Search results for: carbon fiber reinforced composite

Authors: Qian Huiya, Feng Lin

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The progressive collapse of reinforced concrete (RC) structures will cause huge casualties and property losses. Therefore, it is necessary to evaluate the ability of structures against progressive collapse accurately. This paper numerically investigated the effect of storey number on the mechanism and quantitative contribution of the Vierendeel action (VA) in progressive collapse under corner column removal scenario. First, finite element (FE) models of multi-storey RC frame structures were developed using LS-DYNA. Then, the accuracy of the modeling technique was validated by test results conducted by the authors. Last, the validated FE models were applied to investigated the structural behavior of the RC frames with different storey numbers from one to six storeys. Results found the multi-storey substructure formed additional plastic hinges at the beam ends near the corner column in the second to top storeys, and at the lower end of the corner column in the first storey. The average ultimate resistance of each storey of the multi-storey substructures were increased by 14.0% to 18.5% compared with that of the single-storey substructure experiencing no VA. The contribution of VA to the ultimate resistance was decreased with the increase of the storey number.

Keywords: progressive collapse, reinforced concrete structure, storey number, Vierendeel action

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Authors: Y. J. Lin, Y. F. Lin

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CO2 is the primary greenhouse gas which causes global warming in recent years. As the carbon capture and storage (CCS) getting maturing, the reuse of carbon dioxide which made from CCS is the important issue. In this way, the most common method is the synthesis of cyclic carbonate chemicals from the cycloaddition reaction of carbon dioxide and epoxide. The catalyst plays an important role in the CO2/epoxide cycloaddition reactions. The Lewis acid and base sites are both needed on the catalyst surface for the help of epoxide ring opening, leading to the synthesis of cyclic carbonate. Furthermore, the larger specific surface area and more active site of the catalyst are also needed to enhance the efficiency of the CO2/epoxide cycloaddition reactions. Aerogel is a mesoporous nanomaterial (pore size between 2~50 nm) with high specific surface area and porosity (at least 90%) and low density. In this study, the ternary metal oxide aerogels, Mg-doped Al2O3 aerogels, with higher specific surface area and Lewis acid and base sites on the aerogel surface are successfully prepared by using a facile sol-gel reaction. The as-prepared Mg-doped Al2O3 aerogels are also served as heterogenous catalyst for the CO2/propylene- oxide cycloaddition reaction. Compared to the pristine Al2O3 aerogels, the Mg-doped Al2O3 aerogels possessed both Lewis acid and base sites on the surface are able to enhance the efficiency of the CO2/propylene oxide cycloaddition reactions. As a result, the as-prepared Mg-doped Al2O3 aerogels are a promising and novel catalyst for the CO2/epoxide cycloaddition reactions.

Keywords: ternary, metal oxide aerogel, CO2 reuse, cycloaddition, propylene oxide

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Authors: Kopal Verma, Umesh C. Kulshrestha

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The mountainous regions are very crucial for a country because of their importance for weather, water supply, forests, and various other socio-economic benefits. But the increasing population and its demand for energy and infrastructure have contributed very high loadings of air pollution. Various activities such as cooking, heating, manufacturing, transport, etc. contribute various particulate and gaseous pollutants in the atmosphere. This study was focused upon indoor air pollution and was carried out in four rural households of the Baggi village located in the Hamirpur District of the Himachal Pradesh state. The residents of Baggi village use biomass as fuel for cooking on traditional stove (Chullah). The biomass types include wood (mainly Beul, Grewia Optiva), crop residue and dung cakes. This study aimed to determine the organic carbon (OC), elemental carbon (EC), major cations and anions in the indoor air of each household. During non-cooking hours, it was found that the indoor air contained OC and EC as low as 21µg/m³ and 17µg/m³ respectively. But during cooking hours (with biomass burning), the levels of OC and EC were raised significantly by 91.2% and 85.4% respectively. Then the residents were advised to switch over as per our soft approach options. In the first approach change, they were asked to prepare the meal partially on Chullah using biomass and partially with liquefied petroleum gas (LPG). By doing this change, a considerable reduction in OC (53.1%) and in EC (41.8%) was noticed. The second change of approach included the cooking of entire meal by using LPG. This resulted in the reduction of OC (84.1%) and EC (73.3%) as compared to the values obtained during cooking entirely with biomass. The carbonaceous aerosol levels were higher in the morning hours than in the evening hours because of more biomass burning activity in the morning. According to a general survey done with the residents, the study provided them an awareness about the air pollution and the harmful effects of biomass burning. Some of them correlated their ailments like weakened eyesight, fatigue and respiratory problems with indoor air pollution. This study demonstrated that by replacing biomass with clean fuel such as LPG, the indoor concentrations of EC and OC can be reduced substantially.

Keywords: biomass burning, carbonaceous aerosol, elemental carbon, organic carbon, LPG

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Authors: Özgür Öztürk, Cumhur Sipahi, Hande Yeşil

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Implant retained restorations commonly consist of a metal-framework veneered with ceramic or composite facings. The increasing and expanding use of indirect resin composites in dentistry is a result of innovations in materials and processing techniques. Of special interest to the implant restorative field is the possibility that composites present significantly lower peak vertical and transverse forces transmitted at the peri-implant level compared to metal-ceramic supra structures in implant-supported restorations. A 43-year-old male patient referred to the department of prosthodontics for an implant retained fixed prosthesis. The clinical and radiographic examination of the patient demonstrated the presence of an implant in the right mandibular first molar tooth region. A considerable amount of marginal bone loss around the implant was detected in radiographic examinations combined with a remarkable peri-implant soft tissue deficiency. To minimize the chewing loads transmitted to the implant-bone interface it was decided to fabricate an indirect composite resin veneered single metal crown over a screw-retained abutment. At the end of the treatment, the functional and aesthetic deficiencies were fully compensated. After a 6 months clinical and radiographic follow-up period the not any additional pathologic invasion was detected in the implant-bone interface and implant retained restoration did not reveal any vehement complication.

Keywords: dental implant, fixed partial dentures, indirect composite resin, peri-implant defects

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Authors: Jarosław Milewski, Rafał Bernat

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This paper presents an analysis of using cryogenic separation unit for recovering fuel from anode off gas of molten carbonate fuel cells (MCFCs) in order to upgrade the efficiently of the unit. In the proposed solution, the CSU is used for condensing water and carbon dioxide from anode off gas, and re-cycling the rest of the stream to the anode, saving certain amount of fuel (at least 30%). The resulting system efficiency is increased considerably. CSU, virtually consumes power, thus this solution has energy penalty as well, on the other hand, MCFC generates large amount of heat at elevated temperature, thus part of the CSU can be based on absorption chiller. In all cases, a high amount of fuel is obtained after condensation of water and carbon dioxide and re-cycled to the anode inlet. Based on mathematical modeling done previously, the concept and guidelines for forthcoming experimental investigations are presented in this paper. During planned experiments, an existing single cell laboratory stand will be equipped with re-cycle device (a fan, a peristaltic pump, etc.). Parallel, a mixture of anode off gas will be cooled down for determining the proper temperature for the separation of water and carbon dioxide.

Keywords: cryogenic separation, experiments, fuel cells, molten carbonate fuel cells

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Authors: Jeremy Moloney

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A major oil and gas operator in western Canada producing approximately 50,000 BOE per day of sour fluids was experiencing increased water production along with decreased oil production over several years. The higher water volumes being produced meant an increase in the operator’s incumbent corrosion inhibitor (CI) chemical requirements but with reduced oil production revenues. Thus, a cost-effective corrosion inhibitor solution was sought to deliver enhanced corrosion mitigation of the carbon steel pipeline infrastructure but at reduced chemical injection dose rates. This paper presents the laboratory work conducted on the development of a corrosion inhibitor under the operator’s simulated sour operating conditions and then subsequent field testing of the product. The new CI not only provided extremely good levels of general and localized corrosion inhibition and outperformed the incumbent CI under the laboratory test conditions but did so at vastly lower concentrations. In turn, the novel CI product facilitated field chemical injection rates to be optimized and reduced by 40% compared with the incumbent whilst maintaining superior corrosion protection resulting in significant cost savings and associated sustainability benefits for the operator.

Keywords: carbon steel, sour gas, hydrogen sulphide, localized corrosion, pitting, corrosion inhibitor

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Authors: Oloniyo Rebecca Olajumoke

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The unstable free radicals molecules oxidize cells throughout the body to cause oxidative stress, which has been implicated in the pathogenesis of many chronic diseases. Thus, the consumption of antioxidant-rich snacks could help to reduce the production of these free radicals in the body. This study aimed at producing antioxidant–rich biscuits from an underutilized pearl millet and agricultural waste from orange peel flour (PMF and OPF, respectively) blends. Biscuits were produced from PMF, and OPF blends using various proportions (95:05; 90:10; 85:15; 80:20 with 100% PMF as control. The functional properties of the flours, as well as the antioxidant properties, physical evaluation, and consumer acceptability of the biscuits, were evaluated. The functional properties of the composite flour showed an increase in oil absorption capacity (7.73-8.80 g/ml), water absorption capacity (6.82-7.21 g/ml), foaming (3.91-5.88 g/ml), and emulsification (52.85-58.82 g/ml) properties. The increased addition of OPF significantly (p<0.05) increased the antioxidant properties of the biscuits produced from the composite flour. For instance, the ferric reducing properties (0.10-0.4 mgAAE/g), total flavonoid (1.20-8.12 mg QE/g), and ABTS radical scavenging (1.17-2.19 mmol/TEAC/g) of the composite flours were increasingly comparable to those of 100% PMF. The physical parameters of the biscuit were significantly different (p<0.05) from one another. The addition of OPF into PMF reduced the weight, diameter, and spread ratio of biscuits produced while contrarily increasing the height of the biscuit. The incorporation of OPF at 5% (95:05) substitution yielded a consumedly acceptable biscuit product. The significant increase in antioxidant properties with an increase in OPF during the production of biscuits would therefore increase the nutritional value and potential health benefits.

Keywords: orange peel, biscuit, antioxidant, pearl millet

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Authors: Musa Najimu, Isam Aljundi

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In this study, the development of mixed matrix membrane (MMM) containing carbide-derived carbon (CDC) for the separation of CO₂ was investigated. MMM with four different loadings (0.1 to 2 wt%) were prepared by the dry/wet phase inversion technique. Prior to this, the formula of the control polysulfone (PSF) membrane was optimized in terms of the PSF concentration in a mixture of NMP/THF solvents and ethanol. Prepared samples were characterized and tested for CO₂ and CH₄ gas permeation. The optimization of the control PSF membrane revealed that 30 wt% PSF is the critical polymer concentration in the formulation. Characterization results unveiled reinforcement of thermal stability and improved polarity imparted by CDC in the MMM, in addition to uniform dispersion of filler up to 1 wt% loading. Furthermore, the incorporation of CDC in PSF membrane formulation enhanced both the CO₂ permeance and ideal selectivity over the control membrane. A CDC loading of 0.5 wt% resulted in the highest CO₂ permeance of 5.5 GPU corresponding to 120% increase in permeance while a CDC loading of 1 wt% resulted in the highest selectivity (CO₂ /CH₄) of 27 corresponding to 29% increase in selectivity. Studies of operating temperature effect showed that an optimum operating temperature for M1.0 membrane is 20 ⁰C. In addition, the feed pressure studies showed that high pressure feeds will favor high performance of the membrane and a good CO₂ /CH₄ separation.

Keywords: carbide derived carbon, mixed matrix membrane, CO₂ separation, polysulfone

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Authors: Štěpán Hýsek, Petra Gajdačová, Milan Podlena

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Annual plants are becoming more and more popular source of lignin and cellulose. In those days a lot of research is carried out in order to evaluate the possibility of utilization of fibres and particles from these plants in composite materials production. These lingo-cellulosic materials seem to be a great alternative to wood, however, due to waxy and silica layers on the surface of these stalks, one additional technological step is needed–erosion of the layers for the purpose of achieving better adhesion between particle and adhesive. In this research, we used several kinds of particle pre-treatment, in order to modify surface properties of these particles. Further, an adhesive was applied to the particles using laboratory blender and board were produced using laboratory press. Both physical and mechanical properties of boards were observed. It was found out that the surface modification of particles had statistically significant effect on properties of produced boards.

Keywords: annual plant, composites, mechanical properties, particleboard

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Authors: N. H. Hamid, A. Azmi, M. I. Adiyanto

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This main purpose of this paper is to evaluate the seismic performance of double bay two-storey reinforced concrete frame under in-plane lateral cyclic loading which designed using Eurocode 8 (EC8) by taking into account of seismic loading. The prototype model of reinforced concrete frame was constructed in one-half scale tested under in-plane lateral cyclic loading starts with ±0.2% drift, ±0.25% up to ±3.0% drift with the increment of ±0.25%. The performance of the RC frame is evaluated in terms of the hysteresis loop (load vs. displacement), stiffness, ductility, lateral strength, stress-strain relationship and equivalent viscous damping. Visual observation of the crack pattern after testing were observed where the beam- column joint suffer the most severe damage as it is the critical part in moment resisting frame. Spalling of concrete starts occurred at ±2.0% drift and become worse at ±2.5% drift. The experimental result shows that the maximum lateral strength of specimen is 99.98 kN and ductility of the specimen is µ=4.07 which lies between 3≤µ≤6 in order to withstand moderate to severe earthquakes.

Keywords: ductility, equivalent viscous damping, hysteresis loops, lateral strength, stiffness

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Authors: Gadanya, A.M., Ponfa, S., Jibril, M.M., Abubakar, S. M.

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Background: Edible insects such as grasshopper are important sources of food for humans, and have been consumed as traditional foods by many indigenous communities especially in Africa, Asia, and Latin America. These communities have developed their skills and techniques in harvesting, preparing, consuming, and preserving edible insects, widely contributing to the role played by the use of insects in human nutrition. Aim/ objective: This study was aimed at determining the effect of insect enriched sprouted soyabean /millet based food on some gut health markers in albino rats. Methods. Four different formulations of Complementary foods (i.e Complementary Food B (CFB): sprouted millet (SM), Complementary Food C (CFC): sprouted soyabean (SSB), Complementary Food D (CFD): sprouted soybean and millet (SSBM) in a ratio of (50:50) and Complementary Food E (CFE): insect (grasshopper) enriched sprouted soybean and millet (SSBMI) in a ratio of (50:25:25)) were prepared. Proximate composition and short chain fatty acid contents were determined. Thirty albino rats were divided into5 groups of six rats each. Group 1(CDA) were fed with basal diet and served as a control group, while groups 2,3,4 and 5 were fed with the corresponding complimentary foods CFB, CFC, CFD and CFE respectively daily for four weeks. Concentrations of fecal protein, serum total carotenoids and nitric oxide were determined. DNA extraction for molecular isolation and characterization were carried out followed by PCR, the use of mega 11 software and NCBI blast for construction of the phylogenetic tree and organism identification respectively. Results: Significant increase (P<0.05) in percentage ash, fat, protein and moisture contents, as well as short chain fatty acid (acetate, butyrate and propionate) concentrations were recorded in the insect enriched sprouted composite food (CFE) when compared with the CFA, CFB, CFC and CFD composite food. Faecal protein, carotenoid and nitric oxide concentrations were significantly lower (P>0.05) in group 5 in comparison to groups 1to 4. Ruminococcus bromii and Bacteroidetes were molecularly isolated and characterized by 16s rRNA from the sprouted millet/sprouted soybean and the insect enriched sprouted soybean/sprouted millet based food respectively. The presence of these bacterial strains in the feaces of the treated rats is an indication that the gut of the treated rats is colonized by good gut bacteria, hence, an improved gut health. Conclusion: Insect enriched sprouted soya bean/sprouted millet based complementary diet showed a high composition of ash, fat, protein and fiber. Thus, could increase the availability of short chain fatty acids whose role to the host organism cannot be overemphasized. It was also found to have decrease the level of faecal protein, carotenoid and nitric oxide in the serum which is an indication of an improvement in the immune system function.

Keywords: gut-health, insect, millet, soybean, sprouted

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Authors: Shan-e-Fatima, Mushtaq Khan, Syed Imran Hussian

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Plasma arc welding technology is used for welding SS-304L with A-36. Two different optimize butt welded joints were produced by using austenitic filler alloy E-309L and with direct fusion at 45 A, 2mm/sec by keeping plasma gas flow rate at 0.5LPM. Microstructure analysis of the weld bead was carried out. The results reveal complex heterogeneous microstructure in austenitic base filler alloy sample where as full martensite was found in directly fused sample.

Keywords: fusion zone microstructure, stainless steel, low carbon steel, plasma arc welding

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Authors: H. H. Lee, D. Y. Kim, S. W. Lee, J. H. Kim, J. H. Kim, W. Z. Oh, S. J. Choi

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In recent years, carbon nanotubes (CNTs) have been widely employed as a sorbent for the removal of various metal ions from water due to their unique properties such as large surface area, light mass density, high porous and hollow structure, and strong interaction between the pollutant molecules and CNTs. To apply CNTs to the sorption of Cs+ from aqueous solutions, they must first be functionalized to increase their hydrophilicity and therefore, enhance their applicability to the sorption of polar and relatively low-molecular-weight species. The objective of this study is to investigate the preparation of magnetically separable multi-walled carbon nanotubes (MWCNTs-m) as a sorbents for the removal of Cs+ from aqueous solutions. The MWCNTs-m was prepared using pristine MWCNTs and iron precursor Fe(acac)3. For the selective removal of Cs+ from aqueous solutions, the MWCNTs-m was functionalized with zinc hexacyanoferrate (MWCNTs-m-ZnFC). The physicochemical properties of the synthesized sorbents were characterized with various techniques, including transmission electron microscopy (TEM), specific surface area analysis, Fourier transform-infrared (FT-IR) spectroscopy, and vibrating-sample magnetometer. The MWCNTs-m-ZnFC was found to be easily separated from aqueous solutions by using magnetic field. The MWCNTs-m-ZnFC exhibited a high capacity for sorbing Cs+ from aqueous solutions because of their strong affinity for Cs+ and specific surface area. The sorption ability of the MWCNTs-m-ZnFC for Cs+ was maintained even in the presence of co-existing ions (Na+). Considering these results, the CNT-m-ZnFCs have great potential for use as an effective sorbent for the selective removal of radioactive Cs+ ions from aqueous solutions.

Keywords: multi-walled carbon nanotubes, magnetic materials, cesium, zinc hexacyanoferrate, sorption

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Authors: Anwaar O. Ali, Mahmoud Fathy Mubarak, Mahmoud Ibrahim Abdou, Hector Cano Esteban, Amany A. Aboulrous

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Corrosion resistance and lubrication are crucial characteristics required for geothermal drilling fluids. In this study, a ZnO/Fe₂O₃ nanocomposite was fabricated and incorporated into the structure of Cetyltrimethylammonium bromide (CTAB). Several physicochemical techniques were utilized to analyze and describe the synthesized nanomaterials. The surface morphology of the composite was assessed through scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX). The corrosion inhibition capabilities of these materials were explored across various corrosive environments. The weight loss and electrochemical methods were utilized to determine the corrosion inhibition activity of the prepared nanomaterials. The results demonstrate a high level of protection achieved by the composite. Additionally, the lubricant coefficient and extreme pressure properties were evaluated.

Keywords: nanofluid, corrosion, geothermal drilling fluids, ZnO/Fe2O3

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Authors: X. Wang, J. S. Kuang

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The Fixed-angle Softened Truss Model with Tension-stiffening (FASTMT) has a superior performance in predicting the shear behaviour of reinforced concrete (RC) membrane elements, especially for the post-cracking behaviour. Nevertheless, massive computational work is inevitable due to the multiple transcendental equations involved in the stress-strain relationship. In this paper, an iterative root-finding technique is introduced to FASTMT for solving quickly the transcendental equations of the tension-stiffening effect of RC membrane elements. This fast FASTMT, which performs in MATLAB, uses the bisection method to calculate the tensile stress of the membranes. By adopting the simplification, the elapsed time of each loop is reduced significantly and the transcendental equations can be solved accurately. Owing to the high efficiency and good accuracy as compared with FASTMT, the fast FASTMT can be further applied in quick prediction of shear behaviour of complex large-scale RC structures.

Keywords: bisection method, FASTMT, iterative root-finding technique, reinforced concrete membrane

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Authors: Zahra Jandaghian, Mehdi Ghobadi, Michal Bartko, Alex Hayes, Marianne Armstrong, Alexandra Thompson, Michael Lacasse

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The Intergovernmental Panel on Climate Change (IPCC) report stated the urgent need to cut greenhouse gas emissions to avoid the adverse impacts of climatic changes. The United Nations has forecasted that nearly 70 percent of people will live in urban areas by 2050 resulting in a doubling of the global building stock. Given that buildings are currently recognised as emitting 40 percent of global carbon emissions, there is thus an urgent incentive to decarbonize existing buildings and to build net-zero carbon buildings. To attain net zero carbon emissions in communities in the future requires action in two directions: I) reduction of emissions; and II) removal of on-going emissions from the atmosphere once de-carbonization measures have been implemented. Nature-based solutions (NBS) have a significant role to play in achieving net zero carbon communities, spanning both emission reductions and removal of on-going emissions. NBS for the decarbonisation of buildings can be achieved by using green roofs and green walls – increasing vertical and horizontal vegetation on the building envelopes – and using nature-based materials that either emit less heat to the atmosphere thus decreasing photochemical reaction rates, or store substantial amount of carbon during the whole building service life within their structure. The NBS approach can also mitigate urban flooding and overheating, improve urban climate and air quality, and provide better living conditions for the urban population. For existing buildings, de-carbonization mostly requires retrofitting existing envelopes efficiently to use NBS techniques whereas for future construction, de-carbonization involves designing new buildings with low carbon materials as well as having the integrity and system capacity to effectively employ NBS. This paper presents the opportunities and challenges in respect to the de-carbonization of buildings using NBS for both building retrofits and new construction. This review documents the effectiveness of NBS to de-carbonize Canadian buildings, identifies the missing links to implement these techniques in cold climatic conditions, and determine a road map and immediate approaches to mitigate the adverse impacts of climate change such as urban heat islanding. Recommendations are drafted for possible inclusion in the Canadian building and energy codes.

Keywords: decarbonization, nature-based solutions, GHG emissions, greenery enhancement, buildings

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Authors: Kiran P. Chadayamuri, Saransh Bagdi

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Increasing imbalance between energy supply and demand has made nations and companies involved in the energy sector to boost up their research and find suitable solutions. With the high rates at which conventional oil and gas resources are depleting, efficient exploration and exploitation of heavy oil could just be the answer. Heavy oil may be defined as crude oil having API gravity value of less than 20⁰. They are highly viscous, have low hydrogen to carbon ratios and are known to produce high carbon residues. They have high contents of asphaltenes, heavy metals, sulphur and nitrogen in them. Due to these properties extraction, transportation and refining of crude oil have its share of challenges. Lack of suitable technology has hindered its production in the past, but now things are going in a more positive direction. The aim of this paper is to study the various advantages of heavy oil, associated limitations and its feasibility as a fuel of the future.

Keywords: energy, heavy oil, fuel, future

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Authors: Krishna Nand, Mohammad Taufik

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Fused Filament Fabrication (FFF) is one of the most popular additive manufacturing (AM) technology. In FFF technology, a wire form material (filament) is fed inside a heated chamber, where it gets converted into semi-solid form and extruded out of a nozzle to be deposited on the build platform to fabricate the part. FFF technology is expanding and covering the market at a very rapid rate, so the need of raw materials for 3D printing is also increasing. The cost of 3D printing is directly affected by filament cost. To make 3D printing more economic, a compact and portable filament/wire extrusion system is needed. Wire extrusion systems to extrude ordinary wire/filament made of a single material are available in the market. However, extrusion system to make a composite wire/filament are not available. Hence, in this study, initial efforts have been made to develop a table-top composite wire extruder. The developed system is consisted of mechanical parts, electronics parts, and a control system. A multiple channel hopper, extrusion screw, melting chamber and nozzle, cooling zone, and spool winder are some mechanical parts. While motors, heater, temperature sensor, cooling fans are some electronics parts, which are used to develop this system. A control board has been used to control the various process parameters like – temperature and speed of motors. For the production of composite wire/filament, two different materials could be fed through two channels of hopper, which will be mixed and carried to the heated zone by extrusion screw. The extrusion screw is rotated by a motor, and the speed of this motor will be controlled by the controller as per the requirement of material extrusion rate. In the heated zone, the material will melt with the help of a heating element and extruded out of the nozzle in the form of wire. The developed system occupies less floor space due to the vertical orientation of its heating chamber. It is capable to extrude ordinary filament as well as composite filament, which are compatible with 3D printers available in the market. Further, the developed system could be employed in the research and development of materials, processing, and characterization for 3D printer. The developed system presented in this study could be a better choice for hobbyists and researchers dealing with the fused filament fabrication process to reduce the 3D printing cost significantly by recycling the waste material into 3D printer feed material. Further, it could also be explored as a better alternative for filament production at the commercial level.

Keywords: additive manufacturing, 3D Printing, filament extrusion, pellet extrusion

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Authors: Pouya Kaafi, Gholamreza Ghodrati Amiri

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Abnormal loads due to natural events, implementation errors and some other issues can lead to occurrence of progressive collapse in structures. Most of the past researches consist of 2- Dimensional (2D) models of steel frames without consideration of the floor system effects, which reduces the accuracy of the modeling. While employing a 3-Dimensional (3D) model and modeling the concrete slab system for the floors have a crucial role in the progressive collapse evaluation. In this research, a 3D finite element model of a 5-story steel building is modeled by the ABAQUS software once with modeling the slabs, and the next time without considering them. Then, the progressive collapse potential is evaluated. The results of the analyses indicate that the lack of the consideration of the slabs during the analyses, can lead to inaccuracy in assessing the progressive failure potential of the structure.

Keywords: abnormal loads, composite floor system, intermediate steel moment resisting frame system, progressive collapse

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Authors: Sumana Kumar, Abha Misra

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Micro-supercapacitors hold great attention as one of the promising energy storage devices satisfying the increasing quest for miniaturized and portable devices. Despite having impressive power density, superior cyclic lifetime, and high charge-discharge rates, micro-supercapacitors still suffer from low energy density, which limits their practical application. The energy density (E=1/2CV²) can be increased either by increasing specific capacitance (C) or voltage range (V). Asymmetric micro-supercapacitors have attracted great attention by using two different electrode materials to expand the voltage window and thus increase the energy density. Currently, versatile fabrication technologies such as inkjet printing, lithography, laser scribing, etc., are used to directly or indirectly pattern the electrode material; these techniques still suffer from scalable production and cost inefficiency. Here, we demonstrate the scalable production of a three-dimensional (3D) carbon foam (CF) based asymmetric micro-supercapacitor by spray printing technique on an array of interdigital electrodes. The solid-state asymmetric micro-supercapacitor comprised of CF-MnO positive electrode and CF-Fe₂O₃ negative electrode achieves a high areal capacitance of 18.4 mF/cm² (2326.8 mF/cm³) at 5 mV/s and a wider potential window of 1.4 V. Consequently, a superior energy density of 5 µWh/cm² is obtained, and high cyclic stability is confirmed with retention of the initial capacitance by 86.1% after 10000 electrochemical cycles. The optimized decoration of pseudocapacitive metal oxides in the 3D carbon network helps in high electrochemical utilization of materials where the 3D interconnected network of carbon provides overall electrical conductivity and structural integrity. The research provides a simple and scalable spray printing method to fabricate an asymmetric micro-supercapacitor using a custom-made mask that can be integrated on a large scale.

Keywords: asymmetric micro-supercapacitors, high energy-density, hybrid materials, three-dimensional carbon-foam

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Authors: Julieta Daniela Chelaru, Maria Gorea

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The massive demolition of old buildings in recent years has generated tons of waste, especially brick waste. Thus, a concern of recent research is the use of this waste for the production of environmentally friendly concrete. At the same time, corrosion in classical concrete is a current problem. In this context, in the present paper a study was carried out on the corrosion of metal reinforcement in cement mortars with brick waste. The corrosion process was analyzed on four compositions of mortars without and with 15 %, 25 % and 35 % bricks waste replacing the sand. The brick waste has a majority content in SiO2, Al₂O₃, FeO₃ and CaO. The grain size distribution of brick waste was close to that of the sand (dₘₐₓ = 3 mm). The preparation method of the samples was similar to ordinary mortars. The corrosion properties of concrete, at different waste bricks concentrations, on rebar, were investigated by electrochemical measurements (Tafel curves and EIS) at 1 and 6 months. The results obtained at 6 months revealed that the addition of the bricks waste in mortar are improved the anticorrosion properties, in the case of all samples compared with the sample with 0% bricks waste. The best results were obtained in the case of the sample with 15% bricks waste (the efficiency was ≈ 90 %). The corrosion intermediary layer formed on the rebar surface was determined by SEM-EDX.

Keywords: EIS, steel corrosion, steel reinforced concrete, waste materials

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Authors: Ju-Na Hwang, Min-Hae Park, Kee-Joe Lim

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Many studies have been conducted on DC transmission. Of power apparatus for DC transmission, High Voltage Direct Current (HVDC) cable systems are being evaluated because of the increase in power demand and transmission distance. Therefore, dc insulation characteristics of Liquid Silicone Rubber (LSR), which has various advantages such as short curing time and the ease of maintenance, were investigated to assess its performance as a HVDC insulation material for cable joints. The electrical performance of LSR added to Nano-Aluminum Trihydrate (ATH) was confirmed by measurements of the breakdown strength and electrical conductivity. In addition, field emission scanning electron microscope (FE-SEM) was used as a means of confirmation of nano-filler dispersion state. The LSR nano-composite was prepared by compounding LSR filled nano-sized ATH filler. The DC insulation properties of LSR added to nano-sized ATH fillers were found to be superior to those of the LSR without filler.

Keywords: liquid silicone rubber, nano-composite, HVDC insulation, cable joints

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Authors: W. S. Mohamed, A. A. Hammam

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Sandy soils under arid and semi-arid conditions are characterized by poor physical and biochemical properties such as low water retention, rapid organic matter decomposition, low nutrients use efficiency, and limited crop productivity. Addition of organic amendments is crucial to develop soil properties and consequently enhance nutrients use efficiency and lessen organic carbon decomposition. Two years field experiments were developed to investigate the feasibility of using poultry manure and its derived biochar integrated with different levels of N fertilizer as a soil amendment for newly reclaimed sandy soils in Western Desert of El-Minia Governorate, Egypt. Results of this research revealed that poultry manure and its derived biochar addition induced pronounced effects on soil moisture content at saturation point, field capacity (FC) and consequently available water. Data showed that application of poultry manure (PM) or PM-derived biochar (PMB) in combination with inorganic N levels had caused significant changes on a range of the investigated sandy soil biochemical properties including pH, EC, mineral N, dissolved organic carbon (DOC), dissolved organic N (DON) and quotient DOC/DON. Overall, the impact of PMB on soil physical properties was detected to be superior than the impact of PM, regardless the inorganic N levels. In addition, the obtained results showed that PM and PM application had the capacity to stimulate vigorous growth, nutritional status, production levels of wheat and sorghum, and to increase soil organic matter content and N uptake and recovery compared to control. By contrast, comparing between PM and PMB at different levels of inorganic N, the obtained results showed higher relative increases in both grain and straw yields of wheat in plots treated with PM than in those treated with PMB. The interesting feature of this research is that the biochar derived from PM increased treated sandy soil organic carbon (SOC) 1.75 times more than soil treated with PM itself at the end of cropping seasons albeit double-applied amount of PM. This was attributed to the higher carbon stability of biochar treated sandy soils increasing soil persistence for carbon decomposition in comparison with PM labile carbon. It could be concluded that organic manures applied to sandy soils under arid and semi-arid conditions are subjected to high decomposition and mineralization rates through crop seasons. Biochar derived from organic wastes considers as a source of stable carbon and could be very hopeful choice for substituting easily decomposable organic manures under arid conditions. Therefore, sustainable agriculture and productivity in newly reclaimed sandy soils desire one high rate addition of biochar derived from organic manures instead of frequent addition of such organic amendments.

Keywords: biochar, dissolved organic carbon, N-uptake, poultry, sandy soil

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Authors: Doaa S. Mahmoud, Nivin M. Ahmed, Salwa H. El-Sabbagh

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The rheometric characteristics and physicomechanical properties of bentonite / acrylonitrile-butadiene rubber (NBR) were investigated. The influences of adding bentonite (Bt) and / or modified bentonite (organo-Bt) to the rubber were observed. Scanning electron microscopy (SEM) showed that the rubber chains may be confined within the interparticle space and the Bt particles presented a physical dispersion in NBR matrix. Bentonite (Bt) was modified with tetra butyl phosphonium bromide (TBP) in order to produce organo-Bt. The modification was carried out at 0.5, 1 and 2 cation exchange capacity (CEC) of bentonite. Results showed that the maximum torque of organo-Bt / NBR composite increases at high bentonite loading. The scorch time (tS2) and cure time (tC90) of the organo-Bt / NBR composites decreased simultaneously relative to those of the neat NBR. The prepared composite exhibited significant improvement in mechanical compared with that of neat NBR.

Keywords: acrylonitrile-butadiene rubber, bentonite, composites, physico-mechanical properties

Procedia PDF Downloads 267

Authors: Lebogang L. R. Mphahlele, Bruce B. Sithole

Abstract:

Chicken meat is the highest consumed meat in south Africa, with a per capita consumption of >33 kg yearly. Hence, South Africa produces over 250 million kg of waste chicken feathers each year, the majority of which is landfilled or incinerated. The discarded feathers have caused environmental pollution and natural protein resource waste. Therefore, the valorisation of waste chicken feathers is measured as a more environmentally friendly and cost-effective treatment. Feather contains 91% protein, the main component being beta-keratin, a fibrous and insoluble structural protein extensively cross linked by disulfide bonds. Keratin is usually converted it into nanofibers via electrospinning for a variety of applications. keratin nanofiber composites have many potential biomedical applications for their attractive features, such as high surface-to-volume ratio and very high porosity. The application of nanofibers in the biomedical wound dressing requires antimicrobial properties for materials. One approach is incorporating inorganic nanoparticles, among which silver nanoparticles played an important alternative antibacterial agent and have been studied against many types of microbes. The objective of this study is to combine synthetic polymer, chicken feather keratin, and antibacterial nanoparticles to develop novel electrospun antibacterial nanofibrous composites for possible wound dressing application. Furthermore, this study will converting a two-dimensional electrospun nanofiber membrane to three-dimensional fiber networks that resemble the structure of the extracellular matrix (ECM)

Keywords: chicken feather keratin, nanofibers, nanoparticles, nanocomposites, wound dressing

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Authors: Irshad U. Khan, Tanmay Paul, Murali Mohan Seepana

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This paper presents a study on synthesizing and characterizing a Copper oxide doped Carbon (CuO-C) electrocatalyst for the negative half-cell reactions of Vanadium Redox Flow Battery (VRFB). The CuO was synthesized using a microreactor. The electrocatalyst was characterized using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Field Emission Scanning Electron Microscopy (SEM). The electrochemical performance was assessed by linear sweep voltammetry (LSV). The findings suggest that the synthesized CuO exhibited favorable crystallinity, morphology, and surface area, which reflects improved cell performance.

Keywords: ECSA, electrocatalyst, energy storage, Tafel

Procedia PDF Downloads 92

Authors: S. Melvin Samuel, Jayanta Bhattacharya

Abstract:

In the present study, a graphene oxide/chitosan (GO-CS) composite material was prepared and used as an adsorbent for the removal of methylene blue (MB) from aqueous solution. The synthesized GO-CS adsorbent was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopes (SEM), transmission electron microscopy (TEM), Raman spectroscopy and thermogravimetric analysis (TGA). The removal of MB was conducted in batch mode. The effect of parameters influencing the adsorption of MB such as pH of the solution, initial MB concentration, shaking speed, contact time and adsorbent dosage were studied. The results showed that the GO-CS composite material has high adsorption capacity of 196 mg/g of MB solution at pH 9.0. Further, the adsorption of MB on GO-CS followed pseudo second order kinetics and equilibrium adsorption data well fitted by the Langmuir isotherm model. The study suggests that the GO-CS is a favorable adsorbent for the removal of MB from aqueous solution.

Keywords: Methylene blue, Graphene oxide-chitosan, Isotherms, Kinetics.

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Authors: Minsu Kim, Hae-Chang Cho, Jae Hoon Chung, Inwook Heo, Kang Su Kim

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For safe design of the UHPC flexural members, accurate estimations of their shear strengths are very important. However, since the shear strengths are significantly affected by various factors such as tensile strength of concrete, shear span to depth ratio, volume ratio of steel fiber, and steel fiber factor, the accurate estimations of their shear strengths are very challenging. In this study, therefore, the Adaptive Neuro-Fuzzy System (ANFIS), which has been widely used to solve many complex problems in engineering fields, was introduced to estimate the shear strengths of UHPC flexural members. A total of 32 experimental results has been collected from previous studies for training of the ANFIS algorithm, and the well-trained ANFIS algorithm provided good estimations on the shear strengths of the UHPC test specimens. Acknowledgement: This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT & Future Planning(NRF-2016R1A2B2010277).

Keywords: ultra-high-performance concrete, ANFIS, shear strength, flexural member

Procedia PDF Downloads 190

Authors: S. Buloyan, V. Mamikonyan, H. Hakobyan, H. Harutyunyan, H. Gasparyan

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The liver is the strongest regenerating organ of the organism, and even with 2/3 surgically removed, it can regenerate completely. Hence, liver cirrhosis may only develop when the regenerating system is off. We present the results of a comparative study of structural and functional characteristics of rat liver tissue under the conditions of toxic liver cirrhosis development, induced by carbon tetrachloride, and its prevention/treatment by natural compounds with antioxidant and immune stimulating action. Studies were made on Wister rats, weighing 120~140 g. Grape seeds extracts, separately and in combination with well known anticirrhotic drug ursodeoxycholic acid (ursodiol) have demonstrated effectiveness in prevention of liver cirrhosis development and its treatment.

Keywords: carbon tetrachloride, GSE, liver cirrhosis, prevention, treatment

Procedia PDF Downloads 487

Authors: Rataya Yanaphan, Saksiri Kuppatarat, Sarita Pinmanee

Abstract:

Hemp (Cannabis sativa L. ssp. Sativa) cultivation for fiber is limited by extremely high labor cost, especially for the removal of the leaves before harvest. This study evaluated chemical defoliants as a means to remove the leaves of hemp before harvest, in an effort to reduce labor expenditures in the production on hemp fiber. This study was conducted by spraying the leaves of hemp with five different treatments: saline solution, Urea (CH4N2O), Ethephon, copper Sulphate (CuSO4) and water (control) before harvesting. The largest percentage of leaf loss 6 days after spraying was with saline solution (43%), followed by Ethephon (32%). However, saline solution also caused drying of the stems but Ethephon did not. Thus, Ethephon was evaluated in the second experiment by spraying with Ethephon concentrations of 0, 10, 15 and 20 ml per 1 liter of water at 7 days before harvest. Spraying with 0.5% Ethephon resulted in 13.6% leaf fall. Spraying with 1.5% and 2% Ethephon resulted in 82.2% and 82.3 % leaf fall, respectively. In addition, using Ethephon to defoliate hemp had no detrimental effect the yield. Therefore, Ethephon concentration at 15 ml per 1 liter of water will be recommended for use in removing hemp leaves by spraying at 7 days before harvest to lower labor cost.

Keywords: defoliation technology, ethephon, hemp cultivation, saline solution

Procedia PDF Downloads 223