Search results for: porous PVDF hollow fiber membrane

Authors: Samra Isadounene, Amar Boukerrou, Dalila Hammiche

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In this work, the composites were prepared with poly(lactic acid) (PLA) and olive husk flour (OHF) with different percentages (10, 20 and 30%) using extrusion method followed by injection molding. The morphological, mechanical properties and thermal behavior of composites were investigated. Tensile strength and elongation at break of composites showed a decreasing trend with increasing fiber content. On the other hand, Young modulus and storage modulus were increased. The addition of OHF resulted in a decrease in thermal stability of composites. The presence of OHF led to an increase in percentage of crystallinity (Xc) of PLA matrix.

Keywords: biopolymers, composites, mechanical properties, poly(lactic acid)

Procedia PDF Downloads 238

Authors: Lotfi Hedi Khezami, Mohamed Ben Rabha, N. Sboui, Mounir Gaidi, B. Bessais

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Metal-nano particle-assisted Chemical Etching is an extraordinary developed wet etching method of producing uniform semiconductor nano structure (nano wires) from patterned metallic film on crystalline silicon surface. The metal films facilitate the etching in HF and H2O2 solution and produce silicon nanowires (SiNWs). Creation of different SiNWs morphologies by changing the etching time and its effects on optical and opto electronic properties was investigated. Combination effect of formed SiNWs and stain etching treatment in acid (HF/HNO3/H2O) solution on the surface morphology of Si wafers as well as on the optical and opto electronic properties are presented in this paper.

Keywords: stain etching, porous silicon, silicon nanowires, reflectivity, lifetime, solar cells

Procedia PDF Downloads 448

Authors: Arian Ebneyamini, Hoda Azimi, Jules Thibaults, F. Handan Tezel

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In this study, a modification of Hennepe model for pervaporation separation of butanol from aqueous solutions using Polydimethylsiloxane (PDMS) mixed matrix membranes has been introduced and validated by experimental data. The model was compared to the original Hennepe model and few other models which are applicable for membrane gas separation processes such as Maxwell, Lewis Nielson and Pal. Theoretical modifications for non-ideal interface morphology have been offered to predict the permeability in case of interface void, interface rigidification and pore-blockage. The model was in a good agreement with experimental data.

Keywords: butanol, PDMS, modeling, pervaporation, mixed matrix membranes

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Authors: Mulubrhan Berihu

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Due to the design versatility, availability, and cost efficiency, concrete continues to be the most used construction material on earth. However, the production of Portland cement, the primary component of concrete mix is causing to have a serious effect on environmental and economic impacts. This shows there is a need to study using of supplementary cementitious materials (SCMs). The most commonly used supplementary cementitious materials are wastes, and the use of these industrial waste products has technical, economic, and environmental benefits besides the reduction of CO2 emission from cement production. This paper aims to document the effect on the strength property of concrete due to the use of low cement by maximizing supplementary cementitious materials like fly ash. The amount of cement content was below 250 kg/m3, and in all the mixes, the quantity of powder (cement + fly ash) is almost kept at about 500 kg. According to this, seven different cement content (250 kg/m3, 195 kg/m3, 150 kg/m3, 125 kg/m3, 100 kg/m3, 85 kg/m3, 70 kg/m3) with different amount of replacement of SCMs was conducted. The mix proportion was prepared by keeping the water content constant and varying the cement content, SCMs, and water-to-binder ratio. Based on the different mix proportions of fly ash, a range of mix designs was formulated. The test results showed that using up to 85 kg/m3 of cement is possible for plain concrete works like hollow block concrete to achieve 9.8 Mpa, and the experimental results indicate that strength is a function of w/b. The experiment result shows a big difference in gaining of compressive strength from 7 days to 28 days and this obviously shows the slow rate of hydration of fly ash concrete. As the w/b ratio increases, the strength decreases significantly. At the same time, higher permeability was seen in the specimens which were tested for three hours than one hour.

Keywords: efficiency factor, cement content, compressive strength, mix proportion, w/c ratio, water permeability, SCMs

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Authors: Yehia Manawi, Viktor Kochkodan, Muataz Hussien

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In this paper, the effect of adding Arabic Gum (AG) to the dope solutions of polyethersulfone (PES) was studied. The aim of adding AG is to enhance the properties of ultrafiltration membranes such as hydrophilicity, porosity and selectivity. several AG loading (0.1-3.0 wt.%) in PES/ N-Methyl-2-pyrrolidone (NMP) casting solutions were prepared to fabricate PES membranes using phase inversion technique. The surface morphology, hydrophilicity and selectivity of the cast PES/AG membranes were analyzed using scanning electron microscopy and contact angle measurements. The selectivity of the fabricated membranes was also tested by filtration of oil solutions (1 ppm) and found to show quite high removal efficiency. The effect of adding AG to PES membranes was found to increase the permeate flux and porosity as well as reducing surface roughness and the contact angle of the membranes.

Keywords: antifouling, Arabic gum, polyethersulfone membrane, ultrafiltration

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Authors: María Canal-Rodríguez, María Arnaiz, Natalia Rey-Raap, Ana Arenillas, Jon Ajuria

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The constant demand of electrical energy, as well as the increase in environmental concern, lead to the necessity of investing in clean and eco-friendly energy sources that implies the development of enhanced energy storage devices. Li-ion batteries (LIBs) and Electrical double layer capacitors (EDLCs) are the most widespread energy systems. Batteries are able to storage high energy densities contrary to capacitors, which main strength is the high-power density supply and the long cycle life. The combination of both technologies gave rise to Li-ion capacitors (LICs), which offers all these advantages in a single device. This is achieved combining a capacitive, supercapacitor-like positive electrode with a faradaic, battery-like negative electrode. Due to the abundance and affordability, dual carbon-based LICs are nowadays the common technology. Normally, an Active Carbon (AC) is used as the EDLC like electrode, while graphite is the material commonly employed as anode. LICs are potential systems to be used in applications in which high energy and power densities are required, such us kinetic energy recovery systems. Although these devices are already in the market, some drawbacks like the limited power delivered by graphite or the energy limiting nature of AC must be solved to trigger their used. Focusing on the anode, one possibility could be to replace graphite with Hard Carbon (HC). The better rate capability of the latter increases the power performance of the device. Moreover, the disordered carbonaceous structure of HCs enables storage twice the theoretical capacity of graphite. With respect to the cathode, the ACs are characterized for their high volume of micropores, in which the charge is storage. Nevertheless, they normally do not show mesoporous, which are really important mainly at high C-rates as they act as transport channels for the ions to reach the micropores. Usually, the porosity of ACs cannot be tailored, as it strongly depends on the precursor employed to get the final carbon. Moreover, they are not characterized for having a high electrical conductivity, which is an important characteristic to get a good performance in energy storage applications. A possible candidate to substitute ACs are carbon aerogels (CAs). CAs are materials that combine a high porosity with great electrical conductivity, opposite characteristics in carbon materials. Furthermore, its porous properties can be tailored quite accurately according to with the requirements of the application. In the present study, CAs with controlled porosity were obtained from polymerization of resorcinol and formaldehyde by microwave heating. Varying the synthesis conditions, mainly the amount of precursors and pH of the precursor solution, carbons with different textural properties were obtained. The way the porous characteristics affect the performance of the cathode was studied by means of a half-cell configuration. The material with the best performance was evaluated as cathode in a LIC versus a hard carbon as anode. An analogous full LIC made by a high microporous commercial cathode was also assembled for comparison purposes.

Keywords: li-ion capacitors, energy storage, tailored porosity, carbon aerogels

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Authors: Khawar Ali

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We present the numerical study of unsteady hydromagnetic (MHD) flow and heat transfer characteristics of a viscous incompressible electrically conducting water-based hybrid metallic nanofluid (containing Cu-Au/ H₂O nanoparticles) between two orthogonally moving porous coaxial disks with suction. Different from the classical shooting methodology, we employ a combination of a direct and an iterative method (SOR with optimal relaxation parameter) for solving the sparse systems of linear algebraic equations arising from the FD discretization of the linearized self similar nonlinear ODEs. Effects of the governing parameters on the flow and heat transfer are discussed and presented through tables and graphs. The findings of the present investigation may be beneficial for the electronic industry in maintaining the electronic components under effectiveand safe operational conditions.

Keywords: heat transfer enhancement, hybrid metallic nanofluid, viscous dissipation and joule heating effect , Two dimensional flow

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Authors: Weitao Zhou, Qing Wang, Jianxin He, Shizhong Cui

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Mesoporous Tussah silk fibroin (TSF) spheres were fabricated via the self-assembly of TSF molecules in aqueous solutions. The results showed that TSF particles were approximately three-dimensional spheres with the diameter ranging from 500nm to 6μm without adherence. More importantly, the surface morphology is mesoporous structure with nano-pores of 20nm - 200nm in size. Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) studies demonstrated that mesoporous TSF spheres mainly contained beta-sheet conformation (44.1 %) as well as slight amounts of random coil (13.2 %). Drug release test was performed with 5-fluorouracil (5-Fu) as a model drug and the result indicated the mesoporous TSF microspheres had a good capacity of sustained drug release. It is expected that these stable and high-crystallinity mesoporous TSF sphere produced without organic solvents, which have significantly improved drug release properties, is a very promising material for controlled gene medicines delivery.

Keywords: Tussah silk fibroin, porous materials, microsphere, drug release

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Authors: Syed W. Hasan, Zhiqun Tian

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Wet spinning provides a facile and economic route to fabricate graphene nanofibers (GFs) on mass scale. Nevertheless, the pristine GFs exhibit significantly low electrical and mechanical properties owing to stacked graphene sheets and weak inter-atomic bonding. In this report, we present highly conductive Ag-decorated-GFs (Ag/GFs). The SEM micrographs show Ag nanoparticles (NPs) (dia ~10 nm) are homogeneously distributed throughout the cross-section of the fiber. The Ag NPs provide a conductive network for the electrons flow raising the conductivity to 1.8(10^4) S/m which is 4 times higher than the pristine GFs. Our results surpass the conductivities of graphene fibers doped with CNTs, Nanocarbon, fullerene, and Cu. The chemical and structural attributes of Ag/GFs are further elucidated through XPS, AFM and Raman spectroscopy.

Keywords: Ag nanoparticles, Conductive fibers, Graphene, Wet spinning

Procedia PDF Downloads 142

Authors: C. Román, M. Guevara, P. Salas, D. Duclap, J. Houenou, C. Poupon, J. F. Mangin, P. Guevara

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Diffusion Magnetic Resonance Imaging (dMRI) allows the non-invasive study of human brain white matter. From diffusion data, it is possible to reconstruct fiber trajectories using tractography algorithms. Our previous work consists in an automatic method for the identification of short association bundles of the superficial white matter (SWM), based on a whole brain inter-subject hierarchical clustering applied to a HARDI database. The method finds representative clusters of similar fibers, belonging to a group of subjects, according to a distance measure between fibers, using a non-linear registration (DTI-TK). The algorithm performs an automatic labeling based on the anatomy, defined by a cortex mesh parcelated with FreeSurfer software. The clustering was applied to two independent groups of 37 subjects. The clusters resulting from both groups were compared using a restrictive threshold of mean distance between each pair of bundles from different groups, in order to keep reproducible connections. In the left hemisphere, 48 reproducible bundles were found, while 43 bundles where found in the right hemisphere. An inter-hemispheric bundle correspondence was then applied. The symmetric horizontal reflection of the right bundles was calculated, in order to obtain the position of them in the left hemisphere. Next, the intersection between similar bundles was calculated. The pairs of bundles with a fiber intersection percentage higher than 50% were considered similar. The similar bundles between both hemispheres were fused and symmetrized. We obtained 30 common bundles between hemispheres. An atlas was created with the resulting bundles and used to segment 78 new subjects from another HARDI database, using a distance threshold between 6-8 mm according to the bundle length. Finally, a laterality index was calculated based on the bundle volume. Seven bundles of the atlas presented right laterality (IP_SP_1i, LO_LO_1i, Op_Tr_0i, PoC_PoC_0i, PoC_PreC_2i, PreC_SM_0i, y RoMF_RoMF_0i) and one presented left laterality (IP_SP_2i), there is no tendency of lateralization according to the brain region. Many factors can affect the results, like tractography artifacts, subject registration, and bundle segmentation. Further studies are necessary in order to establish the influence of these factors and evaluate SWM laterality.

Keywords: dMRI, hierarchical clustering, lateralization index, tractography

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Authors: Sadaf Karkoodi, Hassan Karampour

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There is a growing interest in the construction industry towards hybrid systems. The hybrid systems use construction materials such as timber, steel, and concrete smartly, can be prefabricated, and are cost-effective and sustainable solutions to an industry targeting reduced carbon footprint. Moreover, in case of periodical shortage in timber resources, reusable and waste wood such as fibres can be used in the hybrid modules, which facilitates the circular economy. In this research, a hybrid frame is proposed and experimentally validated by introducing dried wood fibre products inside cold-formed steel square hollow sections without using any adhesives. As such, fibre-filled steel tubular (FFST) columns, beams, and 2D frames are manufactured and tested. The results show that the FFST columns have stiffness and strength 44% and 55% higher than cold-formed steel columns, respectively. The bearing strength of the FFST beams shows an increase of 39.5% compared to steel only. The flexural stiffness and strength of the FFST beams are 8.5% and 28% higher than the bare steel beams, respectively. The FFST frame depicted an 18.4% higher ultimate load capacity than the steel-only frame under a mid-point concentrated load. Moreover, the FFST beam-to-column bolted connection showed high ductile performance. The initial results and the proposed simple manufacturing process suggest that the proposed FFST concept can be upscaled and used in real structures.

Keywords: wood fibre, reusing wood, fibre-filled steel, hybrid construction

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Authors: Milind D. Meshram

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Ascarids are the most frequent worm parasite of dogs and cats. There are two species that commonly infect dogs: Toxocara canis and Toxascaris leonina. Adult roundworms live in the stomach and intestines and can grow to 7 inches (18 cm) long. A female may lay 200,000 eggs in a day. The eggs are protected by a hard shell. They are extremely hardy and can live for months or years in the soil. A dog aged about 6 years, from Satara was referred to Teaching Veterinary Clinical Complex (TVCC) with a complaint of abdominal pain, anorexia, loss of condition and dull body coat with mucous pale membrane. The clinical examination revealed Anaemia, palpation of abdomen revealed enlargement of liver, slimy feel of the intestine loop, diarrhea.

Keywords: therapeutic management, Toxocara canis, induced hepatitis, dogs

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Authors: Serap Kaymakci, Dogan Gundogdu, M. Bugra Yagcioglu

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Erosion (soil erosion) is a phenomenon in which the soil on the slope surface is exposed to natural influences such as wind, rainfall, etc. in open areas. The most natural solution to prevent erosion is to plant surfaces exposed to erosion. However, proper ground and natural conditions must be provided in order for planting to occur. Erosion is prevented in a fast and natural way and the loss of soil is reduced mostly. Lead to allowing plants to hold onto the soil with its three-dimensional and hollow structure are as follows: The types of geomat called MacMat that is used in a case study in Turkey in order to prevent water carry over due to rainfall. The geosynthetic combined with double twisted steel wire mesh. That consists of 95% Zn–5% Al alloy coated double twisted steel wire based that is a reinforced MacMat (geosynthetic three-dimensional erosion control mat) obtained by a polypropylene consisted (mesh type 8x10-Wire diam. 2.70 mm–95% Zn–5% Al alloy coated). That is developed by the progress of the technology. When using reinforced MacMat on top clay liners, fixing pins should not be used as they will rupture the mats. Mats are simply anchored (J Type) in the top trench and, if necessary, in intermediate berm trenches. If the slope angle greater than 20°, it is necessary to use additional rebar depending soil properties also. These applications may have specific technical and installation requirements. In that project, the main purpose is erosion control after that is greening. There is a slope area around the factory which is located in Gebze, İstanbul.

Keywords: erosion, GeoMat, geosynthetic, slope

Procedia PDF Downloads 176

Authors: Makhan Maharjan, Mani Ulaganathan, Vanchiappan Aravindan, Srinivasan Madhavi, Jing-Yuan Wang, Tuti Mariana Lim

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There is great interest to exploit sustainable, low-cost, renewable resources as carbon precursors for energy storage applications. Research on development of energy storage devices has been growing rapidly due to mismatch in power supply and demand from renewable energy sources This paper reported the synthesis of porous activated carbon from biomass waste and evaluated its performance in supercapicators. In this work, we employed orange peel (waste material) as the starting material and synthesized activated carbon by pyrolysis of KOH impregnated orange peel char at 800 °C in argon atmosphere. The resultant orange peel-derived activated carbon (OP-AC) exhibited a high BET surface area of 1,901 m2 g-1, which is the highest surface area so far reported for the orange peel. The pore size distribution (PSD) curve exhibits the pores centered at 11.26 Å pore width, suggesting dominant microporosity. The OP-AC was studied as positive electrode in combination with different negative electrode materials, such as pre-lithiated graphite (LiC6) and Li4Ti5O12 for making different hybrid capacitors. The lithium ion capacitor (LIC) fabricated using OP-AC with pre-lithiated graphite delivered a high energy density of ~106 Wh kg–1. The energy density for OP-AC||Li4Ti5O12 capacitor was ~35 Wh kg–1. For comparison purpose, configuration of OP-AC||OP-AC capacitors were studied in both aqueous (1M H2SO4) and organic (1M LiPF6 in EC-DMC) electrolytes, which delivered the energy density of 6.6 Wh kg-1 and 16.3 Wh kg-1, respectively. The cycling retentions obtained at current density of 1 A g–1 were ~85.8, ~87.0 ~82.2 and ~58.8% after 2500 cycles for OP-AC||OP-AC (aqueous), OP-AC||OP-AC (organic), OP-AC||Li4Ti5O12 and OP-AC||LiC6 configurations, respectively. In addition, characterization studies were performed by elemental and proximate composition, thermogravimetry, field emission-scanning electron microscopy, Raman spectra, X-ray diffraction (XRD) pattern, Fourier transform-infrared, X-ray photoelectron spectroscopy (XPS) and N2 sorption isotherms. The morphological features from FE-SEM exhibited well-developed porous structures. Two typical broad peaks observed in the XRD framework of the synthesized carbon implies amorphous graphitic structure. The ratio of 0.86 for ID/IG in Raman spectra infers high degree of graphitization in the sample. The band spectra of C 1s in XPS display the well resolved peaks related to carbon atoms in various chemical environments; for instances, the characteristics binding energies appeared at ~283.83, ~284.83, ~286.13, ~288.56, and ~290.70 eV which correspond to sp2 -graphitic C, sp3 -graphitic C, C-O, C=O and π-π*, respectively. Characterization studies revealed the synthesized carbon to be promising electrode material towards the application for energy storage devices. The findings opened up the possibility of developing high energy LICs from abundant, low-cost, renewable biomass waste.

Keywords: lithium-ion capacitors, orange peel, pre-lithiated graphite, supercapacitors

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Authors: Ahmed H. Elkholy

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An elastic analysis is developed to obtain the distribution of stresses, strains, bending moment and deformation for a thin hollow, variable thickness cylindrical specimen when subjected to different biaxial loadings. The specimen was subjected to a combination of internal pressure, axial tensile loading and external pressure. Several axial to circumferential stress ratios were investigated in detail. The analytical model was then validated using experimental results obtained from a test rig using several biaxial loadings. Based on the preliminary results obtained, the specimen was then modified geometrically to ensure uniform strain distribution through its wall thickness and along its gauge length. The new design of the specimen has a higher buckling strength and a maximum value of equivalent stress according to the maximum distortion energy theory. A cyclic function generator of the standard servo-controlled, electro-hydraulic testing machine is used to generate a specific signal shape (sine, square,…) at a certain frequency. The two independent controllers of the electronic circuit cause an independent movement to each servo-valve piston. The movement of each piston pressurizes the upper and lower sides of the actuators alternately. So, the specimen will be subjected to axial and diametral loads independent of each other. The hydraulic system has two different pressures: one pressure will be responsible for axial stress produced in the specimen and the other will be responsible for the tangential stress. Changing the two pressure ratios will change the stress ratios accordingly. The only restriction on the maximum stress obtained is the capacity of the testing system and specimen instability due to buckling.

Keywords: biaxial, fatigue, stress, testing

Procedia PDF Downloads 128

Authors: Robert J. Sutton, Jon Elvins, Sean Casey, Eifion Jewell, Justin R. Searle

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Thermochemical storage utilises chemical salts which store and release energy a fully reversible endo/exothermic chemical reaction. Highly porous vermiculite impregnated with CaCl2, LiNO3 and MgSO4 (SIMs – Salt In Matrices) are proposed as potential materials for long-term thermochemical storage. The behavior of these materials during typical hydration and dehydration cycles is investigated. A simple moisture experiment represents the hydration, whilst thermogravimetric analysis (TGA) represents the dehydration. Further experiments to approximate the energy density and to determine the peak output temperatures of the SIMs are conducted. The CaCl2 SIM is deemed the best performing SIM across most experiments, whilst the results of MgSO4 SIM indicate difficulty associated with energy recovery.

Keywords: hydrated states, inter-seasonal heat storage, moisture sorption, salt in matrix

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Authors: Awni H. Alkhazaleh, Baljinder K. Kandola

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In this study, a form-stable composite Paraffin/Nanoclay (PA-NC) has been prepared by absorbing PA into porous particles of NC to be used for low-temperature latent heat thermal energy storage. The leakage test shows that the maximum mass fraction of PA that can be incorporated in NC without leakage is 60 wt.%. Differential scanning calorimetry (DSC) has been used to measure the thermal properties of the PA and PA-NC both before and after incorporation in plasterboard (PL). The mechanical performance of the samples has been evaluated in flexural mode. The thermal energy storage performance has been studied using a small test chamber (100 mm × 100 mm × 100 mm) made from 10 mm thick PL and measuring the temperatures using thermocouples. The flammability of the PL+PL-NC has been discussed using a cone calorimeter. The results indicate that the form composite PA has good potential for use as thermal energy storage materials in building applications.

Keywords: building materials, flammability, phase change materials, thermal energy storage

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Authors: A. Khosrozadeh, M. A. Darabi, M. Xing, Q. Wang

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Fabrication of a high-performance supercapacitor (SC) using a flexible cellulose-based composite film of polyaniline (PANI), reduced graphene oxide (RGO), and silver nanowires (AgNWs) is reported. The flexibility, high capacitive behaviour, and cyclic stability of the entire device make it a good candidate for wearable SCs. The results show that a capacitance as high as 73.4 F/g (1.6 F/cm2) at a discharge rate of 1.1 A/g is achieved by the device. In addition, the SC demonstrates a power density up to 468.8 W/kg and an energy density up to 5.1 wh/kg. The flexibility of the composite film is attributed to the binding effect of cellulose fibers as well as reinforcing effect of AgNWs. The excellent electrochemical performance of the device is found to be owing to the synergistic effect between PANI/RGO/AgNWs ternary in a cushiony cellulose matrix and porous structure of the composite.

Keywords: cellulose, polyaniline, reduced graphene oxide, silver, super capacitor

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Authors: Archana Sharma, Vijayashree Nayak, Ashok Kumar

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Three-dimensional matrices were fabricated from blend of natural-natural polymers like carrageenan-gelatin and synthetic -natural polymers such as PEG- gelatin (PEG of different molecular weights (2,000 and 6,000) using two different crosslinkers; glutaraldehyde and EDC-NHS by cryogelation technique. Blends represented a feasible approach to design 3-D scaffolds with controllable mechanical, physical and biochemical properties without compromising biocompatibility and biodegradability. These matrices possessed interconnected porous structure, good mechanical strength, biodegradable nature, constant swelling kinetics, ability to withstand high temperature and visco-elastic behavior. Hemocompatibility of cryogel matrices was determined by coagulation assays and hemolytic activity assay which demonstrated that these cryogels have negligible effects on coagulation time and have excellent blood compatibility. In vitro biocompatibility (cell-matrix interaction) inferred good cell adhesion, proliferation, and secretion of ECM on matrices. These matrices provide a microenvironment for the growth, proliferation, differentiation and secretion of ECM of different cell types such as IMR-32, C2C12, Cos-7, rat bone marrow derived MSCs and human bone marrow MSCs. Hoechst 33342 and PI staining also confirmed that the cells were uniformly distributed, adhered and proliferated properly on the cryogel matrix. An ideal scaffold used for tissue engineering application should allow the cells to adhere, proliferate and maintain their functionality. Neurotransmitter analysis has been done which indicated that IMR-32 cells adhered, proliferated and secreted neurotransmitters when they interacted with these matrices which showed restoration of their functionality. The cell-matrix interaction up to molecular level was also evaluated so to check genotoxicity and protein expression profile which indicated that these cryogel matrices are non-genotoxic and maintained biofunctionality of cells growing on these matrices. All these cryogels, when implanted subcutaneously in balb/c mice, showed no adverse systemic or local toxicity effects at implantation site. There was no significant increase in inflammatory cell count has otherwise been observed after scaffold implantation. These cryogels are supermacroporous and this porous structure allows cell infiltration and proliferation of host cells. This showed the integration and presence of infiltrated cells into the cryogel implants. Histological analysis confirmed that the implanted cryogels do not have any adverse effect in spite of host immune system recognition at the site of implantation, on its surrounding tissues and other vital host organs. In vivo biocompatibility study after in vitro biocompatibility analysis has also concluded that these synthesized cryogels act as important biological substitutes, more adaptable and appropriate for transplantation. Thus, these cryogels showed their potential for soft tissue engineering applications.

Keywords: cryogelation, hemocompatibility, in vitro biocompatibility, in vivo biocompatibility, soft tissue engineering applications

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Authors: Ines Antunes, Andrea Massari, Concetta Bartucca

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Greenhouse gasses (GHG) role in the atmosphere has been well known since the 19th century; however, researchers have begun to relate them to climate changes only in the second half of the following century. From this moment, scientists started to correlate the presence of GHG such as CO₂ with the global warming phenomena. This has raised the awareness not only of those who were experts in this field but also of public opinion, which is becoming more and more sensitive to environmental pollution and sustainability issues. Nowadays the reduction of GHG emissions is one of the principal objectives of EU nations. The target is an 80% reduction of emissions in 2050 and to reach the important goal of carbon neutrality. Road sector is responsible for an important amount of those emissions (about 20%). The most part is due to traffic, but a good contribution is also given directly or indirectly from road construction and maintenance. Raw material choice and reuse of post-consumer plastic rather than a cleverer design of roads have an important contribution to reducing carbon footprint. Bituminous membranes can be successfully used as reinforcement systems in asphalt layers to improve road pavement performance against cracking. Composite materials coupling membranes with grids and/or fabrics should be able to combine improved tensile properties of the reinforcement with stress absorbing and waterproofing effects of membranes. Polyglass, with its brand dedicated to road construction and maintenance called Polystrada, has done more than this. The company's target was not only to focus sustainability on the final application but also to implement a greener mentality from the cradle to the grave. Starting from production, Polyglass has made important improvements finalized to increase efficiency and minimize waste. The installation of a trigeneration plant and the usage of selected production scraps inside the products as well as the reduction of emissions into the environment, are one of the main efforts of the company to reduce impact during final product build-up. Moreover, the benefit given by installing Polystrada products brings a significant improvement in road lifetime. This has an impact not only on the number of maintenance or renewal that needs to be done (build less) but also on traffic density due to works and road deviation in case of operations. During the end of the life of a road, Polystrada products can be 100% recycled and milled with classical systems used without changing the normal maintenance procedures. In this work, all these contributions were quantified in terms of CO₂ emission thanks to an LCA analysis. The data obtained were compared with a classical system or a standard production of a membrane. What it is possible to see is that the usage of Polyglass products for street maintenance and building gives a significant reduction of emissions in case of membrane installation under the road wearing course.

Keywords: CO₂ emission, LCA, maintenance, sustainability

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Authors: Keivan Jamshidi

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Myiasis is defined as the infestation of living tissues of vertebrates by larvae of flies. Gingival myiasis is an uncommon type of myiasis. In oral inspection of a death dog (Garmsar, Iran) for routine training postmortem investigation, gingival myiasis was found. Only one larva was removed from the lesions and sent to a parasitology laboratory for identification. For histopathological studies, affected area of the gingiva was cut and placed in 10% formalin, and then sent to pathology laboratory. On parasitological examination the causative agent of this condition was found as larva of Wohlfahrtia magnifica. Histopathological examination of the injured gingiva showed hyperplasia of squamous epithelial tissue and acanthosis in mucosal membrane, hyperemia and infiltration of mononuclear cells and eosinophils into lamina propria. The present report seems to be the first report of gingival myiasis in dog in Iran.

Keywords: Wohlfahrtia magnifica, gingiva, myiasis, dog

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Authors: Vaclav Sadilek, Miroslav Vorechovsky

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The paper deals with the classical fiber bundle model of equal load sharing, sometimes referred to as the Daniels' bundle or the democratic bundle. Daniels formulated a multidimensional integral and also a recursive formula for evaluation of the strength cumulative distribution function. This paper describes three algorithms for evaluation of the recursive formula and also their implementations with source codes in high-level programming language Python. A comparison of the algorithms are provided with respect to execution time. Analysis of orders of magnitudes of addends in the recursion is also provided.

Keywords: equal load sharing, mpmath, python, strength of Daniels' bundle

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Authors: Zulkifli, I. W. Eltara, Anawati

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Understanding the complementary roles of surface energy and roughness on natural nonwetting surfaces has led to the development of a number of biomimetic superhydrophobic surfaces, which exhibit apparent contact angles with water greater than 150 degrees and low contact angle hysteresis. However, superoleophobic surfaces—those that display contact angles greater than 150 degrees with organic liquids having appreciably lower surface tensions than that of water—are extremely rare. In addition to chemical composition and roughened texture, a third parameter is essential to achieve superoleophobicity, namely, re-entrant surface curvature in the form of overhang structures. The overhangs can be realized as fibers. Superoleophobic surfaces are appealing for example, antifouling, since purely superhydrophobic surfaces are easily contaminated by oily substances in practical applications, which in turn will impair the liquid repellency. On the other studied have demonstrate that such aqueous nanofibrillar gels are unexpectedly robust to allow formation of highly porous aerogels by direct water removal by freeze-drying, they are flexible, unlike most aerogels that suffer from brittleness, and they allow flexible hierarchically porous templates for functionalities, e.g. for electrical conductivity. No crosslinking, solvent exchange nor supercritical drying are required to suppress the collapse during the aerogel preparation, unlike in typical aerogel preparations. The aerogel used in current work is an ultralight weight solid material composed of native cellulose nanofibers. The native cellulose nanofibers are cleaved from the self-assembled hierarchy of macroscopic cellulose fibers. They have become highly topical, as they are proposed to show extraordinary mechanical properties due to their parallel and grossly hydrogen bonded polysaccharide chains. We demonstrate that superoleophobic nanocellulose aerogels coating by sol-gel method, the aerogel is capable of supporting a weight nearly 3 orders of magnitude larger than the weight of the aerogel itself. The load support is achieved by surface tension acting at different length scales: at the macroscopic scale along the perimeter of the carrier, and at the microscopic scale along the cellulose nanofibers by preventing soaking of the aerogel thus ensuring buoyancy. Superoleophobic nanocellulose aerogels have recently been achieved using unmodified cellulose nanofibers and using carboxy methylated, negatively charged cellulose nanofibers as starting materials. In this work, the aerogels made from unmodified cellulose nanofibers were subsequently treated with fluorosilanes. To complement previous work on superoleophobic aerogels, we demonstrate their application as cargo carriers on oil, gas permeability, plastrons, and drag reduction, and we show that fluorinated nanocellulose aerogels are high-adhesive superoleophobic surfaces. We foresee applications including buoyant, gas permeable, dirt-repellent coatings for miniature sensors and other devices floating on generic liquid surfaces.

Keywords: superoleophobic, nanocellulose, aerogel, sol-gel

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Authors: Priyankar P. Deka, Sutanu Samanta

Abstract:

This paper describes the development of new class of epoxy based hybrid composites reinforced with jute and filled with rice husk flour. Rice husk flour is added in 0%, 1%, 3%, 5% by weight. Epoxy resin and triethylene tetramine (T.E.T.A) is used as matrix and hardener respectively. It investigates the mechanical properties of the composites and a comparison is done for monolithic jute composite and the filled ones. The specimens are prepared according to the ASTM standards and experimentation is carried out using INSTRON 8801. The result shows that with the increase of filler percentage the tensile properties increases but compressive and flexural properties decreases.

Keywords: jute, mechanical characterization, natural fiber, rice husk

Procedia PDF Downloads 285

Authors: Demet Yavuz

Abstract:

Freeze-thaw cycles are one of the greatest threats to concrete durability. Lately, protection against this threat excites scientists’ attention. Air-entraining admixtures have been widely used to produce freeze-thaw resistant at concretes. The use of air-entraining agents (AEAs) enhances not only freeze-thaw endurance but also the properties of fresh concrete such as segregation, bleeding and flow ability. This paper examines the effects of air-entraining on compressive strength of concrete. Air-entraining is used between 0.05% and 0.4% by weight of cement. One control and four fiber reinforced concrete mixes are prepared and three specimens are tested for each mix. It is concluded from the test results that when air entraining is increased the compressive strength of concrete reduces for all mixes with AEAs.

Keywords: concrete, air-entraining, compressive strength, mechanical properties

Procedia PDF Downloads 277

Authors: Anwar H. Radwan, Jan Mrlina, El-Sayed A. Issawy, Ali Rayan, Salah M. Mahmoud

Abstract:

Geodynamic investigations in the Aswan Lake region were started after the M=5.5 earthquake in 1981, triggered by the lake water fluctuations. Besides establishing the seismological networks, also the geodetic observations focused on the Kalabsha and Sayal fault zones were started. It was found that the Kalabsha fault is an active dextral strike-slip with normal component indicating uplift on its southern side. However, the annual velocity rates in both components do not exceed 2 mm/y, and do not therefore represent extremely active faulting. We also launched gravity monitoring in 1997, and performed another two campaigns in 2000 and 2002. The observed non- tidal temporal gravity changes indicate rather the flood water infiltration into the porous Nubian sandstone, than tectonic stress effect. The station nearest to the lake exhibited about 60 μGal positive gravity change within the 1997-2002 period.

Keywords: gravity monitoring, surface movements, Lake Aswan, groundwater change

Procedia PDF Downloads 503

Authors: Reshma Jolly, Mohammad Shakir, Mohammad Shoeb Khan, Noor E. Iram

Abstract:

A nanocomposite system integrating hydroxyapatite, chitin and starch (n-HA/CT/ST) has been synthesized via co-precipitation approach at room temperature, addressing the issues of biocompatibility, mechanical strength and cytotoxicity required for Bone tissue engineering. The interactions, crystallite size and surface morphology against n-HA/CT (nano-hydroxyapatite/chitin) nanocomposite have been obtained by correlating and comparing the results of FTIR, SEM, TEM and XRD. The comparative study of the bioactivity of n-HA/CT and n-HA/CT/ST nanocomposites revealed that the incorporation of starch as templating agent improved these properties in n-HA/CT/ST nanocomposite. The rise in thermal stability in n-HA/CT/ST nanocomposite as compared to n-HA/CT has been observed by comparing the TGA results. The comparison of SEM images of both the scaffolds indicated that the addition of ST influenced the surface morphology of n-HA/CT scaffold which appeared to be rougher and porous. The MTT assay on murine fibroblast L929 cells and in-vitro bioactivity of n-HA/CT/ST matrix referred superior non-toxic property of n-HA/CT/ST nanocomposite and higher possibility of osteo-integration in-vivo, respectively.

Keywords: bioactive, chitin, hyroxyapatite, nanocomposite

Procedia PDF Downloads 493

Authors: Heungsu Lee, Youngseok Kim, Jonghwa Yi, Chul Park

Abstract:

A landing pier is subjected to safety assessment by visual inspection and design data, but it is difficult to check the damage in real-time. In this study, real - time damage detection and safety evaluation methods were studied. As a result of structural analysis of the arbitrary landing pier structure, the inflection point of deformation and moment occurred at 10%, 50%, and 90% of pile length. The critical value of Fiber Bragg Grating (FBG) sensor was set according to the safety factor, and the FBG sensor application method for real - time safety evaluation was derived.

Keywords: FBG sensor, harbor structure, maintenance, safety evaluation system

Procedia PDF Downloads 218

Authors: Khelil Khadidja

Abstract:

In this paper, blackness of dark solitons is considered. The exact combination between nonlinearity and dispersion is responsible of solitons stability. Dark solitons get born when dispersion is abnormal and balanced by nonlinearity, at the opposite of brillant solitons which is born by normal dispersion and nonlinearity together. Thanks to their stability, dark solitons are suitable for transmission by optical fibers. Dark solitons which are a solution of Nonlinear Schrodinger equation are simulated with Matlab to discuss the influence of coefficient of blackness. Results show that there is a direct proportion between the coefficient of blackness and the intensity of dark soliton. Those gray solitons are stable and convenient for transmission.

Keywords: abnormal dispersion, nonlinearity, optical fiber, soliton

Procedia PDF Downloads 198

Authors: Prakash Kattire, Rahul Pathare, Nilesh Tawde

Abstract:

A canopy is an overhead roof structure generally used at the entrance of a building to provide shelter from rain and sun and may also be used for decorative purposes. In this paper, the canopy structure to cover the conveyor line has been studied. Existing most of the canopy structures are made of steel and glass, which makes a heavier structure, so the purpose of this study is to weight and cost optimization of the canopy. To achieve this goal, the materials of construction considered are Polyvinyl chloride (PVC) natural composite, Fiber Reinforced Plastic (FRP), and Structural steel Fe250. Designing and modeling were done in Solid works, whereas Altair Inspire software was used for the optimization of the structure. Through this study, it was found that there is a total 10% weight reduction in the structure with sufficient reserve for structural strength.

Keywords: canopy, composite, FRP, PVC

Procedia PDF Downloads 146