Search results for: multi walled carbon nanotubes (MWCNTs)

Authors: D. Moser, D. Pinto, A. Cipriano

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A Disaster Management System (DMS) for countries with different disasters is very important. In the world different disasters like earthquakes, tsunamis, volcanic eruption, fire or other natural or man-made disasters occurs and have an effect on the population. It is also possible that two or more disasters arisen at the same time, this means to handle multi-risk situations. To handle such a situation a Decision Support System (DSS) based on multiagents is a suitable architecture. The most known DMSs deal with one (in the case of an earthquake-tsunami combination with two) disaster and often with one particular disaster. Nevertheless, a DSS helps for a better realtime response. Analyze the existing systems in the literature and expand them for multi-risk disasters to construct a well-organized system is the proposal of our work. The here shown work is an approach of a multi-risk system, which needs an architecture, and well-defined aims. In this moment our study is a kind of case study to analyze the way we have to follow to create our proposed system in the future.

Keywords: decision support system, disaster management system, multi-risk, multiagent system

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Authors: Hee Jae Shin, In Pyo Cha, Min Sang Lee, Hyun Kyung Yoon, Tae Ho Kim, Yoon Sun Lee, Lee Ku Kwac, Hong Gun Kim

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Non-destructive testing and evaluation techniques for assessing the integrity of composite structures are essential to both reduce manufacturing costs and out of service time of transport means due to maintenance. In this study, Analyze into non-destructive test characterization of carbon fiber reinforced plastics(CFRP) internal and external defects using thermo-graphic camera and transient thermography method. non-destructive testing were characterized by defect size(∅8,∅10,∅12,∅14) and depth(1.2mm,2.4mm).

Keywords: Non-Destructive Test (NDT), thermal characteristic, thermographic camera, Carbon Fiber Reinforced Plastics(CFRP).

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Authors: Lin Yunuo, Seow Xing Quan, Burra Venkata Durga Kumar

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In this modern era, the cloud operating system is the world trend applied in various industries such as business, healthy, etc. In order to deal with the large capacity of requirements in cloud computing, research come up with multi-tenant cloud computing to maximize the benefits of server providers and clients. However, there are still issues in multi-tenant cloud computing especially regarding resource allocation. Issues such as inefficient resource utilization, large latency, lack of scalability and elasticity and poor data isolation had caused inefficient resource allocation in multi-tenant cloud computing. Without a doubt, these issues prevent multitenancy reaches its best condition. In fact, there are multiple studies conducted to determine the optimal resource allocation to solve these problems these days. This article will briefly introduce the cloud operating system, Multi-tenant cloud computing and resource allocation in cloud computing. It then discusses resource allocation in multi-tenant cloud computing and the current challenges it faces. According to the issue ‘ineffective resource utilization’, we will discuss an efficient dynamic scheduling technique for multitenancy, namely Multi-tenant Dynamic Resource Scheduling Model (MTDRSM). Moreover, there also have some recommendations to improve the shortcoming of this model in this paper’s final section.

Keywords: cloud computing, cloud operation system, multitenancy, resource allocation, utilization of cloud resources

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Authors: Mahmut Genc, Seda Genc

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Wine is the most popular alcoholic drink in the World with 274.4 million of hectoliter annual production in the year of 2015. The wine industry is very important for some regions as well as creating significant value in their economies. This industry is very sensitive to the global warming since viticulture highly depends on climate and geographical region. Sustainability concept is a crucial issue for the wine industry and sustainability performances of wine production processes should be determined. Although wine production industry is an energy intensive sector as a whole, the most energy intensive products are widely used both in the viti and vinicultural process. In this study, gate-to-gate LCA approach in energy resource utilization and global warming potential impacts for white wine production line were attempted and carbon footprint and exergy destruction footprint were calculated, accordingly. As a result, carbon footprint and exergy destruction footprint values were calculated to be 1.75 kg CO2eq and 365.3kW, respectively.

Keywords: carbon footprint, exergy analysis, exergy destruction footprint, white wine

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Authors: Millicent N. Khumalo, Phesheya E. Dlamini

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Shrub-encroachment leads to a gain or loss of soil organic carbon (SOC) in previously open rangelands. The stabilization mechanisms controlling the storage of soil organic carbon (SOC) within aggregates of shrub-encroached grassland soils are poorly understood, especially in shallow plinthic soils. In this study, physical fractionation of surface soils (0- 10 cm) collected from open and shrub-encroached grasslands was conducted to determine the distribution of SOC within macro-and- microaggregates. Soil aggregates were classified into four fractions by a wet-sieving procedure, namely >2000 (large macro-aggregates), 212-2000 (small macro-aggregates), 50-212 (microaggregates) and < 50µm (silt+clay). In both shrub-encroached and open grassland soils, SOC was greater in the silt+clay fraction. In this fraction, SOC was on average 133% greater in shrub-encroached compared to open grassland. The greater SOC within the silt+clay fraction is due to the greater surface area and thus more exchange sites for carbon absorption. This implies that the SOC physically protected within the silt+clay is stored long-term.

Keywords: aggregate fractions, shrub-encroachment, soil organic carbon, stabilization

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Authors: Jaejin Han, Jinsub Choi

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Vanadium redox flow battery (VRFB) is a type of redox flow battery which uses vanadium ionic solution as electrolyte. Inside the VRFB, 2.5mm thickness of graphite is generally used as bipolar plate for anti-corrosion of current collector. In this research, thick graphite bipolar plate was substituted by 0.126mm thickness of dimensionally stable anode which was coated with IrO2 on an anodic nanotubular TiO2 substrate. It can provide dimensional advantage over the conventional graphite when the VRFB is used as multi-stack. Ir was coated by using spray coating method in order to enhance electric conductivity. In this study, various electrochemical characterizations were carried out. Cyclic voltammetry data showed activation of Ir in the positive electrode of VRFB. In addition, polarization measurements showed Ir-coated DSA had low overpotential in the positive electrode of VRFB. In cell test results, the DSA-used VRFB showed better efficiency than graphite-used VRFB in voltage and overall efficiency.

Keywords: bipolar plate, DSA (dimensionally stable anode), iridium oxide coating, TiO2 nanotubes, VRFB (vanadium redox flow battery)

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Authors: Bongjae Lee, Beom Goo Hwang, Hye Mi Park

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CO₂ capture products manufactured through Carbon Capture and Utilization (CCU) Plant that collect CO₂ directly from power plants require accurate measurements of the amount of CO₂ captured. For this purpose, two tests were carried out on the weight loss test. And one was analyzed using a carbon dioxide quantification device. First, the ignition loss analysis was performed by measuring the weight of the sample at 550°C after the first conversation and then confirming the loss when ignited at 950°C. Second, in the thermogravimetric analysis, the sample was divided into two sections of 40 to 500°C and 500 to 800°C to confirm the reduction. The results of thermal weight loss analysis and thermogravimetric analysis were confirmed to be almost similar. However, the temperature of the ignition loss analysis method was 950°C, which was 150°C higher than that of the thermogravimetric method at a temperature of 800°C, so that the difference in the amount of weight loss was 3 to 4% higher by the heat loss analysis method. In addition, the tendency that the CO₂ content increases as the reaction time become longer is similarly confirmed. Third, the results of the wet titration method through the carbon dioxide quantification device were found to be significantly lower than the weight loss method. Therefore, based on the results obtained through the above three analysis methods, we will establish a method to analyze the accurate amount of CO₂. Acknowledgements: This work was supported by the Korea Institute of Energy Technology Evaluation and planning (No. 20152010201850).

Keywords: carbon capture and utilization, CCU, CO2, CO2 capture products, analysis method

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Authors: George Oliveira, Luana D. Fronza, Luiza Medeiros, Patricia D. M. Plentz

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The research presented in this article is part of a wide project that proposes a scheduling system for multi-robots in intelligent warehouses employing multi-robot path-planning (MPP) and multi-robot task allocation (MRTA) to reconcile multiple restrictions (task delivery time, task priorities, charging capacity, and robots battery capacity). We present the software component capable of interconnecting an open streaming processing architecture and robot operating system (ROS), ensuring communication and message exchange between robots and the environment in which they are inserted. Simulation results show the good performance of our proposed technique for connecting ROS and streaming platforms.

Keywords: complex distributed systems, mobile robots, smart warehouses, streaming platforms

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Authors: Salim Khan

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The attainment of the carbon neutrality objective and Sustainable Development Goal 13 (SDG-13) target, which pertains to climate actions, received widespread attention in developing and emerging nations. Given the increasing pace of urbanization, technological advancements, and rapid growth, it is imperative to examine the linear and nonlinear effects of urbanization and economic growth and the linear impact of information and communication technology (ICT) on carbon emissions (CO2e). This study employs the Dynamic System GMM (DSGMM) and Panel Quantile Regression (PQR) methodologies to investigate the causal relationship between urbanization, ICT, economic growth, and their interplay on CO2e in 39 BRI countries from 2001 to 2020. The study's findings indicate that the impact of urbanization on CO2e exhibits linear and nonlinear patterns. The specific nonlinear impact of urbanization leads to a decrease in CO2e, hence facilitating the achievement of carbon neutrality and contributing to SDG-13. The study highlights the importance of ICT in achieving SDG-13 by reducing CO2e, emphasizing the need for informatization. Simultaneously, the findings support the Environmental Kuznets Curve (EKC) hypothesis and support the pollution haven theory. Finally, based on empirical findings, significant policy implications are suggested for achieving SGD 13 and carbon neutrality.

Keywords: urbanization, ICT, CO2 emission, EKC, pollution haven, BRI

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Authors: Sthanu Mahadev, Wen Chan, Melanie Lim

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Anisotropy dominated continuous-fiber composite materials have garnered attention in numerous mechanical and aerospace structural applications. Tailored mechanical properties in advanced composites can exhibit superiority in terms of stiffness-to-weight ratio, strength-to-weight ratio, low-density characteristics, coupled with significant improvements in fatigue resistance as opposed to metal structure counterparts. Extensive research has demonstrated their core potential as more than just mere lightweight substitutes to conventional materials. Prior work done by Mahadev and Chan focused on formulating a modified composite shell theory based prognosis methodology for investigating the structural response of thin-walled circular cylindrical shell type composite configurations under in-plane mechanical loads respectively. The prime motivation to develop this theory stemmed from its capability to generate simple yet accurate closed-form analytical results that can efficiently characterize circular composite shell construction. It showcased the development of a novel mathematical framework to analytically identify the location of the centroid for thin-walled, open cross-section, curved composite shells that were characterized by circumferential arc angle, thickness-to-mean radius ratio, and total laminate thickness. Ply stress variations for curved cylindrical shells were analytically examined under the application of centric tensile and bending loading. This work presents a cost-effective, small-platform experimental methodology by taking advantage of the full-field measurement capability of digital image correlation (DIC) for an accurate assessment of key mechanical parameters such as in-plane mechanical stresses and strains, centroid location etc. Mechanical property measurement of advanced composite materials can become challenging due to their anisotropy and complex failure mechanisms. Full-field displacement measurements are well suited for characterizing the mechanical properties of composite materials because of the complexity of their deformation. This work encompasses the fabrication of a set of curved cylindrical shell coupons, the design and development of a novel test-fixture design and an innovative experimental methodology that demonstrates the capability to very accurately predict the location of centroid in such curved composite cylindrical strips via employing a DIC based strain measurement technique. Error percentage difference between experimental centroid measurements and previously estimated analytical centroid results are observed to be in good agreement. The developed analytical modified-shell theory provides the capability to understand the fundamental behavior of thin-walled cylindrical shells and offers the potential to generate novel avenues to understand the physics of such structures at a laminate level.

Keywords: anisotropy, composites, curved cylindrical shells, digital image correlation

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Authors: Retno Ambarwati Sigit Lestari

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Microalga is one of the organisms that can be considered ideal and potential for raw material of bioenergy production, because the content of lipids in microalga is relatively high. Microalga is an aquatic organism that produces complex organic compounds from inorganic molecules using carbon dioxide as a carbon source, and sunlight for energy supply. Microalga-CO₂ fixation has potential advantages over other carbon captures and storage approaches, such as wide distribution, high photosynthetic rate, good environmental adaptability, and ease of operation. The rates of growth and CO₂ capture of microalga are influenced by CO₂ concentration and light intensity. This study quantitatively investigates the effects of CO₂ concentration on the rates of growth and CO₂ capture of a type of microalga, cultivated in bioreactors. The works include laboratory experiments as well as mathematical modelling. The mathematical models were solved numerically and the accuracy of the model was tested by the experimental data. It turned out that the mathematical model proposed can well quantitatively describe the growth and CO₂ capture of microalga, in which the effects of CO₂ concentration can be observed.

Keywords: Microalga, CO2 concentration, photobioreactor, mathematical model

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Authors: Ali Afaghi, Sehraneh Ghaemi

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The coordination of the multi-agent systems has been one of the interesting topic in recent years, because of its potential applications in many branches of science and engineering such as sensor networks, flocking, underwater vehicles and etc. In the most of the related studies, it is assumed that the dynamics of the multi-agent systems are integer-order and linear and the multi-agent systems with the fractional-order nonlinear dynamics are rarely considered. However many phenomena in nature cannot be described within integer-order and linear characteristics. This paper investigates the leader-following consensus problem for a class of nonlinear fractional-order multi-agent systems based on observer-based cooperative control. In the system, the dynamics of each follower and leader are nonlinear. For a multi-agent system with fixed directed topology firstly, an observer-based consensus protocol is proposed based on the relative observer states of neighboring agents. Secondly, based on the property of the stability theory of fractional-order system, some sufficient conditions are presented for the asymptotical stability of the observer-based fractional-order control systems. The proposed method is applied on a five-agent system with the fractional-order nonlinear dynamics and unavailable states. The simulation example shows that the proposed scenario results in the good performance and can be used in many practical applications.

Keywords: fractional-order multi-agent systems, leader-following consensus, nonlinear dynamics, directed graphs

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Authors: Anisha Mandal, Swambabu Varanasi

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Lead is one of the most prevalent toxic heavy metal ions, and its pollution poses a significant threat to the environment and human health. On the other hand, Ethylenediaminetetraacetic acid is a widely used metal chelating agent that, due to its poor biodegradability, is an incessant pollutant to the environment. For the first time, a green, simple, and cost-effective approach is used to hydrothermally synthesise photoluminescent carbon dots using Moringa Oleifera Gum in a single step. Then, using Moringa Oleifera Gum-derived carbon dots, a photoluminescent "ON-OFF-ON" mechanism for dual mode detection of trace Pb2+ and EDTA was proposed. MOG-CDs detect Pb2+ selectively and sensitively using a photoluminescence quenching mechanism, with a detection limit (LOD) of 0.000472 ppm. (1.24 nM). The quenched photoluminescence can be restored by adding EDTA to the MOG-CD+Pb2+ system; this strategy is used to quantify EDTA at a level of detection of 0.0026 ppm. (8.9 nM). The quantification of Pb2+ and EDTA in actual samples encapsulated the applicability and dependability of the proposed photoluminescent probe.

Keywords: carbon dots, photoluminescence, sensor, moringa oleifera gum

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Authors: Muhammad Shoaib, Hassan M Al-Swaidan

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Saudi Arabia is the major date producer in the world. In order to maximize the production from date tree, pruning of the date trees is required annually. Large amount of this agriculture waste material (palm tree fronds) is available in Saudi Arabia and considered as an ideal source as a precursor for production of activated carbon (AC). The single step procedure for the preparation of micro porous activated carbon (AC) from Saudi date tree fronds using mixture of gases (N2 and CO2) is carried out at carbonization/activation temperature at 850°C and at different ramp rates of 10, 20 and 30 degree per minute. Alloy 330 horizontal reactor is used for tube furnace. Flow rate of nitrogen and carbon dioxide gases are kept at 150 ml/min and 50 ml/min respectively during the preparation. Characterization results reveal that the BET surface area, pore volume, and average pore diameter of the resulting activated carbon generally decreases with the increase in ramp rate. The activated carbon prepared at a ramp rate of 10 degrees/minute attains larger surface area and can offer higher potential to produce activated carbon of greater adsorption capacity from agriculture wastes such as date fronds. The BET surface areas of the activated carbons prepared at a ramp rate of 10, 20 and 30 degree/minute after 30 minutes activation time are 1094, 1020 and 515 m2/g, respectively. Scanning electron microscopy (SEM) for surface morphology, and FTIR for functional groups was carried out that also verified the same trend. Moreover, by increasing the ramp rate from 10 and 20 degrees/min the yield remains same, i.e. 18%, whereas at a ramp rate of 30 degrees/min the yield increases from 18 to 20%. Thus, it is feasible to produce high-quality micro porous activated carbon from date frond agro waste using N2 carbonization followed by physical activation with CO2 and N2 mixture. This micro porous activated carbon can be used as adsorbent of heavy metals from wastewater, NOx SOx emission adsorption from ambient air and electricity generation plants, purification of gases, sewage treatment and many other applications.

Keywords: activated carbon, date tree fronds, agricultural waste, applied chemistry

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Authors: Juniarti, Yusniwati, Anwar. A, Armansyah, Febriamansyah, R.

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Simawang area is one of the critical areas (sub-optimal) that experienced drought from climate changes. Potential dry land belonging to sub-optimal in Simawang, West Sumatera, Indonesia not been fully utilized for agricultural cultivation. Simawang village, West Sumatera, Indonesia is formerly known as the rice barn, due to the climate change area is experiencing a drought, so the rice fields that were once productive now a grazing paddock because of lack of water. This study aims to calculate the soil carbon stock in Simawang village, West Sumatera Indonesia. The study was conducted in Simawang village, Tanah Datar regency, West Sumatera from October 2014 until December 2017. The study was conducted on sub-optimal land to be planted with Cymbopogon nardus L. (Sereh wangi in Indonesian language). Composite soil sampling conducted at a depth of 0-20 cm, 20 – 40 cm. Based on the depth of soil carbon stocks gained higher ground 6473 t ha-1 at a depth of 0-20 cm at a depth of 20-40 cm. Efforts to increase soil carbon is expected to be cultivated through Cymbopogon nardus L. planting has been done.

Keywords: climate changes, sereh wangi (Cymbopogon nardus L.), soil carbon stock, sub optimal land

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Authors: Špela Hajduk, Sean P. Berglund, Matejka Podlogar, Goran Dražić, Fatwa F. Abdi, Zorica C. Orel, Menny Shalom

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Graphitic carbon nitride materials (g-CN) have emerged as an attractive photocatalyst and electrocatalyst for photo and electrochemical water splitting reaction, due to their environmental benignity nature and suitable band gap. Many approaches were introduced to enhance the photoactivity and electronic properties of g-CN and resulted in significant changes in the electronic and catalytic properties. Here we demonstrate the synthesis of thin and homogenous g-CN layer on highly ordered ZnO nanowire (NW) substrate by growing a seeding layer of small supramolecular assemblies on the nanowires. The new synthetic approach leads to the formation of thin g-CN layer (~3 nm) without blocking all structure. Two different deposition methods of carbon nitride were investigated and will be presented. The amount of loaded carbon nitride significantly influences the PEC activity of hybrid material and all the ZnO/g-CNx electrodes show great improvement in photoactivity. The chemical structure, morphology and optical properties of the deposited g-CN were fully characterized by various techniques as X-ray powder spectroscopy (XRD), scanning electron microscopy (SEM), focused ion beam scanning electron microscopy (FIB-SEM), high-resolution scanning microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS).

Keywords: carbon nitride, photoanode, solar water splitting, zinc oxide

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Authors: A. R. Manu, V. K. Agrawal, K. N. Balasubramanya Murthy

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Authentication is required in stored database systems so that only authorized users can access the data and related cloud infrastructures. This paper proposes an authentication technique using multi-factor and multi-dimensional authentication system with multi-level security. The proposed technique is likely to be more robust as the probability of breaking the password is extremely low. This framework uses a multi-modal biometric approach and SMS to enforce additional security measures with the conventional Login/password system. The robustness of the technique is demonstrated mathematically using a statistical analysis. This work presents the authentication system along with the user authentication architecture diagram, activity diagrams, data flow diagrams, sequence diagrams, and algorithms.

Keywords: design, implementation algorithms, performance, biometric approach

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Authors: Tahir Ahmad, M. Kamran, R. Ahmad, M. T. Z. Butt

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Hybrid aluminum metal matrix composites with 1, 2, 3 and 4 wt. % of silica sand nanoparticles and electro-less nickel coated carbon fibers were successfully developed using sand casting technique. Epoxy coating of carbon fibers was removed and phosphorous-nickel coating was successfully applied via electro-less route. The developed hybrid composites were characterized using micro hardness tester, tensile testing, and optical microscopy. The gradual increase of reinforcing phases yielded improved mechanical properties such as hardness and tensile strength. The increase in hardness was attributed to the presence of silica sand nanoparticles whereas electro-less nickel coated carbon fibers enhanced the tensile properties of developed hybrid composites. The microstructure of the developed hybrid composites revealed the homogeneous distribution of both carbon fibers and silica sand nanoparticles in aluminum based hybrid composites. The formation of dendrite microstructure is the main cause of improving mechanical properties.

Keywords: aluminum based hybrid composites, mechanical properties, microstructure, microstructure and mechanical properties relationship

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Authors: Maryam Kiani, Abdul Basit Kiani

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At larger scales, the performance of cementitious materials is impacted by processes occurring at the nanometer scale. These materials boast intricate hierarchical structures with random features that span from the nanometer to millimeter scale. It is fascinating to observe how the nanoscale processes influence the overall behavior and characteristics of these materials. By delving into and manipulating these processes, scientists and engineers can unlock the potential to create more durable and sustainable infrastructure and construction materials. It's like unraveling a hidden tapestry of secrets that hold the key to building stronger and more resilient structures. The present work employs simulations as the computational modeling methodology to predict mechanical properties for carbon/silica based cementitious materials at the molecular/nano scale level. Studies focused on understanding the effect of higher mechanical properties of cementitious materials with carbon silica nanoparticles via Material Studio materials modeling.

Keywords: nanomaterials, SiO₂, carbon black, mechanical properties

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Authors: Daniela Rimnacova, Maryna Vorokhta, Martina Svabova

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CO₂ adsorption capacity of several materials - waste (power fly ash, slag, carbonized sewage sludge), rocks (Czech Silurian shale, black coal), and carbon (synthesized carbon, activated carbon as a reference material) - were measured on dry samples using a unique hand-made manometric sorption apparatus at a temperature of 45 °C and pressures of up to 7 MPa. The main aim was finding utilization of the waste materials and rocks for removal of the air or water pollutants caused by anthropogenic activities, as well as for the carbon dioxide storage. The equilibrium amount of the adsorbate depends on temperature, gas saturation pressure, porosity, surface area and volume of pores, and last but not least, on the composition of the adsorbents. Given experimental conditions can simulate in-situ situations in the rock bed and can be achieved just by a high-pressure apparatus. The CO₂ excess adsorption capacities ranged from 0.018 mmol/g (ash) to 13.55 mmol/g (synthesized carbon). The synthetized carbon had the highest adsorption capacity among all studied materials as well as the highest price. This material is usually used for the adsorption of specific pollutants. The excess adsorption capacity of activated carbon was 9.19 mmol/g. It is used for water and air cleaning. Ash can be used for chemisorption onto ash particle surfaces or capture of special pollutants. Shale is a potential material for enhanced gas recovery or CO₂ sequestration in-situ. Slag is a potential material for capture of gases with a possibility of the underground gas storage after the adsorption process. The carbonized sewage sludge is quite a good adsorbent for the removal and capture of pollutants, as well as shales or black coal which show an interesting relationship between the price and adsorption capacity.

Keywords: adsorption, CO₂, high pressure, porous materials

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Authors: A. Acidi, A. Abbaci

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We present the viability of using thermally stable, practically non-volatile ionic liquids as corrosion inhibitors in aqueous monoethanolamine system. Carbon steel 1020, which widely used as construction material in CO2 capture plants, has been taken as a test material. Corrosion inhibition capacities of typical room-temperature ionic liquids constituting imidazolium cation in concentration range ≤ 3% by weight in CO2 capture applications were investigated. Electrochemical corrosion experiments using the potentiodynamic polarization technique for measuring corrosion current were carried out. The results show that ionic liquids possess ability to suppressing severe operational problems of corrosion in typical CO2 capture plants.

Keywords: carbon dioxide, carbon steel, monoethanolamine, corrosion rate, ionic liquids, tafel fit

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Authors: Majid Khalili

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This paper deals with a bi-objective hybrid no-wait flowshop scheduling problem minimizing the makespan and total weighted tardiness, in which we consider transportation times between stages. Obtaining an optimal solution for this type of complex, large-sized problem in reasonable computational time by using traditional approaches and optimization tools is extremely difficult. This paper presents a new multi-objective variable neighborhood algorithm (MOVNS). A set of experimental instances are carried out to evaluate the algorithm by advanced multi-objective performance measures. The algorithm is carefully evaluated for its performance against available algorithm by means of multi-objective performance measures and statistical tools. The related results show that a variant of our proposed MOVNS provides sound performance comparing with other algorithms.

Keywords: no-wait hybrid flowshop scheduling; multi-objective variable neighborhood algorithm; makespan; total weighted tardiness

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Authors: Liu De-jun, Fu Jing, Zhang Rong, Luo Tian, Ma Ning

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Cs-137, the radioactive fission products of uranium, can be easily dissolved in water during the accident of nuclear power plant, such as Chernobyl, Three Mile Island, Fukushima accidents. The concentration of Cs in the groundwater around the nuclear power plant exceeded the standard value almost 10,000 times after the Fukushima accident. The adsorption capacity of Titanate nano-materials for radioactive cation (Cs+) is very strong. Moreover, the radioactive ion can be tightly contained in the nanotubes or nanofibers without reversible adsorption, and it can safely be fixed. In addition, the nano-material has good chemical stability, thermal stability and mechanical stability to minimize the environmental impact of nuclear waste and waste volume. The preparation of titanate nanotubes or nanofibers was studied by hydrothermal methods, and chemical kinetics of removal of Cs by nano-materials was obtained. The adsorption time with maximum adsorption capacity and the effects of pH, coexisting ion concentration and the optimum adsorption conditions on the removal of Cs by titanate nano-materials were also obtained. The adsorption boundary curves, adsorption isotherm and the maximum adsorption capacity of Cs-137 as tracer on the nano-materials were studied in the research. The experimental results showed that the removal rate of Cs-137 in 0.01 tons of waste water with only 1 gram nano-materials could reach above 98%, according to the optimum adsorption conditions.

Keywords: preparation, titanate, cs-137, removal, nuclear

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Authors: Ching Louis Liu, Edmund Kazmierczak, Tim Miller

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Safety analysis for multi-agent systems is complicated by the, potentially nonlinear, interactions between agents. This paper proposes a method for analyzing the safety of multi-agent systems by explicitly focusing on interactions and the accident data of systems that are similar in structure and function to the system being analyzed. The method creates a Bayesian network using the accident data from similar systems. A feature of our method is that the events in accident data are labeled with HAZOP guide words. Our method uses an Ontology to abstract away from the details of a multi-agent implementation. Using the ontology, our methods then constructs an “Interaction Map,” a graphical representation of the patterns of interactions between agents and other artifacts. Interaction maps combined with statistical data from accidents and the HAZOP classifications of events can be converted into a Bayesian Network. Bayesian networks allow designers to explore “what it” scenarios and make design trade-offs that maintain safety. We show how to use the Bayesian networks, and the interaction maps to improve multi-agent system designs.

Keywords: multi-agent system, safety analysis, safety model, integration map

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Authors: Juniarti Yuni

Abstract:

Simawang area is one of the critical areas (sub-optimal) that experienced drought from climate changes. Potential dry land belonging to sub-optimal in Simawang, West Sumatera, Indonesia not been fully utilized for agricultural cultivation. Simawang village, West Sumatera, Indonesia is formerly known as the rice barn, due to the climate change area is experiencing a drought, so the rice fields that were once productive now a grazing paddock because of lack of water. This study aims to calculate the soil carbon stock in Simawang village, West Sumatera Indonesia. The study was conducted in Simawang village, Tanah Datar regency, West Sumatera from October 2014 until December 2017. The study was conducted on sub-optimal land to be planted with Cymbopogon nardus L. (Sereh wangi in Indonesian language). Composite soil sampling conducted at a depth of 0-20 cm, 20–40 cm. Based on the depth of soil carbon stocks gained higher ground 6473 T/Ha at a depth of 0-20 cm at a depth of 20-40 cm. Efforts to increase soil carbon is expected to be cultivated through Cymbopogon nardus L. planting has been done.

Keywords: climate changes, sereh wangi (Cymbopogon nardus L.), soil carbon stock, sub optimal land

Procedia PDF Downloads 291

Authors: P. A. Broodryk, A. F. Van Der Merwe, H. W. J. P. Neomagus

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The production of the clear liquid fertilizer ammonium polyphosphate (APP) is best achieved by the pyrolysis of urea phosphate, as it produces a product that is free from any of the impurities present in the raw phosphoric acid it was made from. This is a multiphase, multi-step reaction that produces carbon dioxide and ammonia as gasses and ammonium polyphosphate as liquid products. The polyphosphate chain length affects the solubility and thus the applicability of the product as liquid fertiliser, thus proper control of the reaction conditions is thus required for the use of this reaction in the production of fertilisers. This study investigates the reaction kinetics of the aforementioned reaction, describing a mathematical model for the kinetics of the reaction along with the accompanying rate constants. The reaction is initially exothermic, producing only carbon dioxide as a gas product and ammonium diphosphate, at higher temperatures the reaction becomes endothermic, producing ammonia gas as an additional by-product and longer chain polyphosphates, which when condensed too far becomes highly water insoluble. The aim of this study was to (i) characterise the pyrolysis reaction of urea phosphate by determining the mechanisms and the associated kinetic constants, and (ii) to determine the optimum conditions for ammonium diphosphate production. A qualitative investigation was also done to find the rate of hydrolysis of APP as this provides an estimate of the shelf life of an APP clear liquid fertiliser solution.

Keywords: ammonium polyphosphate, kinetics, pyrolysis, urea phosphate

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Authors: Farzad Jafarpour Taher, Maghsud Solimanpur

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Production planning is one of the complex tasks in multi-product firms that produce a wide range of products. Since resources in mass production companies are limited and different products use common resources, there must be a careful plan so that firms can respond to customer needs efficiently. Azar-battery Company is a firm that provides twenty types of products for its customers. Therefore, careful planning must be performed in this company. In this research, the current conditions of Azar-battery Company were investigated to provide a mathematical programming model to determine the optimum production rate of the products in this company. The production system of this company is multi-stage, multi-product and multi-period. This system is studied in terms of a one-year planning horizon regarding the capacity of machines and warehouse space limitation. The problem has been modeled as a linear programming model with deterministic demand in which shortage is not allowed. The objective function of this model is to minimize costs (including raw materials, assembly stage, energy costs, packaging, and holding). Finally, this model has been solved by Lingo software using the branch and bound approach. Since the computation time was very long, the solver interrupted, and the obtained feasible solution was used for comparison. The proposed model's solution costs have been compared to the company’s real data. This non-optimal solution reduces the total production costs of the company by about %35.

Keywords: multi-period, multi-product production, multi-stage, production planning

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Authors: Humayun R. H. Kabir

Abstract:

A reinforced concrete dome-built 60 years ago- of circular shape of diameter of 30 m was in distressed conditions due to adverse weathering effects, such as high temperature, wind, and poor maintenance. It was decided to restore the dome to its full strength for future use. A full material strength and durability check including petrography test were conducted. It was observed that the concrete strength was in acceptable range, while bars were corroded more than 40% to their original configurations. Widespread cracks were almost in every meter square. A strengthening program with filling the cracks by injection method, and carbon fiber layup and wrap was considered. Ultra Sound Pulse Velocity (UPV) test was conducted to observe crack depth. Ground Penetration Radar (GPR) test was conducted to observe internal bar conditions and internal cracks. Finally, a load test was conducted to certify the carbon fiber effectiveness, injection method procedure and overall behavior of dome.

Keywords: dome, strengthening program, carbon fiber, load test

Procedia PDF Downloads 240

Authors: Agnieszka S. Dzielendziak, Lindsay-Marie Armstrong, Matthew E. Potter, Robert Raja, Pier J. A. Sazio

Abstract:

Reducing carbon dioxide, CO₂, is one of the greatest global challenges. Conversion of CO₂ for utilisation across synthetic fuel, pharmaceutical, and agrochemical industries offers a promising option, yet requires significant research to understanding the complex multiscale processes involved. To experimentally understand and optimize such processes at that catalytic sites and exploring the impact of the process at reactor scale, is too expensive. Computational methods offer significant insight and flexibility but require a more detailed multi-scale approach which is a significant challenge in itself. This work introduces a computational approach which incorporates detailed catalytic models, taken from experimental investigations, into a larger-scale computational flow dynamics framework. The reactor-scale species transport approach is modified near the catalytic walls to determine the influence of catalytic clustering regions. This coupling approach enables more accurate modelling of velocity, pressures, temperatures, species concentrations and near-wall surface characteristics which will ultimately enable the impact of overall reactor design on chemical conversion performance.

Keywords: catalysis, CCU, CO₂, multi-scale model

Procedia PDF Downloads 240

Authors: Zhaoyang Liu

Abstract:

It has been highly desired to develop a high-performance membrane for separating oil/water emulsions with the combined features of high water flux, high oil separation efficiency, and high mechanical stability. Here, we demonstrated a design for high-performance membranes constructed with ultra-long titanate nanofibers (over 30 µm in length)/cellulose microfibers. An integrated network membrane was achieved with these ultra-long nano/microfibers, contrast to the non-integrated membrane constructed with carbon nanotubes (5 µm in length)/cellulose microfibers. The morphological properties of the prepared membranes were characterized by A FEI Quanta 400 (Hillsboro, OR, United States) environmental scanning electron microscope (ESEM). The hydrophilicity, underwater oleophobicity and oil adhesion property of the membranes were examined using an advanced goniometer (Rame-hart model 500, Succasunna, NJ, USA). More specifically, the hydrophilicity of membranes was investigated by analyzing the spreading process of water into membranes. A filtration device (Nalgene 300-4050, Rochester, NY, USA) with an effective membrane area of 11.3 cm² was used for evaluating the separation properties of the fabricated membranes. The prepared oil-in-water emulsions were poured into the filtration device. The separation process was driven under vacuum with a constant pressure of 5 kPa. The filtrate was collected, and the oil content in water was detected by a Shimadzu total organic carbon (TOC) analyzer (Nakagyo-ku, Kyoto, Japan) to examine the separation efficiency. Water flux (J) of the membrane was calculated by measuring the time needed to collect some volume of permeate. This network membrane demonstrated good mechanical flexibility and robustness, which are critical for practical applications. This network membrane also showed high separation efficiency (99.9%) for oil/water emulsions with oil droplet size down to 3 µm, and meanwhile, has high water permeation flux (6.8 × 10³ L m⁻² h⁻¹ bar⁻¹) at low operation pressure. The high water flux is attributed to the interconnected scaffold-like structure throughout the whole membrane, while the high oil separation efficiency is attributed to the nanofiber-made nanoporous selective layer. Moreover, the economic materials and low-cost fabrication process of this membrane indicate its great potential for large-scale industrial applications.

Keywords: membrane, inorganic nanofibers, oil/water separation, emulsions

Procedia PDF Downloads 158