Journal articles: 'Wet lay-up'

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Daken, H. H., A. A. Ismail, and F. Rashed. "Productivity improvement and resin-waste reduction in composites wet lay-up facilities." Journal of Materials Processing Technology 41, no. 1 (February 1994): 1–21. http://dx.doi.org/10.1016/0924-0136(94)90173-2.

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Morshed, Syed Ahnaf, Tyler J. Young, William M. Chirdon, Qian Zhang, and Jovan Tatar. "Durability of wet lay-up FRP bonded to concrete with nanomodified epoxy adhesives." Journal of Adhesion 96, no. 13 (December 26, 2018): 1141–66. http://dx.doi.org/10.1080/00218464.2018.1556647.

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Kook, Joong-Suk, and Tadaharu Adachi. "Mechanical Properties of GFRP Laminates Manufactured by Process Combined with Wet Lay-Up and Vacuum Curing." Key Engineering Materials 306-308 (March 2006): 845–50. http://dx.doi.org/10.4028/www.scientific.net/kem.306-308.845.

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In this study, a manufacturing process for glass fiber reinforced plastics (GFRP) laminates was developed to improve volume fraction of fibers and mechanical properties. The manufacturing process is combination with wet lay-up and vacuum curing under atmosphere pressure for production of large and complicated structure as a leisure boat and so on. Several kinds of GFRP laminates were produced to consider optimum conditions of the process from viewpoint of volume fraction of fibers and mechanical properties. Volume fractions of fibers in GFRP laminates were measured and cross sections were observed by an optical microscope. The volume fraction in the GFRP laminate made by the suggested method was improved to 41 %, although the one made by conventional wet lay-up method was 17.7 %. Because a lot of large voids included in the laminates were drastically decreased due to the methods. For each laminate, three-point bending test was performed to measure elastic modulus and fracture toughness. Elastic modulus was improved from 5.39 GPa to 8.91 GPa with high volume fractions of fibers. Fracture toughness was improved from 8.19 MPa m1/2 to 16.6 MPa m1/2. Therefore, it was obtained that the method combined with wet lay-up and vacuum curing is easy process for manufacturing large and complicated structure to improve excellent mechanical properties and accuracy of structural shape.

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Shi, Jia-Wei, Wen-Hai Cao, Lei Chen, and Ang-Lin Li. "Durability of wet lay-up BFRP single-lap joints subjected to freeze–thaw cycling." Construction and Building Materials 238 (March 2020): 117664. http://dx.doi.org/10.1016/j.conbuildmat.2019.117664.

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Al-Shawaf, Ahmed. "Modelling wet lay-up CFRP–steel bond failures at extreme temperatures using stress-based approach." International Journal of Adhesion and Adhesives 31, no. 6 (September 2011): 416–28. http://dx.doi.org/10.1016/j.ijadhadh.2011.02.005.

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Al-Shawaf, Ahmed, and Xiao-Ling Zhao. "Adhesive rheology impact on wet lay-up CFRP/steel joints’ behaviour under infrastructural subzero exposures." Composites Part B: Engineering 47 (April 2013): 207–19. http://dx.doi.org/10.1016/j.compositesb.2012.11.012.

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Al-Shawaf, Ahmed. "Influence of fibres’ stiffness on wet lay-up CFRP/steel joints’ behaviour under subzero exposures." Composites Part B: Engineering 73 (May 2015): 61–71. http://dx.doi.org/10.1016/j.compositesb.2014.02.013.

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Sussmann, Marli, Mehrad Amirkhosravi, Maya Pishvar, and M. Altan. "Fabrication of High Quality, Large Wet Lay-Up/Vacuum Bag Laminates by Sliding a Magnetic Tool." Polymers 10, no. 9 (September 5, 2018): 992. http://dx.doi.org/10.3390/polym10090992.

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This study presents a novel method to fabricate high-quality, large composite parts which can be used in a wet lay-up/vacuum bag (WLVB) process. The new method utilizes a commercial lifting magnet, which is commonly used for transporting ferrous plates, to apply a magnetic consolidation pressure on the WLVB composite lay-up. The pressure is applied on a large area of the laminate by slowly sliding the magnet over the vacuum bag surface, which leads to an improved laminate quality. When further improvement is desirable, multiple passes of the magnet can be performed, where each pass successively compacts the lay-up. To explore the feasibility of implementing this technique, random mat and plain weave glass/epoxy laminates were fabricated, and their properties compared to conventional WLVB laminates. The effects of the number of moving passes of the lifting magnet on the laminate microstructure and properties are also investigated. As a result of multiple passes, the fiber volume fraction in random mat and plain weave laminates increases to 34% and 53%, representing 80% and 16% improvements, respectively. In addition, the void volume fraction reduces almost by 60% to a very low level of 0.7% and 1.1%, respectively. Consequently, the flexural properties considerably enhance by 20–81%, which demonstrates the potential of the proposed method to produce WLVB parts with substantially higher quality. It is also shown that there exists an optimal number of passes, depending on the fabric type where additional passes induce new voids as a result of excessive resin removal.

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Amirkhosravi, Mehrad, Maya Pishvar, and M. Cengiz Altan. "Improving laminate quality in wet lay-up/vacuum bag processes by magnet assisted composite manufacturing (MACM)." Composites Part A: Applied Science and Manufacturing 98 (July 2017): 227–37. http://dx.doi.org/10.1016/j.compositesa.2017.03.032.

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Tahir, Muhammad, Zhenyu Wang, and Kanwar Majid Ali. "Axial compressive behavior of square concrete columns confined with CFRP strip ties using wet lay-up technique." Construction and Building Materials 200 (March 2019): 282–92. http://dx.doi.org/10.1016/j.conbuildmat.2018.12.127.

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Hallonet, A., E. Ferrier, L. Michel, and Brahim Benmokrane. "Durability and tensile characterization of wet lay-up flax/epoxy composites used for external strengthening of RC structures." Construction and Building Materials 205 (April 2019): 679–98. http://dx.doi.org/10.1016/j.conbuildmat.2019.02.040.

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Mohammadi, Tayyebeh, Baolin Wan, Jian-Guo Dai, and Chao Zhu. "Prediction of Load Capacity Variation in FRP Bonded Concrete Specimens Using Brownian Motion." Mathematical Problems in Engineering 2015 (2015): 1–9. http://dx.doi.org/10.1155/2015/632912.

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In wet lay-up process, dry fiber sheets are saturated with a polymer and applied to the concrete surface by hand. This causes relatively large variation in properties of the cured FRP composite material. It is hard to know the exact mechanical properties of the FRP constructed by wet lay-up process. In addition, the stiffness of FRP changes during debonding process due to different amount of concrete attached to the debonded FRP at different locations. It is also inevitable to have considerable variations in the strength of concrete. Therefore, the behaviour of FRP bonded concrete members varies among specimens even when the same materials are used. The variation of localized FRP stiffness and concrete strength can be combined in a single parameter as variation of the localized interfacial fracture energy. In an effort to effectively model the effects of the variation of interfacial fracture energy on the load versus deflection responses of FRP bonded concrete specimens subjected to Mode I and Mode II loading, a random white noise using a one-dimensional standard Brownian motion is added to the governing equations, yielding stochastic differential equations. By solving these stochastic equations, the bounds of load carrying capacity variation with 95% probability are found for different experimental tests.

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Li, Shan, Jiyue Hu, and Huitao Ren. "The Combined Effects of Environmental Conditioning and Sustained Load on Mechanical Properties of Wet Lay-Up Fiber Reinforced Polymer." Polymers 9, no. 12 (June 23, 2017): 244. http://dx.doi.org/10.3390/polym9070244.

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Michel, M., and E. Ferrier. "Effect of curing temperature conditions on glass transition temperature values of epoxy polymer used for wet lay-up applications." Construction and Building Materials 231 (January 2020): 117206. http://dx.doi.org/10.1016/j.conbuildmat.2019.117206.

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Hou, T. H., H. L. Belvin, and N. J. Johnston. "Automated Tow Placed LARC™-PETI-5 Composites." High Performance Polymers 13, no. 4 (December 2001): 323–36. http://dx.doi.org/10.1088/0954-0083/13/4/310.

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LARC™-PETI-5 is a PhenylEthynyl-Terminated Imide resin developed at NASA Langley Research Center (LARC) during the 1990s. It offers a combination of attractive composite and adhesive properties. IM7/LARC™-PETI-5 composites exhibit thermal and thermo-oxidative stability typical of polyimides, superior chemical resistance and processability, excellent mechanical properties, toughness and damage tolerance. It was selected for study in the High Speed Research program aimed at developing technologies for a future supersonic aircraft, the High Speed Civil Transport, with a projected life span of 60 000 h at a cruise speed up to March 2.4. Robust autoclave processing cycles for LARC™-PETI-5 composites have been thoroughly designed and demonstrated, which involved hand lay-up of solvent-ladened ‘wet’ prepregs. However, this type of processing is not only costly but also environmentally unfriendly. Volatile management and shrinkage could become serious problems in the fabrication of large complex airframe structural subcomponents. Robotic tow placement technology utilizing ‘dry’ material forms represents a new fabrication process which overcomes these deficiencies. This work evaluates and compares mechanical properties of composites fabricated by heated head automated tow placement (dry process) with those obtained by hand lay-up/autoclave fabrication (wet process). Thermal and rheological properties of the robotically as-placed uncured composites were measured. A post-cure cycle was designed due to the requirement of the PETI-5 resin for a 370 °C/1 h hold to reach full cure, conditions which cannot be duplicated during heated head robotic placement. Mechanical properties such as 0° flexural strength and modulus, open hole tensile and compressive strength and moduli, reduced section compression dogbone compressive strength, and modified zippora-medium small (MZ-MS) tensile and compressive properties were obtained on the post-cured panels. These properties compared favourably with those obtained from the wet process.

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Ganapathi, A. S., Sunil C. Joshi, and Zhong Chen. "Bleeder Thickness Optimization for Controlling Resin Content in Thick Laminated Composites." Advanced Materials Research 740 (August 2013): 698–703. http://dx.doi.org/10.4028/www.scientific.net/amr.740.698.

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Thick laminated composites are manufactured commonly by vacuum bagging of fiber-resin mix or prepregs on a suitable mould and, subsequently curing the lay-up at high temperature and pressure in an either autoclave or oven. At these pressures and temperatures, excess resin bleeds out of the lay-up during the initial stages of the curing. The amount of resin bleed is also a function of the bleeder parameters. Bleeder is a porous fibrous media that is laid around stacked lay-up to provide pathway for volatiles as well as absorb and hold the excess resin. Thicker or highly porous bleeders generally absorb higher amount of resin resulting in a resin starved laminate whereas very thin or denser bleeder leads to resin-rich areas within the laminate. It is thus important to select optimum bleeder parameters in order to achieve a desired resin volume fraction and its uniformity in a composite laminate upon curing. This paper details the simulation of the manufacturing of a thick laminated composite, where a significant amount resin is likely to flow out of a curing lay-up, leading to an optimization of bleeder parameters. A coupled, transient FE analysis is conducted that involves not only the heat transfer, resin flow and cure reaction kinetics simulation but also the simulation of the compaction of the wet laminate and the bleeder layers until the laminate is fully cured. Details of an experiment conducted to find compression characteristics of bleeder of varying thickness and the number of layers and related data that was used in the FE analysis are discussed in this paper. It is found that bleeder thickness significantly affects the amount of resin bleeding out from the curing laminate. As a result, the resin volume fraction of the laminate is affected. Case studies carried out to highlight the optimum bleeder thickness for a lay-up, and the method used to decide the thickness and the number of bleeder layers, are presented.

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Srinivasababu, Nadendla, and Devarakonda Avinash. "Role of Two Stage Wet Layup Manufacturing Method to Fabricate and Test Chemically Treated Dora Hemp Particulate FRP Composites." Applied Mechanics and Materials 787 (August 2015): 548–52. http://dx.doi.org/10.4028/www.scientific.net/amm.787.548.

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Increasing concern about the environmental pollution, clear understanding of uncertainty of petroleum products resulted in the utilization of eco-friendly materials. In the present work dora hemp natural fibre is made into particulate form through chemical treatment. Then it is reinforced at 3.98 wt % into the polyester matrix to fabricate the composite lamina by “Two Stage Wet Layup”. A special focus is made in describing the hand/wet lay-up procedure. The post cured and machined composite specimens as per ASTM procedures are tested to determine the mechanical properties. Dora hemp particulate composites have showed the tensile strength, modulus 12.57 MPa, 197.47 MPa respectively. In the bending load they have showed a flexural strength, modulus of 38.08 MPa, 1.78 GPa respectively. The composites under the impact load had shown impact strength of 1.38 kJ/m2.

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Amid, Hooman, Ali Asghar Asgharian Jeddi, Manouchehr Salehi, Hadi Dabiryan, and Reza Pejman. "Investigation of Circular Woven Composite Preforms for Composite Pipes." Autex Research Journal 16, no. 2 (June 1, 2016): 100–108. http://dx.doi.org/10.1515/aut-2015-0036.

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Abstract The main traditional technique for commercial manufacturing of composite pipes is filament winding in which the winding angle and the discontinuity of the structure (caused by starting and ending points of the winding process) are two important matters of concern. In the present study, circular woven fabric with its orthogonal net-shaped continuous structure was produced from polyester yarns. Fabric was wet with epoxy and hand lay-up was used to manufacture the composite pipes. Composite pipes were subjected to internal hydrostatic pressure and their burst strength was recorded. In addition, tensile strength of flat laminas was assessed in the warp and weft directions. We estimated and analysed the failure strength of composite pipes using Tresca’s failure criterion and Finite Element (FE) modeling. The experimental burst strength was almost 23% more than the FE model and 77% more than the theoretical estimate.

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Abraham, D., S. Matthews, and R. McIlhagger. "A comparison of physical properties of glass fibre epoxy composites produced by wet lay-up with autoclave consolidation and resin transfer moulding." Composites Part A: Applied Science and Manufacturing 29, no. 7 (July 1998): 795–801. http://dx.doi.org/10.1016/s1359-835x(98)00055-4.

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Sciolti, Margherita Stefania, Mariaenrica Frigione, and Maria Antonietta Aiello. "Wet Lay-Up Manufactured FRPs for Concrete and Masonry Repair: Influence of Water on the Properties of Composites and on Their Epoxy Components." Journal of Composites for Construction 14, no. 6 (December 2010): 823–33. http://dx.doi.org/10.1061/(asce)cc.1943-5614.0000132.

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21

AYYANAR, Athijayamani, Ramkumar GP, Alavudeen AZIZ BATCHA, and Thiruchitrambalam MANI. "Study of Mechanical Properties of Alkali Treated SZF/SF/VE Hybrid Composites under Wet Condition." Materials Science 27, no. 2 (May 5, 2021): 224–31. http://dx.doi.org/10.5755/j02.ms.25410.

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Mechanical properties of vinyl ester hybrid composites reinforced with alkali treated Smilax zeylanica and sisal fibers were studied at wet condition in the present communication. Hybrid composites were fabricated by using a simple hand lay up technique based on three different fiber loading of 25, 35, and 45 wt.% with alkali treated fibers. Hybrid composite specimens were then subjected to the water absorption test to observe the behaviours of composite specimens at wet condition under mechanical loads such as tensile, flexural and impact. Water absorption test was carried out in two ways at distilled water environment at room temperature. First way test was conducted for 10 days to observe the percentage of water particle absorption of hybrid composites. Second way test was performed for 5 days to determine the mechanical properties of hybrid composites at wet condition to observe its durability when they are used in outdoor applications. Mechanical properties of hybrid composite specimens at wet conditions were compared with the dry composite specimens. Experimental results showed that the percentage of the water particle absorption in the alkali treated hybrid fiber composites is lower as compared to the untreated hybrid fiber composites. Mechanical properties of alkali treated hybrid fiber composites at wet condition are slightly reduced as compared to the treated hybrid fiber composite at dry condition. As a result, it is observed that the resistance for the penetration of the water particles is higher for the alkali treated smilax zeylanica and sisal fibers reinforced vinyl ester hybrid composites. The fracture surfaces of the hybrid composite specimens were examined by scanning electron microscope to understand the effects of water absorption on the mechanical properties.

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Stringer, L. G. "Optimization of the wet lay-up/vacuum bag process for the fabrication of carbon fibre epoxy composites with high fibre fraction and low void content." Composites 20, no. 5 (September 1989): 441–52. http://dx.doi.org/10.1016/0010-4361(89)90213-9.

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Abd El-baky, MA, and MA Attia. "Water absorption effect on the in-plane shear properties of jute–glass–carbon-reinforced composites using Iosipescu test." Journal of Composite Materials 53, no. 21 (October 30, 2018): 3033–45. http://dx.doi.org/10.1177/0021998318809525.

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The main objective of the present paper is to study the water absorption of jute–glass–carbon-reinforced epoxy composites and its subsequent effect on the in-plane shear performance of these composites. The effects of the reinforcement hybridization, stacking sequence and relative fabric amounts on the shear behavior of dry and wet conditioned composite specimens are reported and discussed. Composites have been fabricated in inter-ply configuration using the hand lay-up process. The prepared specimens have been subjected to distilled water and sea water immersion at room temperature for 60 days. Results indicated that water uptake of jute-reinforced composite and its hybrids with glass and/or carbon follows Fickian-like behavior. Water uptake induces a significant decrease in the in-plane shear strength. Hybridizing jute fabric with glass and/or carbon fabrics improves the in-plane shear properties of both dry and wet specimens. The stacking sequence and relative fabric amounts have a noticeable effect on the studied shear properties. Also, the hybrid composite with jute as facings and glass as core, JGJ, offers the most balanced set of properties on a cost-effective basis compared to the other studied hybrids.

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Agarwal, Kuldeep, Suresh K. Kuchipudi, Benoit Girard, and Matthew Houser. "Mechanical properties of fiber reinforced polymer composites: A comparative study of conventional and additive manufacturing methods." Journal of Composite Materials 52, no. 23 (March 7, 2018): 3173–81. http://dx.doi.org/10.1177/0021998318762297.

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Fiber reinforced polymer composites have been around for many decades but recently their use has started to increase in multiple industries such as automotive, aerospace, and construction. The conventional composite manufacturing processes such as wet lay-up, resin transfer molding, automatic lay ups etc. suffer from a lot of practical and material issues which have limited their use. The mechanical properties of the parts produced by such processes also suffer from variation that causes problems downstream. Composites based additive manufacturing processes such as Fused Deposition Modeling and Composite Filament Fabrication are trying to remove some of the barriers to the use of composites. Additive manufacturing processes offer more design and material freedom than conventional composite manufacturing processes. This paper compares conventional composite processes for the manufacturing of Epoxy-Fiberglass fiber reinforced polymers with composite filament fabrication based Nylon-Fiberglass fiber reinforced polymers. Mechanical properties such as tensile strength, elastic modulus, and fatigue life are compared for the different processes. The effect of process parameters on these mechanical properties for the composite filament fabrication based process is also examined in this work. It is found that the composite filament fabrication based process is very versatile and the parts manufactured by this process can be used in various applications.

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Sadikin, Aziatul Niza, N. Othman, and Mohd Ghazali Mohd Nawawi. "Effect of Pre-Treatment of Lignocellulosic Fiber on Mechanical Properties of Chitosan-Filled Filter Media." Advanced Materials Research 931-932 (May 2014): 210–14. http://dx.doi.org/10.4028/www.scientific.net/amr.931-932.210.

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The newly developed non-woven filter media are composed of randomly oriented fibrous fibers from empty fruit bunch fibers. The wet lay-up method was adopted for filter media fabrication. The aim of this study is to investigate the effect of pre-treatment of lignocellulosic fibers on the mechanical properties of fibrous filter media. The study also aims to examine the effect of chitosan application as binder on the tensile strength of fibrous filter media from treated and untreated fibers. The fibers were treated with sodium hydroxide solution, diethyl ether, ethanol and hot water. The pre-treatment enhance the fibrous filter media properties, while filter media from untreated empty fruit bunch fibers showed lower mechanical properties. The changes in mechanical properties followed the order: alkali-treated > diethyl ether > ethanol > hot water > untreated empty fruit bunch fibers.

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Vincent, Thomas, and Togay Ozbakkloglu. "Axial Compressive Behavior of High- and Ultra High-Strength Concrete-Filled AFRP Tubes." Advanced Materials Research 671-674 (March 2013): 626–31. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.626.

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Concrete-filled FRP tubes (CFFTs) have received significant research attention over the last two decades. However, the experimental studies on the behavior of CFFTs filled with high- and ultra high-strength concretes (HSC and UHSC) remain very limited. This paper presents the results of an experimental study on the compressive behavior of circular HSC- and UHSC-filled fiber reinforced polymer (FRP) tubes (HSCFFTs and UHSCFFTs). A total of 24 aramid fiber made CFFTs were tested under uniaxial compression to investigate the influences of concrete strength, amount of confinement and manufacturing method of FRP tubes. The influence of tube manufacturing method was investigated with specimens manufactured with either automated filament winding or manual wet lay-up techniques. In this paper the experimentally recorded stress-strain relationships are presented graphically and key experimental outcomes discussed. The results indicate that the manufacturing method of the FRP tubes significantly influence the compressive behavior of CFFTs.

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Tan, Chye Lih, Azwan Iskandar Azmi, and Noorhafiza Muhammad. "Performance Evaluations of Carbon/Glass Hybrid Polymer Composites." Advanced Materials Research 980 (June 2014): 8–12. http://dx.doi.org/10.4028/www.scientific.net/amr.980.8.

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In this work, the influence of hybrid effect on carbon and glass fiber reinforced polymer (FRP) on the mechanical performance for structural application was studied. The hybrid fiber reinforced polymer (FRP) composites made from woven E-glass and carbon fibers with epoxy resin. The FRP hybrid composites were fabricated using vacuum-assisted resin transfer moulding process, which is capable of producing constant thickness with high volume fractions of composite panels compared to that of traditional wet hand lay-up method. Mechanical performance of the FRP hybrid composites were evaluated against full carbon or glass fiber reinforced polymer composites. Important properties such as tensile strength, flexural strength and volume fraction of reinforcement were determined according to the ASTM standards. It was found that the mechanical properties of carbon-glass hybrid composites exhibited significant improvement in term of strength and strain respectively compared to that of full glass FRP composites and full carbon FRP composites.

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Bergant, Zoran, Adriana Savin, and Janez Grum. "Effects of manufacturing technology on static, multi-frequency dynamic mechanical analysis and fracture energy of cross-ply and quasi-isotropic carbon/epoxy laminates." Polymers and Polymer Composites 26, no. 5-6 (June 2018): 358–70. http://dx.doi.org/10.1177/0967391118798266.

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The magnitude of improvement of mechanical properties of laminates using expensive technologies is important to justify the investment in new equipment. The objective of this research is to evaluate the mechanical properties of a cross-ply and quasi-isotropic symmetrical plain weave carbon-epoxy laminate produced with a vacuum bagging method and an autoclave processing method for a given set of epoxy/carbon fabric types. Autoclave-processed laminates exhibit higher static strengths, higher moduli in tension, compression and bending but lower Charpy impact toughness. New findings about materials properties were deduced from dynamic multi-frequency tests between 1 Hz and 50 Hz where it was found that the activation energy was 1.8 times higher in autoclave-processed specimens. Autoclave laminates had, on an average, 1.7-times lower damping ratio in the glassy plateau region and a 3-times lower peak damping ratio in the glass transition region than wet lay-up specimens.

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Coskun, Onur, and Halit S. Türkmen. "Bending Fatigue Behaviour of Laminated Sandwich Beams." Advanced Materials Research 445 (January 2012): 548–53. http://dx.doi.org/10.4028/www.scientific.net/amr.445.548.

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In this study, the bending fatigue behaviour of laminated sandwich beams, which are made of carbon/epoxy face sheets and aramid honeycomb core, has been investigated experimentally. The wet hand lay-up technique is used and curing is processed on the heated vacuum table at an elevated temperature to manufacture the sandwich beams. The experimental set-up for bending fatigue test provides a cantilever in one end and a cyclic load at the free end with constant displacement amplitude at room temperature. The load applied to the beam is measured using a load cell during the bending test. Different displacement amplitudes are performed. Mechanical properties, bending stiffness and free vibration frequency of the sandwich beam are investigated. The bending test of the beams and vibration identification test using a vibration analyzer, a hammer and an accelerometer are performed to measure the bending stiffness and determination of free vibration frequency of the clamped sandwich beams before starting and after completion of the fatigue tests. The bending stiffness and free vibration frequencies before and after the fatigue tests are compared to understand the effect of repeated loadings on the mechanical performance of the laminated sandwich beams.

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Yakubu, S. T., T. S. Olugbemi, P. Onimisi, and O. T. Lasisi. "Effects of indomie noodle waste (INW) on serum lipid profile of broiler birds fed during the wet season." Nigerian Journal of Animal Production 44, no. 2 (December 26, 2020): 96–100. http://dx.doi.org/10.51791/njap.v44i2.1015.

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Instant noodles are widely consumed in Nigeria, with large of its by-products although high in energy but constituting environmental pollution in the production areas if allowed to lay waste. An eight-week feeding trial using 240 five-days old Hubbard flex broiler chicks was conducted to access the effect of feeding graded levels of indomie noodle waste (INW) in isonitrogenous diets on serum lipid profile of birds. Birds were allotted five treatments containing three replicates having sixteen birds per replicate in a completely randomized design. Five diets were compounded containing indomie noodle waste at 0, 25, 50, 75 and 100% replacing maize in the diets. Feed and water were provided ad libitum. At the end of the experiment, blood samples were collected from severed jugular veins of two birds per replicate and subjected to laboratory analysis for Total Cholesterol, High density lipoproteins, Low density lipoproteins and Triglycerides. Results showed that increase in INW in the diets of broilers increased total cholesterol (148.24mg/dl -192.06mg/dl, SD 61.68) and triglyceride (27.07mg/dL-91.52mg/dl, SD 40.79), favored high density lipoproteins (37.38mg/dL - 77.34mg/Dl, SD 31.88), and lowered values for low density lipoproteins (72.18mg/dL - 112.14mg/dL, SD 58.06) though there was no statistical difference (P>0.05) across the treatments. Indomie noodle waste has the potential to replace maize up to 100% with good effects on High Density Lipoproteins, Total Cholesterol within range and lower Low Density Lipoproteins values.

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Ascione, Luigi, Geminiano Mancusi, and Anna D'Aponte. "Fabric-Reinforced Cementitious Matrix (FRCM): A New Italian Guideline under Development." Key Engineering Materials 624 (September 2014): 3–10. http://dx.doi.org/10.4028/www.scientific.net/kem.624.3.

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In addition toFibre-Reinfocedcomposite materials, which are made of long glass/carbon/aramid fibers embedded in a polymer matrix (FRP), the use ofFRCMcomposites (Fabric-Reinforced Cementitious Matrix) is becoming more and more widespread. As far as this specific case, the inorganic matrix guarantees many advantages, especially when dealing with masonry substrates, including a good compatibility from both a physical and a chemical point of view and the possibility of wet lay-up application. Despite their wide use in technical applications, the constitutive behavior and the failure mechanisms of FRCMs have not been adequately studied. As a consequence, a final assessment upon which criteria have to be used for verification and qualification ofFRCMsis still missing. In the context of a recent experimental program-still under development-cooperated by many Italian academic laboratories, that is aimed at detecting the main features of the constitutive behavior of these materials, a discussion seems to be appropriate on the initial experimental results obtained at Salerno University on manyFRCMspecimens tested under uniaxial tensile loads.

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Niranjan, Raja R., S. Junaid Kokan, R. Sathya Narayanan, S. Rajesh, V. M. Manickavasagam, and B. Vijaya Ramnath. "Fabrication and Testing of Abaca Fibre Reinforced Epoxy Composites for Automotive Applications." Advanced Materials Research 718-720 (July 2013): 63–68. http://dx.doi.org/10.4028/www.scientific.net/amr.718-720.63.

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The natural fibre composite materials are nowadays playing a vital role in replacing the conventional and synthetic materials for industrial applications. This paper proposes a natural fiber composite made of Abaca fibre as reinforcing agent with Epoxy resin as the matrix, manufactured using Hand Lay-up method. Glass Fiber Reinforced Plastics (woven rovings) are used to improve the surface finish and impart more strength and stiffness to natural fibers. In this work, the fibers are arranged in alternative layers of abaca in horizontal and vertical orientation. The mechanical properties of the composite are determined by testing the samples for tensile and flexural strength. It is observed that the tensile strength of the composite material is dependent on the strength of the natural fiber and also on the interfacial adhesion between the reinforcement and the matrix. The composite is developed for automobile dashboard/mudguard application. It may also be extended to biomedical, electronics and sports goods manufacturing. It can also be used in marine products due to excellent resistance of abaca to salt water damage since the tensile strength when it is wet.

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Saghafi, Mahdi, Nader Tabatabaee, and Soheil Nazarian. "Performance Evaluation of Slurry Seals Containing Reclaimed Asphalt Pavement." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 1 (January 2019): 358–68. http://dx.doi.org/10.1177/0361198118821908.

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Preventive pavement maintenance methods such as slurry seals are cost-effective treatments that increase the longevity of pavements. The incorporation of recycled materials such as reclaimed asphalt pavement (RAP) into asphalt pavement helps to further reduce costs and energy consumption. The present research studied the feasibility of incorporating RAP into slurry seal mixtures or RAP slurry seals. Two slurry seal mixtures containing cement and hydrated lime as fillers were tested. The first mixture comprised slurry seal made with virgin aggregate and the second used RAP as the aggregate. The wet track abrasion test (WTAT) and loaded wheel test (LWT) were conducted to evaluate the performance of the mixtures. Wet cohesion and friction tests (sand patch and British pendulum) were performed on the selected slurry seal mixtures with the best performance under WTAT and LWT. The results show that it is possible to prepare slurry seal containing RAP. Although the curing time relative to the virgin aggregates increased by 1 h for RAP aggregate, the wear value in the WTAT decreased by half. Lateral displacement and the British pendulum test results improved considerably for slurry seals made with RAP aggregates. The results of the sand patch test on WTAT samples showed that slurry seals made with RAP should be lightly rolled after lay-down to improve their friction life. Cost analysis indicates that the use of RAP as an aggregate in slurry seal decreased costs by up to 14%. RAP slurry seal showed better overall performance with lower cost than the virgin slurry seal.

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Sadikin, A. N., R. R. Ali, N. Othman, and Mohd Ghazali Mohd Nawawi. "A Simple and Cost-Effective Method for Fabricating Chitosan-Filled Filter Media from Lignocellulosic Biomass." Applied Mechanics and Materials 606 (August 2014): 61–65. http://dx.doi.org/10.4028/www.scientific.net/amm.606.61.

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The newly developed non-woven filter media are composed of randomly oriented fibrous fibers from lignocellulosic biomass. The aim of this study is to investigate the feasibility of incorporating chitosan solution in fibrous filter media made from lignocellulosic biomass. The wet lay-up method was adopted for filter media fabrication. Diluted acetic acid was used as medium to dissolve the chitosan powder. Chitosan solution was applied to the fiber using two different deposition techniques, namely, spray method and addition method. The tensile test demonstrated that the filter media using spray method outperformed a filter media made from by addition technique. From the FT-IR spectrum, when the chitosan was added to empty fruit bunches fibers, the absorption peaks at around 1642 cm-1 are clearly identified that showing the presence of amine group in the fibers. The changes observed in the spectra indicated the possible interaction of functional groups between chitosan and cellulose in the fibers. The newly developed non-woven filter media integrates the functions for both the deep filtration and mechanical screen, thus it will be an alternative medium in oily wastewater treatment industry.

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Zhang, Xiaotong, and Ying Yan. "Catalytic combustion of isopropanol over Co–ZSM-5 zeolite membrane catalysts in structured fixed-bed reactor." Royal Society Open Science 5, no. 8 (August 2018): 180587. http://dx.doi.org/10.1098/rsos.180587.

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Catalytic combustion of isopropanol in the structured fixed-bed reactor was investigated over Co–ZSM-5 zeolite membrane catalysts. Firstly, ZSM-5 zeolite membrane catalysts with different Si/Al ratios were coated onto the surface of stainless steel fibres via secondary growth method and wet lay-up paper-making method. Then, cobalt oxides were loaded onto the zeolite membranes by impregnation method. The performance of catalytic combustion of isopropanol was conducted over the prepared zeolite membrane catalysts, and the experimental results showed that the catalyst with infinite Si/Al ratio has the highest catalytic activity for the combustion with the lowest T 90 of isopropanol (285°C). Finally, the effects of bed structure, feed concentration, gas hourly space velocity and reaction temperature on the catalytic performance were investigated to analyse the kinetics of isopropanol over the catalyst with infinite Si/Al ratio in the structured fixed-bed reactor. The results showed that the longer residence time could cause higher reaction contact efficiency of isopropanol combustion. T 90 of isopropanol can be dramatically decreased by 105°C in the fixed-bed reactor packed with Co–ZSM-5 zeolite membrane catalysts, compared to the fixed-bed reactor packed with granular catalyst.

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Sun, Wenbin, Ying Luo, and Huasheng Sun. "Experimental Studies on the Elastic Properties of Carbon Fiber Reinforced Polymer Composites Prefabricated of Unidirectional Carbon Fiber Fabrics and a Modified Rule of Mixtures in the Parallel Direction." Advanced Composites Letters 27, no. 1 (January 2018): 096369351802700. http://dx.doi.org/10.1177/096369351802700104.

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Carbon fiber (CF) fabrics can be installed manually onto the surfaces of existing structural members to establish a carbon fiber reinforced polymer (CFRP) reinforcemenet system, even in areas of limited access. Actual mechanical properties, such as the ultimate tensile strength (UTS), elastic modulus (EM), and ultimate rupture strain (URS), are essential for application in engineering practice and theoretical analysis of CFRP strengthening system. In this study, 16 CFRP strips were prefabricated of unidirectional CF sheet by a wet lay-up technique, and were tested to evaluate their elastic parameters. Test results indicated that experimental values of all specimens were much lower than that of CF fabrics, which were provided by manufacturer, and the stress-strain curves were observed to deviate slightly from a perfectly linear relationship at the later stage of loading. Comparing with the predictions of the rule of mixtures (ROM), the experimental data have large deviations and opposite laws. An orientated-design model was derived to modify the linear ROM by the regression analysis. A modified rule of mixtures (MROM) was suggested to describe the elastic properties of CFRP composite in the parallel direction.

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MAVRILAS, DIMOSTHENIS, THEODORA TSAPIKOUNI, DIMITRIOS MIKROULIS, GRIGORIOS BITZIKAS, VASSILIOS DIDILIS, KOSMAS TSAKIRIDIS, FOTIS KONSTANTINOU, and GEORGIOS BOUGIOUKAS. "DYNAMIC MECHANICAL PROPERTIES OF ARTERIAL AND VENOUS GRAFTS USED IN CORONARY BYPASS SURGERY." Journal of Mechanics in Medicine and Biology 02, no. 03n04 (September 2002): 329–37. http://dx.doi.org/10.1142/s0219519402000502.

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In this work we studied the frequency dependence of the dynamic mechanical characteristic s of saphenous vein (SV) and internal mammary artery (IMA) grafts. Rectangular longitudinal strips from 14 patients were tested under cyclic uniaxial tensile loading in the frequency range of 0.1–20 Hz, at 37°C in wet conditions. The dynamic mechanical parameters (the storage modulus ES and the hysteresis ratio h (loading/loop area)) together with the collagen phase modulus EH were computed as a function of frequency. The results showed that in all graft types ES and EH varied with frequency in the range 0.5–10 Hz, presenting a maximum in the neighboring of 1 Hz. The hysteresis ratio h was increased in the frequency range 1–20 Hz. It seems from the results that the physical resonance frequency of the components of the tissue responsible for their elastic behavior may lay in the range around 1 Hz, while that for the viscous behavior in the range of 20 Hz or more. Early clinical outcomes of both grafting were studied in parallel. In a one-year postoperative period the follow-up (clinical examination, electrocardiography, echocardiography and stress test) did not reveal any sign of graft occlusion or severe stenosis except one perioperative infraction but without any correlation to the graft quality.

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Tidemann, Sonia C. "Causes of the decline of the Gouldian Finch Erythrura gouldiae." Bird Conservation International 6, no. 1 (March 1996): 49–61. http://dx.doi.org/10.1017/s0959270900001301.

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SummaryPopulations of Gouldian Finch Erythrura gouldiae, an estrildid endemic to northern Australia, declined markedly during the last two or three decades. A survey revealed the species in two areas of Northern Territory, with an estimated 2,000 individuals, including juveniles. Recaptures were low either because of mortality or dispersal. Gouldian Finches eat predominantly Sorghum spp. seeds, but consume other seeds before Sorghum ripens. Other finches declined as cattle increased. Gouldian Finches breed in tree hollows of predominantly two species of eucalypts that grow on rocky slopes. They require water within about 4 km of the nest site. There was no shortage of nesting hollows at the known breeding sites. Fires in the early to mid-dry season allow birds access to seed without damaging trees, but later fires can destroy trees with nest hollows and remove shade. Average clutch-size is 5.2. About 72% of eggs laid, and 63% of nests, fledged young. Pairs lay up to three clutches in a season (February-August), the length of which may depend on rainfall during the preceding wet season. Air-sac mite (Sternostoma tracheacolum), found in 62% of Gouldian Finches sampled, may be preventing the species recovering to former numbers. New colonies of Gouldian Finches should be identified, populations monitored, and habitat managed by effecting patchy burns by low-intensity fires early in the dry season.

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Ramraji, K., K. Rajkumar, and P. Sabarinathan. "Mechanical and free vibration properties of skin and core designed basalt woven intertwined with flax layered polymeric laminates." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 234, no. 22 (May 4, 2020): 4505–19. http://dx.doi.org/10.1177/0954406220922257.

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Design of fiber-reinforced polymer damping laminates has been attracting great interest in industrial sectors for lightweight structural damping applications. The present work investigates the impact of skin, core, neutral, and alternate intertwined basalt/flax fabric on the mechanical and vibrational properties of the newly designed polymeric laminate. The designed sequence structure was fabricated using a wet hand lay-up technique with hydraulic compression. Tensile and flexural strength of intertwined multilayer basalt/flax woven composite were studied. An effect of the intertwining on the tensile and flexural strength fractured surface of the composites has been further evaluated. Free vibration technique was used for recording vibration response and the related damping frequencies of intertwining composites. A cantilever mode impact hammer was used for generating periodic signals of the designed composite systems. Damping ratios and damped natural frequencies were calculated with several plies and sequence of flax/basalt woven in the composite. The experimental results revealed that the damped natural frequencies of class II, skin basalt layer intertwined seven core flax layered composite (B2F7) was high, followed by two skin basalt layers intertwined core flax layered composite (B4F5). The addition of the flax layer enhanced the natural frequency to the higher value. It was found that the skin basalt layer with intertwined flax layered B2F7 design structure exhibits maximum damping value with acceptable mechanical properties.

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Kalny, Ondrej, Robert J. Peterman, Guillermo Ramirez, C. S. Cai, and Dave Meggers. "Structural Performance of Fiber-Reinforced Polymer Honeycomb Sandwich Panels: Evaluation of Size Effect and Wrap Strengthening." Transportation Research Record: Journal of the Transportation Research Board 1845, no. 1 (January 2003): 191–99. http://dx.doi.org/10.3141/1845-21.

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Stiffness and ultimate load-carrying capacities of glass fiber-reinforced polymer honeycomb sandwich panels used in bridge applications were evaluated. Eleven full-scale panels with cross-section depths ranging from 6 to 31.5 in. (152 to 800 mm) have been tested to date. The effect of width-to-depth ratio on unit stiffness was found to be insignificant for panels with a width-to-depth ratio between 1 and 5. The effect of this ratio on the ultimate flexural capacity is uncertain because of the erratic nature of core-face bond failures. A simple analytical formula for bending and shear stiffness, based on material properties and geometry of transformed sections, was found to predict service-load deflections within 15% accuracy. Although some factors influencing the ultimate load-carrying capacity were clearly identified in this study, a reliable analytical prediction of the ultimate flexural capacity was not attained. This is because failures occur in the bond material between the outer faces and core, and there are significant variations in bond properties at this point due to the wet lay-up process, even for theoretically identical specimens. The use of external wrap layers may be used to shift the ultimate point of failure from the bond (resin) material to the glass fibers. Wrap serves to strengthen the relatively weak core–face interface and is believed to bring more consistency in determining the ultimate load-carrying capacity.

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Siddique, Sheraz Hussain, Dr Saira Faisal, Bilal Zahid, and Chunhong Wang. "Tensile Properties of Bagasse Fiber Composites." July 2021 40, no. 3 (July 1, 2021): 502–11. http://dx.doi.org/10.22581/muet1982.2103.05.

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Bagasse is a waste generated in abundance from the sugarcane industry. This investigation was planned to convert bagasse waste into a useful composite. For this purpose the bagasse waste was obtained from sugar cane juice producer. In this study, the extraction of bagasse fibers was done manually and they were treated with sodium hydroxide. The treated bagasse fibers had higher tensile properties as compared to untreated ones, so the alkali treated fibers were used as reinforcement for making composites. Hand lay-up technique was used to manufacture bagasse composite samples. The fiber length (1 inch and 2 inch) and fiber weight percentage (10 wt% and 20 wt%) were considered as variables. It was found that better tensile properties were obtained with higher fiber length (2 inch) and weight percentage (20 wt%). Bagasse-cotton fabric composites were also produced using cotton fabric as a base material and the bagasse fibers were sandwiched between a printed and plain cotton fabric. The idea was to consider these composites useful for sun-shades or for decorative purposes. It was also found that bagasse-cotton fabric reinforced composites had higher tensile strength and strain; however the modulus had reduced due to higher elongation of cotton fabrics. With the increase in the weight percentage the tensile properties had reduced this might be because during the composite manufacturing the epoxy resin had to pass through the fabric to wet the bagasse fiber out and they were not wetted out properly. This phenomenon needs further investigation.

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Boylston, John W., Paul J. Riley, and Gary W. Van Tassel. "The Lay-Up and Reactivation of LNG Tankers: Lessons Learned." Journal of Ship Production 10, no. 03 (August 1, 1994): 174–83. http://dx.doi.org/10.5957/jsp.1994.10.3.174.

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The Liquid natural gas (LNG) industry went from a projected boom in the 1970's to a contracted industry in the 1980's, when many ships were either permanently or temporarily laid up. In the 1990s, many laid-up LNG carriers are being reactivated after as many as 12 years in lay-up. While the capital cost of an LNG carrier should dictate maximum preservation of the asset, the LNG industry is not immune to having to make hard economic decisions during slack times. In this paper, the authors present specific alternate lay-up procedures, together with the relative costs of these alternatives. LNG carriers are steam vessels, as are many of the vessels in the Ready Reserve Fleet (RRF). However, many of the conclusions reached can also be applied to motor vessels, and as such could be of interest to operators and shipyards in all phases of the RRF program. The subjects of dehumidification, inert gas plants, ballast tank coatings and drydocking, among others, are discussed.

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Jain, Sanyam, Zahir Merchant, Neil Kire, Jwalant Patel, Ankit Patel, and Vishal Kundnani. "Learning Curve of Microendoscopic Discectomy in Single-Level Prolapsed Intervertebral Disc in 120 Patients." Global Spine Journal 10, no. 5 (August 6, 2019): 571–77. http://dx.doi.org/10.1177/2192568219866169.

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Study Design: Retrospective study of prospectively collected data. Objective: To evaluate learning curve of tubular microendoscopic discectomy (MED) in lumbar prolapsed intervertebral disc (PIVD) patients based on surgical and clinical parameters and delineate the challenges faced in early cases while practicing MED in large series of patients. Methods: This study was an institutional review board–approved retrospective study of the first 125 consecutive patients with single-level lumbar PIVD managed with tubular MED from 2008 to 2016 with a minimum 2-year follow-up. A total of 120 patients available at final follow-up were divided into quartiles (30 each) as per the date of surgery, with each consecutive group serving as a control for the previous group. Preoperatively and postoperatively clinical parameters (pain scores [Visual Analogue Scale; VAS], functional disability [Oswestry Disability Index; ODI] score, modified MacNab criteria), perioperative parameters (operative time, blood loss, hospital stay), technical issues (guide wire migration, tube docking–related problems, dural tear), and postoperative complications (postoperative leg pain, neural injury, infection, recurrence) were evaluated. Statistical analysis—logarithm curve-fit regression analysis and ANOVA test. Results: The sample consisted of 75 males and 45 females (mean age: 42.54 years) with no significant difference among the quartiles. There was significant difference ( P < .005) noted in mean operative time (quartile 1, 87.33 minutes; quartile 2, 58.5 minutes) and mean blood loss (quartile 1, 76.33 mL; quartile 2, 32.66 mL) between quartile 1 and quartile 2, with no further significant reduction in quartile 3 and quartile 4. Significant difference ( P < .005) in clinical parameters (VAS preoperative/postoperative 5.28/0.99; ODI preoperative/postoperative 32.18/12.08) were noted but was not associated with surgical experience. Overall, 90% (108 out of 120) of the patients had good to excellent results according to the modified MacNab criteria. The mean hospital stay did not show any significant difference among the quartiles. Guide wire migrated issues, neural injury, dural tear, and tube docking–related problems were significantly reduced after quartile 1. However, recurrence occurred at any phase. Infection occurred in one patient in quartile 1. Although blood loss and operative time showed a declining trend, it was not significant after quartile 2. So asymptote lay in quartile 1 and we recommend that novice surgeon should perform 25 to 30 cases to achieve mastery in this technique. Conclusion: For mastering the art of tubular MED for lumbar PIVD and to reduce its learning curve, novice surgeons can avoid the challenges and problems faced during initial cases with improvement in surgical skills by practicing on cadavers, wet labs, and bone-saw models following certain recommendations that we have after achieving asymptote. Familiarity with instrumentation, communication between surgical team, and defined expectations from radiology technicians are key to reduce the learning curve.

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Ho, C. C., D. McC Newbery, and M. E. D. Poore. "Forest composition and inferred dynamics in Jengka Forest Reserve, Malaysia." Journal of Tropical Ecology 3, no. 1 (February 1987): 25–56. http://dx.doi.org/10.1017/s0266467400001103.

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ABSTRACT1211 trees of 3 ft (0.91 m) girth or more were enumerated in 288 1-ch2 (about 400 m2) quadrats forming a 11.7 ha plot on the mainly Segamat soil series, Jengka Forest Reserve, Peninsular Malaysia, in 1964. Of the 261 taxa, 84% were identified to species. Five per cent of the area was of the permanently wetter Akob soil series. The plot was topographically flat and lay about 3 km west of the plot on the Batu Anam soil series, described in an earlier paper. Data on the chemical composition of the three soils are summarized here from a survey in 1967.The vegetation on the Segamat series is of the Shorea-Dipterocarpus type of lowland dipterocarp forest. It has an unusually high abundance of the Euphorbiaceae (25% of trees) and a clear dominant species, Elateriospermum tapos. E. tapos, which regenerates profusely in the shade, grows up in small gaps and is strongly clumped, and appears well suited to the very friable, relatively nutrient-rich soil of the Segamat series, with lower soil-water holding capacity especially in dry periods.Forest on the Segamat series is floristically very different from that on the Batu Anam series. This is most likely due to large differences in soil properties, the latter being of lower clay content, less nutrient-rich and, having a greater soil-water holding capacity at least in dry periods. It was dominated by Dipterocarpaceae.Classification of quadrats on the Segamat series highlighted four classes; vegetation of the main E. tapos-dominated type on relatively dry soil (54% of plot area), vegetation on the wet Akob soil (21%), an association of shade-tolerant, mainly understorey trees beneath non-E. tapos-associated emergents (11%), and an association of long-lived, light-demanding pioneer trees of late-successional stages (11%); 3% of plot had no enumerated trees. Ordination showed that the plot was largely homogeneous with respect to edaphic factors but clearly displayed stages in forest succession.The possible dynamics of the Segamat forest are inferred in terms of species autecology. Two hypotheses are advanced to explain the composition of the Segamat forest: (a) a dynamic equilibirum, (b) a non-equilibrium recovery from a recent catastrophe. The latter was thought more likely. Compared with the more benign Batu Anam environment, where co-dominants might be ‘ecologically equivalent’, the more selective soil conditions on the Segamat leads to reduced equivalence, with accidents of regeneration playing a smaller role in the local distribution of the most abundant species.

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Sambo, Banake E., and Ehiabhi C. Odion. "Clipped Cowpea (Vigna unguiculata (L.) Walp) Fodder Utilization: A Potential for Income Growths of Resource Poor Farmers in the Savannah Regions of Nigeria." Sustainable Agriculture Research 5, no. 1 (January 19, 2016): 70. http://dx.doi.org/10.5539/sar.v5n1p70.

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Cowpea features prominently in the farming systems of the semi-arid tropics where they are grown for fodder used as feed for livestock. Traditional farm varieties are the indeterminate, spreading type which grow fast; cover the soil surface and produce large quantities of biomass. Studies have focused on the use of such green crop materials for soil fertility improvement. But, it’s been highlighted that a green manure crop should also be a cover crop of economic value. Such crops should raise the farmers’ income not only indirectly by improving soil fertility but also directly by yielding products of economic importance such as food and fodder. In addition, trading in these residues (fodder/ haulms) can be highly remunerating. It is against this background that this study was carried out at the Institute for Agricultural Research, Ahmadu Bello University, Samaru, Zaria, Nigeria; During the 2002-2005 wet seasons; to determining the influence of intra-row spacing, clipping height and time on the productivity and income growth potential of the dual purpose cowpea (Vigna unguiculata (L.) Walp). The experimental lay out was a Randomized Complete Block Design (RCBD); replicated three times. The data was analyzed statistically using the analysis of variance test (ANOVA); and the means compared using the Duncan Multiple Range Test (DMRT). Results showed that, clipping management, facilitated the production of large (15 t ha-1) amounts of green plant biomass on-farm. This could be put to various uses by the resource poor farmer who usually is cash strapped at the peak of the farming (dry) season. The farmer could choose to keep and use the fodder to feed animals, and/ or trade it off and use the proceeds (<s>N</s> 41, 000.00 - <s>N</s> 46, 000.00 - Nigerian Naira equivalent) to subsidize on fertilizer requirement and/ or meet up with immediate socio-economic family demands. Additionally, considering the high amount (187 kg-1) of N-added to the soil (i.e. about 4 bags of Urea fertilizer), a cost saving of about <s>N</s> 24, 000.00 was made by the resource poor farmer; which could have otherwise been invested into the procurement of N-fertilizer input. It is concluded that such pro-poor income growths originating from the adoption of such innovative clipping management technological farming practices as this, needs to be encouraged and supported; as this hold immense potential of increasing the income of resource poor, low income, and low technology farmers. Indeed, it is a veritable tool for the reduction of food insecurity and poverty viz. economic empowerment in the region.

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Smith, Frazer Howard. "Field joint coating of pipelines – effect of soluble salt contamination on 2-layer heat shrink sleeve performance." Anti-Corrosion Methods and Materials 63, no. 2 (March 7, 2016): 105–15. http://dx.doi.org/10.1108/acmm-09-2015-1573.

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Purpose – During offshore pipe-lay, pipe lengths with anticorrosion coating are welded together, and, to facilitate the welding process, the ends of the pipe remain uncoated. A wide range of field joint coating (FJC) types is available for coating this bare section, functioning in conjunction with the pipeline cathodic protection system to provide an anti-corrosion system or package. This paper aims to relate to two-layer type heat shrink sleeves (2LHSS), which commonly are used for FJC of concrete-weighted offshore pipelines where the sleeve typically is over-coated with a solid or foam type polyurethane “infill”. Similar sleeves also are used sometimes in exposed conditions on lines without concrete over-coating. The maximum allowable soluble salt contamination prior to application of high-performance coating systems can vary, depending upon the coating type, but typically has been set at 20 mg/m2 (de la Fuente et al., 2006). The first layer of three-layer heat shrink sleeve (3LHSS) systems for pipeline FJC, liquid epoxy, falls into this category (ISO_21809-3:2008, 2008). In contrast, the 2LHSS system does not use a liquid epoxy first layer but relies instead on the bonding of a “mastic” layer directly to the pipe metal surface. The maximum acceptable concentration of salt contamination on prepared metal surfaces prior to the application of 2LHSS has been a subject of debate and was the focus of this study. International standards for FJC do not provide a maximum salt level. However, some companies have continued to specify low thresholds for the maximum allowable salt level for 2LHSS, which can result in expensive delays in production during offshore pipe-lay. In this study, salt contamination levels of up to 120 mg/m2 were found to have no effect on peeling performance after accelerated aging by hot water immersion. Furthermore, preparation for welding and the use of potable water during ultrasonic testing procedures prior to FJC, typically reduces the salt contamination level to below 50 mg/m2 providing a strong case for the deletion of salt contamination testing for 2LHSS. Design/methodology/approach – The potential risk of failure of the coating due to poor surface cleanliness/contamination was assessed by testing the adhesion between the coating and the steel substrate to which the coating is adhering, following a period of hot water immersion. Compliance with ISO 21809-3 “Annex I” requires 28 days’ immersion at maximum operating temperature. For this study, to create a severe situation, the test rings were subjected to accelerated aging by water immersion at the HSS upper specified temperature of 65°C for more than twice the specified period (ISO_21809-3:2008, 2008). Two HSS were tested; one was widely used in applications where exposure to moderate mechanical stress is required, having a high shear strength type mastic “hybrid” adhesive containing a significant proportion of amorphous polypropylene blended with tackifiers and ethylene vinyl acetate (EVA), Andrenacci et al. (2009) referred to as “Type A”. The second, referred to as “Type B”, is widely used in applications where it is covered by a layer of “infill”, typically consisting of polyurethane foam or solid polyurethane elastomer, i.e. typical design methodology for concrete coated pipelines. “Type B” HSS had a more moderate strength traditional type mastic than “Type A” containing a significant percentage of butyl rubber with asphalt, activation agents and tackifying resins. To determine how to apply the salt contamination without causing flash rust, a mini-study was completed on the steel substrate. After numerous trials, it was found impossible to not to form visible rust on the pipe surface. The extent of rusting was minimised by heating the pipe immediately after the application of the salt solution. Findings – High levels of sea salt on power tool prepared pipe surfaces were investigated by peel testing of 2LHSS after hot water immersion and compared against peel tests undertaken prior to hot water immersion. The test conditions were considered severe: salt contamination levels of up to 120 mg/m2 applied on power tool cleaned pipe surfaces that had been aged for one year without prior grit blasting. The accelerated ageing procedure had twice the specified (ISO_21809-3:2008, 2008) water immersion duration, and the test samples had exposed edges providing the possibility for moisture to creep under the coating. The test results showed that there were no noticeable deleterious effects on the performance of the two most commonly used FJCs, 2LHSS. Therefore, it was concluded that, as the level of salt contamination on prepared pipe surfaces after wet non-destructive testing typically is much lower than the levels tested in this study, pipe surfaces prepared for the application of 2LHSS type do not require specific additional measures to further reduce salt contamination, provided that care is taken to ensure that these conditions are maintained consistently during pipe laying operations. Practical implications – The frequency of salt contamination testing of power tool cleaned surfaces prior to mastic type heat shrink sleeves can be minimised, and perhaps omitted entirely, provided the above criteria are satisfied. Originality/value – A literature review revealed there was little published information on the testing of 2LHSS and nothing related to hot water immersion testing. Hence, the results of this investigation have provided useful industrial data regarding the effect of hot water ageing and the influence of surface salt contamination on field joint corrosion prevention capabilities.

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Jacksi, Karwan, Subhi Zeebaree, and Nazife Dimililer. "Design and Implementation of LOD Explorer: A LOD Exploration and Visualization Model." Journal of Applied Science and Technology Trends 1, no. 2 (April 6, 2020): 31–39. http://dx.doi.org/10.38094/jastt1214.

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The quantity of data published on the Web according to principles of Linked Data (LD) is increasing intensely. However, this data is still largely limited to be used up by domain professionals and users who understand LD technologies. Therefore, it is essential to develop tools to enhance intuitive perceptions of LD for lay users. The features of LD point to various challenges for an easy-to-use data presentation. In this research, the technical details behind the LOD Explorer, which is a tool for exploring the Web of Data, is presented, the efficiency and scalability of the system has been tested using several different platforms, and the results of experiments indicated an outstanding performance.

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Demircan, Ozgur, Shinsuke Ashibe, Tatsuya Kosui, and Asami Nakai. "Modeling of tensile and bending properties of biaxial weft knitted composites." Science and Engineering of Composite Materials 22, no. 3 (May 1, 2015): 303–13. http://dx.doi.org/10.1515/secm-2013-0274.

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AbstractWithin the scope of experiments, the effect of aramid and glass yarns as stitch and biaxial (warp and weft) yarns in the biaxial weft knitted (BWK) composite was compared. After production of four types of composite panel using the hand lay-up method, the tensile and bending properties of the BWK composites were investigated both experimentally and numerically. The composite with the glass stitch and biaxial yarns exhibited higher tensile and bending properties than did the composite with the aramid stitch and biaxial yarns. The good agreement between the experimental results and the numerical results validated the applicability of the finite-element method for the BWK composites. The laminate beam theory was utilized as another modeling method for calculation of the bending modulus.

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Huang, Zheng-Ming, X. C. Teng, and S. Ramakrishna. "Progressive Failure Analysis of Laminated Knitted Fabric Composites Under 3-Point Bending." Journal of Thermoplastic Composite Materials 14, no. 6 (November 2001): 499–522. http://dx.doi.org/10.1106/uw1g-83l2-91w9-g47y.

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The bending behavior of laminated beams reinforced with differently arranged plain-weft knitted fabrics has been investigated in this paper. Experiments were carried out to measure the bending stiffness and strength of six layers knitted fabric rein-forced epoxy composite laminates under 3-point bending. The laminate lay-ups of [0/0/0/0/0/0], [90/90/90/90/90/90] and [0/-45/45/45/-45/0] have been taken into account, where 0 denotes that the fabric wale direction is arranged along the beam axial direction. A simulation procedure is presented to analyze the bending property of the laminated beams based on the bridging micromechanics model and the classical lamination theory. It has been found that the use of a stress failure criterion only is no longer enough for estimating the ultimate bending strength of the laminate. An additional critical deflection condition is also required. By using only the constituent properties, which were measured using bulk material specimens independently, and the fabric knitting and lay-up parameters, the predicted stiffness and strength agree favorably with the experimental data.

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Joffe, Roberts. "Performance of Non-Crimp Fabric Composites in Shear." Key Engineering Materials 425 (January 2010): 45–59. http://dx.doi.org/10.4028/www.scientific.net/kem.425.45.

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Experimental results of performance of non-crimp fabric composites are presented in this paper. In order to characterize in-plane shear properties of these composites, tensile and compression tests of [±452]S specimens were carried out. Two directions of loading are considered: warp (Shear warP: SP) and weft (Shear wefT: ST). This corresponds to laminates with the following lay-up: SP = [+45/-45/+45/-45]S; ST = [-45/+45/-45/+45]S. Although both types of laminates are cut from the same plate, mechanical performance in tension is rather different: laminate cut in weft direction exhibit higher shear modulus, shear strength and shear strain at failure than samples cut in warp direction. Fractography showed that different behavior of the materials is caused by much earlier damage initiation and accumulation in SP laminates. Analysis of images obtained from optical microscopy indicated that premature failure is most likely caused by stitches that prevent free rotation of bundles (shear deformation).

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Journal articles on the topic 'Wet lay-up'

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