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Records Added in April 2021
Records added in April 2021
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Showing records 151 to 175 of 175. [First] Page: 3 4 5 6 7 Last
Life-Cycle Assessment of Dairy Products—Case Study of Regional Cheese Produced in Portugal
Óscar Soares Nunes, Pedro Dinis Gaspar, José Nunes, Paula Quinteiro, Ana Cláudia Dias, Radu Godina
April 16, 2021 (v1)
Keywords: cheese production process, cradle-to-gate, dairy industry, life cycle assessment, ReCiPe method
Nowadays, there is a growing promotion to label products ecologically in European markets. Knowing that daily products have relevant environmental impact associated with their production, it is of utmost importance to analyse all the related production processes for a better understanding of each process impact. The present study analysed the potential environmental impacts of a Portuguese regional product, the Beira Baixa cheese, coming from the largest national sheep milk region. So, a life cycle assessment (LCA) methodology is used from -cradle-to -gate, including the supplying of the animal feedstock. Impact calculations are performed using the ReCiPe midpoint 2008 method, allowing an analysis of the environmental impacts contributing to climate change, terrestrial acidification, freshwater and marine eutrophication of all productive processes. The results have shown that the greatest impacts occur within the milk production process for all four selected impact categories. This hap... [more]
Degradation of Direct Blue 1 through Heterogeneous Photocatalysis with TiO2 Irradiated with E-Beam
Elvia Gallegos, Florinella Muñoz Bisesti, Katherine Vaca-Escobar, Cristian Santacruz, Lenys Fernández, Alexis Debut, Patricio J. Espinoza-Montero
April 16, 2021 (v1)
Keywords: Adsorption, Direct Blue 1, electron-beam, heterogeneous photocatalysis, irradiated TiO2
Most dyes used in the textile industry are chemically stable and poorly biodegradable, therefore, they are persistent in the environment and difficult to degrade by conventional methods. An alternative treatment for this kind of substance is heterogeneous photocatalysis using TiO2, so, in this work, it is proposed to degrade Direct Blue 1 (DB1) using microparticulate TiO2 irradiated with e-beam at three different doses: 5, 10 and 20 kGy (J/kg). The DB1 degradation was implemented in a batch reactor (DB1 initial concentration = 50 mg L−1, pH 2.5, TiO2 concentration = 200 mg L−1). We have demonstrated that the photocatalytic power of TiO2, when irradiated with e-beam (5, 10, 20 kGy), varies slightly, with minor effects on photodegradation performance. However, the dose of 10 kGy showed a slightly better result, according to the DB1 photodegradation rate constant. Adsorption process was not affected by irradiation; its isotherm was fitted to Freundlich’s mathematical model. The DB1 photod... [more]
SuperPro Designer®, User-Oriented Software Used for Analyzing the Techno-Economic Feasibility of Electrical Energy Generation from Sugarcane Vinasse in Colombia
Licelly Canizales, Fredy Rojas, Carlos A. Pizarro, Nelson. H. Caicedo-Ortega, M. F. Villegas-Torres
April 16, 2021 (v1)
Keywords: anaerobic digestion, sensitivity analysis, sugarcane-based vinasse, SuperPro Designer®, Technoeconomic Analysis
SuperPro Designer® is a process simulator software used for analyzing the techno-economic feasibility of large-scale bioprocesses. Its predetermined built-in features allow for easy implementation by non-experts, but a lack of examples limits its appropriation. This study aims to validate the implementation of SuperPro Designer® by non-experts for the techno-economic analysis of anaerobic digestion in Colombia, using vinasse as feedstock. These results demonstrate the financial feasibility of such a process when a processing flow rate of 25 m3/h is ensured. Additionally, this study validates the manageability of the tool for assessing the economic feasibility of a technology, a key practice during technology development regardless of the area of expertise.
High-Throughput Raman Spectroscopy Combined with Innovate Data Analysis Workflow to Enhance Biopharmaceutical Process Development
Stephen Goldrick, Alexandra Umprecht, Alison Tang, Roman Zakrzewski, Matthew Cheeks, Richard Turner, Aled Charles, Karolina Les, Martyn Hulley, Chris Spencer, Suzanne S. Farid
April 16, 2021 (v1)
Keywords: cation exchange chromatography, high-throughput, mammalian cell culture, monitoring, process analytical technology, Raman spectroscopy, scale-down technologies
Raman spectroscopy has the potential to revolutionise many aspects of biopharmaceutical process development. The widespread adoption of this promising technology has been hindered by the high cost associated with individual probes and the challenge of measuring low sample volumes. To address these issues, this paper investigates the potential of an emerging new high-throughput (HT) Raman spectroscopy microscope combined with a novel data analysis workflow to replace off-line analytics for upstream and downstream operations. On the upstream front, the case study involved the at-line monitoring of an HT micro-bioreactor system cultivating two mammalian cell cultures expressing two different therapeutic proteins. The spectra generated were analysed using a partial least squares (PLS) model. This enabled the successful prediction of the glucose, lactate, antibody, and viable cell density concentrations directly from the Raman spectra without reliance on multiple off-line analytical devices... [more]
A Numerical Investigation on De-NOx Technology and Abnormal Combustion Control for a Hydrogen Engine with EGR System
Hao Guo, Song Zhou, Jiaxuan Zou, Majed Shreka
April 16, 2021 (v1)
Keywords: Computational Fluid Dynamics, exhaust gas recirculation, hydrogen engine, knocking, pre-ignition
The combustion emissions of the hydrogen-fueled engines are very clean, but the problems of abnormal combustion and high NOx emissions limit their applications. Nowadays hydrogen engines use exhaust gas recirculation (EGR) technology to control the intensity of premixed combustion and reduce the NOx emissions. This study aims at improving the abnormal combustion and decreasing the NOx emissions of the hydrogen engine by applying a three-dimensional (3D) computational fluid dynamics (CFD) model of a single-cylinder hydrogen-fueled engine equipped with an EGR system. The results indicated that peak in-cylinder pressure continuously increased with the increase of the ignition advance angle and was closer to the top dead center (TDC). In addition, the mixture was burned violently near the theoretical air−fuel ratio, and the combustion duration was shortened. Moreover, the NOx emissions, the average pressure, and the in-cylinder temperature decreased as the EGR ratio increased. Furthermore,... [more]
Olive Tree Leaves—A Source of Valuable Active Compounds
Fereshteh Safarzadeh Markhali, José A. Teixeira, Cristina M. R. Rocha
April 16, 2021 (v1)
Keywords: bioactive compounds, by-products, Extraction, olive leaves, polyphenols, Renewable and Sustainable Energy
The agricultural and processing activities of olive crops generate a substantial amount of food by-products, particularly olive leaves, which are mostly underexploited, representing a significant threat to the environment. Olive leaves are endowed with endogenous bioactive compounds. Their beneficial/health-promoting potential, together with environmental protection and circular economy, merit their exploitation to recover and reuse natural components that are potentially safer alternatives to synthetic counterparts. These biomass residues have great potential for extended industrial applications in food/dietary systems but have had limited commercial uses so far. In this regard, many researchers have endeavoured to determine a green/sustainable means to replace the conventional/inefficient methods currently used. This is not an easy task as a sustainable bio-processing approach entails careful designing to maximise the liberation of compounds with minimum use of (i) processing time, (... [more]
Preparation and Characterization of New Electrically Conductive Composites Based on Expanded Graphite with Potential Use as Remote Environmental Detectors
Martin Prostredný, Igor Krupa, Zdenko Špitalský
April 16, 2021 (v1)
Subject: Materials
Keywords: composite, elastomer, engine oil, environmental sensor, expanded graphite
The presented paper is focused on studying electrically conductive composites based on an elastomeric matrix and expanded graphite as the filler. A potential application as an environmental remote detector was studied. The influence of filler particle size, film thickness, detector length, temperature, and the amount of oil on the detector response rate were explored. Peel tests were performed in order to investigate the adhesion of prepared detector films to different materials. Expanded graphite with average particle size 5 µm was chosen for the experiments due to its fastest response. Decreasing the detector film thickness has caused an increase in the response rate but also a decrease in the signal measured. The response rate of the detector system was in a practical range even for lower temperatures. From the obtained data, the proposed detector seems to be suitable for a practical application.
Phytotoxicity and Effect of Ionic Liquids on Antioxidant Parameters in Spring Barley Seedlings: The Impact of Exposure Time
Robert Biczak, Barbara Pawłowska, Wiesław Pilis, Jan Szczegielniak, Jacek Wróbel, Arkadiusz Telesiński
April 16, 2021 (v1)
Keywords: antioxidant enzyme activity, ionic liquids, oxidative stress, photosynthetic pigments, phytotoxicity
The influence of the ionic liquids (ILs) tetrabutylammonium bromide [TBA][Br], 1-butyl-3-methylimidazole bromide [BMIM][Br], and tetrabutylphosphonium bromide [TBP][Br] added at different concentrations to the soil were studied for the growth and development of spring barley seedlings. Samples were harvested at three different time points: day 7, 14, and 21 after addition of ILs. The results show that [TBP][Br] was the most toxic. The introduction of this IL at the dose of 100 mg kg−1 of soil DM decreased the growth of seedlings at all test dates. The addition of the studied ILs to the soil in higher doses resulted in an increase in peroxidase and catalase activity, which may indicate the occurrence of oxidative stress in plants. An increase in the content of plant dry matter weight, contents of H2O2 and proline and a decrease in the content of photosynthetic pigments in barley seedlings were also observed. The malondialdehyde content and superoxide dismutase activity fluctuated random... [more]
Scope and Limitations of the Mathematical Models Developed for the Forward Feed Multi-Effect Distillation Process—A Review
Omer Mohamed Abubaker Al-Hotmani, Mudhar Abdul Alwahab Al-Obaidi, Yakubu Mandafiya John, Raj Patel, Iqbal M Mujtaba
April 16, 2021 (v1)
Keywords: Dynamic Modelling, forward feed MED, Modelling, seawater desalination, steady-state modeling
Desalination has become one of the obvious solutions for the global water crisis due to affording high-quality water from seawater and brackish water resources. As a result, there are continuing efforts being made to improve desalination technologies, especially the one producing high-quantity freshwater, i.e., thermal desalination. This improvement must be accomplished via enhancement of process design through optimization which is implicitly dependent on providing a generic process model. Due to the scarcity of a comprehensive review paper for modeling multi-effect distillation (MED) process, this topic is becoming more important. Therefore, this paper intends to capture the evolution of modeling the forward feed MED (most common type) and shed a light on its branches of steady-state and dynamic modeling. The maturity of the models developed for MED will be thoroughly reviewed to clarify the general efforts made highlighting the advantages and disadvantages. Depending on the outputs... [more]
Antibacterial Activity of Chitosan Nanoparticles: A Review
Murugesan Chandrasekaran, Ki Deok Kim, Se Chul Chun
April 16, 2021 (v1)
Subject: Biosystems
Keywords: antibacterial activity, bacteria, chitosan, chitosan nanoparticles, gram negative bacteria, gram positive bacteria
In recent years, nanotechnology has attracted attention in many fields because it has several up-and-coming novel uses. Many researchers have suggested that chitosan nanoparticles (CS-NPs) and their derivatives are one of the best nanomaterials for delivering antibacterial activity. CS-NPs have a broad spectrum of antibacterial activity, but they manifest different inhibitory efficacy against gram-negative (G−) and gram-positive (G+) bacterial species. The mechanism of antibacterial action is an intricate process that varies between G− and G+ bacteria as a result of the differences in cell wall and cell membrane chemistry. In previous studies, greater antibacterial activity was more evident against G− bacteria than G+ bacteria, whereas in some studies G+ bacteria were more sensitive. Researchers predicted that the varied responses of bacteria are caused by the mixed hydrophilicity and negative charge distribution on the bacterial surface. Moreover, its activity depends on a number of v... [more]
Supported Palladium Nanocatalysts: Recent Findings in Hydrogenation Reactions
Marta A. Andrade, Luísa M. D. R. S. Martins
April 16, 2021 (v1)
Keywords: carbon material, catalyst, hydrogenation, mesoporous silica, MOF, nanoparticles, palladium, supported, zeolite
Catalysis has witnessed a dramatic increase on the use of metallic nanoparticles in the last decade, opening endless opportunities in a wide range of research areas. As one of the most investigated catalysts in organic synthesis, palladium finds numerous applications being of significant relevance in industrial hydrogenation reactions. The immobilization of Pd nanoparticles in porous solid supports offers great advantages in heterogeneous catalysis, allowing control of the major factors that influence activity and selectivity. The present review deals with recent developments in the preparation and applications of immobilized Pd nanoparticles on solid supports as catalysts for hydrogenation reactions, aiming to give an insight on the key factors that contribute to enhanced activity and selectivity. The application of mesoporous silicas, carbonaceous materials, zeolites, and metal organic frameworks (MOFs) as supports for palladium nanoparticles is addressed.
Drag Effect of Carbon Emissions on the Urbanisation Process: Evidence from China’s Province Panel Data
Jiajia Li, Jiangang Shi, Heng Li, Kaifeng Duan, Rui Zhang, Quanwei Xu
April 16, 2021 (v1)
Subject: Energy Policy
Keywords: carbon emission, drag effect, panel cointegration, urban development
This study attempts to measure the drag effect of carbon emissions on China’s economic growth by incorporating carbon emissions as an endogenous variable into an economic growth model and by relaxing the assumption that the size of the economy will remain unchanged. The drag effect of carbon emissions on the process of urbanisation is derived based on the intrinsic relationship between economic growth and urban development. Then, unit root and cointegration tests are performed using panel data from 30 provincial regions in Mainland China from 2003 to 2016 to prove and estimate the resistance caused by carbon emission in the process of urbanisation. Results show that the drag effect of carbon emission between 2003 and 2016 has a certain negative impact on the process of urbanisation in China. Due to the constraints of carbon emissions, the growth rate of China’s economic growth and urbanization level is 0.74% and 4.96% lower than that without constraints, respectively. Therefore, in the... [more]
Optimization Design of a Two-Vane Pump for Wastewater Treatment Using Machine-Learning-Based Surrogate Modeling
Sang-Bum Ma, Sung Kim, Jin-Hyuk Kim
April 16, 2021 (v1)
Keywords: Computational Fluid Dynamics (CFD), Machine Learning, Optimization, Reynolds-averaged Navier-Stokes (RANS), two-vane pump
This paper deals with three-objective optimization, using machine-learning-based surrogate modeling to improve the hydraulic performances of a two-vane pump for wastewater treatment. For analyzing the internal flow field in the pump, steady Reynolds-averaged Navier-Stokes equations were solved with the shear stress transport turbulence model as a turbulence closure model. The radial basis neural network model, which is an artificial neural network, was used as the surrogate model and trained to improve prediction accuracy. Three design variables related to the geometry of blade and volute were selected to optimize concurrently the objective functions with the total head and efficiency of the pump and size of the waste solids. The optimization results obtained by using the model showed highly accurate prediction values, and compared with the reference design, the optimum design provided improved hydraulic performances.
Production of Hydrogen Sulfide by Fermentation in Rumen and Its Impact on Health and Production of Animals
Ali Mujtaba Shah, Jian Ma, Zhisheng Wang, Rui Hu, Xueying Wang, Quanhui Peng, Felix Kwame Amevor, Naqash Goswami
April 16, 2021 (v1)
Keywords: animal health, Fermentation, hydrogen sulfide, rumen, ruminants
Hydrogen sulfide is a Janus-faced molecule with many beneficial and toxic effects on the animal health. In ruminants, rumen fermentation plays a vital role in the digestion and absorption of nutrients. During rumen fermentation, the production of hydrogen sulfide can occur, and it can be rapidly absorbed into the body of the animals through the intestinal wall. If the production of hydrogen sulfide concentration is higher in the rumen, it can cause a toxic effect on ruminants known as poliomyelitis. The production of hydrogen sulfide depends on the population of sulfate-reducing bacteria in the rumen. In rodents, H2S maintains the normal physiology of the gastrointestinal tract and also improves the healing of the chronic gastric ulcer. In the gut, H2S regulates physiological functions such as inflammation, ischemia−reperfusion injury and motility. In this review article, we summarize the toxicity occurrence in the body of animals due to high levels of hydrogen sulfide production and a... [more]
Socheongryongtang Modulates Asthma-Related Changes via Modulation of TNF-α and T-bet as well as IFN-γ in an Asthma Murine Model
So-Hyeon Bok, Seung Sik Cho, Chun-Sik Bae, Bossng Kang, Hong-Seok Son, Dae-Hun Park
April 16, 2021 (v1)
Subject: Biosystems
Keywords: asthma, IFN-γ, socheongryongtang, T-bet, TNF-α
In 2017 the World Health Organization (WHO) reported that 235 million people suffered from asthma, and that 383,000 deaths were due to asthma in 2015. Asthma cannot be completely eradicated and the medications for asthma are associated with many adverse effects. Socheongryongtang is one of the prescriptions which has traditionally been used for the treatment of pulmonary disease, but the anti-asthmatic mechanism is unclear. To investigate the anti-asthmatic mechanism of socheongryongtang, BALB/c mice were divided into five groups: control, asthma-induced control, dexamethasone treatment, and 150 mg/kg or 1500 mg/kg socheongryongtang treatment and several biomarkers were analyzed, such as white blood cell (WBC) and differential counts in broncheoalveolar fluid (BALF), immunoglobulin E (IgE) in serum, and morphological changes/helper T cell-related cytokines/transcription factor in the lung. The therapeutic ingredients were also analyzed. Socheongryongtang inhibited the neutrophils diffe... [more]
Membrane System-Based Improved Neural Networks for Time-Series Anomaly Detection
Wenxiang Guo, Xiyu Liu, Laisheng Xiang
April 16, 2021 (v1)
Keywords: anomaly detection, convolutional neural networks, long short-term memory, membrane systems, time series
Anomaly detection in time series has attracted much attention recently and is quite a challenging task. In this paper, a novel deep-learning approach (AL-CNN) that classifies the time series as normal or abnormal with less domain knowledge is proposed. The proposed algorithm combines Convolutional Neural Networks (CNNs) and Long Short-Term Memory (LSTM) to effectively model the spatial and temporal information contained in time-series data, the techniques of Squeeze-and-Excitation are applied to implement the feature recalibration. However, the difficulty of selecting multiple parameters and the long training time of a single model make AL-CNN less effective. To alleviate these challenges, a hybrid dynamic membrane system (HM-AL-CNN) is designed which is a new distributed and parallel computing model. We have performed a detailed evaluation of this proposed approach on three well-known benchmarks including the Yahoo S5 datasets. Experiments show that the proposed method possessed a rob... [more]
Mixing of Bi-Dispersed Milli-Beads in a Rotary Drum. Mechanical Segregation Analyzed by Lab-Scale Experiments and DEM Simulation
Aline Mesnier, Roman Peczalski, Guilhem Mollon, Séverine Vessot-Crastes
April 16, 2021 (v1)
Keywords: bi-dispersed bed, DEM simulation, optical observation, particulate solid, rotary drum, size and density segregation
Mechanical flow and segregation phenomena within a bed composed of milli-metric size spherical beads rotated in a horizontal drum were investigated. The beads population was bi-dispersed, with two kinds of binary (half by half) compositions: a bi-size bed with two different sizes and a bi-density bed with two different densities. The distributions of the beads were observed optically on the front side of the bed by means of a lab-scale drum prototype. Different numbers and lengths of peripheral straight baffles were tested as well as different drum filling ratios. The photographical data were processed to obtain the front layer mechanical segregation index. This experimental index was compared to the simulated one, obtained by means of commercial discrete element software EDEM. The simulations were corroborated by the experiments provided that the friction coefficients of the discrete elements method (DEM) model were correctly adjusted. The global segregation index was also calculated... [more]
Coupling of Water Activity and Colour Development of Roast Duck Skin under Forced Convection Drying
Yingbo Peng, Xiuyun Guo, Muneer Ahmed Jamali, Yawei Zhang
April 16, 2021 (v1)
Keywords: forced hot-air drying, hazardous chemicals, red index, roast duck, water activity
Roasting meat involves simultaneous heat and mass transfer, colour and flavour development and the formation of hazardous chemicals. The objectives of this study were to evaluate the effects of temperature and time on colour, 3,4-benzo(a)pyrene (BaP) and heterocyclic aromatic amines (HCAs) in roast duck skin during forced hot-air drying at less than 130 °C. The results showed that surface and internal temperatures of duck carcasses increased with drying time, rising to 111.9 and 83.7 °C, respectively. The curves of water activity (aw) and red index (a*) intersected at 50 min because of the decrease in aw and the increase in a* on the skin with drying time. The drastic decline in aw promoted colour development on the duck surface. BaP and carcinogenic HCAs were not detected in hot-air drying ducks, convincing us that the mild cooking method under forced hot-air drying could effectively reduce or eliminate the risk of certain human cancers.
Review of Natural Compounds for the Management and Prevention of Lymphoma
Yongmin Cho, Moon Nyeo Park, Seungjin Noh, Seog Young Kang, Bonglee Kim
April 16, 2021 (v1)
Subject: Biosystems
Keywords: apoptosis, cancer system biology, cell cycle arrest, lymphoma, natural products
Lymphoma is a type of blood cancer that can be categorized into two types-Hodgkin lymphoma (HL) and Non-Hodgkin lymphoma (NHL). A total of 509,590 and 79,990 cases of NHL and HL were newly diagnosed in 2018, respectively. Although conventional therapy has stridden forward over recent decades, its adverse effects are still a hurdle to be solved. Thus, to help researchers develop better lymphoma treatment, this study aims to review the systematic anticancer data for natural products and their compounds. A variety of natural products showed anticancerous effects on lymphoma by regulation of intracellular mechanisms including apoptosis as well as cell cycle arrest. As these results shed light on the potential to substitute conventional therapy with natural products, it may become a promising strategy for lymphoma treatment in the near future.
Discovering Low Toxicity Ionic Liquids for Saccharomyces cerevisiae by Using the Agar Well Diffusion Test
Fatiha Missoun, Antonia Pérez de los Ríos, Víctor Ortiz-Martínez, María José Salar-García, Jesús Hernández-Fernández, Francisco José Hernández-Fernández
April 16, 2021 (v1)
Subject: Biosystems
Keywords: agar well diffusion test, biocompatibility, ionic liquids, Saccharomyces cerevisiae, toxicity
Ionic liquids (ILs) are new solvents widely used in many technologies due to their unique and advantageous physicochemical properties. In biotechnological applications, ILs can be used along with microorganisms such as Saccharomyces cerevisiae. Due to the enormous number of ILs that can be synthesized through the combination of different anions and cations, it is necessary to have an easy and quick tool for the preliminary screening of their biocompatibility for being used in biotechnological applications. In this work, the agar well diffusion test was successfully applied as a rapid method to identify toxic/nontoxic ILs toward S. cerevisiae. Sixty-three ILs containing a diverse set of cations and anions were used. Through this methodology, nine fully biocompatible ILs toward S. cerevisiae were identified, including: [Bmim+] [NO3−], [HOPmim+] [NO3−], [Bmim+] [NTf2−], [N8,8,8,1+] [NTf2−], [S2,2,2+] [NTf2−], [EMPyr+] [NTf2−], [BMPi+] [NTf2−], [Moxa+] [MeSO4−] and [Chol+] [H2PO4−]. The an... [more]
Biomimetic Vanadate and Molybdate Systems for Oxidative Upgrading of Iono- and Organosolv Hard- and Softwood Lignins
Lucía Penín, Matteo Gigli, Federica Sabuzi, Valentín Santos, Pierluca Galloni, Valeria Conte, Juan Carlos Parajó, Heiko Lange, Claudia Crestini
April 16, 2021 (v1)
Keywords: biomimetic, catalytic lignin oxidation, ionosolv, lignin, molybdate, organosolv, oxidative lignin upgrade, vanadate
Recently reported acetosolv soft- and hardwood lignins as well as ionosolv soft- and hardwood lignins were transformed into monomeric aromatic compounds using either a vanadate or a molybdate-based catalyst system. Monomers were generated with remarkable, catalyst-dependent selectivity and high depolymerisation yields via oxidative exo- and endo-depolymerisation processes. Using the vanadate−hydrogen peroxide system on acetosolv pine lignin, vanillin and isovanillin were produced as main products with depolymerisation yields of 31%. Using the molybdate system on acetosolv and ionosolv lignin, vanillic acid was the practically exclusive product, with depolymerisation yields of up to 72%. Similar selectivities, albeit with lower depolymerisation yields of around 50% under standardised conditions, were obtained for eucalyptus acetosolv lignin, producing vanillin and syringaldehyde or vanillic acid as products, by using the vanadate- or the molybdate-based systems respectively.
Validating the Efficiency of the FeS2 Method for Elucidating the Mechanisms of Contaminant Removal Using Fe0/H2O Systems
Minhui Xiao, Xuesong Cui, Rui Hu, Willis Gwenzi, Chicgoua Noubactep
April 16, 2021 (v1)
Subject: Materials
Keywords: dye discoloration, FeS2 method, MB method, removal mechanism, zero-valent iron
There is growing interest in using pyrite minerals (FeS2) to enhance the efficiency of metallic iron (Fe0) for water treatment (Fe0/H2O systems). This approach contradicts the thermodynamic predicting suppression of FeS2 oxidation by Fe0 addition. Available results are rooted in time series correlations between aqueous and solid phases based on data collected under various operational conditions. Herein, the methylene blue method (MB method) is used to clarify the controversy. The MB method exploits the differential adsorptive affinity of MB onto sand and sand coated with iron corrosion products to assess the extent of Fe0 corrosion in Fe0/H2O systems. The effects of the addition of various amounts of FeS2 to a Fe0/sand mixture (FeS2 method) on MB discoloration were characterized in parallel quiescent batch experiments for up to 71 d (pH0 = 6.8). Pristine and aged FeS2 specimens were used. Parallel experiments with methyl orange (MO) and reactive red 120 (RR120) enabled a better discus... [more]
Solid Circulating Velocity Measurement in a Liquid−Solid Micro-Circulating Fluidised Bed
Orlando L. do Nascimento, David A. Reay, Vladimir Zivkovic
April 16, 2021 (v1)
Keywords: circulating fluidised bed, digital PIV, liquid–solid fluidisation, micro-fluidised bed, wall effects
Liquid−solid circulating fluidised beds (CFB) possess many qualities which makes them useful for industrial operations where particle−liquid contact is vital, e.g., improved heat transfer performance, and consequent uniform temperature, limited back mixing, exceptional solid−liquid contact. Despite this, circulating fluidised beds have seen no application in the micro-technology context. Liquid−solid micro circulating fluidised bed (µCFBs), which basically involves micro-particles fluidisation in fluidised beds within the bed of cross-section or inner diameter at the millimetre scale, could find potential applications in the area of micro-process and microfluidics technology. From an engineering standpoint, it is vital to know the solid circulating velocity, since that dictates the bed capability and operability as processing equipment. Albeit there are several studies on solid circulating velocity measurement in CFBs, this article is introducing the first experimental study on solid c... [more]
Gain-Scheduled Equivalent-Cascade IMC Tuning Method for Water Level Control System of Nuclear Steam Generator
Zuhua Xu, Qingli Fan, Jun Zhao
April 16, 2021 (v1)
Keywords: equivalent cascade, gain scheduling, IMC-PID tuning, nuclear steam generator, water level control
In this paper, a gain-scheduled equivalent-cascade internal-model-control (IMC) tuning method for water level control system of nuclear steam generator is presented. First, a water level control system for a steam generator is transferred into an equivalent cascade-feedforward control system. Second, analytical tuning rules for the equivalent cascade control system are derived based on the IMC-(proportional-integral-derivative) PID method, which can simultaneously tune the primary/secondary loops and avoid the re-identification step. Finally, gain scheduling is performed to eliminate the influence of process nonlinearity. The experimental results of nuclear simulation platform have demonstrated the superiority of the proposed tuning method.
Analysis of a Thermal Energy Storage Tank in a Large District Cooling System: A Case Study
Mohd Amin Abd Majid, Masdi Muhammad, Chima Cyril Hampo, Ainul Bt Akmar
April 16, 2021 (v1)
Keywords: Graphpad Prism, temperature distribution, temperature profile, thermal energy storage, thermocline thickness
This study’s primary goal is to evaluate the performance of a large thermal energy storage tank installed in a Gas District Cooling (GDC) plant. The performance parameters considered in this study include thermocline thickness (WTc), Cumulated Charge (Qcum), and Half Figure of Merit (½ FOM). The operation sensor data of a large Thermal Energy Storage (TES) tank was acquired for this analysis. The recorded temperature sensor from the 1st to 7th January and from 12th to 17th October 2019 was considered in this research. GraphPad prism computer software was deployed for analyses, and the temperature distribution data were analyzed to determine the four temperature parameters (hot water temperature (Th), cool water temperature (Tc), cool water depth (C), and slope gradient (S)) using a non-linear regression curve fitting technique and sigmoid Dose Responses function as integrated with the software. At the end of this research, the relationship between the growth of the determined performan... [more]
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