Search results for: Fiber Bragg Gratings

Authors: R. Z. R. R. Rosdin, N. M. Ali, S. W. Harun, H. Arof

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We have experimentally demonstrated bright-dark pulses in a nonlinear polarization rotation (NPR) based mode-locked Erbium-doped fiber laser (EDFL) with a long cavity configuration. Bright–dark pulses could be achieved when the laser works in the passively mode-locking regime and the net group velocity dispersion is quite anomalous. The EDFL starts to generate a bright pulse train with degenerated dark pulse at the mode-locking threshold pump power of 35.09 mW by manipulating the polarization states of the laser oscillation modes using a polarization controller (PC). A split bright–dark pulse is generated when further increasing the pump power up to 37.95 mW. Stable bright pulses with no obvious evidence of a dark pulse can also be generated when further adjusting PC and increasing the pump power up to 52.19 mW. At higher pump power of 54.96 mW, a new form of bright-dark pulse emission was successfully identified with the repetition rate of 29 kHz. The bright and dark pulses have a duration of 795.5 ns and 640 ns, respectively.

Keywords: Erbium-doped fiber laser, nonlinear polarization rotation, bright-dark pulse, photonic

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Authors: Ashkan Shafee, Ahamd Fahimifar, Sajjad V. Maghvan

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Promotion of the Fiber Reinforced Concrete (FRC) as a construction material for civil engineering projects has invoked numerous researchers to investigate their mechanical behavior. Even though there is satisfactory information about the effects of fiber type and length, concrete mixture, casting type and other variables on the strength and deformability parameters of FRC, the numerical modeling of such materials still needs research attention. The focus of this study is to investigate the feasibility of Concrete Damaged Plasticity (CDP) model in prediction of Macro-synthetic FRC structures behavior. CDP model requires the tensile behavior of concrete to be well characterized. For this purpose, a series of uniaxial direct tension and four point bending tests were conducted on the notched specimens to define bilinear tension softening (post-peak tension stress-strain) behavior. With these parameters obtained, the flexural behavior of macro-synthetic FRC beams were modeled and the results showed a good agreement with the experimental measurements.

Keywords: concrete damaged plasticity, fiber reinforced concrete, finite element modeling, macro-synthetic fibers, uniaxial tensile test

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Authors: Amrit Pal Singh Arora

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The paper reports the results of a study undertaken to study the effects of addition of steel fibres of different aspect ratios on the permeability and strength characteristics of steel fiber reinforced fly ash concrete (SFRC). Corrugated steel fibres having a diameter of 0.6 mm and lengths of 12.5 mm, 30 mm and 50 mm were used in this study. Cube samples of 100 mm x 100 mm x 100 mm were cast from mixes replacing 0%, 10%, 20% and 30% cement content by fly ash with and without fibres and tested for the determination of coefficient of water permeability, compressive and split tensile strengths after 7 and 28 days of curing. Plain concrete samples were also cast and tested for reference purposes. Permeability was observed to decrease significantly for all concrete mixes with the addition of steel fibers as compared to plain concrete. The replacement of cement content by fly ash results in an increase in the coefficient of water permeability. With the addition of fly ash to the plain mix the7 day compressive and split tensile strengths decreased, however both the compressive and split tensile strengths increased with increase in curing age.

Keywords: curing age, fiber shape, fly ash, Darcy’s law, Ppermeability

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Authors: Sofie Verstraete, Stijn Debruyne, Frederik Desplentere

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Considering environmental issues, the interest to apply sustainable materials in industry increases. Specifically for composites, there is an emerging need for suitable materials and bonding techniques. As an alternative to traditional composites, short bio-fiber (cellulose-based flax) reinforced Polylactic Acid (PLA) is gaining popularity. However, these thermoplastic based composites show issues in adhesive bonding. This research focusses on analyzing the effects of the fibers near the bonding interphase. The research applies injection molded plate structures. A first important parameter concerns the fiber volume fraction, which directly affects adhesion characteristics of the surface. This parameter is varied between 0 (pure PLA) and 30%. Next to fiber volume fraction, the orientation of fibers near the bonding surface governs the adhesion characteristics of the injection molded parts. This parameter is not directly controlled in this work, but its effects are analyzed. Surface roughness also greatly determines surface wettability, thus adhesion. Therefore, this research work considers three different roughness conditions. Different mechanical treatments yield values up to 0.5 mm. In this preliminary research, only one adhesive type is considered. This is a two-part epoxy which is cured at 23 °C for 48 hours. In order to assure a dedicated parametric study, simple and reproduceable adhesive bonds are manufactured. Both single lap (substrate width 25 mm, thickness 3 mm, overlap length 10 mm) and double lap tests are considered since these are well documented and quite straightforward to conduct. These tests are conducted for the different substrate and surface conditions. Dog bone tensile testing is applied to retrieve the stiffness and strength characteristics of the substrates (with different fiber volume fractions). Numerical modelling (non-linear FEA) relates the effects of the considered parameters on the stiffness and strength of the different joints, obtained through the abovementioned tests. Ongoing work deals with developing dedicated numerical models, incorporating the different considered adhesion parameters. Although this work is the start of an extensive research project on the bonding characteristics of thermoplastic bio-fiber reinforced composites, some interesting results are already prominent. Firstly, a clear correlation between the surface roughness and the wettability of the substrates is observed. Given the adhesive type (and viscosity), it is noticed that an increase in surface energy is proportional to the surface roughness, to some extent. This becomes more pronounced when fiber volume fraction increases. Secondly, ultimate bond strength (single lap) also increases with increasing fiber volume fraction. On a macroscopic level, this confirms the positive effect of fibers near the adhesive bond line.

Keywords: adhesive bonding, bio-fiber reinforced composite, flax fibers, lap joint

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Authors: Anurag Sharma, Rahul Malhotra, Love Kumar, Harjit Pal Singh

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This paper demonstrates OCDM-ROF based hybrid architecture where data/voice communication is enabled via a permutation of Optical Code Division Multiplexing (OCDM) and Radio-over-Fiber (RoF) techniques under various diverse conditions. OCDM-RoF hybrid network of 16 users with DPSK modulation format has been designed and performance of proposed network is analyzed for 100, 150, and 200 km fiber span length under the influence of linear and nonlinear effect. It has been reported that Polarization Mode Dispersion (PMD) has the least effect while other nonlinearity affects the performance of proposed network.

Keywords: OCDM, RoF, DPSK, PMD, eye diagram, BER, Q factor

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Authors: Dhval Chauhan, Mahesh Chudasama

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This study has been undertaken to give a review of Polyethylene Terephthalate Glycol (PETG) material used in Fused Deposition Modelling (FDM). This paper offers a review of the existing literature on polyethylene terephthalate glycol (PETG) material, the objective of the paper is to providing guidance on different process parameters that can be used to improve the strength of the part by performing various testing like tensile, compressive, flexural, etc. This work is target to find new paths that can be used for further development of the use of fiber reinforcement in PETG material.

Keywords: PETG, FDM, tensile strength, flexural strength, fiber reinforcement

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Authors: Pinghe Wang

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In this paper, we demonstrate a tunable long-cavity passive mode-locked fiber laser. The mode locker is a nonlinear amplifying loop mirror (NALM). The cavity frequency of the laser is 465 kHz because that 404m SMF is inserted in the cavity. A tunable bandpass filter with ~1nm 3dB bandwidth is inserted into the cavity to realize tunable mode locking. The passive mode-locked laser at a fixed wavelength is investigated in detail. The experimental results indicate that the laser operates in dissipative soliton resonance (DSR) region. When the pump power is 400mW, the laser generates the rectangular pulses with 10.58 ns pulse duration, 70.28nJ single-pulse energy. When the pump power is 400mW, the laser keeps stable mode locking status in the range from 1523.4nm to 1575nm. During the whole tuning range, the SNR, the pulse duration, the output power and single pulse energy have a little fluctuation because that the gain of the EDF changes with the wavelength.

Keywords: fiber laser, dissipative soliton resonance, mode locking, tunable

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Authors: Mochamad Chalid, Imam Prabowo

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The pollution due to non-degradable material such as plastics, has led to studies about the development of environmental-friendly material. Because of biodegradability obtained from natural sources, polylactid acid (PLA) and ijuk fiber are interesting to modify into a composite. This material is also expected to reduce the impact of environmental pollution. Surface modification of ijuk fiber through alkalinization with 0.25 M NaOH solution for 30 minutes, was aimed to enhance it’s compatibility to PLA, in order to improve properties of the composite such as the mechanical properties. Alkalinization of the ijuk fibers annihilates some surface components such as lignin, wax and hemicelloluse, so the pore on the surface clearly appeared, decreasing of the density and diameter of the ijuk fibers. The change of the ijuk fiber properties leads to increase the mechanical properties of PLA composites reinforced the ijuk fibers through strengthening of the mechanical interlocking with the PLA matrix. An addition to enhance the distribution of the fibers in the PLA matrix, the stirring during DCM solvent evaporation from the mixture of the ijuk fibers and the dissolved-PLA can reduce amount of the trapped-voids and fibers pull-out phenomena, which can decrease the mechanical properties of the composite.

Keywords: polylactic acid, Arenga pinnata, alkalinization, compatibility, adhesion, morphology, mechanical properties, volume fraction, distributiom

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Authors: Petros M. Chronopoulos, Evangelos Z. Astreinidis

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A major issue of the structural assessment and rehabilitation of existing RC structures is the inadequate lap-splicing of the longitudinal reinforcement. Although prohibited by modern Design Codes, the practice of arranging lap-splices inside the critical regions of RC elements was commonly applied in the past. Today this practice is still the rule, at least for conventional new buildings. Therefore, a lot of relevant research is ongoing in many earthquake prone countries. The rehabilitation of deficient lap-splices of RC elements by means of external confinement is widely accepted as the most efficient technique. If correctly applied, this versatile technique offers a limited increase of flexural capacity and a considerable increase of local ductility and of axial and shear capacities. Moreover, this intervention does not affect the stiffness of the elements and does not affect the dynamic characteristics of the structure. This technique has been extensively discussed and researched contributing to vast accumulation of technical and scientific knowledge that has been reported in relevant books, reports and papers, and included in recent Design Codes and Guides. These references are mostly dealing with modeling and redesign, covering both the enhanced (axial and) shear capacity (due to the additional external closed hoops or jackets) and the increased ductility (due to the confining action, preventing the unzipping of lap-splices and the buckling of continuous reinforcement). An analytical and experimental program devoted to RC members with lap-splices is completed in the Lab. of RC/NTU of Athens/GR. This program aims at the proposal of a rational and safe theoretical model and the calibration of the relevant Design Codes’ provisions. Tests, on forty two (42) full scale specimens, covering mostly beams and columns (not walls), strengthened or not, with adequate or inadequate lap-splices, have been already performed and evaluated. In this paper, the results of twelve (12) specimens under fully reversed cyclic actions are presented and discussed. In eight (8) specimens the lap-splices were inadequate (splicing length of 20 or 30 bar diameters) and they were retrofitted before testing by means of additional external confinement. The two (2) most commonly applied confining materials were used in this study, namely steel and FRPs. More specifically, jackets made of CFRP wraps or light cages made of mild steel were applied. The main parameters of these tests were (i) the degree of confinement (internal and external), and (ii) the length of lap-splices, equal to 20, 30 or 45 bar diameters. These tests were thoroughly instrumented and monitored, by means of conventional (LVDTs, strain gages, etc.) and innovative (optic fibre-Bragg-grating) sensors. This allowed for a thorough investigation of the most influencing design parameter, namely the hoop-stress developed in the confining material. Based on these test results and on comparisons with the provisions of modern Design Codes, it could be argued that shorter (than the normative) lap-splices, commonly found in old structures, could still be effective and safe (at least for lengths more than an absolute minimum), depending on the required ductility, if a properly arranged and adequately detailed external confinement is applied.

Keywords: concrete, fibre-Bragg-grating sensors, lap-splices, retrofitting / rehabilitation

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Authors: Sana Rezig, Yosr Ben Mlik, Mounir Jaouadi, Foued Khoffi, Slah Msahli, Bernard Durand

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Increasing interest in environmental concerns, natural fibers are once again being considered as reinforcements for polymer composites. The main objective of this study is to explore another natural resource, Typha fiber; which is renewable without production cost and available abundantly in nature. The aim of this study was to study the flexural properties of composite resin with and without reinforcing Typha leaf and stem fibers. The specimens were made by the hand-lay-up process using polyester matrix. In our work, we focused on the effect of various treatment conditions (sea water, alkali treatment and a combination of the two treatments), as a surface modifier, on the flexural properties of the Typha fibers reinforced polyester composites. Moreover, weight ratio of Typha leaf or stem fibers was investigated. Besides, both fibers from leaf and stem of Typha plant were used to evaluate the reinforcing effect. Another parameter, which is reinforcement structure, was investigated. In fact, a first composite was made with air-laid nonwoven structure of fibers. A second composite was with a mixture of fibers and resin for each kind of treatment. Results show that alkali treatment and combined process provided better mechanical properties of composites in comparison with fiber treated by sea water. The fiber weight ratio influenced the flexural properties of composites. Indeed, a maximum value of flexural strength of 69.8 and 62,32 MPa with flexural modulus of 6.16 and 6.34 GPawas observed respectively for composite reinforced with leaf and stem fibers for 12.6 % fiber weight ratio. For the different treatments carried out, the treatment using caustic soda, whether alone or after retting seawater, show the best results because it improves adhesion between the polyester matrix and the fibers of reinforcement. SEM photographs were made to ascertain the effects of the surface treatment of the fibers. By varying the structure of the fibers of Typha, the reinforcement used in bulk shows more effective results as that used in the non-woven structure. In addition, flexural strength rises with about (65.32 %) in the case of composite reinforced with a mixture of 12.6% leaf fibers and (27.45 %) in the case of a composite reinforced with a nonwoven structure of 12.6 % of leaf fibers. Thus, to better evaluate the effect of the fiber origin, the reinforcing structure, the processing performed and the reinforcement factor on the performance of composite materials, a statistical study was performed using Minitab. Thus, ANOVA was used, and the patterns of the main effects of these parameters and interaction between them were established. Statistical analysis, the fiber treatment and reinforcement structure seem to be the most significant parameters.

Keywords: flexural properties, fiber treatment, structure and weight ratio, SEM photographs, Typha leaf and stem fibers

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Authors: Ricardo Mendoza, Jason Briceño, Juan F. Santa, Gabriel Peluffo, Mauricio Márquez, Beatriz Cardozo, Carlos Gutiérrez

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The most common controlled method to obtain impact strength of composites materials is performing a Charpy Impact Test which consists of a pendulum with calibrated mass and length released from a known height. In fact, composites components experience impact events in normal operations such as when a tool drops or a foreign object strikes it. These events are categorized into low velocity impact (LVI) which typically occurs at velocities below 10m/s. In this study, the major aim was to calculate the absorbed energy during the impact. Tests were performed on three types of composite panels: fiberglass laminated panels, coir fiber reinforced polyester and coir fiber reinforced polyester subjected to water immersion for 48 hours. Coir fibers were obtained in local plantations of the Caribbean coast of Colombia. They were alkali treated in 5% aqueous NaOH solution for 2h periods. Three type of shape impactors were used on drop-weight impact test including hemispherical, ogive and pointed. Failure mechanisms and failure modes of specimens were examined using an optical microscope. Results demonstrate a reduction in absorbed energy correlated with the increment of water absorption of the panels. For each level of absorbed energy, it was possible to associate a different fracture state. This study compares results of energy absorbed obtained from two impact test methods.

Keywords: coir fiber, polyester composites, low velocity impact, Charpy impact test, drop-weight impact test

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Authors: Amessalu Atenafu Gelaw, Nele Rath

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Currently, laser hardening process is becoming among the most efficient and effective hardening technique due to its significant advantages. The source where heat is generated, the absence of cooling media, self-quenching property, less distortion nature due to localized heat input, environmental friendly behavior and less time to finish the operation are among the main benefits to adopt this technology. This day, a variety of injection machines are used in plastic, textile, electrical and mechanical industries. Due to the fast growing of composite technology, fiber reinforced polymer matrix becoming optional solution to use in these industries. Due, to the abrasion nature of fiber reinforced polymer matrix composite on the injection components, many parts are outdated before the design period. Niko, a company specialized in injection molded products, suffers from the short lifetime of the injection nozzles of the molds, due to the use of fiber reinforced and, therefore, more abrasive polymer matrix. To prolong the lifetime of these molds, hardening the susceptible component like the injecting nozzles was a must. In this paper, the laser hardening process is investigated on Unimax, a type of stainless steel. The investigation to get optimal results for the nozzle-case was performed in three steps. First, the optimal parameters for maximum possible hardenability for the investigated nozzle material is investigated on a flat sample, using experimental testing as well as thermal simulation. Next, the effect of an inclination on the maximum temperature is analyzed both by experimental testing and validation through simulation. Finally, the data combined and applied for the nozzle. This paper describes possible strategies and methods for laser hardening of the nozzle to reach hardness of at least 720 HV for the material investigated. It has been proven, that the nozzle can be laser hardened to over 900 HV with the option of even higher results when more precise positioning of the laser can be assured.

Keywords: absorptivity, fiber reinforced matrix, laser hardening, Nd:YAG laser

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Authors: Hammad Khalid

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In this paper, a strategy for computerized arranging of Fiber to the Home (FTTH) get to systems is proposed. We presented an efficient methodology for arranging access organize framework. The GIS information and a lot of calculations were utilized to make the arranging procedure increasingly programmed. The technique clarifies various strides of the arranging process. Considering various situations, various designs can be produced by utilizing the technique. It was likewise conceivable to produce the designs in an extremely brief temporal contrast with the conventional arranging. A contextual investigation is considered to delineate the utilization and abilities of the arranging technique. The technique, be that as it may, doesn't completely robotize the arranging however, make the arranging procedure fundamentally quick. The outcomes and dialog are displayed and end is given at last.

Keywords: FTTH, GIS, robotize, plan

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Authors: Peyman Sheikholharam Mashhadi

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Difficulties in analyzing real world images in classical image processing and machine vision framework have motivated researchers towards considering the biology-based vision. It is a common belief that mammalian visual cortex has been adapted to the statistics of the real world images through the evolution process. There are two well-known successful models of mammalian visual cortical cells: Independent Component Analysis (ICA) and Independent Subspace Analysis (ISA). In this paper, we statistically analyze the dependencies which remain in the components after applying these models to the natural images. Also, we investigate the response of feature detectors to gratings with various parameters in order to find optimal parameters of the feature detectors. Finally, the selectiveness of feature detectors to phase, in both models is considered.

Keywords: statistics, independent component analysis, independent subspace analysis, phase, natural images

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Authors: H. Alamri

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Natural fiber reinforced composites have attracted researchers for their desirable properties of toughness, high modulus, low density, recyclability, and renewability. In fact, the use of natural fibers in polymer composites has the potential to produce materials with higher specific strength and specific modulus due of their low density. Likewise, polymer-nano-filler composites have been widely investigated for their unique and significant improvement in strength, modulus, impact strength, barrier properties, heat resistance and thermal stability. In this paper, The addition of halloysite nanotubes (HNTs) with three different weight percentages (1%, 3% and 5%) on enhancing barrier and flexural strength and modulus of cellulose-fiber (CF) /epoxy composites after water treatment for six months was studied. Results indicated that water uptake decreased as HNT content increased. The presence of HNT improved flexural strength and flexural modulus of CF/epoxy composites. SEM results showed damages in fiber-matrix interfacial bonding due to water absorption. The addition of HNTs was found to enhance to adhesion between fibers and matrix.

Keywords: mechanical properties, epoxy, nanocomposites, halloysite nanotubes

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Authors: J. Nyenhuis, J. Drelich

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This research study was designed to determine if food crops could be bio-fortified with micro-nutrients by growing sprouts on mineral fortified fiber mats. Diets high in processed foods have been found to lack essential micro-nutrients for optimum human development and overall health. Some micro-nutrients such as copper (Cu) have been found to enhance the inflammatory response through its oxidative functions, thereby having a role in cardiovascular disease (CVD), metabolic syndrome (MetS), diabetes and related complications. Recycled cellulose fibers and clay saturated with micro-nutrient ions can be converted to a novel mineral-metal hybrid material in which the fiber mat becomes a carrier of essential micro-nutrients. The reduction of ionic to metallic copper was accomplished using hydrogen at temperatures ranging from 400o to 600oC. Copper particles with diameters ranging from ~1 to 400-500 nm reside on the recycled fibers that make up the mats. Seeds purchased from a commercial, organic supplier were germinated on the specially engineered cellulose fiber mats that incorporated w10 wt% clay fillers saturated with either copper particles or ionic copper. After the appearance of the first leaves, the sprouts were dehydrated and analyzed for Cu content. Nutrient analysis showed 1.5 to 1.6 increase in Cu of the sprouts grown on the fiber mats with copper particles, and 2.3 to 2.5 increase on mats with ionic copper as compared to the control samples. The antibacterial properties of materials saturated with copper ions at room temperature and at temperatures up to 400°C have been verified with halo method tests against Escherichia Coli in previous studies. E. coli is a known pathogenic risk in sprout production. Copper exhibits excellent antibacterial properties when tested on S. aureus, a pathogenic gram-positive bacterium. This has also been confirmed for the fiber-copper hybrid material in this study. This study illustrates the potential for the use of engineered mats as a viable way to increase the micro-nutrient composition of locally-grown food crops and the need for additional research to determine the uptake, nutritional implications and risks of micro-nutrient bio-fortification.

Keywords: bio-fortification, copper nutrient analysis, micro-nutrient uptake, sprouts and mineral-fortified mats

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Authors: Ammari Abdelhammid

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This work on the characterization of structural elements in metal fiber concrete is devoted to the study of recyclability, as reinforcement for concrete, of chips resulting from the machining of steel parts. We're interested in this study to the Rheological behavior of fresh chips reinforced concrete and its mechanical behavior at a young age. The evaluation of the workability with the LCL workabilimeter shows that optimal sand gravel ratios ( S/G) are S/G = 0.8 and S/G = 1. The study of the content chips (W%) influence on the workability of the concrete shows that the flow time and the S/G optimum increase with W%. For S/G = 1.4, the flow time is practically insensitive to the variation of W%, the concrete behavior is similar to that of self-compacting concrete. Mechanical characterization tests (direct tension, compression, bending, and splitting) show that the mechanical properties of chips concrete are comparable to those of the two selected reference concretes (concrete reinforced with conventional fibers: Eurosteel fibers corrugated and Dramix fibers). Chips provide a significant increase in strength and some ductility in the post-failure behavior of the concrete. Recycling chips as reinforcement for concrete can be favorably considered.

Keywords: fiber concrete, chips, workability, direct tensile test, compression test, bending test, splitting test

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Authors: N. Ouslimani, M. T. Abadlia

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Environment protection is a precondition for sustained growth and a better quality of life for all people on earth. Aqueous industrial effluents are the main sources of pollution. Among the compounds of these effluents, dyes are particularly resistant to discoloration by conventional methods, and discharges present many problems that must be supported. The scientific literature shows that synthetic organic dyes are compounds used in many industrial sectors. They are found in the chemical, car, paper industry and particularly the textile industry, where all the lines and grades of the chemical family are represented. The affinity between the fibers and dyes vary depending on the chemical structure of dyes and the type of materials to which they are applied. It is not uncommon to find that during the dyeing operation from 15 to 20 % of sulfur dyes, and sometimes up to 40 % of the reactants are discharged with the effluent. This study was conducted for the purpose of fading basics dyes from wastewater using as adsorbent fiber waste material. This technique presents an interesting alternative to usual treatment, as it allows the recovery of waste fibers, which can find uses as raw material for the manufacture of cleaning products or in other sectors In this study the results obtained by fading fiber waste are encouraging, given the rate of color removal which is about 90%.This method also helps to decrease BOD and suspended solids MES in an effective way.

Keywords: adsorption, dyes, fiber, valorization, wastewater

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Authors: Sharifah Nabihah Syed Jaafar, Umar Adli Amran, Rasidi Roslan, Chia Chin Hua, Sarani Zakaria

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Bio-composites derived from plant fiber and bio-derived polymer, are likely more ecofriendly and demonstrate competitive performance with petroleum based. In this research, the green phenolic resin was used as a matrix and oil palm empty fruit bunch fiber (EFB) was used as filler. The matrix was synthesized from soda lignin, phenol and hydrochloric acid as a catalyst. The phenolic resin was synthesized via liquefaction and condensation to enhance the combination of phenol during the process. Later, the phenolic resin was mixed with EFB by using mechanical stirrer and was molded with hot press at 180 oC. In this research, the composites were prepared with EFB content of 5%, 10%, 15% and 20%. The samples that viewed under scanning electron microscopy (SEM) showed that the EFB filler remained embedded in the resin. From impact and hardness testing, samples 10% of EFB showed the optimum properties meanwhile sample 15% showed the optimum properties for flexural testing. Thermal stability of the composites was investigated using thermogravimetric (TGA) analysis and found that the weight loss and the activation energy (Ea) of the composites samples were decreased as the filler content increased.

Keywords: EFB, liquefaction, phenol formaldehyde, lignin

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Authors: S. Yousefi Oderji, B. Chen, M. A. Yazdi, J. Yang

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This study investigates the influence of water-binder ratio, mineral admixtures (silica fume and ground granulated blast furnace slag), and copper coated steel fiber on fluidity diameter, compressive and flexural strengths of reactive powder concrete (RPC). The test results show that the binary combination of silica fume and blast-furnace slag provided a positive influence on the mechanical properties of RPC. Although the addition of fibers reduced the workability, results indicated a higher mechanical strength in the inclusion of fibers.

Keywords: RPC, steel fiber, fluidity, mechanical properties

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Authors: Cristina S. Decano, Vitaliana U. Malamug, Melissa E. Agulto, Helen F. Gavino

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This study aimed to introduce new natural fiber to be used in the production of geotextile net for mitigation of soil erosion. Fiber extraction from the stalks was the main challenge faced during the processing of stalks to ropes. Thus, an investigation on the extraction procedures of corn (Zea mays L.) stalk under biological and chemical retting was undertaken. Results indicated significant differences among percent fiber yield as affected by the retting methods used with values of 15.07%, 12.97%, 11.60%, and 9.01%, for dew, water, chemical (1 day after harvest and15 days after harvest), respectively, with the corresponding average extracting duration of 70, 82, 89, and 94 minutes. Physical characterization of the developed corn stalk geotextile net resulted to average mass per unit area of 806.25 g/m² and 241% water absorbing capacity. The effect of corn stalk geotextile net in mitigating soil erosion was evaluated in a laboratory experiment for 30^o and 60^o inclinations with three treatments: bare soil (A₁), corn stalk geotextile net (A₂) and combined cornstalk geotextile net and vegetation cover (A₃). Results revealed that treatment A₂ and A₃ significantly decreased sediment yield and an increase in terms of soil loss reduction efficiency. The cost of corn stalk geotextile net is Php 62.41 per square meter.

Keywords: corn stalk, natural geotextile, retting, soil erosion

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Authors: Sofina Faith C. Navarro, Luke V. Subala, Rica H. Gatus, Alfonzo Ramon DG. Burguete

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Roof tiles, as integral components of buildings, play a crucial role in protecting structures from many things. The study focuses on the production of sustainable roof tiles that address the waste disposal challenges associated with Manila clam shells and mitigate the environmental impact of conventional roof tile materials. Various concentrations of roof tiles are developed, incorporating different proportions of powdered clam shell that contains calcium carbonate and shredded raffia palm fiber. Subsequently, the roof tiles are cast using standard methods and transported to the University of the Philippines Institute of Civil Engineering (UP-ICE) for flexural strength testing. In conclusion, the research aimed to assess the flexural durability of concrete roof tiles with varying concentrations of Raffia Palm Fiber and Manila Clam Shells additives. The findings indicate notable differences in maximum load capacities among the specimens, with C3.1 emerging as the concentration with the highest load-bearing capacity at 313.59729 N. This concentration, with a flexural strength of 2.15214, is identified as the most durable option, with a slightly heavier weight of 1.10 kg. On the other hand, C2.2, with a flexural strength of 0.366 and a weight of 0.80 kg, is highlighted for its impressive durability performance while maintaining a lighter composition. Therefore, for the production of concrete roof tile, C3.1 is recommended for optimal durability, while C2.2 is suggested as a preferable option considering both durability and lightweight characteristics.

Keywords: raffia palm fiber, flexural strength, lightweightness, Manila Clam Shells

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Authors: Alfonzo Ramon Burguete, Rica Gatus, Sofina Faith Navarro, Luke Subala

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Roof tiles, as integral components of buildings, play a crucial role in protecting structures from many things. The study focuses on the production of sustainable roof tiles that address the waste disposal challenges associated with Manila clam shells and mitigate the environmental impact of conventional roof tile materials. Various concentrations of roof tiles are developed, incorporating different proportions of powdered clam shell that contains calcium carbonate and shredded raffia palm fiber. Subsequently, the roof tiles are cast using standard methods and transported to the University of the Philippines Institute of Civil Engineering (UP-ICE) for flexural strength testing. In conclusion, the research aimed to assess the flexural durability of concrete roof tiles with varying concentrations of Raffia Palm Fiber and Manila Clam Shells additives. The findings indicate notable differences in maximum load capacities among the specimens, with C3.1 emerging as the concentration with the highest load-bearing capacity at 313.59729 N. This concentration, with a flexural strength of 2.15214, is identified as the most durable option, with a slightly heavier weight of 1.10 kg. On the other hand, C2.2, with a flexural strength of 0.366 and a weight of 0.80 kg, is highlighted for its impressive durability performance while maintaining a lighter composition. Therefore, for the production of concrete roof tile C3.1 is recommended for optimal durability, while C2.2 is suggested as a preferable option considering both durability and lightweight characteristics.

Keywords: manila clam shells, raffia palm fiber, flexural strength, lightweightness

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Authors: Tatiana Franco, Hugo A. Estupinan

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Banana pseudostem fiber (BPF) and pineapple leaf fiber (PLF) for their excellent mechanical properties and biodegradability characteristics arouse interest in different areas of research. F In tropical regions, where the banana pseudostem and the pineapple leaf are transformed into hard-to-handle solid waste, they can be low-cost raw material and environmentally sustainable in research for composite materials. In terms of functionality of this type of fiber, an open structure would allow the adsorption and retention of organic, inorganic and metallic species. In general, natural fibers have closed structures on their surface with intricate internal arrangements that can be used for the solution of environmental problems and other technological uses, however it is not possible to access their internal structure and sublayers, exposing the fibers in the natural state. An alternative method to chemical and enzymatic treatment are the processes with the plasma treatments, which are known to be clean, economical and controlled. In this type of treatment, a gas contained in a reactor in the form of plasma acts on the fiber generating changes in its structure, morphology and topography. This work compares the effects on fibers of PLF and BPF treated with cold argon plasma, alternating time and current. These fibers are grown in the regions of Antioquia-Colombia. The morphological, compositional and wettability properties of the fibers were analyzed by Raman microscopy, contact angle measurements, scanning electron microscopy (SEM) and atomic force microscopy analysis (AFM). The treatment with cold plasma on PLF and BPF allowed increasing its wettability, the topography and the microstructural relationship between lignin and cellulose.

Keywords: cold plasma, contact angle, natural fibers, Raman, SEM, wettability

Procedia PDF Downloads 156

Authors: Ravi Kant, Banshi D. Gupta

Abstract:

The unbridled application of insecticides to enhance agricultural yield has become a matter of grave concern to both the environment and the human health and, thus pose a potential threat to sustainable development. Fenitrothion is an extensively used organophosphate insecticide whose residues are reported to be extremely toxic for birds, humans and aquatic life. A sensitive, swift and accurate detection protocol for fenitrothion is, thus, highly demanded. In this work, we report an SPR based fiber optic sensor for the detection of fenitrothion, where a nanocomposite arrangement of Ta2O5 and reduced graphene oxide (rGO) (Ta₂O₅: rGO) decorated on silver coated unclad core region of an optical fiber forms the sensing channel. A nanocomposite arrangement synergistically integrates the properties of involved components and consequently furnishes a conducive framework for sensing applications. The modification of the dielectric function of the sensing layer on exposure to fenitrothion solutions of diverse concentration forms the sensing mechanism. This modification is reflected in terms of the shift in resonance wavelength. Experimental variables such as the concentration of rGO in the nanocomposite configuration, dip time of silver coated fiber optic probe for deposition of sensing layer and influence of pH on the performance of the sensor have been optimized to extract the best performance of the sensor. SPR studies on the optimized sensing probe reveal the high sensitivity, wide operating range and good reproducibility of the fabricated sensor, which unveil the promising utility of Ta₂O₅: rGO nanocomposite framework for developing an efficient detection methodology for fenitrothion. FOSPR approach in cooperation with nanomaterials projects the present work as a beneficial approach for fenitrothion detection by imparting numerous useful advantages such as sensitivity, selectivity, compactness and cost-effectiveness.

Keywords: surface plasmon resonance, optical fiber, sensor, fenitrothion

Procedia PDF Downloads 208

Authors: Yasemin Seki, Aysun Akşit

Abstract:

The goal of this research is to modify the surface characterization of jute yarns with different chemical agents to improve the compatibility with a non-polar polymer, polypropylene, when used as reinforcement. A literature review provided no knowledge on surface treatment of jute fibers with sodium perborate trihydrate. This study also aims to compare the efficiency of sodium perborate trihydrate on jute fiber treatment with other commonly used chemical agents. Accordingly, jute yarns were treated with 0.02% potassium dichromate (PD), potassium permanganate (PM) and sodium perborate trihydrate (SP) aqueous solutions in order to enhance interfacial compatibility with polypropylene in this study. The effect of treatments on surface topography, surface chemistry and interfacial shear strength of jute yarns with polypropylene were investigated. XPS results revealed that surface treatments enhanced surface hydrophobicity by increasing C/O ratios of fiber surface. Surface roughness values increased with the treatments. The highest interfacial adhesion with polypropylene was achieved after SP treatment by providing the highest surface roughness values and hydrophobic character of jute fiber.

Keywords: jute, chemical modification, sodium perborate, polypropylene

Procedia PDF Downloads 508

Authors: J. L. Liu, L. Wang, B. Zhu, J. Zhou, W. D. Gao

Abstract:

Fabric textures are very common in our daily life. However, we never explore the representation of fabric textures from neuroscience view. Theoretical studies suggest that primary visual cortex (V1) uses a sparse code to efficiently represent natural images. However, how the simple cells in V1 encode the artificial textures is still a mystery. So, here we will take fabric texture as stimulus to study the response of independent component analysis that is established to model the receptive field of simple cells in V1. Experimental results based on 140 classical fabric images indicate that the receptive fields of simple cells have obvious selectivity in orientation, frequency, and phase when drifting gratings are used to determine their tuning properties. Additionally, the distribution of optimal orientation and frequency shows that the patch size selected from each original fabric image has a significant effect on the frequency selectivity.

Keywords: fabric texture, receptive filed, simple cell, spare coding

Procedia PDF Downloads 475

Authors: Dhiaadin Bahaadin Noory

Abstract:

This research involves the effect of both sizes of reinforced zone and the amount of polypropylene fiber reinforcement on the structural behavior of model-reinforced sand loaded by square footing. The ratio of the side of the square reinforced zone to the footing width (W/B) and the ratio of the square reinforced zone depth to footing width (H/B) has been varied from one to six and from one to three, respectively. The tests were carried out on a small-scale laboratory model in which uniform-graded sand was used as a fill material. It was placed in a highly dense state by hitting a thin wooden board placed on the sand surface with a hammer. The sand was reinforced with randomly oriented discrete fibrillated polypropylene fibers. The test results indicated a significant increase in the bearing capacity and stiffness of the subgrade and a modification of load–the settlement behavior of sand with the size of the reinforced zone and amount of fiber reinforcement. On the basis of the present test results, the optimal side width and depth of the reinforced zone were 4B and 2B, respectively, while the optimal percentage of fibers was 0.4%.

Keywords: square footing, polypropylene fibers, bearing capacity, stiffness, load settlement behavior, relative density

Procedia PDF Downloads 64

Authors: Navid Zarif Karimi, Giangiacomo Minak, Parnian Kianfar

Abstract:

Drilling is one of the most frequently used machining process for glass fiber reinforced polymer composites due to the need for structural joining. In drilling of composite laminates, interlaminar cracking, or delamination, has a detrimental effect on the compressive strength of these materials. The delamination can be controlled by adopting proper drilling condition. In this paper, the effect of feed rate, cutting speed and drill point angle on delamination and residual compressive strength of drilled GFRPs is studied. The objective is to find optimal conditions for maximum residual compressive strength.

Keywords: composite material, delamination, drilling, residual compressive strength

Procedia PDF Downloads 458

Authors: Hee Jae Shin, Lee Ku Kwac, In Pyo Cha, Min Sang Lee, Hyun Kyung Yoon, Hong Gun Kim

Abstract:

In rapid industrial development has increased the demand for high-strength and lightweight materials. Thus, various CFRP (Carbon Fiber Reinforced Plastics) with composite materials are being used. The design variables of CFRP are its lamination direction, order, and thickness. Thus, the hardness and strength of CFRP depend much on their design variables. In this paper, the lamination direction of CFRP was used to produce a symmetrical ply [0°/0°, -15°/+15°, -30°/+30°, -45°/+45°, -60°/+60°, -75°/+75°, and 90°/90°] and an asymmetrical ply [0°/15°, 0°/30°, 0°/45°, 0°/60° 0°/75°, and 0°/90°]. The bending flexure stress of the CFRP specimen was evaluated through a bending test. Its thermal property was measured using an infrared camera. The symmetrical specimen and the asymmetrical specimen were analyzed. The results showed that the asymmetrical specimen increased the bending loads according to the increase in the orientation angle; and from 0°, the symmetrical specimen showed a tendency opposite the asymmetrical tendency because the tensile force of fiber differs at the vertical direction of its load. Also, the infrared camera showed that the thermal property had a trend similar to that of the mechanical properties.

Keywords: Carbon Fiber Reinforced Plastic (CFRP), bending test, infrared camera, composite

Procedia PDF Downloads 398