Search results for: non uniform fiber
1783 Effect of Amount of Crude Fiber in Grass or Silage to the Digestibility of Organic Matter in Suckler Cow Feeding Systems
Authors: Scholz Heiko, Kuhne Petra, Heckenberger Gerd
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Problems during the calving period (December to May) often result in a high body condition score (BCS) at this time. At the end of the grazing period (frequently after early weaning), however, an increase of BCS can often be observed under German conditions. In the last eight weeks before calving, the body condition should be reduced or at least not increased. Rations with a higher amount of crude fiber can be used (rations with straw or late mowed grass silage). Fermentative digestion of fiber is slow and incomplete; that’s why the fermentative process in the rumen can be reduced over a long feeding time. Viewed in this context, feed intake of suckler cows (8 weeks before calving) in different rations and fermentation in the rumen should be checked by taking rumen fluid. Eight suckler cows (Charolais) were feeding a Total Mixed Ration (TMR) in the last eight weeks before calving and grass silage after calving. By the addition of straw (30 % [TMR1] vs. 60 % [TMR2] of dry matter) was varied the amount of crude fiber in the TMR (grass silage, straw, mineral) before calving. After calving of the cow's grass, silage [GS] was fed ad libitum, and the last measurement of rumen fluid took place on the pasture [PS]. Rumen fluid, plasma, body weight, and backfat thickness were collected. Rumen fluid pH was assessed using an electronic pH meter. Volatile fatty acids (VFA), sedimentation, methylene-blue and amount of infusorians were measured. From these 4 parameters, an “index of rumen fermentation” [IRF] in the rumen was formed. Fixed effects of treatment (TMR1, TMR2, GS and PS) and a number of lactations (3-7 lactations) were analyzed by ANOVA using SPSS Version 25.0 (significant by p ≤ 5 %). Rumen fluid pH was significant influenced by variants (TMR 1 by 6.6; TMR 2 by 6.9; GS by 6.6 and PS by 6.9) but was not affected by other effects. The IRF showed disturbed fermentation in the rumen by feeding the TMR 1+2 with a high amount of crude fiber (Score: > 10.0 points) and a very good environment for fermentation during grazing the pasture (Score: 6.9 points). Furthermore, significant differences were found for VFA, methylene blue and the number of infusorians. The use of rations with the high amount of crude fiber from weaning to calving may cause deviations from undisturbed fermentation in the rumen and adversely affect the utilization of the feed in the rumen.Keywords: suckler cow, feeding systems, crude fiber, digestibilty of organic matter
Procedia PDF Downloads 1341782 Continuous Dyeing of Graphene and Polyaniline on Textiles for Electromagnetic Interference Shielding: An Application of Intelligent Fabrics
Authors: Mourad Makhlouf, Meriem Boutamine, Hachemi Hichem, Zoubir Benmaamar, Didier Villemin
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This study explores the use of intelligent textiles for electromagnetic shielding through the continuous dyeing of graphene and polyaniline onto cotton fabric. Graphene was obtained by recycling graphite from spent batteries, and polyaniline was obtained in situ using H2O2. Graphene and polyaniline were bottom-modified on the fiber surface to improve adhesion and achieve a uniform distribution. This study evaluated the effect of the specific gravity percentage on sheet performance and active shielding against electromagnetic interference (EMI). Results showed that the dyed fabrics of graphene, polyaniline, and graphene/polyaniline demonstrated higher conductivity and EMI SE values of 9 to 16 dB in the 8 to 9 GHz range of the X-band, with potential applications in electromagnetic shielding. The use of intelligent textiles offers a sustainable and effective approach to achieving EMI shielding, with the added benefits of recycling waste materials and improving the properties of cotton fabrics.Keywords: 'ntelligent textiles, graphene, polyaniline, electromagnetic shielding, conductivity, recycling.
Procedia PDF Downloads 61781 Tensile Behaviours of Sansevieria Ehrenbergii Fiber Reinforced Polyester Composites with Water Absorption Time
Authors: T. P. Sathishkumar, P. Navaneethakrishnan
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The research work investigates the variation of tensile properties for the sansevieria ehrenbergii fiber (SEF) and SEF reinforced polyester composites respect to various water absorption time. The experiments were conducted according to ATSM D3379-75 and ASTM D570 standards. The percentage of water absorption for composite specimens was measured according to ASTM D570 standard. The fiber of SE was cut in to 30 mm length for preparation of the composites. The simple hand lay-up method followed by compression moulding process adopted to prepare the randomly oriented SEF reinforced polyester composites at constant fiber weight fraction of 40%. The surface treatment was done on the SEFs with various chemicals such as NaOH, KMnO4, Benzoyl Peroxide, Benzoyl Chloride and Stearic Acid before preparing the composites. NaOH was used for pre-treatment of all other chemical treatments. The morphology of the tensile fractured specimens studied using the Scanning Electron Microscopic. The tensile strength of the SEF and SEF reinforced polymer composites were carried out with various water absorption time such as 4, 8, 12, 16, 20 and 24 hours respectively. The result shows that the tensile strength was drop off with increase in water absorption time for all composites. The highest tensile property of raw fiber was found due to lowest moistures content. Also the chemical bond between the cellulose and cementic materials such as lignin and wax was highest due to lowest moisture content. Tensile load was lowest and elongation was highest for the water absorbed fibers at various water absorption time ranges. During this process, the fiber cellulose inhales the water and expands the primary and secondary fibers walls. This increases the moisture content in the fibers. Ultimately this increases the hydrogen cation and the hydroxide anion from the water. In tensile testing, the water absorbed fibers shows highest elongation by stretching of expanded cellulose walls and the bonding strength between the fiber cellulose is low. The load carrying capability was stable at 20 hours of water absorption time. This could be directly affecting the interfacial bonding between the fiber/matrix and composite strength. The chemically treated fibers carry higher load and lower elongation which is due to removal of lignin, hemicellulose and wax content. The water time absorption decreases the tensile strength of the composites. The chemically SEF reinforced composites shows highest tensile strength compared to untreated SEF reinforced composites. This was due to highest bonding area between the fiber/matrix. This was proven in the morphology at the fracture zone of the composites. The intra-fiber debonding was occurred by water capsulation in the fiber cellulose. Among all, the tensile strength was found to be highest for KMnO4 treated SEF reinforced composite compared to other composites. This was due to better interfacial bonding between the fiber-matrix compared to other treated fiber composites. The percentage of water absorption of composites increased with time of water absorption. The percentage weight gain of chemically treated SEF composites at 4 hours to zero water absorption are 9, 9, 10, 10.8 and 9.5 for NaOH, BP, BC, KMnO4 and SA respectively. The percentage weight gain of chemically treated SEF composites at 24 hours to zero water absorption 5.2, 7.3, 12.5, 16.7 and 13.5 for NaOH, BP, BC, KMnO4 and SA respectively. Hence the lowest weight gain was found for KMnO4 treated SEF composites by highest percentage with lowest water uptake. However the chemically treated SEF reinforced composites is possible materials for automotive application like body panels, bumpers and interior parts, and household application like tables and racks etc.Keywords: fibres, polymer-matrix composites (PMCs), mechanical properties, scanning electron microscopy (SEM)
Procedia PDF Downloads 4051780 Dynamic Response of Magnetorheological Fluid Tapered Laminated Beams Reinforced with Nano-Particles
Authors: Saman Momeni, Abolghassem Zabihollah, Mehdi Behzad
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Non-uniform laminated composite structures are being used in many engineering applications where the structures are subjected to unpredicted vibration. To mitigate the vibration response of these structures, recently, magnetorheological fluid (MR), is added to non-uniform (tapered) thickness laminated composite structures to achieve a new generation of the smart composite as MR tapered beam. However, due to the nature of MR fluid, especially the low stiffness, MR tapered beam exhibit lower stiffness and in turn, lower natural frequencies. To achieve the basic design requirements of the structure without MR fluid, one may need to apply a predefined magnetic energy to the structures, requiring a constant source of energy. In the present work, a passive initial stiffness control of MR tapered beam has been studied. The effects of adding nanoparticles on the dynamic response of MR tapered beam has been investigated. It is observed that adding nanoparticles up to 3% may significantly modify the natural frequencies of the structures and achieve dynamic behavior of the structures before addition of MR fluid. Two Models of tapered structures have been taken into consideration. It is observed that adding only 3% of nanoparticles backs the structures to its initial dynamic behavior.Keywords: non uniform laminated structures, MR fluid, nanoparticles, vibration, stiffness
Procedia PDF Downloads 2311779 Modifications in Design of Lap Joint of Fiber Metal Laminates
Authors: Shaher Bano, Samia Fida, Asif Israr
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The continuous development and exploitation of materials and designs have diverted the attention of the world towards the use of robust composite materials known as fiber-metal laminates in many high-performance applications. The hybrid structure of fiber metal laminates makes them a material of choice for various applications such as aircraft skin panels, fuselage floorings, door panels and other load bearing applications. The synergistic effect of properties of metals and fibers reinforced laminates are responsible for their high damage tolerance as the metal element provides better fatigue and impact properties, while high stiffness and better corrosion properties are inherited from the fiber reinforced matrix systems. They are mostly used as a layered structure in different joint configurations such as lap and but joints. The FML layers are usually bonded with each other using either mechanical fasteners or adhesive bonds. This research work is also focused on modification of an adhesive bonded joint as a single lap joint of carbon fibers based CARALL FML has been modified to increase interlaminar shear strength and avoid delamination. For this purpose different joint modification techniques such as the introduction of spews and shoulder to modify the bond shape and use of nanofillers such as carbon nano-tubes as a reinforcement in the adhesive materials, have been utilized to improve shear strength of lap joint of the adhesively bonded FML layers. Both the simulation and experimental results showed that lap joint with spews and shoulders configuration have better properties due to stress distribution over a large area at the corner of the joint. The introduction of carbon nanotubes has also shown a positive effect on shear stress and joint strength as they act as reinforcement in the adhesive bond material.Keywords: adhesive joint, Carbon Reinforced Aluminium Laminate (CARALL), fiber metal laminates, spews
Procedia PDF Downloads 2951778 Study of Ultrasonic Waves in Unidirectional Fiber-Reinforced Composite Plates for the Aerospace Applications
Authors: DucTho Le, Duy Kien Dao, Quoc Tinh Bui, Haidang Phan
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The article is concerned with the motion of ultrasonic guided waves in a unidirectional fiber-reinforced composite plate under acoustic sources. Such unidirectional composite material has orthotropic elastic properties as it is very stiff along the fibers and rather compliant across the fibers. The dispersion equations of free Lamb waves propagating in an orthotropic layer are derived that results in the dispersion curves. The connection of these equations to the Rayleigh-Lamb frequency relations of isotropic plates is discussed. By the use of reciprocity in elastodynamics, closed-form solutions of elastic wave motions subjected to time-harmonic loads in the layer are computed in a simple manner. We also consider the problem of Lamb waves generated by a set of time-harmonic sources. The obtained computations can be very useful for developing ultrasound-based methods for nondestructive evaluation of composite structures.Keywords: lamb waves, fiber-reinforced composite plates, dispersion equations, nondestructive evaluation, reciprocity theorems
Procedia PDF Downloads 1421777 Effect of Air Gap Distance on the Structure of PVDF Hollow Fiber Membrane Contactors for Physical CO2 Absorption
Authors: J. Shiri, A. Mansourizadeh, F. Faghih, H. Vaez
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In this study, porous polyvinylidene fluoride (PVDF) hollow fiber membranes are fabricated via a wet phase-inversion Process and used in the gas–liquid membrane contactor for physical CO2 absorption. Effect of different air gap on the structure and CO2 flux of the membrane was investigated. The hollow fibers were prepared using the wet spinning process using a dope solution containing PVDF/NMP/Licl (18%, 78%, 4%) at the extrusion rate of 4.5ml/min and air gaps of 0, 7, 15cm. Water was used as internal and external coagulants. Membranes were characterized using various techniques such as Field Emission Scanning Electron Microscopy (FESEM), Gas permeation test, Critical Water Entry Pressure (CEPw) to select the best membrane structure for Co2 absorption. The characterization results showed that the prepared membrane at which air gap possess small pore size with high surface porosity and wetting resistance, which are favorable for gas absorption application air gap increased, CEPw had a decrease, but the N2 permeation was decreased. Surface porosity and also Co2 absorption was increased.Keywords: porous PVDF hollow fiber membrane, CO2 absorption, phase inversion, air gap
Procedia PDF Downloads 3861776 Investigation of Delivery of Triple Play Service in GE-PON Fiber to the Home Network
Authors: Anurag Sharma, Dinesh Kumar, Rahul Malhotra, Manoj Kumar
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Fiber based access networks can deliver performance that can support the increasing demands for high speed connections. One of the new technologies that have emerged in recent years is Passive Optical Networks. This paper is targeted to show the simultaneous delivery of triple play service (data, voice and video). The comparative investigation and suitability of various data rates is presented. It is demonstrated that as we increase the data rate, number of users to be accommodated decreases due to increase in bit error rate.Keywords: BER, PON, TDMPON, GPON, CWDM, OLT, ONT
Procedia PDF Downloads 7251775 Localized Analysis of Cellulosic Fibrous Insulation Materials
Authors: Chady El Hachem, Pan Ye, Kamilia Abahri, Rachid Bennacer
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Considered as a building construction material, and regarding its environmental benefits, wood fiber insulation is the material of interest in this work. The definition of adequate elementary representative volume that guarantees reliable understanding of the hygrothermal macroscopic phenomena is very critical. At the microscopic scale, when subjected to hygric solicitations, fibers undergo local dimensionless variations. It is therefore necessary to master this behavior, which affects the global response of the material. This study consists of an experimental procedure using the non-destructive method, X-ray tomography, followed by morphological post-processing analysis using ImageJ software. A refine investigation took place in order to identify the representative elementary volume and the sufficient resolution for accurate structural analysis. The second part of this work was to evaluate the microscopic hygric behavior of the studied material. Many parameters were taken into consideration, like the evolution of the fiber diameters, distribution along the sorption cycle and the porosity, and the water content evolution. In addition, heat transfer simulations based on the energy equation resolution were achieved on the real structure. Further, the problematic of representative elementary volume was elaborated for such heterogeneous material. Moreover, the material’s porosity and its fibers’ thicknesses show very big correlation with the water content. These results provide the literature with very good understanding of wood fiber insulation’s behavior.Keywords: hygric behavior, morphological characterization, wood fiber insulation material, x-ray tomography
Procedia PDF Downloads 2611774 Deformation and Strength of Heat-Shielding Materials in a Long-Term Storage of Aircraft
Authors: Lyudmila L. Gracheva
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Thermal shield is a multi-layer structure that consists of layers made of different materials. The use of composite materials (CM) reinforced with carbon fibers in rocket technologies (shells, bearings, wings, fairings, inter-step compartments, etc.) is due to a possibility of reducing the weight while increasing a structural strength. Structures made of a unidirectional carbon fiber reinforced plastic based on an epoxy resin are used as load-bearing skins for aircraft fairings. The results of an experimental study of the physical and mechanical properties of epoxy carbon fiber reinforced plastics depending on temperature for different storage times of products are presented. With an increasing temperature, the physical and mechanical properties of CM are determined by the thermal and deformation properties of the components and the geometry of their distribution. Samples for the study were cut from natural skins of the head fairings.Keywords: composite material, thermal deformation, carbon fiber, heat shield, epoxy resin, thermal expansion
Procedia PDF Downloads 551773 Effect of Fiber Inclusion on the Geotechnical Parameters of Clayey Soil Subjected to Freeze-Thaw Cycles
Authors: Arun Prasad, P. B. Ramudu, Deep Shikha, Deep Jyoti Singh
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A number of studies have been conducted recently to investigate the influence of randomly oriented fibers on some engineering properties of cohesive soils.Freezing and thawing of soil affects the strength, durability and permeability of soil adversely. Experiments were carried out in order to investigate the effect of inclusion of randomly distributed polypropylene fibers on the strength, hydraulic conductivity and durability of local soil (CL) subjected to freeze–thaw cycles. For evaluating the change in strength of soil, a series of unconfined compression tests as well as tri-axial tests were carried out on reinforced and unreinforced soil samples. All the samples were subjected to seven cycles of freezing and thawing. Freezing was carried out at a temperature of - 15 to -18 °C; and thawing was carried out by keeping the samples at room temperature. The reinforcement of soil samples was done by mixing with polypropylene fibers, 12 mm long and with an aspect ratio of 240. The content of fibers was varied from 0.25 to 1% by dry weight of soil. The maximum strength of soil was found in samples having a fiber content of 0.75% for all the samples that were prepared at optimum moisture content (OMC), and if the OMC was increased (+2% OMC) or decreased (-2% OMC), the maximum strength observed at 0.5% fiber inclusion. The effect of fiber inclusion and freeze–thaw on the hydraulic conductivity was studied increased from around 25 times to 300 times that of the unreinforced soil, without subjected to any freeze-thaw cycles. For studying the increased durability of soil, mass loss after each freeze-thaw cycle was calculated and it was found that samples reinforced with polypropylene fibers show 50-60% less loss in weight than that of the unreinforced soil.Keywords: fiber reinforcement, freezingand thawing, hydraulic conductivity, unconfined compressive strength
Procedia PDF Downloads 3921772 Composite Components Manufacturing in SAE Formula Student, a Case Study of AGH Racing
Authors: Hanna Faron, Wojciech Marcinkowski, Daniel Prusak, Władysław Hamiga
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Interest in composite materials comes out of two basic premises: their supreme mechanical and strength properties,combined with a small specific weight. Origin and evolution of modern composite materials bonds with development of manufacturing of synthetic fibers, which have begun during Second World War. Main condition to achieve intended properties of composite materials is proper bonding of reinforcing layer with appropriate adhesive in manufacturing process. It is one of the fundamental quality evaluation criterion of fabrication processes.Keywords: SAE, formula student, composite materials, carbon fiber, Aramid fiber, hot wire cutter
Procedia PDF Downloads 5061771 Raman Line Mapping on Melt Spun Polycarbonate/MWNT Fiber-Based Nanocomposites
Authors: Poonam Yadav, Dong Bok Lee
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Raman spectroscopy was used for characterization of multi-wall carbon nanotube (MWNT) and Polycarbonate/multi-wall carbon nanotube (PC/MWNT) based fibers with 0.55% and 0.75% of MWNT (PC/MWNT55 and PC/MWNT75). PC/MWNT55 and PC/MWNT75 fibers was prepared by melt spinning device using nanocomposites made by two different route, viz., solvent casting and melt extrusion. Fibers prepared from melt extruded nanocomposites showed smooth and uniform morphology as compared to solvent casting based nanocomposites. The Raman mapping confirmed that the melt extruded based nanocomposites had better dispersion of MWNT in Polycarbonate (PC) than solvent casting carbon nanotube.Keywords: dispersion, melt extrusion, multi-wall carbon nanotube, mapping
Procedia PDF Downloads 3411770 Micromechanics of Stress Transfer across the Interface Fiber-Matrix Bonding
Authors: Fatiha Teklal, Bachir Kacimi, Arezki Djebbar
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The study and application of composite materials are a truly interdisciplinary endeavor that has been enriched by contributions from chemistry, physics, materials science, mechanics and manufacturing engineering. The understanding of the interface (or interphase) in composites is the central point of this interdisciplinary effort. From the early development of composite materials of various nature, the optimization of the interface has been of major importance. Even more important, the ideas linking the properties of composites to the interface structure are still emerging. In our study, we need a direct characterization of the interface; the micromechanical tests we are addressing seem to meet this objective and we chose to use two complementary tests simultaneously. The microindentation test that can be applied to real composites and the drop test, preferred to the pull-out because of the theoretical possibility of studying systems with high adhesion (which is a priori the case with our systems). These two tests are complementary because of the principle of the model specimen used for both the first "compression indentation" and the second whose fiber is subjected to tensile stress called the drop test. Comparing the results obtained by the two methods can therefore be rewarding.Keywords: Fiber, Interface, Matrix, Micromechanics, Pull-out
Procedia PDF Downloads 1141769 Effect of Fibres-Chemical Treatment on the Thermal Properties of Natural Composites
Authors: J. S. S. Neto, R. A. A. Lima, D. K. K. Cavalcanti, J. P. B. Souza, R. A. A. Aguiar, M. D. Banea
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In the last decade, investments in sustainable processes and products have gained space in several segments, such as in the civil, automobile, textile and other industries. In addition to increasing concern about the development of environmentally friendly materials that reduce, energy costs and reduces environmental impact in the production of these products, as well as reducing CO2 emissions. Natural fibers offer a great alternative to replace synthetic fibers, totally or partially, because of their low cost and their renewable source. The purpose of this research is to study the effect of surface chemical treatment on the thermal properties of hybrid fiber reinforced natural fibers (NFRC), jute + ramie, jute + sisal, jute + curauá, and jute fiber in polymer matrices. Two types of chemical treatment: alkalinization and silanization were employed, besides the condition without treatment. Differential scanning calorimetry (DSC), thermogravimetry (TG) and dynamic-mechanical analysis (DMA) were performed to explore the thermal stability and weight loss in the natural fiber reinforced composite as a function of chemical treatment.Keywords: chemical treatment, hybrid composite, jute, thermal
Procedia PDF Downloads 3041768 Detailed Analysis of Multi-Mode Optical Fiber Infrastructures for Data Centers
Authors: Matej Komanec, Jan Bohata, Stanislav Zvanovec, Tomas Nemecek, Jan Broucek, Josef Beran
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With the exponential growth of social networks, video streaming and increasing demands on data rates, the number of newly built data centers rises proportionately. The data centers, however, have to adjust to the rapidly increased amount of data that has to be processed. For this purpose, multi-mode (MM) fiber based infrastructures are often employed. It stems from the fact, the connections in data centers are typically realized within a short distance, and the application of MM fibers and components considerably reduces costs. On the other hand, the usage of MM components brings specific requirements for installation service conditions. Moreover, it has to be taken into account that MM fiber components have a higher production tolerance for parameters like core and cladding diameters, eccentricity, etc. Due to the high demands for the reliability of data center components, the determination of properly excited optical field inside the MM fiber core belongs to the key parameters while designing such an MM optical system architecture. Appropriately excited mode field of the MM fiber provides optimal power budget in connections, leads to the decrease of insertion losses (IL) and achieves effective modal bandwidth (EMB). The main parameter, in this case, is the encircled flux (EF), which should be properly defined for variable optical sources and consequent different mode-field distribution. In this paper, we present detailed investigation and measurements of the mode field distribution for short MM links purposed in particular for data centers with the emphasis on reliability and safety. These measurements are essential for large MM network design. The various scenarios, containing different fibers and connectors, were tested in terms of IL and mode-field distribution to reveal potential challenges. Furthermore, we focused on estimation of particular defects and errors, which can realistically occur like eccentricity, connector shifting or dust, were simulated and measured, and their dependence to EF statistics and functionality of data center infrastructure was evaluated. The experimental tests were performed at two wavelengths, commonly used in MM networks, of 850 nm and 1310 nm to verify EF statistics. Finally, we provide recommendations for data center systems and networks, using OM3 and OM4 MM fiber connections.Keywords: optical fiber, multi-mode, data centers, encircled flux
Procedia PDF Downloads 3731767 Flexural Response of Glass Fiber Reinforced Polymer Sandwich Panels with 3D Woven Honeycomb Core
Authors: Elif Kalkanli, Constantinos Soutis
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The use of textile preform in the advanced fields including aerospace, automotive and marine has exponentially grown in recent years. These preforms offer excellent advantages such as being lightweight and low-cost, and also, their suitability for creating different fiber architectures with different materials whilst improved mechanical properties in certain aspects. In this study, a novel honeycomb core is developed by a 3Dweaving process. The assembly of the layers is achieved thanks to innovative weaving design. Polyester yarn is selected for the 3D woven honeycomb core (3DWHC). The core is used to manufacture a sandwich panel with 2x2 twill glass fiber composite face sheets. These 3DWHC sandwich panels will be tested in three-point bending. The in-plane and out-of-plane (through-the-thickness) mechanical response of the core will be examined as a function of cell size in addition to the flexural response of the sandwich panel. The failure mechanisms of the core and the sandwich skins will be reported in addition to flexural strength and stiffness. Possible engineering applications will be identified.Keywords: 3D woven, assembly, failure modes, honeycomb sandwich panel
Procedia PDF Downloads 1991766 Flexural Strengthening of Steel Beams Using Fiber Reinforced Polymers
Authors: Sally Hosny, Mona G. Ibrahim, N. K. Hassan
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Fiber reinforced polymers (FRP) is one of the most environmentally method for strengthening and retrofitting steel structure buildings. The behaviour of flexural strengthened steel I-beams using FRP was investigated. The finite element (FE) models were developed using ANSYS® as verification cases to simulate the experimental behaviour of using FRP strips to flexure strengthen steel I-beam. Two experimental studies were selected for verification; first examined the effect of different thicknesses and modulus of elasticity while the second studied the effect of applying different carbon fiber reinforced polymers (CFRP) bond lengths. The proposed FE models were in good agreement with the experimental results in terms of failure modes, load bearing capacities and strain distribution on CFRP strips. The verified FE models can be utilized to conduct a parametric study where various widths (40, 50, 60, 70 and 80 mm), thickness (1.2, 2 and 4 mm) and lengths (1500, 1700 and 1800 mm) of CFRP were analyzed. The results presented clearly revealed that the load bearing capacity was significantly increased (+7%) when the width and thickness were increased. However, load bearing capacity was slightly affected using longer CFRP strips. Moreover, applying another glass fiber reinforced polymers (GFRP) of 1500 mm in length, 50 mm in width and thicknesses of 1.2, 2 and 4 mm were investigated. Load bearing capacity of strengthened I-beams using GFRP is less than CFRP by average 8%. Statistical analysis has been conducted using Minitab®.Keywords: FRP, strengthened steel I-beams, flexural, FEM, ANSYS
Procedia PDF Downloads 2741765 Influence of Scrap Tyre Steel Fiber on Mechanical Properties of High Performance Concrete
Authors: Isyaka Abdulkadir, Egbe Ngu-Ntui Ogork
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This research aims to investigate the use of Scrap Tyre Steel Fibers (STSF) for the production of fiber reinforced high performance concrete. The Scrap Tyre Steel Fibers (STSF) were obtained from dealers that extracted the fibers by burning the scrap tyres and were characterized. The effect of STSF was investigated on grade 50 concrete of 1:1.28:1.92 with water cement ratio of 0.39 at additions of STSF of 0, 0.5, 1.0, 1.5, 2.0 and 2.5% by volume of concrete. The fresh concrete was tested for slump while the hardened concrete was tested for compressive and splitting tensile strengths, respectively at curing ages of 3, 7, 28 and 56 days in accordance with standard procedure. The results indicate that slump decreased with increase in STSF, while compressive and splitting tensile strengths increased with increase in STSF up to 1.5% and reduction in strength with increase in STSF above 1.5%. 1.5% STSF was considered as the optimum dosage with a 28 days increase in compressive strength and splitting tensile strength of 12.3% and 43.8% respectively, of control.Keywords: compressive strength, high performance concrete, scrap tyre steel fiber, splitting tensile strength
Procedia PDF Downloads 2061764 Search for APN Permutations in Rings ℤ_2×ℤ_2^k
Authors: Daniel Panario, Daniel Santana de Freitas, Brett Stevens
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Almost Perfect Nonlinear (APN) permutations with optimal resistance against differential cryptanalysis can be found in several domains. The permutation used in the standard for symmetric cryptography (the AES), for example, is based on a special kind of inversion in GF(28). Although very close to APN (2-uniform), this permutation still contains one number 4 in its differential spectrum, which means that, rigorously, it must be classified as 4-uniform. This fact motivates the search for fully APN permutations in other domains of definition. The extremely high complexity associated to this kind of problem precludes an exhaustive search for an APN permutation with 256 elements to be performed without the support of a suitable mathematical structure. On the other hand, in principle, there is nothing to indicate which mathematically structured domains can effectively help the search, and it is necessary to test several domains. In this work, the search for APN permutations in rings ℤ2×ℤ2k is investigated. After a full, exhaustive search with k=2 and k=3, all possible APN permutations in those rings were recorded, together with their differential profiles. Some very promising heuristics in these cases were collected so that, when used as a basis to prune backtracking for the same search in ℤ2×ℤ8 (search space with size 16! ≅244), just a few tenths of a second were enough to produce an APN permutation in a single CPU. Those heuristics were empirically extrapolated so that they could be applied to a backtracking search for APNs over ℤ2×ℤ16 (search space with size 32! ≅2117). The best permutations found in this search were further refined through Simulated Annealing, with a definition of neighbors suitable to this domain. The best result produced with this scheme was a 3-uniform permutation over ℤ2×ℤ16 with only 24 values equal to 3 in the differential spectrum (all the other 968 values were less than or equal 2, as it should be the case for an APN permutation). Although far from being fully APN, this result is technically better than a 4-uniform permutation and demanded only a few seconds in a single CPU. This is a strong indication that the use of mathematically structured domains, like the rings described in this work, together with heuristics based on smaller cases, can lead to dramatic cuts in the computational resources involved in the complexity of the search for APN permutations in extremely large domains.Keywords: APN permutations, heuristic searches, symmetric cryptography, S-box design
Procedia PDF Downloads 1521763 Experimental Investigation of Low Strength Concrete (LSC) Beams Using Carbon Fiber Reinforce Polymer (CFRP) Wrap
Authors: Furqan Farooq, Arslan Akbar, Sana Gul
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Inadequate design of seismic structures and use of Low Strength Concrete (LSC) remains the major aspect of structure failure. Parametric investigation (LSC) beams based on experimental work using externally applied Carbon Fiber Reinforce Polymer (CFRP) warp in flexural behavior is studied. The ambition is to know the behavior of beams under loading condition, and its strengthening enhancement after inducing crack is studied, Moreover comparison of results using abacus software is studied. Results show significant enhancement in load carrying capacity, experimental work is compared with abacus software. The research is based on the conclusion that various existing structure but inadequacy in seismic design could increase the load carrying capacity by applying CFRP techniques, which not only strengthened but also provide them to resist even larger potential earthquake by improving its strength as well as ductility.Keywords: seismic design, carbon fiber, strengthening, ductility
Procedia PDF Downloads 1901762 Arthroscopic Assisted Fibertape Technique For Recurrent MPFL Reconstruction - Case Series Done In The UK Population
Authors: Naufal Ahmed, Michael Lwin
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Background: MPFL reconstructions are ideally performed with au-tografts like gracilis semitendinosus tendon, which may be associated with donor site morbidity and complications. In this case series, we have tried to use fiber tape, which avoids the above complications and also keeps the graft virgin. This kind of synthetic graft has been used successfully in rotator cuffs and ACJ reconstructions with good results. Materials and methods: It was a retrospective data analysis of 45 patients who underwent this procedure from 2014-2020 under a single consultant in a DGH . These patiens have been followed up at 6 weeks, 6 months, 1 year, and 1 ½ years with clinical assessment and KOOS scores. We compared the results with the NJR and also with the Belgium report and was found to be satisfactory and comparable with them. Surgical technique : We used Arthrex fiber tape for the reconstruction of MPFL . Initially, two parallel holes drilled over sup aspect of the patella with help of an image intensifier, and then fiber wire passed through them from the medial to the lateral side and back to the medial side. The fiber wire was attached to the schottle point on the femoral side, giving a good extra articular internal brac-ing to the MPFL. All patients were scoped before the procedure, and the final tightening over the femoral side was done directly under vision to see the position of the patella. Results: We had 45 MPFL reconstructions along with 4 additional procedures 1 ACLR, 2 ACL REPAIR, 1 TTT advancement ( revision MPFL ). There were 14 males and 31 females, and their average age was 25 (13-55 ). We did not have any donor site morbidity, no infection, no fractures, no recurrent dislocations, no reoperations yet. Conclusion: Fiber tape is a feasible and appropriate option for MPFL reconstruction. We haven’t seen any re -operation in our 5 year follow up. This technique avoids the use of autograft, which can be used in the future if needed for revision surgeries. We don’t lose anything by following this simple novel technique.Keywords: arthroscopy, fibertape, MPFL reconstruction, recurrent patella dislocation
Procedia PDF Downloads 1351761 Vibrations of Thin Bio Composite Plates
Authors: Timo Avikainen, Tuukka Verho
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The use of natural fibers as reinforcements is growing increasingly in polymers which are involved in e.g. structural, vibration, and acoustic applications. The use of bio composites is being investigated as lightweight materials with specific properties like the ability to dissipate vibration energy and positive environmental profile and are thus considered as potential replacements for synthetic composites. The macro-level mechanical properties of the biocomposite material depend on several parameters in the detailed architecture and morphology of the reinforcing fiber structure. The polymer matrix phase is often applied to remain the fiber structure in touch. A big role in the packaging details of the fibers is related to the used manufacturing processes like extrusion, injection molding and treatments. There are typically big variances in the detailed parameters of the microstructure fibers. The study addressed the question of how the multiscale simulation methodology works in bio composites with short pulp fibers. The target is to see how the vibro – acoustic performance of thin–walled panels can be controlled by the detailed characteristics of the fiber material. Panels can be used in sound-producing speakers or sound insulation applications. The multiscale analysis chain is tested starting from the microstructural level and continuing via macrostructural material parameters to the product component part/assembly levels. Another application is the dynamic impact type of loading, exposing the material to the crack type damages that is in this study modeled as the Charpy impact tests.Keywords: bio composite, pulp fiber, vibration, acoustics, impact, FEM
Procedia PDF Downloads 701760 Immobilization of Lead in Contaminated Soil Using Enzyme Induced Calcite Precipitation (EİCP) Along with Coconut Fiber Biochar (CFB)
Authors: Kaniz Roksana, Aluthgun Hewage Shaini, Cheng Zhu
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Lead is environmentally hazardous because it may persist for a long time in soil, water, and air, and it can travel large distances when carried by wind or water. Lead is toxic to many different species of organisms and has the potential to disrupt ecosystem stability. Moreover, lead can contaminate crops and livestock, which can then have an adverse effect on human health. This study was conducted to use the enzyme-induced calcium carbonate precipitation (EICP) technique from soybean crude extract urease along coconut fiber derived biochar’s (CFB) to bioremediate lead. To study the desorption rates of heavy metals from the soil, lead (Pb) was added to the soil at load ratios of 50 and 100 mg/kg. There were five separate treatment soil columns created: control sample, only CFB, only EICP, EICP with 2% (w/w) CFB, and EICP with 4% (w/w) CFB. Laboratory scale experiment demonstrates significant lead removal from soil. The amount of CaCO₃ precipitated in the soil was measured using a gravimetric acid digestion test, which related heavy metal desorption to the amount of precipitated calcium carbonate. These findings were validated using a scanning electron microscope (SEM), which revealed calcium carbonate and lead coprecipitation. As a result, the study reveals that the EICP technique, in conjunction with coconut fiber biochar, could be an efficient alternative in the remediation of heavy metal ion-contaminated soils.Keywords: enzyme induced calcium carbonate precipitation (EICP), coconut fiber derived biochar’s (CFB), bioremediation, heavy metal
Procedia PDF Downloads 661759 Properties Modification of Fiber Metal Laminates by Nanofillers
Authors: R. Eslami-Farsani, S. M. S. Mousavi Bafrouyi
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During past decades, increasing demand of modified Fiber Metal Laminates (FMLs) has stimulated a strong trend towards the development of these structures. FMLs contain several thin layers of metal bonded with composite materials. Characteristics of FMLs such as low specific mass, high bearing strength, impact resistance, corrosion resistance and high fatigue life are attractive. Nowadays, increasing development can be observed to promote the properties of polymer-based composites by nanofillers. By dispersing strong, nanofillers in polymer matrix, modified composites can be developed and tailored to individual applications. On the other hand, the synergic effects of nanoparticles such as graphene and carbon nanotube can significantly improve the mechanical, electrical and thermal properties of nanocomposites. In present paper, the modifying of FMLs by nanofillers and the dispersing of nanoparticles in the polymers matrix are discussed. The evaluations have revealed that this approach is acceptable. Finally, a prospect is presented. This paper will lead to further work on these modified FML species.Keywords: fiber metal laminate, nanofiller, polymer matrix, property modification
Procedia PDF Downloads 2001758 Evaluation of Rhus lancea and Celtis africana as Browse for Mixed-Feeders in Captivity
Authors: France Phiri, Arnold Kanengoni, Dawood Hattas, Khanyisile Mbatha
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A study was carried out to determine seasonal changes in fiber composition and condensed tannin (CT) concentrations in Rhus lancea and Celtis africana and their effects on feed intake and blood metabolites in mixed-feeders. Rhus lancea and C. africana were analysed for dry matter (DM), acid detergent lignin (ADL), acid detergent fiber (ADF), neutral detergent fiber (NDF) and CT concentrations over four seasons; early wet (EWS), late wet (LWS), early dry (EDS) and late dry (LDS). Twelve indigenous male goats were kept in metabolic crates for periods of 21 days per season and fed one of two diet combinations; the test diet comprised R. lancea and C. africana (denoted as BROWSE) and the lucerne diet comprised lucerne (Medicago sativa and concentrates (CON). Feed intake, body weight and blood metabolites were determined in all goats over each study period. Goats fed BROWSE in the EDS, LDS and LWS lost weight while goats fed CON gained weight (P < 0.05). Goats fed CON had higher urea, alkaline phosphatase and gamma-glutamyl transferase concentrations than those fed BROWSE (P < 0.05). Creatinine and cholesterol concentrations in all goats across LWS, EDS and LDS were lower than the normal range, while total protein and globulin concentrations were higher. The goats fed BROWSE had higher creatinine concentrations (P < 0.05) than those fed CON. Cholesterol concentrations were higher (P < 0.05) in goats fed BROWSE than in those on CON fed. It was concluded that goats fed BROWSE lost weight, indicating insufficient nutrients for maintenance requirements.Keywords: fiber, maintenance, condense tannins, blood metabolites
Procedia PDF Downloads 1871757 Matrix Completion with Heterogeneous Cost
Authors: Ilqar Ramazanli
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The matrix completion problem has been studied broadly under many underlying conditions. The problem has been explored under adaptive or non-adaptive, exact or estimation, single-phase or multi-phase, and many other categories. In most of these cases, the observation cost of each entry is uniform and has the same cost across the columns. However, in many real-life scenarios, we could expect elements from distinct columns or distinct positions to have a different cost. In this paper, we explore this generalization under adaptive conditions. We approach the problem under two different cost models. The first one is that entries from different columns have different observation costs, but within the same column, each entry has a uniform cost. The second one is any two entry has different observation cost, despite being the same or different columns. We provide complexity analysis of our algorithms and provide tightness guarantees.Keywords: matroid optimization, matrix completion, linear algebra, algorithms
Procedia PDF Downloads 991756 Effect of Synthetic Jet on Wind Turbine Noise
Authors: Reda Mankbadi
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The current work explores the use of Synthetic Jet Actuators (SJAs) for control of the acoustic radiation of a low-speed transitioning airfoil in a uniform stream. In the adopted numerical procedure, the actuator is modeled without its resonator cavity through imposing a simple fluctuating-velocity boundary condition at the bottom of the actuator's orifice. The orifice cavity, with the properly defined boundary condition, is then embedded into the airfoil surface. High-accuracy viscous simulations are then conducted to study the effects of the actuation on sound radiated by the airfoil. Results show that SJA can considerably suppress the radiated sound of the airfoil in uniform incoming stream.Keywords: simulations, aeroacoustics, wind turbine noise, synthetic jet actuators (SJAs)
Procedia PDF Downloads 3471755 Numerical Solution of Manning's Equation in Rectangular Channels
Authors: Abdulrahman Abdulrahman
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When the Manning equation is used, a unique value of normal depth in the uniform flow exists for a given channel geometry, discharge, roughness, and slope. Depending on the value of normal depth relative to the critical depth, the flow type (supercritical or subcritical) for a given characteristic of channel conditions is determined whether or not flow is uniform. There is no general solution of Manning's equation for determining the flow depth for a given flow rate, because the area of cross section and the hydraulic radius produce a complicated function of depth. The familiar solution of normal depth for a rectangular channel involves 1) a trial-and-error solution; 2) constructing a non-dimensional graph; 3) preparing tables involving non-dimensional parameters. Author in this paper has derived semi-analytical solution to Manning's equation for determining the flow depth given the flow rate in rectangular open channel. The solution was derived by expressing Manning's equation in non-dimensional form, then expanding this form using Maclaurin's series. In order to simplify the solution, terms containing power up to 4 have been considered. The resulted equation is a quartic equation with a standard form, where its solution was obtained by resolving this into two quadratic factors. The proposed solution for Manning's equation is valid over a large range of parameters, and its maximum error is within -1.586%.Keywords: channel design, civil engineering, hydraulic engineering, open channel flow, Manning's equation, normal depth, uniform flow
Procedia PDF Downloads 2091754 Reactive Fabrics for Chemical Warfare Agent Decomposition Using Particle Crystallization
Authors: Myungkyu Park, Minkun Kim, Sunghoon Kim, Samgon Ryu
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Recently, research for reactive fabrics which have the characteristics of CWA (Chemical Warfare Agent) decomposition is being performed actively. The performance level of decomposition for CWA decomposition in various environmental condition is one of the critical factors in applicability as protective materials for NBC (Nuclear, Biological, and Chemical) protective clothing. In this study, results of performance test for CWA decomposition by reactive fabric made of electrospinning web and reactive particle are presented. Currently, the MOF (metal organic framework) type of UiO-66-NH₂ is frequently being studied as material for decomposing CWA especially blister agent HD [Bis(2-chloroethyl) sulfide]. When we test decomposition rate with electrospinning web made of PVB (Polyvinyl Butiral) polymer and UiO-66-NH₂ particle, we can get very high protective performance than the case other particles are applied. Furthermore, if the repellant surface fabric is added on reactive material as the component of protective fabric, the performance of layer by layered reactive fabric could be approached to the level of current NBC protective fabric for HD decomposition rate. Reactive fabric we used in this study is manufactured by electrospinning process of polymer which contains the reactive particle of UiO-66-NH₂, and we performed crystalizing process once again on that polymer fiber web in solvent systems as a second step for manufacturing reactive fabric. Three kinds of polymer materials are used in this process, but PVB was most suitable as an electrospinning fiber polymer considering the shape of product. The density of particle on fiber web and HD decomposition rate is enhanced by secondary crystallization compared with the results which are not processed. The amount of HD penetration by 24hr AVLAG (Aerosol Vapor Liquid Assessment Group) swatch test through the reactive fabrics with secondary crystallization and without crystallization is 24 and 146μg/cm² respectively. Even though all of the reactive fiber webs for this test are combined with repellant surface layer at outer side of swatch, the effects of secondary crystallization of particle for the reactive fiber web are remarkable.Keywords: CWA, Chemical Warfare Agent, gas decomposition, particle growth, protective clothing, reactive fabric, swatch test
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