Search results for: Fiber Bragg Gratings

Authors: Bhupeshwaran Mani, S. Radha, A. Jawahar, A. Sivasubramanian

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Here, we study the characteristic feature of conventional (ON-OFF keying) and soliton based transmission system. We consider 20 Gbps transmission system implemented with Conventional Single Mode Fiber (C-SMF) to examine the role of Gaussian pulse which is the characteristic of conventional propagation and hyperbolic-secant pulse which is the characteristic of soliton propagation in it. We note the influence of these pulses with respect to different dispersion lengths and soliton period in conventional and soliton system, respectively, and evaluate the system performance in terms of quality factor. From the analysis, we could prove that the soliton pulse has more consistent performance even for long distance without dispersion compensation than the conventional system as it is robust to dispersion. For the length of transmission of 200 Km, soliton system yielded Q of 33.958 while the conventional system totally exhausted with Q=0.

Keywords: dispersion length, retrun-to-zero (rz), soliton, soliton period, q-factor

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Authors: Jafaru Ibrahim, Tonga Agadi Danladi, Haruna Sani

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Many telecommunications industry are looking for new ways to maximize their investment in communication networks while ensuring reliable and secure information transmission. There is a variety of communications medium solutions, the two must popularly in used are wireless technology and wired options, such as copper and fiber-optic cable. Wired network has proven its potential in the olden days but nowadays wireless communication has emerged as a robust and most intellect and preferred communication technique. Each of these types of communication medium has their advantages and disadvantages according to its technological characteristics. Wired and wireless networking has different hardware requirements, ranges, mobility, reliability and benefits. The aim of the paper is to compare both the Wired and Wireless medium on the basis of various parameters such as usability, cost, efficiency, flexibility, coverage, reliability, mobility, speed, security etc.

Keywords: cost, mobility, reliability, speed, security, wired, wireless

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Authors: K. Khadidja

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Solitons are stable solution of nonlinear Schrodinger equation. Their stability is due to the exact combination between nonlinearity and dispersion which causes pulse broadening. Higher order solitons are born when nonlinear length is N multiple of dispersive length. Soliton order is determined by the number N itself. In this paper, evolution of higher order solitons is illustrated by simulation using Matlab. Results show that higher order solitons change their shape periodically, the reason why they are bad for transmission comparing to fundamental solitons which are constant. Partial analysis of a soliton of higher order explains that the periodic shape is due to the interplay between nonlinearity and dispersion which are not equal during a period. This class of solitons has many applications such as generation of supercontinuum and the impulse compression on the Femtosecond scale. As a conclusion, the periodicity which is harmful to transmission can be beneficial in other applications.

Keywords: dispersion, nonlinearity, optical fiber, soliton

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Authors: Ammar Maziz, Mostapha Tarfaoui, Said Rechak

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The high mechanical performance of composite pipes can be adversely affected by their low resistance to impact loads. Loads in dynamic origin are dangerous and cause consequences on the operation of pipes because the damage is often not detected and can affect the structural integrity of composite pipes. In this work, an advanced 3-D finite element (FE) model, based on the use of intralaminar damage models was developed and used to predict damage under low-velocity impact. The performance of the numerical model is validated with the confrontation with the results of experimental tests. The results show that at low impact energy, the damage happens mainly by matrix cracking and delamination. The model capabilities to simulate the low-velocity impact events on the full-scale composite structures were proved.

Keywords: composite materials, low velocity impact, FEA, dynamic behavior, progressive damage modeling

Procedia PDF Downloads 172

Authors: Murat Yucel, Murat Yucel, Nail Ferhat Ozturk, Halim Haldun Goktas, Cemal Gemci, Fatih Vehbi Celebi

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In this study, Brillouin gain spectrum (BGS) is experimentally analyzed in the Brillouin optical time domain reflectometry (BOTDR) and Brillouin optical time domain analyzer (BOTDA). For this purpose, the signal level of the microwave generator is varied and the effects of BGS are investigated. In the setups, 20 km conventional single mode fiber is used to both setups and laser wavelengths are selected around 1550 nm. To achieve best results, it can be used between 5 dBm to 15 dBm signal level of microwave generator for BOTDA and BOTDR setups.

Keywords: microwave signal level, Brillouin gain spectrum, BOTDA, BOTDR

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Authors: Jintang Zhou, Zhengjun Yao, Tiantian Yao

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Li₀.₃₅Zn₀.₃Fe₂.₃₅O₄(LZFO) grafted with polyaniline (PANI) fibers was synthesized by in situ polymerization. FTIR, XRD, SEM, and vector network analyzer were used to investigate chemical composition, micro-morphology, electromagnetic properties and microwave absorbing properties of the composite. The results show that PANI fibers were grafted on the surfaces of LZFO particles. The reflection loss exceeds 10 dB in the frequency range from 2.5 to 5 GHz and from 15 to 17GHz, and the maximum reflection loss reaches -33 dB at 15.9GHz. The enhanced microwave absorption properties of LZFO/PANI-fiber composites are mainly ascribed to the combined effect of both dielectric loss and magnetic loss and the improved impedance matching.

Keywords: Li₀.₃₅Zn₀.₃Fe₂.₃₅O₄, polyaniline, electromagnetic properties, microwave absorbing properties

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Authors: Rachid El Aidani, Phuong Nguyen-Tri, Toan Vu-Khanh

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This study intends to show the influence of the hydrolytic degradation on the properties of the e-PTFE/NOMEX® membranes used in fire-protective clothing. The modification of water vapour permeability, morphology and chemical structure was examined by MOCON Permatran, electron microscopy scanning (SEM), and ATR-FTIR, respectively. A decrease in permeability to water vapour of the aged samples was observed following closure of transpiration pores. Analysis of fiber morphology indicates the appearance of defects at the fibers surface with the presence of micro cavities as well as the of fibrils. ATR-FTIR analysis reveals the presence of a new absorption band attributed to carboxylic acid terminal groups generated during the amide bond hydrolysis.

Keywords: hydrolytic ageing, moisture membrane, water vapor permeability, morphology

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Authors: Yassir M. Abbas, Mohammad Iqbal Khan, Galal Fare

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In the present work, the structural responses of 12 ultrahigh-performance concrete (UHPC) beams to four-point loading conditions were experimentally and analytically studied. The inclusion of a fibrous system in the UHPC material increased its compressive and flexural strengths by 31.5% and 237.8%, respectively. Based on the analysis of the load-deflection curves of UHPC beams, it was found that UHPC beams with a low reinforcement ratio are prone to sudden brittle failure. This failure behavior was changed, however, to a ductile one in beams with medium to high ratios. The implication is that improving UHPC beam tensile reinforcement could result in a higher level of safety. More reinforcement bars also enabled the load-deflection behavior to be improved, particularly after yielding.

Keywords: ultrahigh-performance concrete, moment capacity, RC beams, hybrid fiber, ductility

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Authors: Asim Cengiz, Dede Basturk, Hakan Ozalp

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Practicing recurring resistance workout such as may cause changes in human muscle. These changes may be because combination if several factors determining physical fitness. Thus, it is important to identify these changes. Several studies were reviewed to investigate these changes. As a result, the changes included positive modifications in amplified citrate synthase (CS) maximal activity, increased capacity for pyruvate oxidation, improvement on molecular signaling on human performance, amplified resting muscle glycogen and whole GLUT4 protein content, better health outcomes such as enhancement in cardiorespiratory fitness. Sprint training also have numerous long long-term changes inhuman body such as better enzyme action, changes in muscle fiber and oxidative ability. This is important because SV is the critical factor influencing maximal cardiac output and therefore oxygen delivery and maximal aerobic power.

Keywords: sprint, training, performance, exercise

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Authors: Sh. Minapoor, S. Ajeli

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Non-crimp three-dimensional (3D) orthogonal carbon fabrics are one of the useful textiles reinforcements in composites. In this paper, flexural and bending properties of a carbon non-crimp 3D orthogonal woven reinforcement are experimentally investigated. The present study is focused on the understanding and measurement of the main bending parameters including flexural stress, strain, and modulus. For this purpose, the three-point bending test method is used and the load-displacement curves are analyzed. The influence of some weave's parameters such as yarn type, geometry of structure, and fiber volume fraction on bending behavior of non-crimp 3D orthogonal carbon fabric is investigated. The obtained results also represent a dataset for the simulation of flexural behavior of non-crimp 3D orthogonal weave carbon composite reinforcement.

Keywords: non-crimp 3D orthogonal weave, carbon composite reinforcement, flexural behavior, three-point bending

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Authors: E. Fereydouni, Laleh Maleknia , M. E. Olya

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The present research, nylon fabric dyed by pressure method with nano-Si, nano-Ti particles and SiO2-TiO2 nancomposite. The influence of the amount of Si, Ti and SiO2-TiO2 on the performance of nylon fabric was investigated by the use of Fourier transform infrared spectrophotometer (FTIR), horizontal flammability apparatus (HFA), scanning electron microscope (SEM), electron dispersive X-ray spectroscope (EDX), water contact angle tester (WCA) and CIE LAB colorimetric system. The possible interactions between particles and nylon fiber were elucidated by the FTIR spectroscopy. Results indicated that the stabilized nanoparticles and nanocomposite enhances flame retardancy of nylon fabrics. Also, the prominet features of nanoparticles and nanocomposite treatment can note increase of adsorption and fixation of dye.

Keywords: nano-Si, nano- Ti, SiO2-TiO2 nancomposite, nylon fabric, flame retardant nylon

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Authors: Janjira Triped, Wipada Sanongraj, Wipawee Khamwichit

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The research work covered in this study includes the morphological structure and optical properties of TiO2-coated silk fibroin (SF) filters at 2.5% wt. TiO2/vol. PVA solution. SEM micrographs revealed the fibrous morphology of the TiO2-coated SF filters. An average diameter of the SF fiber was estimated to be approximately 10µm. Also, it was confirmed that TiO2 can be adhered more on SF filter surface at higher TiO2 dosages. The activity of semiconductor materials was studied by UV-VIS spectrophotometer method. The spectral data recorded shows the strong cut off at 390 nm. The calculated band-gap energy was about 3.19 eV. The photocatalytic activity of the filter was tested for gaseous formaldehyde removal in a modeling room with the total volume of 2.66 m3. The highest removal efficiency (54.72 ± 1.75%) was obtained at the initial formaldehyde concentration of about 5.00 ± 0.50ppm.

Keywords: photocatalytic oxidation process, formaldehyde (HCHO), silk fibroin (SF), titanium dioxide (TiO2)

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Authors: Laura Gonzalez, Santiago Benavides, Martha Elena Londono, Ana Elisa Casas, Adriana Restrepo-Osorio

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Cotton products are sensitive to microorganisms due to its ability to retain moisture, which might cause change into the coloration, mechanical properties reduction or foul odor generation; consequently, this represents risks to the health of users. Nowadays, have been carried out researches to give antibacterial properties to textiles using different strategies, which included the use of silver nanoparticles (AgNPs). The antibacterial behavior can be affected by laundering process reducing its effectiveness. In the other way, the environmental impact generated for the synthetic antibacterial agents has motivated to seek new and more ecological ways for produce AgNPs. The aims of this work are to determine the antibacterial activity of cotton fabric functionalized with green (G) and commercial (C) AgNPs after twenty washing cycles, also to evaluate morphological and color changes. A plain weave cotton fabric suitable for dyeing and two AgNPs solutions were use. C a commercial product and G produced using an ecological method, both solutions with 0.5 mM concentration were impregnated on cotton fabric without stabilizer, at a liquor to fabric ratio of 1:20 in constant agitation during 30min and then dried at 70 °C by 10 min. After that the samples were subjected to twenty washing cycles using phosphate-free detergent simulated on agitated flask at 150 rpm, then were centrifuged and dried on a tumble. The samples were characterized using Kirby-Bauer test determine antibacterial activity against E. coli y S. aureus microorganisms, the results were registered by photographs establishing the inhibition halo before and after the washing cycles, the tests were conducted in triplicate. Scanning electron microscope (SEM) was used to observe the morphologies of cotton fabric and treated samples. The color changes of cotton fabrics in relation to the untreated samples were obtained by spectrophotometer analysis. The images, reveals the presence of inhibition halo in the samples treated with C and G AgNPs solutions, even after twenty washing cycles, which indicated a good antibacterial activity and washing durability, with a tendency to better results against to S. aureus bacteria. The presence of AgNPs on the surface of cotton fiber and morphological changes were observed through SEM, after and before washing cycles. The own color of the cotton fiber has been significantly altered with both antibacterial solutions. According to the colorimetric results, the samples treated with C lead to yellowing while the samples modified with G to red yellowing Cotton fabrics treated AgNPs C and G from 0.5 mM solutions exhibited excellent antimicrobial activity against E. coli and S. aureus with good laundering durability effects. The surface of the cotton fibers was modified with the presence of AgNPs C and G due to the presence of NPs and its agglomerates. There are significant changes in the natural color of cotton fabric due to deposition of AgNPs C and G which were maintained after laundering process.

Keywords: antibacterial property, cotton fabric, fastness to wash, Kirby-Bauer test, silver nanoparticles

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Authors: C. N. Okafor, M. Maaza, T. A. E. Mokrani

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A proton exchange membrane has been developed for Direct Methanol Fuel Cell (DMFC). The nanofiber network composite membranes were prepared by interconnected network of Nafion (perfuorosulfonic acid) nanofibers that have been embedded in an uncharged and inert polymer matrix, by electro-spinning. The spinning solution of Nafion with a low concentration (1 wt. % compared to Nafion) of high molecular weight poly(ethylene oxide), as a carrier polymer. The interconnected network of Nafion nanofibers with average fiber diameter in the range of 160-700nm, were used to make the membranes, with the nanofiber occupying up to 85% of the membrane volume. The matrix polymer was cross-linked with Norland Optical Adhesive 63 under UV. The resulting membranes showed proton conductivity of 0.10 S/cm at 25°C and 80% RH; and methanol permeability of 3.6 x 10-6 cm2/s.

Keywords: composite membrane, electrospinning, fuel cell, nanofibers

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Authors: Hamed Khosravi, Reza Eslami-Farsani

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Increased interest in lightweight and efficient structural components has created the need for selecting materials with improved mechanical properties. To do so, composite materials are being widely used in many applications, due to durability, high strength and modulus, and low weight. Among the various composite structures, grid-stiffened structures are extensively considered in various aerospace and aircraft applications, because of higher specific strength and stiffness, higher impact resistance, superior load-bearing capacity, easy to repair, and excellent energy absorption capability. Although there are a good number of publications on the design aspects and fabrication of grid structures, little systematic work has been reported on their material modification to improve their properties, to our knowledge. Therefore, the aim of this research is to study the reinforcing effect of silica nanoparticles on the flexural properties of epoxy/E-glass isogrid panels under three-point bending test. Samples containing 0, 1, 3, and 5 wt.% of the silica nanoparticles, with 44 and 48 vol.% of the glass fibers in the ribs and skin components respectively, were fabricated by using a manual filament winding method. Ultrasonic and mechanical routes were employed to disperse the nanoparticles within the epoxy resin. To fabricate the ribs, the unidirectional fiber rovings were impregnated with the matrix mixture (epoxy + nanoparticles) and then laid up into the grooves of a silicone mold layer-by-layer. At once, four plies of woven fabrics, after impregnating into the same matrix mixture, were layered on the top of the ribs to produce the skin part. In order to conduct the ultimate curing and to achieve the maximum strength, the samples were tested after 7 days of holding at room temperature. According to load-displacement graphs, the bellow trend was observed for all of the samples when loaded from the skin side; following an initial linear region and reaching a load peak, the curve was abruptly dropped and then showed a typical absorbed energy region. It would be worth mentioning that in these structures, a considerable energy absorption was observed after the primary failure related to the load peak. The results showed that the flexural properties of the nanocomposite samples were always higher than those of the nanoparticle-free sample. The maximum enhancement in flexural maximum load and energy absorption was found to be for the incorporation of 3 wt.% of the nanoparticles. Furthermore, the flexural stiffness was continually increased by increasing the silica loading. In conclusion, this study suggested that the addition of nanoparticles is a promising method to improve the flexural properties of grid-stiffened fibrous composite structures.

Keywords: grid-stiffened composite structures, nanocomposite, three point flexural test , energy absorption

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Authors: A. Boumedine, K. Benfriha, S. Lecheb

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Manufacturing methods for products and structures made of composite materials reduce the number of parts and integrate technical functions, this advantage of composite materials leads to a lot of innovation but also to a reduction of costs and a gain in quality. A material has attributes: its density, it’s resistance, it’s cost, it’s resistance to corrosion. For the design of a product, a certain profile of these attributes is required: low density, resistance removed, low cost. The problem is then to identify this attribute profile and to compare it with those of the materials, in order to find the one that comes closest. The aim of this work is to demonstrate the feasibility of characterizing a mini turbine made of 3D printed fiber-filled composite material by the process of additive manufacturing, then compare the performance of the alloy turbine with the composite turbine according to the results of the simulation by Abaqus software.

Keywords: additive manufacturing, composite materials, design, 3D printer, turbine

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Authors: M. Soleimani, D. Cree, C. Chafe, L. Bates

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The accidental release of petroleum products into the environment could have harmful consequences to our ecosystem. Different techniques such as mechanical separation, membrane filtration, incineration, treatment processes using enzymes and dispersants, bioremediation, and sorption process using sorbents have been applied for oil spill remediation. Most of the techniques investigated are too costly or do not have high enough efficiency. This study was conducted to determine the sorption performance of hemp byproducts (cellulosic materials) in terms of sorption capacity and kinetics for hydrophobic and hydrophilic fluids. In this study, heavy oil, light oil, diesel fuel, and water/water vapor were used as sorbate fluids. Hemp stalk in different forms, including loose material (hammer milled (HM) and shredded (Sh) with low bulk densities) and densified forms (pellet form (P) and crumbled pellets (CP)) with high bulk densities, were used as sorbents. The sorption/retention tests were conducted according to ASTM 726 standard. For a quick-purpose application of the sorbents, the sorption tests were conducted for 15 min, and for an ideal sorption capacity of the materials, the tests were carried out for 24 h. During the test, the sorbent material was exposed to the fluid by immersion, followed by filtration through a stainless-steel wire screen. Water vapor adsorption was carried out in a controlled environment chamber with the capability of controlling relative humidity (RH) and temperature. To determine the kinetics of sorption for each fluid and sorbent, the retention capacity also was determined intervalley for up to 24 h. To analyze the kinetics of sorption, pseudo-first-order, pseudo-second order and intraparticle diffusion models were employed with the objective of minimal deviation of the experimental results from the models. The results indicated that HM and Sh materials had the highest sorption capacity for the hydrophobic fluids with approximately 6 times compared to P and CP materials. For example, average retention values of heavy oil on HM and Sh was 560% and 470% of the mass of the sorbents, respectively. Whereas, the retention of heavy oil on P and CP was up to 85% of the mass of the sorbents. This lower sorption capacity for P and CP can be due to the less exposed surface area of these materials and compacted voids or capillary tubes in the structures. For water uptake application, HM and Sh resulted in at least 40% higher sorption capacity compared to those obtained for P and CP. On average, the performance of sorbate uptake from high to low was as follows: water, heavy oil, light oil, diesel fuel. The kinetic analysis indicated that the second-pseudo order model can describe the sorption process of the oil and diesel better than other models. However, the kinetics of water absorption was better described by the pseudo-first-order model. Acetylation of HM materials could improve its oil and diesel sorption to some extent. Water vapor adsorption of hemp fiber was a function of temperature and RH, and among the models studied, the modified Oswin model was the best model in describing this phenomenon.

Keywords: environment, fiber, petroleum, sorption

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Authors: W. Badla

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A significant portion of the buildings constructed in Algeria is structural frames with infill panels which are usually considered as non structural components and are neglected in the analysis. However, these masonry panels tend to influence the structural response. Thus, these structures can be regarded as seismic risk buildings, although in the Algerian seismic code there is little guidance on the seismic evaluation of infilled frame buildings. In this study, three RC frames with 2, 4, and 8 story and subjected to three recorded Algerian accelerograms are studied. The diagonal strut approach is adopted for modeling the infill panels and a fiber model is used to model RC members. This paper reports on the seismic evaluation of RC frames with brick infill panels. The results obtained show that the masonry panels enhance the load lateral capacity of the buildings and the infill panel configuration influences the response of the structures.

Keywords: seismic design, RC frames, infill panels, non linear dynamic analysis

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Authors: Sri Sai Ramya Bojedla, Falguni Pati

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Nature provides the best of solutions to humans. One such incredible gift to regenerative medicine is silk. The literature has publicized a long appreciation for silk owing to its incredible physical and biological assets. Its bioactive nature, unique mechanical strength, and processing flexibility make us curious to explore further to apply it in the clinics for the welfare of mankind. In this study, Antheraea mylitta and Bombyx mori silk fibroin microfibers are developed by two economical and straightforward steps via degumming and hydrolysis for the first time, and a bioactive composite is manufactured by mixing silk fibroin microfibers at various concentrations with polycaprolactone (PCL), a biocompatible, aliphatic semi-crystalline synthetic polymer. Reconstructive surgery in any part of the body except for the maxillofacial region deals with replacing its function. But answering both the aesthetics and function is of utmost importance when it comes to facial reconstruction as it plays a critical role in the psychological and social well-being of the patient. The main concern in developing adequate bone graft substitutes or a scaffold is the noteworthy variation in each patient's bone anatomy. Additionally, the anatomical shape and size will vary based on the type of defect. The advent of additive manufacturing (AM) or 3D printing techniques to bone tissue engineering has facilitated overcoming many of the restraints of conventional fabrication techniques. The acquired patient's CT data is converted into a stereolithographic (STL)-file which is further utilized by the 3D printer to create a 3D scaffold structure in an interconnected layer-by-layer fashion. This study aims to address the limitations of currently available materials and fabrication technologies and develop a customized biomaterial implant via 3D printing technology to reconstruct complex form, function, and aesthetics of the facial anatomy. These composite scaffolds underwent structural and mechanical characterization. Atomic force microscopic (AFM) and field emission scanning electron microscopic (FESEM) images showed the uniform dispersion of the silk fibroin microfibers in the PCL matrix. With the addition of silk, there is improvement in the compressive strength of the hybrid scaffolds. The scaffolds with Antheraea mylitta silk revealed higher compressive modulus than that of Bombyx mori silk. The above results of PCL-silk scaffolds strongly recommend their utilization in bone regenerative applications. Successful completion of this research will provide a great weapon in the maxillofacial reconstructive armamentarium.

Keywords: compressive modulus, 3d printing, maxillofacial reconstruction, natural fiber reinforced composites, silk fibroin microfibers

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Authors: Chris Miskelly, Eoin Cunningham, Beatrice Smyth, John. D. Holbrey, Gosia Swadzba-Kwasny, Emily L. Byrne, Yoan Delavoux, Mantian Li.

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Recently, the use of ionic liquids (ILs) for the preparation of lignocellulose derived cellulosic materials as alternatives to petrochemical feedstocks has been the focus of considerable research interest. While the technical viability of IL-based lignocellulose treatment methodologies has been well established, the high cost of reagents inhibits commercial feasibility. This work aimed to assess the technoeconomic viability of the preparation of cellulose rich materials (CRMs) using protic ionic liquids (PILs) synthesized from low cost alkylamines and sulphuric acid. For this purpose, the tertiary alkylamines, triethylamine, and dimethylbutylamine were selected. Bulk scale production cost of the synthesized PILs, triethylammonium hydrogen sulphate and dimetheylbutylammonium hydrogen sulphate, was reported as $0.78 kg-1 to $1.24 kg-1. CRMs were prepared through the treatment of common wheat (Triticum aestivum) straw with these PILs. By controlling treatment parameters, CRMs with a cellulose content of ≥ 80 wt% were prepared. This was achieved using a T. aestivum straw to PIL loading ratio of 1:15 w/w, a treatment duration of 180 minutes, and ethanol as a cellulose antisolvent. Infrared spectra data and decreased onset degradation temperature of CRMs (ΔTONSET ~ 70 °C) suggested the formation of cellulose sulphate esters during treatment. Chemical derivatisation can aid the dispersion of prepared CRMs in non-polar polymer/ composite matrices, but act as a barrier to thermal processing at temperatures above 150 °C. It was also shown that treatment increased the crystallinity of CRMs (ΔCrI ~ 40 %) without altering the native crystalline structure or crystallite size (~ 2.6 nm) of cellulose; peaks associated with the cellulose I crystalline planes (110), (200), and (004) were observed at Bragg angles 16.0 °, 22.5 ° and 35.0 ° respectively. This highlighted the inability of assessed PILs to dissolve crystalline cellulose and was attributed to the high acidity (pKa ~ - 1.92 to - 6.42) of sulphuric acid derived anions. Electron micrographs revealed that the stratified multilayer tissue structure of untreated T. aestivum straw was significantly modified during treatment. T. aestivum straw particles were disassembled during treatment, with prepared CRMs adopting a golden-brown film-like appearance. This work demonstrated the degradation of non-cellulosic fractions of lignocellulose without dissolution of cellulose. It is the first to report on the derivatisation of cellulose during treatment with protic hydrogen sulphate ionic liquids, and the potential implications of this with reference to biopolymer feedstock preparation.

Keywords: cellulose, extraction, protic ionic liquids, esterification, thermal stability, waste valorisation, biopolymer feedstock

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Authors: Shahriar Shahbazpanahi, Alaleh Kamgar

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So far, the conventional experimental and theoretical analysis in fracture mechanics have been applied to study concrete flexural- cracked beams, which are strengthened using fiber reinforced polymer (FRP) composite sheets. However, there is still little knowledge about the shear capacity of a side face FRP- strengthened shear-cracked beam. A numerical analysis is herein presented to model the fracture mechanics of a four-point RC beam, with two inclined initial notch on the supports, which is strengthened with side face FRP sheets. In the present study, the shear crack is forced to conduct by using an initial notch in supports. The ABAQUS software is used to model crack propagation by conventional cohesive elements. It is observed that the FRP sheets play important roles in preventing the propagation of shear cracks.

Keywords: crack, FRP, shear, strengthening

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Authors: Maryam Meftahi, Yashar Hamidzadeh

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In recent decades, the amount of solid waste production has been rising. In the meantime, plastic waste is one of the major parts of urban solid waste, so, recycling plastic waste from water bottles has become a serious challenge in the whole world. The experimental program includes the study of the effect of waste plastic fibers on maximum dry density (MDD), optimum moisture content (OMC) with different sizes and contents. Also, one dimensional consolidation tests were carried out to evaluate the benefit of utilizing randomly distributed waste plastics fiber to improve the engineering behavior of a tested soils. Silty soil specimens were prepared and tested at five different percentages of plastic waste content (i.e. 0.25%, 0.50%, 0.75%, 1% and 1.25% by weight of the parent soil). The size of plastic chips used, are 4 mm, 8 mm and 12 mm long and 4 mm in width. The results show that with the addition of waste plastic fibers, the MDD and OMC and also the compressibility of soil decrease significantly.

Keywords: silty soil, waste plastic, compaction, consolidation, reinforcement

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Authors: Hazleen Anuar, Nur Aimi Mohd Nasir

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Durian skin is a newly explores natural fibre potentially reinforced polyolefin for diverse applications. In this work, investigation on the effect of coupling agent, maleic anhydride polypropylene (MAPP) on the mechanical, morphological and thermal properties of polypropylene (PP) reinforced with durian skin fibre (DSF) was conducted. The presence of 30 wt% DSF significantly reduced the tensile strength of PP-DSF composite. Interestingly, even though the same trend goes to PP-DSF with the presence of MAPP, the reduction is only about 4% relative to unreinforced PP and 18% higher than PP-DSF without MAPP (untreated composite or UTC). The used of MAPP in treated composite (TC) also increased the tensile modulus, flexural properties and degradation temperature. The enhanced mechanical properties are consistent with good interfacial interaction as evidenced under scanning electron microscopy.

Keywords: durian skin fiber, coupling agent, mechanical properties, thermogravimetry analysis

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Authors: Devendra Kumar Pandey, Debabrata Chakraborty

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The advancement in various concrete ingredients like plasticizers, additives and fibers, etc. has enabled concrete technologists to develop many viable varieties of special concretes in recent decades. Such various varieties of concrete have significant enhancement in green as well as hardened properties of concrete. A prudent selection of appropriate type of concrete can resolve many design and application issues in construction projects. This paper focuses on usage of self-compacting concrete, high early strength concrete, structural lightweight concrete, fiber reinforced concrete, high performance concrete and ultra-high strength concrete in the structures. The modified properties of strength at various ages, flowability, porosity, equilibrium density, flexural strength, elasticity, permeability etc. need to be carefully studied and incorporated into the design of the structures. The paper demonstrates various mixture combinations and the concrete properties that can be leveraged. The selection of such products based on the end use of structures has been proposed in order to efficiently utilize the modified characteristics of these concrete varieties. The study involves mapping the characteristics with benefits and savings for the structure from design perspective. Self-compacting concrete in the structure is characterized by high shuttering loads, better finish, and feasibility of closer reinforcement spacing. The structural design procedures can be modified to specify higher formwork strength, height of vertical members, cover reduction and increased ductility. The transverse reinforcement can be spaced at closer intervals compared to regular structural concrete. It allows structural lightweight concrete structures to be designed for reduced dead load, increased insulation properties. Member dimensions and steel requirement can be reduced proportionate to about 25 to 35 percent reduction in the dead load due to self-weight of concrete. Steel fiber reinforced concrete can be used to design grade slabs without primary reinforcement because of 70 to 100 percent higher tensile strength. The design procedures incorporate reduction in thickness and joint spacing. High performance concrete employs increase in the life of the structures by improvement in paste characteristics and durability by incorporating supplementary cementitious materials. Often, these are also designed for slower heat generation in the initial phase of hydration. The structural designer can incorporate the slow development of strength in the design and specify 56 or 90 days strength requirement. For designing high rise building structures, creep and elasticity properties of such concrete also need to be considered. Lastly, certain structures require a performance under loading conditions much earlier than final maturity of concrete. High early strength concrete has been designed to cater to a variety of usages at various ages as early as 8 to 12 hours. Therefore, an understanding of concrete performance specifications for special concrete is a definite door towards a superior structural design approach.

Keywords: high performance concrete, special concrete, structural design, structural lightweight concrete

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Authors: María Luisa Gonzalez-SanJose, Javier Garcia-Lomillo, Raquel Del Pino, Miriam Ortega-Heras, Maria Dolores Rivero-Perez, Pilar Muñiz-Rodriguez

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One of the most preoccupant problems related to the diet of the occidental societies is the high salt intake. In Spain, salt intake is almost twice as recommended by the World Health Organization (WHO). A lot of negative health effects of high sodium intake have been described being the hypertension, cardiovascular and coronary diseases ones of the most important. Due to this fact, government and other institutions are working on the gradual reduction of this consumption. Intake of meat products have been described as the main processed products that bring salt to the diet, followed by snacks and savory crackers. However, fortunately, the food industry has also raised awareness of this problem and is working intensely, and in recent years attempts to reduce the salt content in processed products, and is developing special lines with low sodium content. It is important to consider that processed food are the main source of sodium in occidental countries. One of the possible strategies to reduce the salt content in food is to find substitutes that can emulate their taste properties without adding much sodium or products that mask or substitute salty sensations with other flavors and aromas. In this sense, multiple products have been proposed and used until now. Potassium salts produce similar salty sensations without bring sodium, however their intake should be also limited, by healthy reasons. Furthermore, some potassium salts shows some better notes. Other alternatives are the use of flavor enhancers, spices, aromatic herbs, sea-plant derivate products, etc. The wine pomace is rich in potassium salts, content organic acid and other flavored substances, therefore it could be an interesting raw material to obtain derived products that could be useful as alternative ‘seasonings’. Considering previous comments, the main aim of this study was to evaluate the possible use of a natural seasoning, made from red wine pomace, in two different foods, crackers and burgers. The seasoning was made in the pilot plant of food technology of the University of Burgos, where the studied crackers and patties were also made. Different members of the University, students, docent and administrative personal, taste the products, and a trained panel evaluated salty intensity. The seasoning in addition to potassium contain significant levels of dietary fiber and phenolic compounds, which also makes it interesting as a functional ingredient. Both burgers and crackers made with the seasoning showed better taste that those without salt. Obviously, they showed lower sodium content than normal formulation, and were richer in potassium, antioxidant and fiber. Then, they showed lower values of the relation Na/K. All these facts are correlated with more ‘healthy’ products especially to that people with hypertension and other coronary dysfunctions.

Keywords: healthy foods, low salt, seasoning, wine pomace

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Authors: Faruk Ortes, Baris Sayin, Tarik Serhat Bozkurt, Cemil Akcay

Abstract:

The technique using near-surface mounted (NSM) carbon fiber-reinforced polymer (CFRP) composites has proved to be an reliable strengthening technique. However, the effects of different parameters for the use of NSM CFRP are not fully developed yet. This study focuses on the development of a numerical modeling that can predict the behavior of reinforced concrete (RC) beams strengthened with NSM FRP rods exposed to bending loading and the efficiency of various parameters such as CFRP rod size and filling material type are evaluated by using prepared models. For this purpose, three different models are developed and implemented in the ANSYS® software using Finite Element Analysis (FEA). The numerical results indicate that CFRP rod size and filling material type are significant factors in the behavior of the analyzed RC beams.

Keywords: numerical model, FEA, RC beam, NSM technique, CFRP rod, filling material

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Authors: Jeffri Ramli, Brabha Nagaratnam, Keerthan Poologanathan, Wai Ming Cheung, Thadshajini Suntharalingham

Abstract:

Fiber-reinforced self-compacting concrete (FRSCC) combines the benefits of SCC of high flowability and randomly dispersed short fibres together in one single concrete. Fibres prevent brittle behaviour and improve several mechanical properties of SCC. In this paper, an experimental investigation of the effect of three-dimensional (3D) fibres on the mechanical properties of SCC has been conducted. Seven SCC mixtures, namely SCC with no fibres as a reference mix, and six 3D steel fibre reinforced SCC mixes were prepared. Two different sizes of 3D steel fibres with perimeters of 115 mm and 220 mm at different fibre contents of 1%, 2%, and 3% (by cement weight) were considered. The mechanical characteristics were obtained through compressive, splitting tensile, and flexural strength tests. The test results revealed that the addition of 3D fibres improves the mechanical properties of SCC.

Keywords: self-compacting concrete, three-dimensional steel fibres, mechanical properties, compressive strength, splitting tensile strength, flexural strength

Procedia PDF Downloads 153

Authors: A. S. Ibrahim Mamane, S. Giljean, M.-J. Pac, G. L’Hostis

Abstract:

Fiber reinforced composite laminates are particularly subject to residual stresses due to their heterogeneity and the complex chemical, mechanical and thermal mechanisms that occur during their processing. Residual stresses are now well known to cause damage accumulation, shape instability, and behavior disturbance in composite parts. Many works exist in the literature on techniques for minimizing residual stresses in thermosetting and thermoplastic composites mainly. To study in-depth the influence of processing mechanisms on the formation of residual stresses and to minimize them by establishing a reliable correlation, it is essential to be able to measure very precisely the profile of residual stresses in the composite. Residual stresses are important data to consider when sizing composite parts and predicting their behavior. The incremental hole drilling is very effective in measuring the gradient of residual stresses in composite laminates. This method is semi-destructive and consists of drilling incrementally a hole through the thickness of the material and measuring relaxation strains around the hole for each increment using three strain gauges. These strains are then converted into residual stresses using a matrix of coefficients. These coefficients, called calibration coefficients, depending on the diameter of the hole and the dimensions of the gauges used. The reliability of the incremental hole drilling depends on the accuracy with which the calibration coefficients are determined. These coefficients are calculated using a finite element model. The samples’ features and the experimental conditions must be considered in the simulation. Any mismatch can lead to inadequate calibration coefficients, thus introducing errors on residual stresses. Several calibration coefficient correction methods exist for isotropic material, but there is a lack of information on this subject concerning composite laminates. In this work, a Python program was developed to automatically generate the adequate finite element model. This model allowed us to perform a parametric study to assess the influence of experimental errors on the calibration coefficients. The results highlighted the sensitivity of the calibration coefficients to the considered errors and gave an order of magnitude of the precisions required on the experimental device to have reliable measurements. On the basis of these results, improvements were proposed on the experimental device. Furthermore, a numerical method was proposed to correct the calibration coefficients for different types of materials, including thick composite parts for which the analytical approach is too complex. This method consists of taking into account the experimental errors in the simulation. Accurate measurement of the experimental errors (such as eccentricity of the hole, angular deviation of the gauges from their theoretical position, or errors on increment depth) is therefore necessary. The aim is to determine more precisely the residual stresses and to expand the validity domain of the incremental hole drilling technique.

Keywords: fiber reinforced composites, finite element simulation, incremental hole drilling method, numerical correction of the calibration coefficients, residual stresses

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Authors: N. Hasbullah, K. A. Sekak

Abstract:

The sulfonated poly (ether ether ketone) SPEEK nanofiber membrane were successfully electrospun for Polymer Electrolyte Membrane (PEM) in Proton Exchange Membrane Fuel Cell (PEMFC) and their nanosized properties were investigated. The poly (ether ether ketone) PEEK victrex® grade 90p was sulfonated with concentrated sulfuric acid (95-98% w/w) at room temperature for 60 hours sulfonation times. The degree sulfonation of SPEEK are 70% was determined by H1 NMR and the functional groups of the SPEEK were characterize using FTIR. Then, the SPEEK nanofiber membrane were prepared via electrospinning method using DMAC as a solvent. The SPEEK sample were successfully electrospun using predetermine set up. FESEM show the electrospun fiber mat surface and confirmed the nanostructure membrane cell.

Keywords: polymer electrolyte membrane (PEM), sulfonated poly (ether ether ketone) (SPEEK), degree sulfonation, Electrospinning, Nanofibers

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Authors: Janet Kaningen, Richard N. Kaningen, Jonas Kaningen

Abstract:

This paper aims to discover the best ways to improve production efficiency, cost efficiency, community cohesion, and long-term sustainability in Ghana's housing delivery. Advanced Construction Technologies (ACTs) are set to become the sustainable mainstay of the construction industry due to the demand for innovative housing solutions. Advances in material science, building component production, and assembly technologies are leading to the development of next-generation materials such as polymeric-fiber-based products, light-metal alloys, and eco-materials. Modular housing construction has become more efficient and cost-effective than traditional building methods and is becoming increasingly popular for commercial, industrial, and residential projects. Effective project management and logistics will be imperative in the future speed and cost of modular construction housing.

Keywords: technology blending, sustainability, housing, Ghana

Procedia PDF Downloads 87