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Adsorption kinetics, isotherms and desorption studies of mercury from aqueous solution at different temperatures on magnetic sodium alginate-thiourea microbeads

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Environmental Nanotechnology, Monitoring and Management 2019年 12卷

作者： Patiño-Ruiz, D. Bonfante, H. De Ávila, G. Herrera, Adriana Doctorate in Engineering Program Nanomaterials and Computer Aided Process Engineering Research Group Universidad de Cartagena Cartagena Colombia Chemical Engineering Program Process Design and Biomass Use Group Universidad de Cartagena Cartagena Colombia Chemical Engineering Program Nanomaterials and Computer Aided Process Engineering Research Group Universidad de Cartagena Cartagena Colombia

Magnetite (Fe3O4) nanoparticles and thiourea were employed to modify sodium alginate microbeads for adsorption of Hg ions from aqueous solution. The Fe3O4 nanoparticles were initially synthesized by co-precipitation m... 详细信息

Magnetite (Fe₃O₄) nanoparticles and thiourea were employed to modify sodium alginate microbeads for adsorption of Hg ions from aqueous solution. The Fe₃O₄ nanoparticles were initially synthesized by co-precipitation method. Fourier infrared spectroscopy (FTIR) determined the presence of hydroxyl, carboxyl, thiol and amine functional groups in the microbead molecular structure. According to BET and BJH methods, the MAT microbeads had surface area, pore diameter and volume of 7.3472 m²/g, 12.9058 nm and 0.0255 cm³/g, respectively. Scanning electron microscopy (SEM) equipped with an EDX system allowed to obtain morphological information of the MAT microbeads, in which was observed the main elements introduced by the presence of thiol groups and iron ions. The result of saturation magnetization (M_s) performed by a vibrating sample magnetometer (VSM), is common for superparamagnetic materials, which slightly decreased due to the low amount of magnetic nanoparticles in the microbead structure. Adsorption kinetics showed that highest rate was about 98% in the first 20 min, and then decreased to zero. Pseudo-first order was the model that better fitted to experimental data with a value about 2.6 mg/g. Meanwhile, adsorption isotherm was better described using Langmuir model, suggesting that the Hg ions adsorption was mainly given by electrostatic interaction and chemical bonding among the functional groups, as well as the formation of a saturated layer onto the microbead surface occupying all the available sites. © 2019

关键词： Adsorption Magnetic nanoparticles Mercury Sodium alginate microbeads Thiourea

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Photovoltaic Microinverter with Hybrid Energy Storage System (HESS) and Virtual Impedance Control for Injection into a Microgrid

Photovoltaic Microinverter with Hybrid Energy Storage System...

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IEEE Annual Southern Power Electronics Conference (SPEC)

作者： Patricio Gaisse Javier Muñoz Marco Rivera Carlos Restrepo Galina Mirzaeva Engineering Systems Doctoral Program Faculty of Engineering University of Talca Curicó Chile Department of Electrical Engineering Faculty of Engineering Universidad de Talca Curicó Chile Doctorate in Engineering Systems Faculty of Engineering Universidad de Talca Curicó Chile School of Electrical Engineering and Computer Science The University of Newcastle Callaghan NSW Australia

In this work, a photovoltaic (PV) microinverter is developed, which includes an hybrid energy storage system based on a battery and an ultracapacitor that are connected in parallel to the dc-link through two buck-boost bidirectional converters. The PV panel is connected in parallel to dc-link through an unidirectional boost converter. For the dc-ac stage, a two-stage Flyback / H-bridge inverter will be considered, which will be used to inject the available power into a microgrid. The study proposes the necessary control strategies to manage the power flow according to generation and injection conditions, where a virtual impedance loop is incorporated in the control of the energy storage elements. The presented results confirm the suitability of the proposed strategy.

关键词： Photovoltaic systems Microgrids Hybrid power systems Batteries Circuit stability Topology Impedance

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Methodology for the design of a nanosatellite telecommunication system in S-Band based on Software for Digital Mission engineering

Methodology for the design of a nanosatellite telecommunicat...

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International Conference on AeroSpace Science and Technology 2023, ICASST 2023

作者： García-Guillén, L.A. Sanchéz-Sanchéz, J.L. Ramírez-Aguilar, J.A. Ferrer-Pérez, J.A. Romo-Fuentes, J.C. Farah-Simón, A. Chávez-Moreno, R.G. Sánchez Hernández, D.C. Sánchez-Guzmán, J.A. Valdés-Galicia, J.F. Master's and Doctorate Programm in Engineering Engineering Faculty Universidad Nacional Autónoma de México CDMX Mexico Bachelor's in Aero Systems Electronics Engineering Universidad Aeronáutica en Querétaro Queretaro Mexico Advanced Technology Unit School of Engineering UNAM Queretaro Juriquilla Mexico Astronomy Institute Universidad Nacional Autónoma de México CDMX Mexico Faculty of Informatics Autonomous University of Queretaro Queretaro Juriquilla Mexico Space Program University Universidad Nacional Autónoma de México CDMX Mexico

A trend in the development of nanosatellite platforms for technology demonstration has increased in both private industry and academic projects. Communication link design plays a crucial role in the success of space missions, enabling efficient and reliable data transmission between satellites and ground stations. In this context, the use of advanced tools such as System Tool Kit (STK) has gained significant importance by enabling a comprehensive analysis of the technical and operational aspects of the communication link. In an effort to make the future design of the communications subsystem payload on a nanosatellite more efficient and accessible, this paper shows a methodology for the efficient use of STK to perform link analysis. © Published under licence by IOP Publishing Ltd.

关键词： Nanosatellites

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Species diversity and dominance of Oligochaeta in copper and cadmium polluted soil 10

Species diversity and dominance of Oligochaeta in copper and...

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10th International Seminar on New Paradigm and Innovation of Natural Sciences and itsApplication, ISNPINSA 2020

作者： Ulfah, M. Anggoro, S. Soeprobowati, T.R. Syafrudin, S. Department of Biology Faculty of Mathematics Science and Information Technology Universitas PGRI Semarang Semarang Indonesia Doctorate Program of Environmental Science School of Postgraduate Studies Univesitas Diponegoro Semarang Indonesia Faculty of Fisheries and Marine Science Universitas Diponegoro Semarang Indonesia Department of Biology Faculty of Science and Mathematics Universitas Diponegoro Semarang Indonesia Department of Enviromental Engineering Faculty of Engineering Universitas Diponegoro Semarang Indonesia School of Postgraduate Studies Universitas Diponegoro Semarang Indonesia

The aim of this study was to determine the dominance and species diversity of oligochaeta were studied incopper and cadmium polluted soil. This location is used for the garbage disposal of Jatibarang Landfill Semarang City residents, Central Java. Oligochaeta were collected from 5 research sites. The research method used is field experiment. Oligochaeta sampling was carried out based on a random sampling method. Oligochaeta sampling in Jatibarang Landfill was carried out at a depth of 25 cm. Analysis of oligochaeta diversity includes species diversity using the index formula Shannon-Wienner and dominance with the index formula Simpson. The species diversity (Shannon-Weiner Index) showed value of 0.191 (site 1), 0.411 (site 2), 0.539 (site 3), 0.137 (site 4), 0.443 (site 5) and the dominance calculated was 0.207 (site 1), 0.024 (site 2), 0.279 (site 3), 0.045 (site 4), 0.031 (site 5) which indicates that the diversity and the dominance were inversely related. The population density (individuals/m2) of the Oligochaeta species at 5 research sites showed variations. The total density of L. terrestris recorded was 280.66 (site 1), 59.66 (site 2), 130.33 (site 3), 136.66 (site 4), 62 (site 5), and the total density of Pheretrima sp 14 (site 1), 10 (site 2), 39 (site 3), 4.33 (site 4), 12 (site 5). Two species of Oligochaeta showed high richness whereas some were sparsely populated. © Published under licence by IOP Publishing Ltd.

关键词： Biodiversity

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Seawater Intrusion Modeling on Groundwater Confined Aquifer in Semarang

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Procedia Environmental Sciences 2015年 23卷 110-115页

作者： Edy Suhartono P. Purwanto S. Suripin Doctorate Program Of Environmental Studies Post Graduate Program Diponegoro University Jl. Imam Barjo SH No. 5 Semarang-Indonesia-50000 Polytechnic State Of Semarang Jl. Prof.Sudarto SH Semarang - Indonesia- 50000 Department Of Chemical Engineering Faculty Of Engineering Diponegoro University Jl. Prof.Sudarto SH Semarang – Indonesia- 50000 Department Of Civil Engineering Faculty Of Engineering Diponegoro University Jl. Prof.Sudarto SH Semarang – Indonesia- 50000

The focus of this study is to identify and describe of a seawater intrusion in confined aquifer modelling in Semarang with a descriptive quantitative analytical method. The results showed potentially experiencing seawater intrusion which increased of 0.575 km2/years. Seawater intrusion models divide to 3 models are the western route have a maximum error is 27.9%, then the middle route have the maximum error is 41.1% and the eastern route have the maximum error is 40%. In 2035, the seawater intrusion on western route is predicted about 3.0 km from the coastline, 4 km for middle route, and about 3.25 km for eastern route. This is one of the information that from right now, the management of a groundwater in the confined aquifer in Semarang is necessary to supervise and better and more optimal controlling

关键词： Coastal Areas Groundwater Chloride Seawater Intrusions

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Environmental sustainability criteria in the multi-oriented shipbuilding industry in Indonesia

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Australian Journal of Maritime and Ocean Affairs 2024年第4期16卷 410-430页

作者： Azhar, Ali Harahab, Nuddin Putra, Fadilla Kurniawan, Andi Department of Naval Architecture and Ship Building Faculty of Engineering and Marine Science Hang Tuah University Surabaya Indonesia Postgraduate Environmental Science Doctorate Program Brawijaya University Malang Indonesia

Preliminary studies have highlighted the potential of Indonesia's geographical, suprastructural, and infrastructural conditions to develop a strong shipbuilding industry, which is crucial for the success of the world maritime axis program and sea toll. However, despite high expectations, the industry faces challenges that threaten business sustainability, leading to bankruptcies. To assess business sustainability, it is essential to establish criteria and sub-criteria, which previous studies have overlooked, focusing only on technical and economic factors. Therefore, this research generally aims to develop and analyze environmentally friendly sustainable criteria in the multi-oriented shipyard industry so that it develops in accordance with the vision, mission, goals and strategies. The criteria development process involves identifying and reviewing relevant articles, classifying and refining the criteria, conducting expert validity testing, Pearson Product Moment validity testing, and reliability testing using the Alpha (Cronbach) method. The expert validity testing indicates that ‘people' received the highest average score of 4.67 among the criteria, and ‘infrastructure' scored the highest in the sub-criteria, with a score of 4.75. The validity testing with the Pearson Product Moment method demonstrates that the criteria and sub-criteria are valid and the reliability of 32 sub-criteria indicating their influence on promoting multi-oriented and environmentally sustainable shipbuilding industries. © 2023 Informa UK Limited, trading as Taylor & Francis Group.

关键词： Indonesia Shipyard Industry SPSS software sustainability

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Green synthesis of iron oxide nanoparticles using Cymbopogon citratus extract and sodium carbonate salt: Nanotoxicological considerations for potential environmental applications

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Environmental Nanotechnology, Monitoring and Management 2020年 14卷

作者： Patiño-Ruiz, David Sánchez-Botero, Lina Tejeda-Benitez, Lesly Hinestroza, Juan Herrera, Adriana Engineering Doctorate Program Nanomaterials and Computer-Aided Process Engineering Research Group Universidad de Cartagena Cartagena 130010 Colombia Department of Fiber Science and Apparel Design Cornell University Ithaca United States Chemical Engineering Program Nanomaterials and Computer-Aided Process Engineering Research Group Universidad de Cartagena Cartagena 130010 Colombia

Synthesis of functional and biocompatible nanomaterials, based on the green chemistry paradigm, aims to innovate by using environmentally friendly techniques. Green synthesis using natural extracts instead of chemicals is proving to be an efficient route to prepare metal and metal oxide nanoparticles. In this study, the green synthesis of iron oxide nanoparticles (FeO-NPs) is reported, using a Cymbopogon citratus (C. citratus) extract and sodium carbonate as the reducing and pH stabilizer agents, respectively. FeO-NPs are extensively studied and applied due to the exceptional physicochemical properties, outstanding the superparamagnetism, and the large surface area. These properties are corroborated using different characterization techniques, in which a regular crystal structure and the magnetic response are similar compared with FeO-NPs synthesized via the traditional methods. The presence of magnetite and maghemite (Fe₃O₄ and γ-Fe₂O₃) phases are evidenced. A major composition of Fe₃O₄ allows predominant superparamagnetism. However, surface functionalization reduces the spin coordination avoiding a high saturation magnetization. The presence of phytochemical content in the C. citratus allows the reduction of iron(III) to iron(II) using H⁺ radicals produced from hydroxyl and carbonyl groups, and the in-situ functionalization using these groups. Additionally, the biocompatibility of the FeO-NPs is evaluated performing a nanotoxicological assessment, in which Caenorhabditis elegans nematodes are used as the biological model. The presence of organic molecules on FeO-NPs promotes no toxicity and low effects on the locomotion, growth, and reproduction, suggesting a low risk using these functional nanoparticles for environmental applications, and outstanding the synthesis route with a green approach. © 2020 Elsevier B.V.

关键词： Caenorhabditis elegans Cymbopogon citratus extract Ecotoxicological effects FeO nanoparticles Green synthesis Sodium carbonate

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Absorber of paper waste and rice husk to reduce noice in car cabin of electrical vehicle

Absorber of paper waste and rice husk to reduce noice in car...

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Joint International Conference on Rural Information & Communication Technology and Electric-Vehicle Technology (rICT & ICeV-T)

作者： R. Hari Setyanto Kuncoro Diharjo Prabang Setyono I Made Miasa Student in Doctorate Degree Sebelas Maret University Surakarta Indonesia Dept of Mechanical Engineering Faculty of Engineering Sebelas Maret University Surakarta Indonesia Dept. Environmental Science Postgraduate Program Sebelas Maret University Surakarta Indonesia Dept. of Mechanical Engineering Faculty of Engineering Gadjah Mada University Surakarta Indonesia

This study was conducted to determine the potential of office paper waste and rice husk as acoustic cell material as an absorbent noise. The acoustic cell material combines waste paper and rice husk are given a binder of PVA (polyvinyl acetate). Studies conducted with specimens of making destroy paper then mixed with rice husk. Previous chemically treated rice husks with alkali method governed by variations immersion 0, 1, 2, 3, and 4 hours, the purpose of this treatment is to remove lignin and determine the effect on noise absorption. Variations in the composition of office paper (OP) : rice husk (RH) are 90:10, 85:15, 80:20, while the variation is the addition of PVA binder 6, 8, and 10% of the total weight of the OP + RH. Variations compaction is 3:4, 4:4, and 5:4, and the specimen thickness variation is 1, 1.5, 2 cm. 2 microphone impedance test is based on ASTM E1050 used for noise absorption test specimens. Impedance test showed that the optimal noise absorption occurs in specimens composition; OP:RH (80:20), PVA 6 %, rice husk without alkali treatment (0 hours), 3:4 compaction, and specimen thickness 2 cm. The noise absorption coefficient (α) is optimal from 0.3 to 0.4.

关键词： Noise Absorption Acoustics Compaction Materials Educational institutions Impedance

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Study on Development and Application of Lightweight Overhead Contact Line Poles for Emergency Recovery

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Transactions of the Korean Institute of Electrical Engineers 2023年第11期72卷 1568-1574页

作者： Cho, Ho-Ryung Nam, Han-Seok Kim, Jong-Nam You, Hong-Kuk Na, Young-Jae Kim, Jae-Moon Department of Transportation Systems Engineering Graduate School of Transportation Korea National University of Transportation Korea Republic of Graduate School of Transportation Department of Transportation System Engineering Doctorate Program OCS solution Co. Ltd Korea Republic of Korea Railroad Corporation Korea Republic of Department of Transportation Systems Engineering Korea National University of Transportation Korea Republic of

In the event of loss of roadbed on an electric railway line due to typhoon or heavy rain damage caused by abnormal weather, or damage to a subway pole due to an unexpected train derailment, installation of catenary poles for emergency recovery is necessary to restore the electric railways. Conventional emergency catenary poles are made of steel, so they are very heavy, and the length per unit is large, making transportation and installation inconvenient. Also, there is a risk of industrial accidents due to workers' musculoskeletal disorders. In this study, we developed an emergency recovery catenary pole using aluminum, a lightweight material, and researched and developed a slimmer rail fastening device that can also be applied to concrete ballast. The developed product underwent factory testing and reference testing, was assembled and installed on a field test, and then a safety test was performed. The product developed is expected to minimize disruption to train operations and prevent industrial accidents for related workers by safety and quickly restoring electric railways. Copyright © The Korean Institute of Electrical Engineers.

关键词： Poles

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Optimizing Neural Networks for Academic Performance Classification Using Feature Selection and Resampling Approach

Mendel

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Mendel 2023年第2期29卷 261-272页

作者： Supriyadi, Didi Purwanto, Purwanto Warsito, Budi Doctorate Program of Information Systems School of Postgraduate Studies Universitas Diponegoro Semarang Indonesia Department of Chemical Engineering Faculty of Engineering Universitas Diponegoro Semarang Indonesia Department of Statistics Faculty of Science and Mathematics Universitas Diponegoro Semarang Indonesia Department of Information System Faculty of Informatics Institut Teknologi Telkom Purwokerto Banyumas Indonesia

The features present in large datasets significantly affect the performance of machine learning models. Redundant and irrelevant features will be rejected and cause a decrease in machine learning model performance. This paper proposes HyFeS-ROS-ANN: Hybrid Feature Selection and Resampling combination method for binary classification using artificial neural network multilayer perceptron (MLP). The first stage of this approach is to use a combination of two feature selection methods to select essential features that are highly correlated with model performance. The second stage of this approach is to use a combination of resampling methods to handle unbalanced data classes. Both approaches are applied to the academic performance classification model using the MLP neural network. This research dataset is obtained using three-dimensional (3D) frameworks such as the Big Five Personality to determine the Personality that affects academic performance from the student dimension, the Family Influence Scale (FIS), which measures factors that affect academic performance from the family dimension, and Higher Education Institutions Service Quality (HEISQUAL) to measure service quality and its influence on academic performance from the Education institution dimension. Previous research shows that the CoR-ANN algorithm has a model accuracy rate of 94%. The research results based on the dataset show that our proposed method can improve accuracy by selecting more relevant and essential features in improving model performance. The results show that the features are reduced from 135 to 108, while the HyFS-ROS-ANN model for binary classification accuracy increases to 100%. © 2023, Brno University of Technology. All rights reserved.

关键词： Feature Selection

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