Search results for: recycled carbon fiber

Authors: Mohamed Youssry, Dominique Guyomard, Bernard Lestriez

Abstract:

In order to enhance the energy and power densities of electrodes for energy storage systems, the formulation and processing of electrode slurries proved to be a critical issue in determining the electrode performance. In this study, we introduce novel approach to formulate carbon black slurries based on microemulsion and lyotropic liquid crystalline phases (namely, lamellar phase) composed of non-ionic surfactant (Triton X100), decanol and water. Simultaneous measurements of electrical properties of slurries under shear flow (rheology) have been conducted to elucidate the microstructure evolution with the surfactant concentration and decanol/water ratio at rest, as well as, the structural transition under steady-shear which has been confirmed by rheo-microscopy. Interestingly, the carbon black slurries at low decanol/water ratio are weak-gel (flowable) with higher electrical conductivity than those at higher ratio which behave strong-gel viscoelastic response. In addition, the slurries show recoverable electrical behaviour under shear flow in tandem with the viscosity trend. It is likely that oil-in-water microemulsion enhances slurries’ stability without affecting on the percolating network of carbon black. On the other hand, the oil-in-water analogous and bilayer structure of lamellar phase cause the slurries less conductive as a consequence of losing the network percolation. These findings are encouraging to formulate microemulsion-based electrodes for energy storage system (lithium-ion batteries).

Keywords: electrode slurries, microemulsion, microstructure transition, rheo-electrical properties

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Authors: O. Alelweet, S. Pavia

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In order to face current compelling environmental problems affecting the planet, the construction industry needs to adapt. It is widely acknowledged that there is a need for durable, high-performance, low-greenhouse gas emission binders that can be used as an alternative to Portland cement (PC) to lower the environmental impact of construction. Alkali activated materials (AAMs) are considered a more sustainable alternative to PC materials. The binders of AAMs result from the reaction of an alkali metal source and a silicate powder or precursor which can be a calcium silicate or an aluminosilicate-rich material. This paper evaluates the particle size, specific surface area, chemical and mineral composition and amorphousness of silicate materials (most industrial waste locally produced in Ireland and Saudi Arabia) to develop alkali-activated binders that can replace PC resources in specific applications. These include recycled ceramic brick, bauxite, illitic clay, fly ash and metallurgical slag. According to the results, the wastes are reactive and comply with building standards requirements. The study also evidenced that the reactivity of the Saudi bauxite (with significant kaolinite) can be enhanced on thermal activation; and high calcium in the slag will promote reaction; which should be possible with low alkalinity activators. The wastes evidenced variable water demands that will be taken into account for mixing with the activators. Finally, further research is proposed to further determine the reactive fraction of the clay-based precursors.

Keywords: alkali activated materials, alkali-activated binders, sustainable building materials, recycled ceramic brick, bauxite, red mud, clay, fly ash, metallurgical slags, particle size, chemical and mineral composition and amorphousness, water demand, particle density

Procedia PDF Downloads 126

Authors: Katarzyna Wal, Wojciech Stawiński, Piotr Rutkowski

Abstract:

The scientific community is paying more and more attention to the problem of air pollution. Carbon dioxide is classified as one of the most harmful gases. Its emissions are generated during fossil fuel burning, waste management, and combustion and are responsible for global warming. Clay minerals constitute a group of promising materials for the role of adsorbents. They are composed of two types of phyllosilicate sheets: tetrahedral and octahedral, which form 1:1 or 2:1 structures. Vermiculite is one of their best-known representative, which can be used as an adsorbent from water and gaseous phase. The aim of the presented work was carbon dioxide adsorption on vermiculite. Acid-activated samples (W_NO3_x) were prepared by acid treatment with different concentrations of nitric acid (1, 2, 3, 4 mol L⁻¹). Vermiculite was subjected to modification in order to increase its porosity and adsorption properties. The prepared adsorbents were characterized using the BET-specific surface area analysis, thermogravimetry (TG), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). Applied modifications significantly increase the specific surface area from 78,21 m² g⁻¹ for the unmodified sample (W_REF) to 536 m² g-1 for W_NO3_4. Obtained results showed that acid treatment tunes the material’s functional properties by increasing the contact surface and generating more active sites in its structure. The adsorption performance in terms carbon dioxide adsorption capacities follows the order of W_REF (25.91 mg g⁻¹) < W_NO3_1 (38.54 mg g⁻¹) < W_NO3_2 (44.03 mg g⁻¹) W_NO3_4 (67.51 mg g⁻¹) < W_NO3_3 (70.48 mg g⁻¹). Acid activation significantly improved the carbon dioxide adsorption properties of modified samples compared to raw material. These results demonstrate that vermiculite-based samples have the potential to be used as effective CO₂ adsorbents. Furthermore, acid treatment is a promising technique for improving the adsorption properties of clay minerals.

Keywords: adsorption, adsorbent, clay minerals, air pollution, environment

Procedia PDF Downloads 148

Authors: Dhaladhuli Pranavi, Amirtham Rajagopal

Abstract:

There are various failure modes in ceramic matrix composites; notable ones are fiber breakage, matrix cracking and fiber matrix debonding. Crack nucleation and propagation in microstructure of such composites requires an understanding of interaction of crack with the multiple inclusion heterogeneous system and interfaces. In order to assess structural integrity, the material parameters especially of the interface that governs the crack growth should be determined. In the present work, a nonlocal phase field approach is proposed to model the crack interface interaction in such composites. Nonlocal approaches help in understanding the complex mechanisms of delamination growth and mitigation and operates at a material length scale. The performance of the proposed formulation is illustrated through representative numerical examples. The model proposed is implemented in the framework of the finite element method. Several parametric studies on interface crack interaction are conducted. The proposed model is easy and simple to implement and works very well in modeling fracture in composite systems.

Keywords: composite, interface, nonlocal, phase field

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Authors: Jian Huang, Weixin Qian, Haitao Zhang, Weiyong Ying

Abstract:

Cobalt-gadolinium catalyst for Fischer-Tropsch synthesis was prepared by impregnation method with commercial silica gel, and its texture properties were characterized by BET, XRD, and TPR. The catalytic performance of the catalyst was tested in a fixed bed reactor. The results showed that the addition of gadolinium to the cobalt catalyst might decrease the size of cobalt particles, and increased the dispersion of catalytic active cobalt phases. The carbon number distributions for the catalysts was calculated by ASF equation.

Keywords: Fischer-Tropsch synthesis, cobalt-based catalysts, gadolinium, carbon number distributions

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Authors: Ghulam Murshid

Abstract:

Carbon dioxide is one of the major greenhouse gas (GHG) contributors. It is an obligation of the industry to reduce the amount of carbon dioxide emission to the acceptable limits. Tremendous research and studies are reported in the past and still the quest to find the suitable and economical solution of this problem needed to be explored in order to develop the most plausible absorber for carbon dioxide removal. Amino acids are reported by the researchers as a potential solvent for absorption of carbon dioxide to replace alkanolamines due to its ability to resist oxidative degradation, low volatility due to its ionic structure and higher surface tension. In addition, the introduction of promoter-like piperazine to amino acid helps to further enhance the solubility. In this work, the effect of piperazine on thermophysical properties and solubility of β-Alanine aqueous solutions were studied for various concentrations. The measured physicochemical properties data was correlated as a function of temperature using least-squares method and the correlation parameters are reported together with it respective standard deviations. The effect of activator piperazine on the CO2 loading performance of selected amino acid under high-pressure conditions (1bar to 10bar) at temperature range of (30 to 60)oC was also studied. Solubility of CO2 decreases with increasing temperature and increases with increasing pressure. Quadratic representation of solubility using Response Surface Methodology (RSM) shows that the most important parameter to optimize solubility is system pressure. The addition of promoter increases the solubility effect of the solvent.

Keywords: amino acids, co2, global warming, solubility

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Authors: S. F. H. Tasfy, N. A. M. Zabidi, M.-S. Shaharun

Abstract:

Utilization of CO2 as a carbon source to produce valuable chemicals is one of the important ways to reduce the global warming caused by increasing CO2 in the atmosphere. Supported metal catalysts are crucial for the production of clean and renewable fuels and chemicals from the stable CO2 molecules. The catalytic conversion of CO2 into methanol is recently under increased scrutiny as an opportunity to be used as a low-cost carbon source. Therefore, series of the bimetallic Cu/ZnO-based catalyst supported by SBA-15 were synthesized via impregnation technique with different total metal loading and tested in the catalytic hydrogenation of CO2 to methanol. The morphological and textural properties of the synthesized catalysts were determined by transmission electron microscopy (TEM), temperature programmed desorption, reduction, oxidation and pulse chemisorption (TPDRO), and N2-adsorption. The CO2 hydrogenation reaction was performed in microactivity fixed-bed system at 250 °C, 2.25 MPa, and H2/CO2 ratio of 3. Experimental results showed that the catalytic structure and performance was strongly affected by the loading of the active site. Where, the catalytic activity, methanol selectivity as well as the space-time yield increased with increasing the metal loading until it reaches the maximum values at a metal loading of 15 wt% while further addition of metal inhibits the catalytic performance. The higher catalytic activity of 14 % and methanol selectivity of 92 % were obtained over Cu/ZnO-SBA-15 catalyst with total bimetallic loading of 15 wt%. The excellent performance of 15 wt% Cu/ZnO-SBA-15 catalyst is attributed to the presence of well disperses active sites with small particle size, higher Cu surface area, and lower catalytic reducibility.

Keywords: hydrogenation of carbon dioxide, methanol synthesis, metal loading, Cu/ZnO-SBA-15 catalyst

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Authors: V. Sadeghi Balkanlou, M. Reza Bagerzadeh Karimi, A. Hasanbakloo, B. Bagheri Azar

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In this paper, the behavior of different types of DST columns has been studied under bending load. Briefly, composite columns consist of an internal carbon steel tube and an external stainless steel wall that the between the walls are filled with concrete. Composite columns are expected to combine the advantages of all three materials and have the advantage of high flexural stiffness of CFDST columns. In this research, ABAQUS software is used for finite element analysis then the results of ultimate strength of the composite sections are illustrated.

Keywords: DST, stainless steel, carbon steel, ABAQUS, straigh columns, tapered columns

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Authors: Anna Piasek, Anna Szymkiewicz, Gabriela Wiktor, Jolanta Pulit-Prociak, Marcin Banach

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Carbon dots (CDs) have great potential for application in many fields of science. They are characterized by fluorescent properties that can be manipulated. The nanomaterial has many advantages in addition to its unique properties. CDs may be obtained easily, and they undergo surface functionalization in a simple way. In addition, there is a wide range of raw materials that can be used for their synthesis. An interesting possibility is the use of numerous waste materials of natural origin. In the research presented here, the synthesis of CDs was carried out according to the principles of Green chemistry. Beet molasses was used as a natural raw material. It has a high sugar content. This makes it an excellent high-carbon precursor for obtaining CDs. To increase the fluorescence effect, we modified the surface of CDs with silver (Ag-CDs) nanoparticles. The process of obtaining CQD was based on the hydrothermal method by applying microwave radiation. Silver nanoparticles were formed via the chemical reduction method. The synthesis plans were performed on the Design of the Experimental method (DoE). Variable process parameters such as concentration of beet molasses, temperature and concentration of nanosilver were used in these syntheses. They affected the obtained properties and particle parameters. The Ag-CDs were analyzed by UV-vis spectroscopy. The fluorescence properties and selection of the appropriate excitation light wavelength were performed by spectrofluorimetry. Particle sizes were checked using the DLS method. The influence of the input parameters on the obtained results was also studied.

Keywords: fluorescence, modification, nanosilver, molasses, Green chemistry, carbon dots

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Authors: Faci Youcef

Abstract:

In the present work, an experimental study is carried out using the digital image correlation (DIC) technique to analyze the damage and behavior of woven composite carbon/epoxy under tensile loading. The tension mechanisms associated with failure modes of bolted joints in advanced composites are studied, as well as displacement distribution and strain distribution. The evolution value of bolt angle inclination during tensile tests was studied. In order to compare the distribution of displacements and strains along the surface, figures of image mapping are made. Several factors that are responsible for the failure of fiber-reinforced polymer composite materials are observed. It was found that strain concentrations observed in the specimens can be used to identify full-field damage onset and to monitor damage progression during loading. Moreover, there is an interaction between laminate pattern, laminate thickness, fastener size and type, surface strain concentrations, and out-of-plane displacement. Conclusions include a failure analysis associated with bolt angle inclinations and supported by microscopic visualizations of the composite specimen. The DIC results can be used to develop and accurately validate numerical models.

Keywords: Carbone, woven, damage, digital image, bolted joint, the inclination of angle

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Authors: Eleni Stefania Kalapoda

Abstract:

The current fossil-fuel based urbanization pattern and the estimated human population growth are increasing the environmental footprint on our planet’s precious resources. To mitigate the estimated skyrocketing in greenhouse gas emissions associated with the construction of new cities and infrastructure over the next 50 years, we need a radical rethink in our approach to construction to deliver a net zero built environment. This paper assesses the carbon footprint of a mass-timber, a steel, and a concrete structural alternative for peri-urban densification in the Hudson Valley's urban fringe, along with examining the updated policy and the building code adjustments that support synergies between timber construction in city making and sustainable management of timber forests. By quantifying the carbon footprint of a structural prototype for four different material assemblies—a concrete (post-tensioned), a mass timber, a steel (composite), and a hybrid (timber/steel/concrete) assembly applicable to the three updated building typologies of the IBC 2021 (Type IV-A, Type IV-B, Type IV-C) that range between a nine to eighteen-story structure alternative—and scaling-up that structural prototype to the size of a neighborhood district, the paper presents a quantitative and a qualitative approach for a forest-based construction economy as well as a resilient and a more just supply chain framework that ensures the wellbeing of both the forest and its inhabitants.

Keywords: mass-timber innovation, concrete structure, carbon footprint, densification

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Authors: Ashish Kumar Singh, Mehak Gulati, Neelam Verma

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Arginine majorly acts as a substrate for the enzyme nitric oxide synthase (NOS) for the production of nitric oxide, a strong vasodilator. Current study demonstrated a novel amperometric approach for estimation of arginine using nitric oxide synthase. The enzyme was co-immobilized in carbon paste electrode with NADP+, FAD and BH4 as cofactors. The detection principle of the biosensor is enzyme NOS catalyzes the conversion of arginine into nitric oxide. The developed biosensor could able to detect up to 10-9M of arginine. The oxidation peak of NO was observed at 0.65V. The developed arginine biosensor was used to monitor arginine content in fruit juices.

Keywords: arginine, biosensor, carbon paste elctrode, nitric oxide

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Authors: T. Abohalkuma, J. Telegdi

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Preparation, characterization, and application of self-assembled monolayers (SAM) formed by fluorophosphonic and undecenyl phosphonic acids on carbon steel surfaces as anticorrosive nanocoatings were demonstrated. The anticorrosive efficacy of these SAM layers was followed by atomic force microscopy, as the change in the surface morphology caused by layer deposition and corrosion processes was monitored. The corrosion process was determined by electrochemical potentiodynamic polarization, whereas the surface wettability of the carbon steel samples was tested with the use of static and dynamic contact angle measurements. Results showed that both chemicals produced good protection against corrosion as they performed as anodic inhibitors, especially with increasing the time of layer formation, which results in a more compact molecular film. According to the atomic force microscope (AFM) images, the fluoro-phosphonic acid self-assembled molecular layer can control the general as well as the pitting corrosion, but the SAM layers of the undecenyl-phosphonic acid cannot inhibit the pitting corrosion. The AFM and the contact angle measurements confirmed the results achieved by electrochemical measurements.

Keywords: nanolayers, corrosion, phosphonic acids, coatings

Procedia PDF Downloads 172

Authors: Salman Naveed, Nitant Gandhi, Grant Billings, Zachary Jones, B. Todd Campbell, Michael Jones, Sachin Rustgi

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Cotton (Gossypium spp.) is the primary source of natural fiber in the U.S. and a major crop in the Southeastern U.S. Despite constant efforts to increase the cotton fiber yield, the yield gain has stagnated. Therefore, we undertook a novel approach to improve the cotton fiber yield by altering its growth habit from perennial to annual. In this effort, we identified genotypes with high-expression alleles of five floral induction and meristem identity genes (FT, SOC1, FUL, LFY, and AP1) from an upland cotton mini-core collection and crossed them in various combinations to develop cotton lines with annual growth habit, optimal flowering time and enhanced productivity. To facilitate the characterization of genotypes with the desired combinations of stacked alleles, we identified markers associated with the gene expression traits via genome-wide association analysis using a 63K SNP Array (Hulse-Kemp et al. 2015 G3 5:1187). Over 14,500 SNPs showed polymorphism and were used for association analysis. A total of 396 markers showed association with expression traits. Out of these 396 markers, 159 mapped to genes, 50 to untranslated regions, and 187 to random genomic regions. Biased genomic distribution of associated markers was observed where more trait-associated markers mapped to the cotton D sub-genome. Many quantitative trait loci coincided at specific genomic regions. This observation has implications as these traits could be bred together. The analysis also allowed the identification of candidate regulators of the expression patterns of these floral induction and meristem identity genes whose functions will be validated via virus-induced gene silencing.

Keywords: cotton, GWAS, QTL, expression traits

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Authors: Chih Yuan Chen, Chien Chon Chen, Jin-Shyong Lin

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The microstructure characterization of tempered nanocrystalline bainitic steel is investigated in the present study. It is found that two types of plastic relaxation, dislocation debris and nanotwin, occurs in the displacive transformation due to relatively low transformation temperature and high carbon content. Because most carbon atoms trap in the dislocation, high dislocation density can be sustained during the tempering process. More carbides only can be found in the high tempered temperature due to intense recovery progression.

Keywords: nanostructure bainitic steel, tempered, TEM, nano-twin, dislocation debris, accommodation

Procedia PDF Downloads 536

Authors: Hadjer Didouh, Mohammed Hadj Melliani, Izzeddine Sameut Bouhaik

Abstract:

Corrosion is a serious problem in industrial installations or metallic transport pipes. Corrosion is an interfacial process controlled by several parameters. The presence of microorganisms affects the kinetics of corrosion. This type of corrosion is often referred as bio-corrosion or corrosion influenced by microorganisms (MIC). The action of a microorganism or a bacterium is carried out by the formation of biofilm following its attachment to the metal surface. The formation of biofilm isolates the metal surface from its environment and allows the bacteria to control the parameters of the metal/bacteria interface. Biofilm formation by sulfate-reducing bacteria (SRB) X52 steel, poses substantial challenges in oil and gas industry SONATRACH of Algeria. This research delves into the complex attachment mechanisms employed by SRB biofilm on X52 carbon steel and investigates strategies for effective mitigation using biocides. The exploration commences by elucidating the underlying mechanisms facilitating SRB biofilm adhesion to X52 carbon steel, considering factors such as surface morphology, electrostatic interactions, and microbial extracellular substances. Advanced microscopy and spectroscopic techniques provide a support to the attachment processes, laying the foundation for targeted mitigation strategies. The use of 100 ppm of Moringa Oleifera extract biocide as a promising approach to control and prevent SRB biofilm formation on X52 carbon steel surfaces. Green extract undergo evaluation for their effectiveness in disrupting biofilm development while ensuring the integrity of the steel substrate. Systematic analysis is conducted on the biocide's impact on the biofilm's structural integrity, microbial viability, and overall attachment strength. This two-pronged investigation aims to deepen our comprehension of SRB biofilm dynamics and contribute to the development of effective strategies for mitigating its impact on X52 carbon steel.

Keywords: bio-corrosion, biofilm, attachement, metal/bacteria interface

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Authors: Marwa Abida, Florian Gehring, Jamel Mars, Alexandre Vivet, Fakhreddine Dammak, Mohamed Haddar

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The demand for bio-based materials in semi-structural and structural applications is constantly growing to conform to new environmental policies. Among them, Plant Fiber Reinforced Composites (PFRC) are attractive for the scientific community as well as the industrial world. Due to their relatively low densities and low environmental impact, vegetal fibers appear to be suitable as reinforcing materials for polymers. However, the major issue of plant fibers and PFRC in general is their hydrophilic behavior (high affinity to water molecules). Indeed, when absorbed, water causes fiber swelling and a loss of mechanical properties. Thus, the environmental loadings (moisture, temperature, UV) can strongly affect their mechanical properties and therefore play a critical role in the service life of PFRC. In order to analyze the influence of conditioning at relative humidity on the behavior of flax fiber reinforced composites, a preliminary study on flax fabrics has been conducted. The conditioning of the fabrics in different humid atmospheres made it possible to study the influence of the water content on the hygro-mechanical behavior of flax reinforcement through mechanical tensile tests. This work shows that increasing the relative humidity of the atmosphere induces an increase of the water content in the samples. It also brings up the significant influence of water content on the stiffness and elongation at break of the fabric, while no significant change of the breaking load is detected. Non-linear decrease of flax fabric rigidity and increase of its elongation at maximal force with the increase of water content are observed. It is concluded that water molecules act as a softening agent on flax fabrics. Two kinds of typical tensile curves are identified. Most of the tensile curves of samples show one unique linear region where the behavior appears to be linear prior to the first yarn failure. For some samples in which water content is between 2.7 % and 3.7 % (regardless the conditioning atmosphere), the emergence of a two-linear region behavior is pointed out. This phenomenon could be explained by local heterogeneities of water content which could induce premature local plasticity in some regions of the flax fabric sample behavior.

Keywords: hygro-mechanical behavior, hygroscopy, flax fabric, relative humidity, mechanical properties

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Authors: Maliheh Raji, Hossein Abolghasemi, Jaber Safdari, Ali Kargari

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Samarium as a rare-earth element is playing a growing important role in high technology. Traditional methods for extraction of rare earth metals such as ion exchange and solvent extraction have disadvantages of high investment and high energy consumption. Emulsion liquid membrane (ELM) as an improved solvent extraction technique is an effective transport method for separation of various compounds from aqueous solutions. In this work, the extraction of samarium from aqueous solutions by ELM was investigated using response surface methodology (RSM). The organic membrane phase of the ELM was a nanofluid consisted of multiwalled carbon nanotubes (MWCNT), Span80 as surfactant, Cyanex 272 as mobile carrier, and kerosene as base fluid. 1 M nitric acid solution was used as internal aqueous phase. The effects of the important process parameters on samarium extraction were investigated, and the values of these parameters were optimized using the Central Composition Design (CCD) of RSM. These parameters were the concentration of MWCNT in nanofluid, the carrier concentration, and the volume ratio of organic membrane phase to internal phase (Roi). The three-dimensional (3D) response surfaces of samarium extraction efficiency were obtained to visualize the individual and interactive effects of the process variables. A regression model for % extraction was developed, and its adequacy was evaluated. The result shows that % extraction improves by using MWCNT nanofluid in organic membrane phase and extraction efficiency of 98.92% can be achieved under the optimum conditions. In addition, demulsification was successfully performed and the recycled membrane phase was proved to be effective in the optimum condition.

Keywords: Cyanex 272, emulsion liquid membrane, MWCNT nanofluid, response surface methology, Samarium

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Authors: M. Ashok Williams, T. V. Lakshmi Kumar

Abstract:

The life cycle of Black carbon aerosols depends on their physical removal processes from the atmosphere during the precipitation events. Black Carbon (BC) mass concentration has been analysed during rainy and non-rainy days of Northeast (NE) Monsoon months of the years 2015 and 2017 over a semi-urban environment near Chennai (12.81 N, 80.03 E), located on the east coast of India. BC, measured using an Aethalometer (AE-31) has been related to the atmospheric boundary layer height (BLH) obtained from the ERA Interim Reanalysis data during rainy and non-rainy days on monthly mean basis to understand the wet removal of BC over the study location. The study reveals that boundary layer height has a profound effect on the BC concentration on rainy days and non rainy days. It is found that the BC concentration in the night time is lower on rainy days compared to non rainy days owing to wash out on rainy days and the boundary layer height remaining nearly the same on rainy and non rainy days. On the other hand, in the daytime, it is found that the BC concentration remains nearly the same on rainy and non rainy days whereas the boundary layer height is lower on rainy days compared to non rainy days. This reveals that in daytime, lower boundary layer heights compensate for the wet removal effect on BC concentration on rainy days. A quantitative relation is found between the product of BC and BLH during rainy and non-rainy days which indicates the extent of redistribution of BC during non-rainy days when compared to the rainy days. Further work on the wet removal processes of the BC is in progress considering the individual rain events and other related parameters like wind speed.

Keywords: black carbon aerosols, atmospheric boundary layer, scavenging processes, tropical coastal location

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Authors: Tze-Sian Pui, Aung Than, Song-Wei Loo, Yuan-Li Hoe

Abstract:

A paper-based electrode devised from an array of carboxylated multi-walled carbon nanotubes (MWNTs) and poly (diallyldimethylammonium chloride) (PDDA) has been successfully developed for the simultaneous detection of dopamine (DA) and ascorbic acid (AA) in 0.1 M phosphate buffer solution (PBS). The PDDA/MWNTs electrodes were fabricated by allowing PDDA to absorb onto the surface of carboxylated MWNTs, followed by drop-casting the resulting mixture onto a paper. Cyclic voltammetry performed using 5 mM [Fe(CN)₆]³⁻/⁴⁻ as the redox marker showed that the PDDA/MWNTs electrode has higher redox activity compared to non-functionalized carboxylated MWNT electrode. Differential pulse voltammetry was conducted with DA concentration ranging from 2 µM to 500 µM in the presence of 1 mM AA. The distinctive potential of 0.156 and -0.068 V (vs. Ag/AgCl) measured on the surface of the PDDA/MWNTs electrode revealed that both DA and AA were oxidized. The detection limit of DA was estimated to be 0.8 µM. This nanocomposite paper-based electrode has great potential for future applications in bioanalysis and biomedicine.

Keywords: dopamine, differential pulse voltammetry, paper sensor, carbon nanotube

Procedia PDF Downloads 137

Authors: Hadjer Didouh, Mohammed Hadj Melliani, Izzeddine Sameut Bouhaik

Abstract:

Corrosion is a serious problem in industrial installations or metallic transport pipes. Corrosion is an interfacial process controlled by several parameters. The presence of microorganisms affects the kinetics of corrosion. This type of corrosion is often referred to as bio-corrosion or corrosion influenced by microorganisms (MIC). The action of a microorganism or a bacterium is carried out by the formation of biofilm following its attachment to the metal surface. The formation of biofilm isolates the metal surface from its environment and allows the bacteria to control the parameters of the metal/bacteria interface. Biofilm formation by sulfate-reducing bacteria (SRB) X52 steel poses substantial challenges in the oil and gas industry SONATRACH of Algeria. This research delves into the complex attachment mechanisms employed by SRB biofilm on X52 carbon steel and investigates innovative strategies for effective mitigation using biocides. The exploration commences by elucidating the underlying mechanisms facilitating SRB biofilm adhesion to X52 carbon steel, considering factors such as surface morphology, electrostatic interactions, and microbial extracellular substances. Advanced microscopy and spectroscopic techniques provide support to the attachment processes, laying the foundation for targeted mitigation strategies. The use of 100 ppm of Moringa Oleifera extract biocide as a promising approach to control and prevent SRB biofilm formation on X52 carbon steel surfaces. Green extracts undergo evaluation for their effectiveness in disrupting biofilm development while ensuring the integrity of the steel substrate. Systematic analysis is conducted on the biocide's impact on the biofilm's structural integrity, microbial viability, and overall attachment strength. This two-pronged investigation aims to deepen our comprehension of SRB biofilm dynamics and contribute to the development of effective strategies for mitigating its impact on X52 carbon steel.

Keywords: attachment, bio-corrosion, biofilm, metal/bacteria interface

Procedia PDF Downloads 74

Authors: Premrudee Kanchanapiya, Supachai Songngam, Thanapol Tantisattayakul

Abstract:

Perfluorooctanoic acid (PFOA) is one of per- and polyfluoroalkyl substances (PFAS) that have increasingly attracted concerns due to their global distribution in environment, persistence, high bioaccumulation, and toxicity. It is important to study the effective treatment to remove PFOA from contaminated water. The feasibility of using commercial coconut shell activated carbon produced in Thailand to remove PFOA from water was investigated with regard to their adsorption kinetics and isotherms of powder activated carbon (PAC-325) and granular activated carbon (GAC-20x50). Adsorption kinetic results show that the adsorbent size significantly affected the adsorption rate of PFOA, and GAC-20x50 required at least 100 h to achieve the equilibrium, much longer than 3 h for PAC-325. Two kinetic models were fitted to the experimental data, and the pseudo-second-order model well described the adsorption of PFOA on both PAC-325 and GAC-20x50. PAC-325 trended to adsorb PFOA faster than GAC-20x50, and testing with the shortest adsorption times (5 min) still yielded substantial PFOA removal (~80% for PAC-325). The adsorption isotherms show that the adsorption capacity of PAC-325 was 0.80 mmol/g, which is 83 % higher than that for GAC-20x50 (0.13 mmol/g), according to the Langmuir fitting.

Keywords: perfluorooctanoic acid, PFOA, coconut shell activated carbons, adsorption, water treatment

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Authors: Chayarat Tantanasarit, Sandhya Babel

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Green mussels (Perna viridis) can effectively remove nutrients from seawater through their filtration process. This study aims to estimate 'net' nutrient removal rate by green mussel through calculation of nutrient uptake and release. Nutrients (carbon, nitrogen, and phosphorus) uptake was calculated based on the mussel filtration rate. Nutrient release was evaluated from carbon, nitrogen, and phosphorus released as mussel feces. By subtracting nutrient release from nutrient uptake, net nutrient removal by green mussel can be found as 3302, 380 and 124 mg/year/indv. Mass balance model was employed to simulate nutrient removal in actual green mussel farming conditions. Mussels farm area, seawater flow rate and amount of mussels were considered in the model. Results show that although larger quantity of green mussel farms lead to higher nutrient removal rate, the maximum green mussel cultivation should be taken into consideration as nutrients released through mussel excretion can strongly affect marine ecosystem.

Keywords: carbon, ecretion, filtration, nitrogen, phosphorus

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Authors: Ihsanullah, Muataz Ali Atieh

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In this study, a low-cost adsorbent carbon fly ash (CFA) was used for the removal of Phenol from the water. The adsorbent characteristics were observed by the Thermogravimetric Analysis (TGA), BET specific surface area analyzer, Zeta Potential and Field Emission Scanning Electron Microscopy (FE-SEM). The effect of pH, agitation speed, contact time, adsorbent dosage, and initial concentration of phenol were studied on the removal of phenol from the water. The optimum values of these variables for maximum removal of phenol were also determined. Both Freundlich and Langmuir isotherm models were successfully applied to describe the experimental data. Results showed that low-cost adsorbent phenol can be successfully applied for the removal of Phenol from the water.

Keywords: phenol, fly ash, adsorption, carbon adsorbents

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Authors: Salman Naseer

Abstract:

One of the main challenges of operating a smart city (SC) is collecting the massive data generated from multiple data sources (DS) and to transmit them to the control units (CU) for further data processing and analysis. These ever-increasing data demands require not only more and more capacity of the transmission channels but also results in resource over-provision to meet the resilience requirements, thus the unavoidable waste because of the data fluctuations throughout the day. In addition, the high energy consumption (EC) and carbon discharges from these data transmissions posing serious issues to the environment we live in. Therefore, to overcome the issues of intensive EC and carbon emissions (CE) of massive data dissemination in Smart Cities, we propose an energy efficient and carbon reduction approach by utilizing the daily mobility of the existing vehicles as an alternative communications channel to accommodate the data dissemination in smart cities. To illustrate the effectiveness and efficiency of our approach, we take the Auckland City in New Zealand as an example, assuming massive data generated by various sources geographically scattered throughout the Auckland region to the control centres located in city centre. The numerical results show that our proposed approach can provide up to 5 times lower delay as transferring the large volume of data by utilizing the existing daily vehicles’ mobility than the conventional transmission network. Moreover, our proposed approach offers about 30% less EC and CE than that of conventional network transmission approach.

Keywords: smart city, delay tolerant network, infrastructure offloading, opportunistic network, vehicular mobility, energy consumption, carbon emission

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Authors: Illyas Md Isa, Mohamad Idris Saidin, Mustaffa Ahmad, Norhayati Hashim

Abstract:

A highly selective and sensitive carbon paste electrode modified with multiwall carbon nanotubes and 2,6–diacetylpyridine-di-(1R)–(-)–fenchone diazine tetracarbonylmolybdenum(0) complex was used for determination of trace amounts of Cu(II) using square wave anodic stripping voltammetry (SWASV). The influences of experimental variables on the proposed electrode such as pH, supporting electrolyte, preconcentration potential and time, and square wave parameters were investigated. Under optimal conditions, the proposed electrode showed a linear relationship with concentration in the range of 1.0 × 10–10 to 1.0 × 10– 6 M Cu(II) with a limit of detection 8.0 × 10–11 M. The relative standard deviation (n = 5) for a solution containing 1.0 × 10– 6 M of Cu(II) was 0.036. The presence of various cations (in 10 and 100-folds concentration) did not interfere. Electrochemical impedance spectroscopy (EIS) showed that the charge transfer at the electrode-solution interface was favourable. The proposed electrode was applied for the determination of Cu(II) in several water samples. Results agreed very well with those obtained by inductively coupled plasma-optical emission spectrometry. The modified electrode was then proposed as an alternative for determination of Cu(II).

Keywords: chemically modified electrode, Cu(II), square wave anodic stripping voltammetry, tetracarbonylmolybdenum(0)

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Authors: Kaisy Xinhong Ye, Su Lin Lim, Jialiang Li, Lei Feng

Abstract:

background: Multiple healthful dietary patterns have been linked with dementia, but limited studies have looked at the role of diet in cognitive health in Asians whose eating habits are very different from their counterparts in the west. This study aimed to derive a dietary pattern that is associated with the risk of cognitive impairment (CI) in the Singaporean population. Method: The analysis was based on 719 community older adults aged 60 and above. Dietary intake was measured using a validated semi-quantitative food-frequency questionnaire (FFQ). Reduced rank regression (RRR) was used to extract dietary pattern from 45 food groups, specifying sugar, dietary fiber, vitamin A, calcium, and the ratio of polyunsaturated fat to saturated fat intake (P:S ratio) as response variables. The RRR-derived dietary patterns were subsequently investigated using multivariate logistic regression models to look for associations with the risk of CI. Results: A dietary pattern characterized by greater intakes of green leafy vegetables, red-orange vegetables, wholegrains, tofu, nuts, and lower intakes of biscuits, pastries, local sweets, coffee, poultry with skin, sugar added to beverages, malt beverages, roti, butter, and fast food was associated with reduced risk of CI [multivariable-adjusted OR comparing extreme quintiles, 0.29 (95% CI: 0.11, 0.77); P-trend =0.03]. This pattern was positively correlated with P:S ratio, vitamin A, and dietary fiber and negatively correlated with sugar. Conclusion: A dietary pattern providing high P:S ratio, vitamin A and dietary fiber, and a low level of sugar may reduce the risk of cognitive impairment in old age. The findings have significance in guiding local Singaporeans to dementia prevention through food-based dietary approaches.

Keywords: dementia, cognitive impairment, diet, nutrient, elderly

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Authors: Yao-Hui Huang, Ming-Chun Yen, Jui-Yen Lin, Yu-Jen Shih

Abstract:

This work investigated the reclamation of boron in industrial wastewaters by a chemical oxo-precipitation (COP) technique at room temperature. In COP, the boric acid was pretreated with H₂O₂, yielding various perborate anions. Afterwards, calcium chloride was used to efficiently remove boron through precipitation of calcium perborate. The important factors included reacted pH and the molar ratio of [Ca]/[B]. Under conditions of pH 11 and [Ca]/[B] of 1, the boron concentration could be reduced immediately from 600 ppm to 50 ppm in 10 minutes. The boron removal was enhanced with a higher [Ca]/[B], which further reduced boron to 20 ppm in 10 minutes. Nevertheless, the dissolution of carbon dioxide potentially affected the efficacy of COP and increased the boron concentration after 10 minutes.

Keywords: chemical oxo-precipitation, boron, carbon dioxide, hydrogen peroxide

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Authors: Spyridon Komaitis, Christos Koutsarnakis, Evangelos Drosos, Aristotelis Kalyvas

Abstract:

This study opts to investigate the intrinsic architecture, morphology, and spatial relationship of the subcortical pathways implicated in the connectivity of the motor/premotor cortex and SMA/pre-SMA complex. Twenty normal, adult, formalin-fixed cerebral hemispheres were explored through the fiber micro-dissection technique. Lateral to medial and medial to lateral dissections focused on the area of interest were performed in a tandem manner and under the surgical microscope. We traced the subcortical architecture, spatial relationships, and axonal connectivity of four major pathways: a) the dorsal component of the SLF (SLF-I) was found to reside in the medial aspect of the hemisphere and seen to connect the precuneus with the SMA and pre-SMA complex, b) the frontal longitudinal system (FLS) was consistently encountered as the natural anterior continuation of the SLF-II and SLF-III and connected the premotor and prefrontal cortices c) the fronto-caudate tract (FCT), a fan-shaped tract, was documented to participate in connectivity of the prefrontal and premotor cortices to the head and body of the caudate nucleus and d) the cortico-tegmental tract(CTT) was invariably recorded to subserve the connectivity of the tegmental area with the fronto-parietal cortex. No hemispheric asymmetries were recorded for any of the implicated pathways. Sub-segmentation systems were also proposed for each of the aforementioned tracts. The structural connectivity and functional specialization of motor and premotor areas in the human brain remain vague to this day as most of the available evidence derives either from animal or tractographic studies. By using the fiber-microdissection technique as our main method of investigation, we provide sound structural evidence on the delicate anatomy of the related white matter pathways.

Keywords: neuroanatomy, premotor, motor, connectivity

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Authors: Nazmul Huda, Ashik Mosaddik, Abdul Awal, Shafiqur Rahman, Rukhsana Shaheen, Mustofa Nabi

Abstract:

Polyherbal formulation Sharbat Deenar is a very popular unani medicine in Bangladesh. It is usually used for different kinds of liver disorders. In absence of reliable and inadequate hepatoprotective agents in conventional medicine, the herbal preparations are preferred for liver diseases. The present study was designed to evaluate the hepatoprotective activity of Sharbat Deenar on carbon tetrachloride (CCl₄) induced hepatotoxicity in male Long-Evans albino rats. Group I served as normal control and received neither formulation nor carbon tetrachloride. Group II received only CCl₄ 1mL/kg body weight of rat intraperitoneally for consecutive 14 days. Group III received CCl₄ 1mL/kg body weight of rat intraperitoneally and Silymarin, in dose 50mg/kg body weight of rat orally. Group IV received CCl₄ 1mL/kg body weight of rat intraperitoneally and Sharbat Deenar 1mL/kg body weight of rat for the same 14 consecutive days. At the end of the study, hepatoprotective activity was evaluated by the levels of total bilirubin, alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP). Histopathological study of rat liver was also carried out. The results showed that polyherbal formulation Sharbat Deenar exhibited a significant hepatoprotective effect. Such an outcome seems to be the synergistic effect of all ingredients of tested herbal formulation. Although this study suggests that Sharbat Deenar may be used to cure or minimize various liver diseases, it needs further study to attain the clarity of mechanism and safety.

Keywords: polyherbal formulation, sharbat deenar, carbon tetrachloride, silymarin, hepatoprotective

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