulsed SPJ, the characteristic of ramp shock changes from “short-term local upstream motion” in the initial stage to “long-term whole downstream motion” in the later stage. The angle and position of the ramp shock changes significantly in the whole control process. In addition, the dynamic pressure measurement result shows that the ramp pressure is reduced by a maximum of 79% compared to that in the base flow field, which indicates that the ramp shock is significantly weakened by SPJ. The effects of some parameters on the control effect of SPJ on the ramp shock are investigated and... [more]
A Review of Process Systems Engineering (PSE) Tools for the Design of Ionic Liquids and Integrated Biorefineries
Nishanth G. Chemmangattuvalappil, Denny K. S. Ng, Lik Yin Ng, Jecksin Ooi, Jia Wen Chong, Mario R. Eden
July 29, 2021 (v1)
Keywords: integrated biorefineries, ionic liquids, molecular design, process optimization, process systems engineering
In this review paper, a brief overview of the increasing applicability of Process Systems Engineering (PSE) tools in two research areas, which are the design of ionic liquids and the design of integrated biorefineries, is presented. The development and advances of novel computational tools and optimization approaches in recent years have enabled these applications with practical results. A general introduction to ionic liquids and their various applications is presented followed by the major challenges in the design of optimal ionic liquids. Significant improvements in computational efficiency have made it possible to provide more reliable data for optimal system design, minimize the production cost of ionic liquids, and reduce the environmental impact caused by such solvents. Hence, the development of novel computational tools and optimization tools that contribute to the design of ionic liquids have been reviewed in detail. A detailed review of the recent developments in PSE applicat... [more]
VectorDisk: A Microfluidic Platform Integrating Diagnostic Markers for Evidence-Based Mosquito Control
Sebastian Hin, Desirée Baumgartner, Mara Specht, Jan Lüddecke, Ehsan Mahmodi Arjmand, Benita Johannsen, Larissa Schiedel, Markus Rombach, Nils Paust, Felix von Stetten, Roland Zengerle, Nadja Wipf, Pie Müller, Konstantinos Mavridis, John Vontas, Konstantinos Mitsakakis
July 29, 2021 (v1)
Subject: Biosystems
Keywords: arboviruses, insecticide resistances, LabDisk, malaria, microfluidics, mosquito monitoring, vector-borne diseases
Effective mosquito monitoring relies on the accurate identification and characterization of the target population. Since this process requires specialist knowledge and equipment that is not widely available, automated field-deployable systems are highly desirable. We present a centrifugal microfluidic cartridge, the VectorDisk, which integrates TaqMan PCR assays in two feasibility studies, aiming to assess multiplexing capability, specificity, and reproducibility in detecting disk-integrated vector-related assays. In the first study, pools of 10 mosquitoes were used as samples. We tested 18 disks with 27 DNA and RNA assays each, using a combination of multiple microfluidic chambers and detection wavelengths (geometric and color multiplexing) to identify mosquito and malaria parasite species as well as insecticide resistance mechanisms. In the second study, purified nucleic acids served as samples to test arboviral and malaria infective mosquito assays. Nine disks were tested with 14 as... [more]
Pharmacoeconomic Analysis of Hemophilia Care in Romania
Petre Serban, Brigitha Vlaicu, Margit Serban, Cristina Emilia Ursu, Adina Traila, Cristian Jinca, Jenel Marian Patrascu, Daniel Andrei, Andrei Kozma, Teodora Smaranda Arghirescu
July 29, 2021 (v1)
Subject: Biosystems
Keywords: hemophilia, ICER, socio-economic burden
Hemophilia, a congenital X linked disease, has the serious burden of bleeding, requiring life-long replacement with coagulation factors (CF). In the present day, there is a continuously improving treatment for this condition. Objective: Our observational, cross-sectional study aims at finding out whether a prophylactic replacement with CF is affordable from the point of view of its cost-effectiveness in our country. Material and methods: A cohort of 122 persons with hemophilia were included in this patient-reported outcome survey, and they answered a questionnaire consisting of 56 items, focused on 4 domains—socio-demographic, medical, quality of health/life and cost/cost-effectiveness. Results and discussion: The markers for quality of health/life were correlated with the direct and indirect costs of care, comparing subgroup 1 of patients with prophylactic vs. subgroup 2 with on-demand replacement. Based on the incremental quality adjusted life years and the incremental costs, we calc... [more]
Experimental Study on the Flow and Heat Transfer of Graphene-Based Lubricants in a Horizontal Tube
Zhongpan Cai, Maocheng Tian, Guanmin Zhang
July 29, 2021 (v1)
Subject: Materials
Keywords: convection heat transfer, graphene, nanofluid, thermal conductivity
To improve the heat transfer characteristics of lubricant, graphene-based lubricants were prepared by adding graphene particles, due to its advantages of excellent thermal conductivity and two-dimensional sheet structure. In the present study, its physical properties were measured. A flow heat transfer experiment platform was built to study the flow and heat transfer characteristics of the graphene lubricating oil in a horizontal circular tube. The results show that the graphene lubricant prepared using a two-step approach had good stability, and the dispersibility was good without the agglomeration phenomenon, according to measurements undertaken using an electron microscope and centrifuge. The thermal conductivity and viscosity of graphene lubricant increased with the increase of the graphene concentration, and the thermal conductivity of graphene lubricant with the same concentration decreased with the increase of temperature. When the concentration was equal, the convective heat tr... [more]
Antifungal Effect of Volatile Organic Compounds from Bacillus velezensis CT32 against Verticillium dahliae and Fusarium oxysporum
Xinxin Li, Xiuhong Wang, Xiangyuan Shi, Baoping Wang, Meiping Li, Qi Wang, Shengwan Zhang
July 29, 2021 (v1)
Subject: Biosystems
Keywords: Bacillus velezensis, biocontrol, vascular wilt pathogens, volatile organic compounds
The present study focuses on the inhibitory effect of volatile metabolites released by Bacillus velezensis CT32 on Verticillium dahliae and Fusarium oxysporum, the causal agents of strawberry vascular wilt. The CT32 strain was isolated from maize straw compost tea and identified as B. velezensis based on 16S rRNA gene sequence analysis. Bioassays conducted in sealed plates revealed that the volatile organic compounds (VOCs) produced by the strain CT32 possessed broad-spectrum antifungal activity against eight phytopathogenic fungi. The volatile profile of strain CT32 was obtained by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). A total of 30 volatile compounds were identified, six of which have not previously been detected in bacteria or fungi: (Z)-5-undecene, decyl formate, 2,4-dimethyl-6-tert-butylphenol, dodecanenitrile, 2-methylpentadecane and 2,2’,5,5’-tetramethyl-1,1’-biphenyl. Pure compounds were tested in vitro for th... [more]
Methanol Synthesis with Steel-Mill Gases: Simulation and Practical Testing of Selected Gas Utilization Scenarios
Kai Girod, Heiko Lohmann, Stefan Schlüter, Stefan Kaluza
July 29, 2021 (v1)
Keywords: Carbon2Chem®, gas recirculation, MegaMax®800, methanol synthesis, process simulation, steel-mill gases
The utilization of CO2-containing steel-mill gases for synthesis of methanol was investigated. Four different scenarios with syngas derived from steel-mill gases were considered. A process model for an industrial methanol production including gas recirculation was applied to provide realistic conditions for catalyst performance tests. A long-term test series was performed in a close-to-practice setup to demonstrate the stability of the catalyst. In addition, the experimental results were used to discuss the quality of the simulation results. Kinetic parameters of the reactor model were fitted. A comparison of two different kinetic approaches and the experimental results revealed which approach better fits CO-rich or CO2-rich steel-mill gases.
Permeate Flux Control in SMBR System by Using Neural Network Internal Model Control
Norhaliza Abdul Wahab, Nurazizah Mahmod, Ramon Vilanova
July 29, 2021 (v1)
Keywords: artificial neural network, fouling, internal model control, membrane bioreactor
This paper presents a design of a data-driven-based neural network internal model control for a submerged membrane bioreactor (SMBR) with hollow fiber for microfiltration. The experiment design is performed for measurement of physical parameters from an actuator input (permeate pump voltage), which gives the information (outputs) of permeate flux and trans-membrane pressure (TMP). The palm oil mill effluent is used as an influent preparation to depict fouling phenomenon in the membrane filtration process. From the experiment, membrane fouling potential is observed from flux decline pattern, with a rapid increment of TMP (above 200 mbar). Membrane fouling is a complex process and the available models in literature are not designed for control system (filtration performance). Therefore, this work proposes an aeration fouling control strategy to measure the filtration performance. The artificial neural networks (Feed-Forward Neural Network—FFNN, Radial Basis Function Neural Network—RBFNN... [more]
Evaluation of Oxidative Stress Parameters in Healthy Saddle Horses in Relation to Housing Conditions, Presence of Stereotypies, Age, Sex and Breed
Luca Molinari, Giuseppina Basini, Roberto Ramoni, Simona Bussolati, Raffaella Aldigeri, Stefano Grolli, Simone Bertini, Fausto Quintavalla
July 29, 2021 (v1)
Keywords: behavior, free radicals, horse, redox status, stereotypy
Oxidative stress plays an important role in the development of many horse diseases and it has been shown that housing has important implications for the psychophysical well-being of horses. The aim of this study is to determine if there are any differences between the redox status in horses in relation to housing conditions. The four housing conditions analyzed were: single box, without external access and without contact (Cat A), single box with external access and possibility of partial contact (Cat B), group housing with box and large paddock (Cat C), pasture with more than 7 horses and the possibility of green forage for the whole year (Cat D). A group of 117 healthy horses were selected in several private stables in Northern Italy. All subjects treated with any type of drug were excluded. At the end of the enrollment, the 117 selected horses were divided into the four housing categories. Stereotypies were highest in the group of horses in single box, without external access and wi... [more]
New Design of the Reversible Jet Fan
Miroslav H. Benišek, Đorđe S. Čantrak, Dejan B. Ilić, Novica Z. Janković
July 29, 2021 (v1)
Keywords: axial fan, design, energy characteristics, jet, reversible, thrust
This paper presents two designs of the axial reversible jet fan, with the special focus on the impeller. The intention was to develop a reversible axial jet fan which operates in the same way in both rotating directions while generating thrust as high as possible. The jet fan model with the outer diameter 499.2 ± 0.1 mm and ten adjustable blades is the same, while it is in-built in two different casings. The first construction is a cylindrical casing, while the second one is profiled as a nozzle. Thrust, volume flow rate, consumed power and ambient conditions were measured after the international standard ISO 13350. Results for both constructions are presented for three impeller blade angles: 28°, 31° and 35°, and rotation speed in the interval n = 400 to 2600 rpm. The smallest differences in thrust, depending on the fan rotation direction, as well as the highest thrust are achieved for the first design with the cylindrical casing and blade angle at the outer diameter of 35°. Therefore... [more]
The Supervision of Dough Fermentation Using Image Analysis Complemented by a Continuous Discrete Extended Kalman Filter
Olivier Paquet-Durand, Viktoria Zettel, Abdolrahim Yousefi-Darani, Bernd Hitzmann
July 29, 2021 (v1)
Keywords: dough fermentation, estimation, extended Kalman filter, model
Dough fermentation is an important step during the preparation of fermented baking goods. For the supervision of dough fermentation, a continuous-discrete extended Kalman filter was applied, which uses an image analysis system as the measurement. By estimation a fixed number of gas bubbles inside the dough, the radius of an average bubble was determined. A mathematical dough model was used by the extended Kalman filter to estimate the radius of the average bubble, the CO2 concentration of the non-gas dough phase and the number of CO2 molecules in the average bubble. During a fermentation of 50 min, the extended Kalman filter estimated that the average radius increased from 50 µm to 127 µm, the CO2 concentration in the non-gas dough increased to 23 mol/m³, and the CO2 amount in the bubble increased from 0.1 × 10−10 to 4 × 10−10 mol. Also, the specific CO2 production rate was estimated to be in the range from 1.5 × 10−3 to more than 4 × 10−3 mol·m³/kg/s. The advantages of an extended Kal... [more]
Inventory of MSWI Fly Ash in Switzerland: Heavy Metal Recovery Potential and Their Properties for Acid Leaching
Wolfgang Zucha, Gisela Weibel, Mirjam Wolffers, Urs Eggenberger
July 29, 2021 (v1)
Subject: Energy Policy
Keywords: acid leaching, heavy metal recovery, MSWI fly ash, properties of fly ash
From the year 2021 on, heavy metals from Swiss municipal solid waste incineration (MSWI) fly ash (FA) must be recovered before landfilling. This is predominantly performed by acid leaching. As a basis for the development of defined recovery rates and for the implementation of the recovery process, the authorities and plant operators need information on the geochemical properties of FA. This study provides extended chemical and mineralogical characterization of all FA produced in 29 MSWI plants in Switzerland. Acid neutralizing capacity (ANC) and metallic aluminum (Al0) were additionally analyzed to estimate the effort for acid leaching. Results show that all FA samples are composed of similar constituents, but their content varies due to differences in waste input and incineration conditions. Based on their geochemical properties, the ashes could be divided into four types describing the leachability: very good (6 FA), good (10 FA), moderate (5 FA), and poor leaching potential (8 FA).... [more]
The Dynamics of Globally Unstable Air-Helium Jets and Its Impact on Jet Mixing Intensity
Agnieszka Pawlowska, Andrzej Boguslawski
July 29, 2021 (v1)
Subject: Other
Keywords: Mixing, mixing length scales, turbulence
The paper presents experimental investigations of the low-density air-helium jets. The paper is aimed at the analysis of the flow conditions promoting the local absolute instability leading to global flow oscillations. A number of the test cases are analysed with a wide range of the shear layer thickness showing conditions favorable for the global modes and also mixing intensity triggered by such a regime. It is shown that high mixing intensity is determined not only by the global regime but also by the vortex pairing process. The results are compared with a recently proposed universal scaling law for an onset into the global mode. The results turn out to be far from this scaling law and the reasons for such discrepancies are discussed. The measurements show also that if the shear layer at the nozzle exit is thin enough the global modes are suppressed. The mechanism leading to the global mode suppression under such conditions is carefully analysed.
Electrochemical Mineralization of Ibuprofen on BDD Electrodes in an Electrochemical Flow Reactor: Numerical Optimization Approach
Alejandro Regalado-Méndez, Martín Ruiz, José A. Hernández-Servín, Reyna Natividad, Rubi Romero, Mario E. Cordero, Carlos Estrada-Vázquez, Ever Peralta-Reyes
July 29, 2021 (v1)
Keywords: BDD electrodes, electrochemical flow reactor, mineralization of ibuprofen, numerical optimization approach, response surface methodology
Statistical analysis was applied to optimize the electrochemical mineralization of ibuprofen with two boron-doped diamond (BDD) electrodes in a continuous electrochemical flow reactor under recirculation batch mode. A central composite rotatable (CCR) experimental design was used to analyze the effect of initial pH (2.95−13.04), current intensity (2.66−4.34 A), and volumetric flow rate (0.16−1.84 L/min) and further optimized by response surface methodology (RSM) to obtain the maximum mineralization efficiency and the minimum specific energy consumption. A 91.6% mineralization efficiency (EM) of ibuprofen with a specific energy consumption (EC) of 4.36 KW h/g TOC within 7 h of treatment was achieved using the optimized operating parameters (pH0 = 12.29, I = 3.26 A, and Q of 1 L/min). Experimental results of RSM were fitted via a third-degree polynomial regression equation having the performance index determination coefficients (R2) of 0.8658 and 0.8468 for the EM and EC, respectively. T... [more]
Evaluation of Direct Ultrasound-Assisted Extraction of Phenolic Compounds from Potato Peels
Shusheng Wang, Amy Hui-Mei Lin, Qingyou Han, Qin Xu
July 29, 2021 (v1)
Keywords: antioxidant, phenolic compound, potato peel, ultrasound
Potato peels (PPs) are generally considered as agriculture waste. The United States alone generates over one million tons of PPs a year. However, PPs contain valuable phenolic compounds with antioxidant activities. In this study, we evaluated the efficiency of ultrasound-assisted extraction techniques in recovering antioxidants from PPs. These techniques included a direct ultrasound-assisted extraction (DUAE), an indirect ultrasound-assisted extraction (IUAE), and a conventional shaking extraction (CSE). Results of this study showed that DUAE was more effective in extracting phenolic compounds than IUAE and CSE. We also evaluated the factors affecting the yield of total phenolic compounds (TPC) in DUAE, including the temperature, time, acoustic power, ratio of solvent to solids, and size of PPs particles. TPC yield of DUAE was higher, and the extraction rate was faster than IUAE and CSE. Furthermore, TPC yield was strongly correlated to the temperature of the mixture of PPs suspension.... [more]
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