Search results for: hierarchical porous carbon

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: Edip Kemal, Sheshov Vlatko, Bojadjieva Julijana, Bogdanovic ALeksandra, Gjorgjeska Irena

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The wave propagation phenomenon in porous domains is of great importance in the field of geotechnical earthquake engineering. In these kinds of problems, the elastic waves propagate from the interior to the exterior domain and require special treatment at the computational level since apart from displacement in the solid-state there is a p-wave that takes place in the pore water phase. In this paper, a study on the implementation of multiphase finite elements is presented. The proposed algorithm is implemented in the ANSYS finite element software and tested on one-dimensional wave propagation considering both pore pressure wave propagation and displacement fields. In the simulation of porous media such as soils, the behavior is governed largely by the interaction of the solid skeleton with water and/or air in the pores. Therefore, coupled problems of fluid flow and deformation of the solid skeleton are considered in a detailed way.

Keywords: wave propagation, multiphase model, numerical methods, finite element method

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Authors: Poonam Yadav, Dong Bok Lee

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Raman spectroscopy was used for characterization of multi-wall carbon nanotube (MWNT) and Polycarbonate/multi-wall carbon nanotube (PC/MWNT) based fibers with 0.55% and 0.75% of MWNT (PC/MWNT55 and PC/MWNT75). PC/MWNT55 and PC/MWNT75 fibers was prepared by melt spinning device using nanocomposites made by two different route, viz., solvent casting and melt extrusion. Fibers prepared from melt extruded nanocomposites showed smooth and uniform morphology as compared to solvent casting based nanocomposites. The Raman mapping confirmed that the melt extruded based nanocomposites had better dispersion of MWNT in Polycarbonate (PC) than solvent casting carbon nanotube.

Keywords: dispersion, melt extrusion, multi-wall carbon nanotube, mapping

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Authors: Juniarti Yuni

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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 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: Humayun R. H. Kabir

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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

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Authors: Paras Ram, Vikas Kumar

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The transmission of Malaria with seasonal were studied through the use of mathematical models. The data from the annual number of Malaria cases reported to the Division of Epidemiology, Ministry of Public Health, Thailand during the period 1997-2011 were analyzed. The transmission of Malaria with seasonal was studied by formulating a mathematical model which had been modified to describe different situations encountered in the transmission of Malaria. In our model, the population was separated into two groups: the human and vector groups, and then constructed a system of nonlinear differential equations. Each human group was divided into susceptible, infectious in hot season, infectious in rainy season, infectious in cool season and recovered classes. The vector population was separated into two classes only: susceptible and infectious vectors. The analysis of the models was given by the standard dynamical modeling.

Keywords: ferrofluid, magnetic field, porous medium, rotating disk, Neuringer-Rosensweig Model

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Authors: Reza Pourjafar, Morteza Sohrabi-Gilani, Mostafa Jamshidi Avanaki, Malek Mohammad Ranjbar

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Cementitious composites like concrete, are the most widely used materials in civil infrastructures. Numerous investigations on fiber’s effect on the properties of cement-based composites have been conducted in the last few decades. The use of fibers such as carbon nanofibers (CNFs) and carbon nanotubes (CNTs) in these materials is an ongoing field and needs further researches and studies. Excellent mechanical, thermal, and electrical properties of carbon nanotubes and nanofibers have motivated the development of advanced nanocomposites with outstanding and multifunctional properties. In this study, the electrical resistance of CNF reinforced cement mortar was examined. Three different dosages of CNF were used, and the resistances were compared to plain cement mortar. One of the biggest challenges in this study is dispersing CNF particles in the mortar mixture. Therefore, polycarboxylate superplasticizer and ultrasonication of the mixture have been selected for the purpose of dispersing CNFs in the cement matrix. The obtained results indicated that the electrical resistance of the CNF reinforced mortar samples decreases with increasing CNF content, which would be the first step towards examining strain and damage monitoring ability of cementitious composites containing CNF for structural health monitoring purposes.

Keywords: carbon nanofiber, cement and concrete, CNF reinforced mortar, smart mater, strain monitoring, structural health monitoring

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Authors: Santhosh Ravichandran, F. J. Rodríguez-Varela

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In this study, a biocarbon (BC) was made from sewage sludge from the water treatment plant (PTAR) in Saltillo, Coahuila, Mexico. The sludge was carbonized in water and then chemically activated by pyrolysis. The biocarbon was evaluated physicochemically using XRD, SEM-EDS, and FESEM. A broad (002) peak attributable to graphitic structures indicates that the material is amorphous. The resultant biocarbon has a high specific surface area (412 m2 g-1), a large pore volume (0.39 cm3 g-1), interconnected hierarchical porosity, and outstanding electrochemical performance. It is appropriate for high-performance supercapacitor electrode materials due to its high specific capacitance of 358 F g-1, great rate capability, and outstanding cycling stability (around 87% capacitance retention after 10,000 cycles, even at a high current density of 19 A g-1). In an aqueous solution, the constructed BC/BC symmetric supercapacitor exhibits increased super capacitor behavior with a high energy density of 29.5 Whkg-1. The concept provides an efficient method for producing high-performance electrode materials for supercapacitors from conventional water treatment biomass wastes.

Keywords: supercapacitors, carbon, material science, batteries

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Authors: Shaikah Alsubayae, Gianluigi Casse, Carlos Chavez, Jon Taylor, Alan Taylor, Mohammad Alsulimane

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Achieving precise radiotherapy through carbon therapy necessitates the accurate monitoring of radiation dose distribution within the patient's body. This process is pivotal for targeted tumor treatment, minimizing harm to healthy tissues, and enhancing overall treatment effectiveness while reducing the risk of side effects. In our investigation, we adopted a methodological approach to monitor secondary proton doses in carbon therapy using Monte Carlo (MC) simulations. Initially, Geant4 simulations were employed to extract the initial positions of secondary particles generated during interactions between carbon ions and water, including protons, gamma rays, alpha particles, neutrons, and tritons. Subsequently, we explored the relationship between the carbon ion beam and these secondary particles. Interaction vertex imaging (IVI) proves valuable for monitoring dose distribution during carbon therapy, providing information about secondary particle locations and abundances, particularly protons. The IVI method relies on charged particles produced during ion fragmentation to gather range information by reconstructing particle trajectories back to their point of origin, known as the vertex. In the context of carbon ion therapy, our simulation results indicated a strong correlation between some secondary particles and the range of carbon ions. However, challenges arose due to the unique elongated geometry of the target, hindering the straightforward transmission of forward-generated protons. Consequently, the limited protons that did emerge predominantly originated from points close to the target entrance. Fragment (protons) trajectories were approximated as straight lines, and a beam back-projection algorithm, utilizing interaction positions recorded in Si detectors, was developed to reconstruct vertices. The analysis revealed a correlation between the reconstructed and actual positions.

Keywords: radiotherapy, carbon therapy, monitor secondary proton doses, interaction vertex imaging

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Authors: Kleiner Marques Marra, Tércio Pedrosa

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This paper reports the production of uranium-molybdenum alloys, which have been considered promising fuel for test and research nuclear reactors. U-Mo alloys were produced in three molybdenum contents: 5 wt.%, 7 wt.%, and 10 wt.%, using an electric vacuum induction furnace. A boron nitride-coated graphite crucible was employed in the production of the alloys and, after melting, the material was immediately poured into a boron nitride-coated graphite mold. The incorporation of carbon was observed, but it happened in a lower intensity than in the case of the non-coated crucible/mold. It is observed that the carbon incorporation increased and alloys density decreased with Mo addition. It was also noticed that the increase in the carbon or molybdenum content did not seem to change the as-cast structure in terms of granulation. The three alloys presented body-centered cubic crystal structure (g phase), after solidification, besides a seeming negative microsegregation of molybdenum, from the center to the periphery of the grains. There were signs of macrosegregation, from the base to the top of the ingots.

Keywords: uranium-molybdenum alloys, incorporation of carbon, solidification, macrosegregation and microsegregation

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Authors: H. Farokhi, A. Bahadoran

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This paper is focused on the absorbance and magnetic properties of a novel nanocomposite based on conducting polymer, carbon black and barium hexaferrite in epoxy resin on the E-glass fibre substrate. The highly conductive nanocomposite was provided by in-situ polymerization of aniline in the presence of carbon black (C) and barium hexaferrite (BaFe12O19) as electromagnetic absorbance material. The structure, morphology, and magnetic properties of samples were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). SEM images showed the uniformly coated PAni on the surface of carbon black and barium hexaferrite. XRD peaks also verified the presence of carbon black and barium hexaferrite in the nanocomposite. The microwave characteristics determined from the magnetic and dielectric properties of the elastomeric composites obtained from scattering data by fitting the samples in a waveguide, where measured in the frequency in X-band frequency range, the range of 8 to 12 GHz. The reflection losses were evaluated to be less than −5dB over the whole X-band frequency (8–12 GHz) for the thickness of 1.4mm.

Keywords: conductive polymer, magnetic materials, capacitance, electrochemical cell

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Authors: Gaurav Malik, Satyendra Mourya, Jyoti Jaiswal, Ramesh Chandra

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The attractive and multifunctional properties of ZnO make it a promising material for the fabrication of highly sensitive and selective efficient gas sensors at room temperature. This presented article focuses on the development of highly selective and sensitive H₂ gas sensor based on the Pd-Pt decorated ZnO framework and its sensing mechanisms. The gas sensing performance of sputter made Pd-Pt/ZnO electrode on anodized porous silicon (PSi) substrate toward H₂ gas is studied under low detection limit (2–500 ppm) of H₂ in the air. The chemiresistive sensor demonstrated sublimate selectivity, good sensing response, and fast response/recovery time with excellent stability towards H₂ at low temperature operation under ambient environment. The elaborate selective measurement of Pd-Pt/ZnO/PSi structure was performed towards different oxidizing and reducing gases. This structure exhibited advance and reversible response to H₂ gas, which revealed that the acquired architecture with ZnO framework is a promising candidate for H₂ gas sensor.

Keywords: sputtering, porous silicon, ZnO framework, XPS spectra, gas sensor

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Authors: Sahar Jami, Iman Valizadeh

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Today banks not only should seek for new customers but also should consider previous maintenance and retention and establish a stable relationship with them. In this term, relationship-manner marketing seeks to make, maintain, and promote the relationship between customers and other stakeholders in benefits to fulfill all involved parties. This fact is possible just by interactive transaction and promises fulfillment. According to the importance of relationship-manner marketing in banks, making context to make relationship-manner marketing has high importance. Therefore, the present study aims at exploring intention condition to relationship-manner marketing in Iran Province Iran Limited bank, and also prioritizing its variables using hierarchical analysis (AHP). There is questionnaire designed in this research to paired comparison of relationship-manner marketing elements. After distributing this questionnaire among statistical society members who are 20 of Iran Limited bank experts, data analysis has been done by Expert Choice software.

Keywords: relationship marketing, relationship market orientation, Saderat Bank of Iran, hierarchical analysis

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Authors: Peloriadi Konstantina, Fakis Dimitris, Grammelis Panagiotis

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Methods for carbon capture and storage (CCS) can play a key role in the reduction of industrial CO₂ emissions, especially in the cement industry, which accounts for 7% of global emissions. Cement industries around the world have committed to address this problem by reaching carbon neutrality by the year 2050. The aim of the work to be presented was to contribute to the decarbonization strategy by integrating the 1st generation oxyfuel technology in cement production plants. This technology has been shown to improve fuel efficiency while providing one of the most cost-effective solutions when compared to other capture methods. A validated simulation of the cement plant was thus used as a basis to develop an oxyfuel retrofitted cement process. The process model for the oxyfuel technology is developed on the ASPEN (Advanced System for Process Engineering) PLUSTM simulation software. This process consists of an Air Separation Unit (ASU), an oxyfuel cement plant with coal and alternative solid fuel (ASF) as feedstock, and a carbon dioxide processing unit (CPU). A detailed description and analysis of the CPU will be presented, including the findings of a literature review and simulation results, regarding the effects of flue gas impurities during operation. Acknowledgment: This research has been conducted in the framework of the EU funded AC2OCEM project, which investigates first and the second generation oxyfuel concepts.

Keywords: oxyfuel technology, carbon capture and storage, CO₂ processing unit, cement, aspen plus

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Authors: Zhidong Zhang

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This study established a mixed method model in assessing statistics learning with Bayesian network models. There are three variants in exploratory sequential designs. There are three linked steps in one of the designs: qualitative data collection and analysis, quantitative measure, instrument, intervention, and quantitative data collection analysis. The study used a scoring model of analysis of variance (ANOVA) as a content domain. The research study is to examine students’ learning in both semantic and performance aspects at fine grain level. The ANOVA score model, y = α+ βx1 + γx1+ ε, as a cognitive task to collect data during the student learning process. When the learning processes were decomposed into multiple steps in both semantic and performance aspects, a hierarchical Bayesian network was established. This is a theory-driven process. The hierarchical structure was gained based on qualitative cognitive analysis. The data from students’ ANOVA score model learning was used to give evidence to the hierarchical Bayesian network model from the evidential variables. Finally, the assessment results of students’ ANOVA score model learning were reported. Briefly, this was a mixed method research design applied to statistics learning assessment. The mixed methods designs expanded more possibilities for researchers to establish advanced quantitative models initially with a theory-driven qualitative mode.

Keywords: exploratory sequential design, ANOVA score model, Bayesian network model, mixed methods research design, cognitive analysis

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Authors: Ryota Kuzuki, Mitsuhiro Kohara, Noboru Kizuki, Satoshi Yoshida, Hidetaka Hirai, Yuta Nezasa

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About fifty years have passed since Japan's gas supply industry became the first in the world to switch from coal and oil to LNG as a city gas feedstock. Since the Japanese government target of net-zero carbon emission in 2050 was announced in October 2020, it has now entered a new era of challenges to commit to the requirement for decarbonization. This paper describes the situation that synthetic methane, produced from renewable energy-derived hydrogen and recycled carbon, is a promising national policy of transition toward net-zero society. In November 2020, the Japan Gas Association announced the 'Carbon Neutral Challenge 2050' as a vision to contribute to the decarbonization of society by converting the city gas supply to carbon neutral. The key technologies is methanation. This paper shows that methanation is a realistic solution to contribute to the decarbonization of the whole country at a lower social cost, utilizing the supply chain that already exists, from LNG plants to burner chips. The challenges during the transition period (2030-2050), as CO2 captured from exhaust of thermal power plants and industrial factories are expected to be used, it is proposed that a system of guarantee of origin (GO) for H2 and CO2 should be established and harmonize international rules for calculating and allocating greenhouse gas emissions in the supply chain, a platform is also needed to manage tracking information on certified environmental values.

Keywords: synthetic methane, recycled carbon fuels, methanation, transition period, environmental value transfer platform

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Authors: O. Benturki, A. Benturki

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Activated carbon was prepared from Jujube seeds by chemical activation with potassium hydroxide (KOH), followed by pyrolysis at 800°C. Batch studies were conducted for kinetic, thermodynamic and equilibrium studies on the adsorption of phenol (P) and 2-4 dichlorophenol (2-4 DCP) from aqueous solution, than the adsorption capacities followed the order of 2-4 dichlorophenol > phenol. The operating variables studied were initial phenols concentration, contact time, temperature and solution pH. Results show that the pH value of 7 is favorable for the adsorption of phenols. The sorption data have been analyzed using Langmuir and Freundlich isotherms. The isotherm data followed Langmuir Model. The adsorption processes conformed to the pseudo-second-order rate kinetics. Thermodynamic parameters such as enthalpy, entropy and Gibb’s free energy changes were also calculated and it was found that the sorption of phenols by Jujuba seeds activated carbon was a spontaneous process The maximum adsorption efficiency of phenol and 2-4 dichlorophenol was 142.85 mg.g−1 and 250 mg.g−1, respectively.

Keywords: activated carbon, adsorption, isotherms, Jujuba seeds, phenols, langmuir

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Authors: A. Saccani, I. Lancellotti, E. Bursi

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Scraps deriving from the production of epoxy-carbon fibers composites have been recycled as a reinforcement to produce building materials. Short chopped fibers (5-7 mm length) have been added at low volume content (max 10%) to produce mortars. The microstructure, mechanical properties (mainly flexural strength) and dimensional stability of the derived materials have been investigated. Two different types of matrix have been used: one based on conventional Portland Cement and the other containing geopolymers formed starting from activated metakaolin and fly ashes. In the second case the materials is almost completely made of recycled ingredients. This is an attempt to produce reliable materials solving waste disposal problems. The first collected results show promising results.

Keywords: building materials, carbon fibres, fly ashes, geopolymers

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Authors: Reza Sadeghi

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Carbon dioxide treatment is one of the new methods for storage pest control. It can be used to replace chemical approaches. In the present study, the mortalities of Oryzaephilus mercator as the key pest of stored products, especially nuts, were studied after being exposed to different CO2 pressures (0.1, 0.2, 0.3, 0.4 and 0.5 bar) within 24 hours. The mortality percentages of O. mercator increased with an increase in CO2 pressure. The results obtained from experiments on the qualitative characteristics of the studied dates through the sensory test revealed that CO2 pressures did not affect their aroma, color, crispness, firmness, and overall acceptance. Therefore, it could be concluded that the atmospheric CO2 gas provided a cost-effective and environmentally friendly method for controlling the insect pests of pumpkin seed, besides preserving their sensory and quality properties.

Keywords: carbon dioxide, control, seed, qualitative characteristics

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Authors: Alaa Y. Ali, Natalie P. Holmes, John Holdsworth, Warwick Belcher, Paul Dastoor, Xiaojing Zhou

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Multi-layered graphene has been produced under low temperature chemical vapour deposition (CVD) growth conditions by utilizing an organic solvent and polymer film source. Poly(methylmethacrylate) (PMMA) was dissolved in chlorobenzene solvent and used as a drop-cast film carbon source on a quartz slide. A source temperature (T_source) of 180 °C provided sufficient carbon to grow graphene, as identified by Raman spectroscopy, on clean copper foil catalytic surfaces.  Systematic variation of hydrogen gas (H₂) flow rate from 25 standard cubic centimeters per minute (sccm) to 100 sccm and CVD temperature (T_growth) from 400 to 800 °C, yielded graphene films of varying quality as characterized by Raman spectroscopy. The optimal graphene growth parameters were found to occur with a hydrogen flow rate of 75 sccm sweeping the 180 °C source carbon past the Cu foil at 600 °C for 1 min. The deposition at 600 °C with a H₂ flow rate of 75 sccm yielded a 2D band peak with ~53.4 cm^-1 FWHM and a relative intensity ratio of the G to 2D bands (I_G/I_2D) of 0.21. This recipe fabricated a few layers of good quality graphene.

Keywords: graphene, chemical vapor deposition, carbon source, low temperature growth

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Authors: Shilpa Sahoo, Michel Louge, Anthony Reeves, Olivier Desjardins, Susan Daniel, Sadik Omowunmi

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The microgravity on the International Space Station (ISS) was exploited to study the imbibition of water into a network of hydrophilic cylindrical capillaries on time and length scales long enough to observe details hitherto inaccessible under Earth gravity. When a drop touches a porous medium, it spreads as if laid on a composite surface. The surface first behaves as a hydrophobic material, as liquid must penetrate pores filled with air. When contact is established, some of the liquid is drawn into pores by a capillarity that is resisted by viscous forces growing with length of the imbibed region. This process always begins with an inertial regime that is complicated by possible contact pinning. To study imbibition on Earth, time and distance must be shrunk to mitigate gravity-induced distortion. These small scales make it impossible to observe the inertial and pinning processes in detail. Instead, in the International Space Station (ISS), astronaut Luca Parmitano slowly extruded water spheres until they touched any of nine capillary plates. The 12mm diameter droplets were large enough for high-speed GX1050C video cameras on top and side to visualize details near individual capillaries, and long enough to observe dynamics of the entire imbibition process. To investigate the role of contact pinning, a text matrix was produced which consisted nine kinds of porous capillary plates made of gold-coated brass treated with Self-Assembled Monolayers (SAM) that fixed advancing and receding contact angles to known values. In the ISS, long-term microgravity allowed unambiguous observations of the role of contact line pinning during the inertial phase of imbibition. The high-speed videos of spreading and imbibition on the porous plates were analyzed using computer vision software to calculate the radius of the droplet contact patch with the plate and height of the droplet vs time. These observations are compared with numerical simulations and with data that we obtained at the ESA ZARM free-fall tower in Bremen with a unique mechanism producing relatively large water spheres and similarity in the results were observed. The data obtained from the ISS can be used as a benchmark for further numerical simulations in the field.

Keywords: droplet imbibition, hydrophilic surface, inertial phase, porous medium

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Authors: Maffo Maffo Nicole Liliane, Mounmemi Kpoumie Hubert, Libalah Moses, Ouandji Angele, Zapfack Louis

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Forest degradation causes biodiversity and carbon loss and thus indirectly contributes to climate change. In order to assess the contribution of forests to climate change mitigation, the present study was conducted in the Ngambe-Ndom-Nyanon Communal Forest with the main objective of assessing the floristic diversity and estimating the carbon stock in the different reservoirs of the said forest. Nine plots of 2000 m² each were installed in 3 TOSs of the forest (young secondary forests, gallery forests and fallow lands) with a total area of 18,000 m² or 1,8 ha. All trees with a Diameter at Breast Height (DBH) ≥ 5 cm were inventoried at 1.30 m from the ground in each plot. Species richness, floristic diversity indices, and structural parameters were studied. 1542 trees divided into 162 species, 122 genera and 44 families were identified. The most important families were listed: Myristicaceae (30.22%), Apocynaceae (25.20%), Fabaceae (24.41%), Euphorbiaceae (22.91%) and Phyllanthaceae (20.23%). The richest genera are: Cola, Macaranga, Oncoba (4 species each); the genera Diospyros, Trichilia, Vitex and Zanthoxylum (3 species each). The ecologically important species within the forest studied are: Funtumia africana (26.14%), Coelocaryon preussii (18.46%), Pycnanthus angolensis (15.57%), Tabernaemontana crassa (14.85%) and Olax subscorpioidea (13.04%). Assessment of carbon stocks in the six forest reservoirs studied (living trees and roots, understorey, dead wood, litter and rootlets) shows that they vary according to the land-use types. It is 119.41 t.C.ha-¹ in gallery forest, 115.2 t.C.ha-¹ in young secondary forest and 90.56 t.C.ha-¹ in fallow. The Wilcoxon statistical test shows that the carbon in the young secondary forest is identical to that in the fallow, which is identical to the carbon in the gallery forest. At the individual species level, the largest diameter class [25-35[ sequesters the most carbon (232.94 tC/ha). This work shows that the quantity of carbon sequestered by a biotope is a function of the age of the stand.

Keywords: floristic diversity, carbon stocks, evergreen forests, communal forest, Ngambé-Ndom-Nyanon

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Authors: Yeidy Sorani Montenegro Camacho, Samir Bensaid, Nunzio Russo, Debora Fino

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LiFeO2 nano-powders were prepared via solution combustion synthesis (SCS) method and were used as carbon gasification catalyst in a reduced atmosphere. The gasification of soot with CO2 and H2O in the presence of CO and H2 (syngas atmosphere) were also investigated under atmospheric conditions using a fixed-bed micro-reactor placed in an electric, PID-regulated oven. The catalytic bed was composed of 150 mg of inert silica, 45 mg of carbon (Printex-U) and 5 mg of catalyst. The bed was prepared by ball milling the mixture at 240 rpm for 15 min to get an intimate contact between the catalyst and soot. A Gas Hourly Space Velocity (GHSV) of 38.000 h-1 was used for the tests campaign. The furnace was heated up to the desired temperature, a flow of 120 mL/min was sent into the system and at the same time the concentrations of CO, CO2 and H2 were recorded at the reactor outlet using an EMERSON X-STREAM XEGP analyzer. Catalytic and non-catalytic soot gasification reactions were studied in a temperature range of 120°C – 850°C with a heating rate of 5 °C/min (non-isothermal case) and at 650°C for 40 minutes (isothermal case). Experimental results show that the gasification of soot with H2O and CO2 are inhibited by the H2 and CO, respectively. The soot conversion at 650°C decreases from 70.2% to 31.6% when the CO is present in the feed. Besides, the soot conversion was 73.1% and 48.6% for H2O-soot and H2O-H2-soot gasification reactions, respectively. Also, it was observed that the carbon gasification in mixed atmosphere, i.e., when simultaneous carbon gasification with CO2 and steam take place, with H2 and CO as co-reagents; the gasification reaction is strongly inhibited by CO and H2, as well has been observed in single atmospheres for the isothermal and non-isothermal reactions. Further, it has been observed that when CO2 and H2O react with carbon at the same time, there is a passive cooperation of steam and carbon dioxide in the gasification reaction, this means that the two gases operate on separate active sites without influencing each other. Finally, despite the extreme reduced operating conditions, it has been demonstrated that the 32.9% of the initial carbon was gasified using LiFeO2-catalyst, while in the non-catalytic case only 8% of the soot was gasified at 650°C.

Keywords: soot gasification, nanostructured catalyst, reducing environment, syngas

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Authors: Felix Aberu

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The high rate of greenhouse gas (CO₂) emission and increased concentration of Carbon Dioxide in the atmosphere are not unconnected to both human and natural activities. This has caused climate change and global warming in the world. The adverse effect of these climatic changes has no doubt threatened human existence. Hence, this study examined the effects of environmental and climate influence on mortality and morbidity rates, with particular reference to the world’s leading CO₂ emission countries, using both the pre-estimation, estimation, and post-estimation techniques for more dependable outcomes. Hence, the System Generalized Method of Moments (SGMM) was adopted as the main estimation technique for the data analysis from 1996 to 2023. The coefficient of carbon emissions confirmed a positive and significant relationship among CO₂ emission, mortality, and morbidity rates in the world’s leading CO₂ emissions countries, which implies that carbon emission has contributed to mortality and morbidity rates in the world. Therefore, significant action should be taken to facilitate the expansion of environmental protection and sustainability initiatives in any CO₂ emissions nations of the world.

Keywords: environmental, mortality, morbidity, health outcomes, carbon emissions

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Authors: Henry Schwartz, Bogdan Iancu, Magnus Gustafsson, Johan Lilius

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The shipping sector generates significant amounts of carbon emissions on annual basis. The excess amount of carbon dioxide is harmful for both the environment and the society, and partly for that reason, there is acute interest to decrease the volume of anthropogenic carbon dioxide emissions in shipping. The usage of the existing cargo carrying capacity can be maximized, and the share of time used in actual transportation operations could be increased if the whole transportation and logistics chain was optimized with the aid of information sharing done through a centralized marketplace and an information-sharing platform. The outcome of this change would be decreased carbon dioxide emission volumes produced per each metric ton of cargo transported by a vessel. Cargo coordination is a platform under development that matches the need for waterborne transportation services with the ships that operate at a given moment in time. In this research, the transition towards adopting cargo coordination is modelled with system dynamics. The model encompasses the complex supply-demand relationships of ship operators and cargo owners. The built scenarios predict the pace at which different stakeholders start using the digitalized platform and by doing so reduce the amount of annual CO2 emissions generated. To improve the reliability of the results, various sensitivity analyses considering the pace of transition as well as the overall impact on the environment (carbon dioxide emissions per amount of cargo transported) are conducted. The results of the study can be used to support investors and politicians in decision making towards more environmentally sustainable solutions. In addition, the model provides concepts and ideas for a wider discussion considering the paths towards carbon neutral transportation.

Keywords: carbon dioxide emissions, energy efficiency, sustainable transportation, system dynamics

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Authors: M. Dehghan, R. Al-Mahaidi, I. Sbarski

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An industrial epoxy adhesive used in Carbon Fiber Reinforced Polymer (CFRP)-strengthening systems was modified by dispersing multi-walled carbon nanotubes (MWCNTs). Nanocomposites were fabricated using solvent-assisted dispersion method and ultrasonic mixing. Thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and tensile tests were conducted to study the effect of nanotubes dispersion on the thermal and mechanical properties of the epoxy composite. Experimental results showed a substantial enhancement in the decomposition temperature and tensile properties of epoxy composite, while, the glass transition temperature (Tg) was slightly reduced due to the solvent effect. The morphology of the epoxy nanocomposites was investigated by SEM. It was proved that using solvent improves the nanotubes dispersion. However, at contents higher than 2 wt. %, nanotubes started to re-bundle in the epoxy matrix which negatively affected the final properties of epoxy composite.

Keywords: carbon fiber reinforced polymer, epoxy, multi-walled carbon nanotube, DMA, glass transition temperature

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Authors: Vineetha Bettaiah, Heggere S. Ranganath

Abstract:

This paper presents a Hierarchical Piecewise Linear Approximation (HPLA) for the representation of time series data in which the time series is treated as a curve in the time-amplitude image space. The curve is partitioned into segments by choosing perceptually important points as break points. Each segment between adjacent break points is recursively partitioned into two segments at the best point or midpoint until the error between the approximating line and the original curve becomes less than a pre-specified threshold. The HPLA representation achieves dimensionality reduction while preserving prominent local features and general shape of time series. The representation permits course-fine processing at different levels of details, allows flexible definition of similarity based on mathematical measures or general time series shape, and supports time series data mining operations including query by content, clustering and classification based on whole or subsequence similarity.

Keywords: data mining, dimensionality reduction, piecewise linear representation, time series representation

Procedia PDF Downloads 272

Authors: Abasse Kamarchou, Ahmed Abdelhafid Bebba, Ali Douadi

Abstract:

The objective of this work is the preparation of an activated carbon from waste date palm from El Oued region, namely the date stones and its use in the treatment of wastewater in this region. The study of the characteristics of this coal has the following results: specific surface 125.86 m2 / g, pore volume 0.039 cm3 / g, pore diameter of 16.25 microns, surface micropores 92.28 m2 / g, the outer surface 33,57 m2 /g, methylene blue number of 13.6 mg / g, iodine number 735.2 mg /g, the functional groups are the number of 4.10-2 mol / g. The optimum conditions for pH, stirring speed, initial concentration, contact time were determined. For organic pollutants, the best conditions are: pH > 8 and pH < 5, a contact time of 5 minutes and an agitation rate of 200 - 300 rpm.

Keywords: date palm, activated carbon, wastewater, El-Oued

Procedia PDF Downloads 306

Authors: Nimisha Jadon, Rajeev Jain, Swati Sharma

Abstract:

A chemically modified carbon paste sensor has been developed for the simultaneous determination of amlodipine (AML) and nebivolol (NBV). Carbon paste electrode (CPE) was fabricated by the addition of Gr/PANI-CeO2. Gr/PANI-CeO2/CPE has achieved excellent electrocatalytic activity and sensitivity. AML and NBV exhibited oxidation peaks at 0.70 and 0.90 V respectively on Gr/ PANI-CeO2/CPE. The linearity range of AML and NBV was 0.1 to 1.6 μgmL-1 in BR buffer (pH 8.0). The Limit of detection (LOD) was 20.0 ngmL-1 for AML and 30.0 ngmL-1 for NBV and limit of quantification (LOQ) was 80.0 ngmL-1 for AML and 100 ngmL-1 for NBV respectively. These analyses were also determined in pharmaceutical formulation and human serum and good recovery was obtained for the developed method.

Keywords: amlodipine, nebivolol, square wave voltammetry, carbon paste electrode, simultaneous quantification

Procedia PDF Downloads 347

Authors: Gagnesh Kumar, Prashant Gupta

Abstract:

This paper investigates the performance of the bundle of single wall carbon nanotubes (SWCNT) for low-power and high-speed interconnects for future VLSI applications. The power dissipation, delay and power delay product (PDP) of SWCNT bundle interconnects are examined and compared with that of the Cu interconnects at 22 nm technology node for both intermediate and global interconnects. The results show that SWCNT bundle consume less power and also faster than Cu for intermediate and global interconnects. It is concluded that the metallic SWCNT has been regarded as a viable candidate for intermediate and global interconnects in future technologies.

Keywords: carbon nanotube, SWCNT, low power, delay, power delay product, global and intermediate interconnects

Procedia PDF Downloads 314