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Sandeep Kumar - One of the best experts on this subject based on the ideXlab platform.
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Recycled milk pouch and virgin low-density polyethylene/linear low-density polyethylene based Coir Fiber composites
Journal of Applied Polymer Science, 2020Co-Authors: Arup Choudhury, Sandeep Kumar, Basudam AdhikariAbstract:The viability of the thermomechanical recycling of postconsumer milk pouches [a 50 : 50 low-density polyethylene/linear low-density polyethylene (LDPE–LLDPE) blend] and their use as polymeric matrices for Coir-Fiber-reinforced composites were investigated. The mechanical, thermal, morphological, and water absorption properties of recycled milk pouch polymer/Coir Fiber composites with different treated and untreated Fiber contents were evaluated and compared with those of virgin LDPE–LLDPE/Coir Fiber composites. The water absorption of the composites measured at three different temperatures (25, 45, and 75°C) was found to follow Fickian diffusion. The mechanical properties of the composites significantly deteriorated after water absorption. The recycled polymer/Coir Fiber composites showed inferior mechanical performances and thermooxidative stability (oxidation induction time and oxidation temperature) in comparison with those observed for virgin polymer/Fiber composites. However, a small quantity of a coupling agent (2 wt %) significantly improved all the mechanical, thermal, and moisture-resistance properties of both types of composites. The overall mechanical performances of the composites containing recycled and virgin polymer matrices were correlated by the phase morphology, as observed with scanning electron microscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
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Coir Fiber based fire retardant nano filler for epoxy composites
Journal of Thermal Analysis and Calorimetry, 2010Co-Authors: Sandeep KumarAbstract:Coir-Fiber-based fire retardant nano filler has been developed for epoxy resin (ER). At first, the Coir Fiber was brominated with saturated bromine water and then treated with stannous chloride solution. After drying, it was grinded to nano dimension and mix well with ER for composites preparations. FTIR, DSC, and TG techniques were used to characterize the brominated Coir Fiber. Gravimetric analysis shows only 10% by mass of bromination on Coir Fiber. Bromination decreases the thermal stability of the Coir Fiber, but it does not affect the final stability of the composites. This study concentrates on the thermal, fire retardant, and morphological properties of nanocomposites prepared by direct mixing. The fire retardancy properties (smoke density and limiting oxygen index) of Coir–epoxy nanocomposites have increased significantly.
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recycled milk pouch and virgin low density polyethylene linear low density polyethylene based Coir Fiber composites
Journal of Applied Polymer Science, 2007Co-Authors: Arup Choudhury, Sandeep Kumar, Basudam AdhikariAbstract:The viability of the thermomechanical recycling of postconsumer milk pouches [a 50 : 50 low-density polyethylene/linear low-density polyethylene (LDPE–LLDPE) blend] and their use as polymeric matrices for Coir-Fiber-reinforced composites were investigated. The mechanical, thermal, morphological, and water absorption properties of recycled milk pouch polymer/Coir Fiber composites with different treated and untreated Fiber contents were evaluated and compared with those of virgin LDPE–LLDPE/Coir Fiber composites. The water absorption of the composites measured at three different temperatures (25, 45, and 75°C) was found to follow Fickian diffusion. The mechanical properties of the composites significantly deteriorated after water absorption. The recycled polymer/Coir Fiber composites showed inferior mechanical performances and thermooxidative stability (oxidation induction time and oxidation temperature) in comparison with those observed for virgin polymer/Fiber composites. However, a small quantity of a coupling agent (2 wt %) significantly improved all the mechanical, thermal, and moisture-resistance properties of both types of composites. The overall mechanical performances of the composites containing recycled and virgin polymer matrices were correlated by the phase morphology, as observed with scanning electron microscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Sergio Neves Monteiro - One of the best experts on this subject based on the ideXlab platform.
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critical length and interfacial strength of palf and Coir Fiber incorporated in epoxy resin matrix
Journal of materials research and technology, 2018Co-Authors: Flavio James Humberto Tommasini Vieira Ramos, Lucio Fabio Cassiano Nascimento, Andre Benhur Da Silva Figueiredo, Sergio Neves MonteiroAbstract:Abstract The several advantages of natural lignocellulosic Fibers (NLFs), such as, economical, technical, environmental and social, make these Fibers an alternative to replace synthetic Fibers in composite materials. The application of NLF as reinforcements in polymeric composites has increased in many industrial sectors from civil construction to automobiles. This demands the characterization of promising Fibers, such as those extracted from leaves of pineapple (PALF) and the mesocarp of coconut fruit (Coir Fiber), for possible application in composites. In the present work, pullout tests were performed to compare the interfacial adhesion with epoxy resin of these two Fibers that have greatly different characteristics. Results showed a critical length 70% higher for the Coir Fiber in comparison to PALF and a interfacial strength 3.5 times smaller, which indicates stronger adhesion of PALF with epoxy resin. This may be justified by the distinct morphological aspects, particularly the rougher surface of PALF. Mechanical tests were also performed in both Coir Fiber and PALF composites. In these tests, it was observed the superiority of mechanical properties for the composite reinforced with 30 vol% of PALF. Additionally, ballistic tests were carried out. In this evaluation, composites were used in a MAS type III against the 7.62 mm ammunition. The results revealed a relatively low depth of penetration (18.2 mm) for the MAS with PALF composite as well as a depth of penetration (31.6 mm) for MAS with Coir composite, both considered efficient according to the personal body armor standard. Therefore, all these results highlight the potential of these Fibers as polymer composites reinforcement in ballistic armors.
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Correlation between the Diameter and the Density of Coir Fiber Using the Weibull Statistic Methodology
Materials Science Forum, 2014Co-Authors: Sergio Neves Monteiro, Frederico Muylaert Margem, Helvio Pessanha Guimarães Santafé Júnior, Lucas Barbosa De Souza Martins, Michel Picanço OliveiraAbstract:Economical, technical and environmental advantages justify the substitution of glass Fiber for lignocellulosic Fibers in polymeric composites. However the uniformity of the glass Fiber dimensions and composition contrast to the lignocellulosic Fibers heterogeneity. In this work, a statistical analysis of the correlation between the diameter and the density of Coir Fiber using the Weibull methodology was performed. The diameter was obtained by profile projector measurements, while the density used precise determinations of the Fibers mass and volume. The results revealed an inverse dependence between the Coir Fiber diameter and its density.
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tensile behavior of lignocellulosic reinforced polyester composites part iii Coir Fiber
Materia-rio De Janeiro, 2010Co-Authors: H P G Santafe, Felipe Perisse Duarte Lopes, Lucas Lopes Da Costa, Sergio Neves MonteiroAbstract:The Fiber extracted from the husk of a coconut fruit, known as Coir Fiber, has been extensively investigated as a second phase incorporation into polymer composites. The moderate strength of the Coir Fiber usually does not represent reinforcement to relatively strong thermoset matrices such as polyester, epoxy and phenolic. However, a selection of thinner Coir Fibers and a post cure treatment of the composite could improve its mechanical performance. Therefore, this work investigated the tensile properties of post-cured polyester matrix composites incorporated with the thinnest Coir Fiber. Tensile specimens with up to 40% in volume of long and aligned Coir Fibers were tested and their fracture analyzed by scanning electron microscopy. A relatively improvement was found in the tensile properties for the amount of 40% of Coir Fiber. These results were compared with similar composites that were bend-tested. The fracture analysis showed a comparatively better Fiber/matrix adhesion.
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mechanical performance of Coir Fiber polyester composites
Polymer Testing, 2008Co-Authors: Sergio Neves Monteiro, L A H Terrones, J R M DalmeidaAbstract:Abstract The structural characteristics and mechanical properties of Coir Fiber/polyester composites were evaluated. The Coir Fibers were obtained from disregarded coconut shells that if not properly processed constitute an environmental hazard. The as-received Coir Fiber was characterized by scanning electron microscopy coupled with X-ray dispersion analysis. Composites prepared with two molding pressures and with amounts of Coir Fiber up to 80 wt% were fabricated. Up to 50 wt% of Fiber, rigid composites were obtained. For amounts of Fiber higher than this figure, the composites performed like more flexible agglomerates. The results obtained for flexural strength allowed comparison of the technical performance of the composites with other conventional materials.
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Mechanical performance of Coir Fiber/polyester composites
Polymer Testing, 2008Co-Authors: Sergio Neves Monteiro, L A H Terrones, José Roberto Moraes D'almeidaAbstract:Abstract The structural characteristics and mechanical properties of Coir Fiber/polyester composites were evaluated. The Coir Fibers were obtained from disregarded coconut shells that if not properly processed constitute an environmental hazard. The as-received Coir Fiber was characterized by scanning electron microscopy coupled with X-ray dispersion analysis. Composites prepared with two molding pressures and with amounts of Coir Fiber up to 80 wt% were fabricated. Up to 50 wt% of Fiber, rigid composites were obtained. For amounts of Fiber higher than this figure, the composites performed like more flexible agglomerates. The results obtained for flexural strength allowed comparison of the technical performance of the composites with other conventional materials.
Mahbub Hasan - One of the best experts on this subject based on the ideXlab platform.
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effect of chemical treatment on the properties of Coir Fiber reinforced polypropylene and polyethylene composites
Polymer Composites, 2017Co-Authors: Mahbub Hasan, Syed M N Hasan, Md Jahangir Hossain, Nazia NafsinAbstract:Chemical treatment of reinforcement material is one of the main ways of improving the mechanical properties of natural Fiber reinforced polymer composites. In the present study, Coir Fiber was used as reinforcement material, while polypropylene (PP) and polyethylene (PE) polymer were used as matrix material. Before reinforcing with polymer, raw Coir Fiber was chemically treated with basic chromium sulfate and sodium bicarbonate in a sieve shaker. Hot-pressed method was used for composite manufacturing during which the Fiber loading was varied at 0, 5, 10, 15, and 20 wt%. Comparison of the properties of raw and chemically treated Coir Fiber reinforced PP and PE was conducted. Mechanical characteristics of the composites were evaluated using tensile, flexural, impact, and hardness tests. Water absorption test was conducted to know water uptake characteristics. Microstructural analysis using a scanning electron microscope was performed to observe the adhesiveness between the matrix and the Fiber. Thermogravimetric analysis was done to observe the physical and chemical changes in Fiber and composites. The results showed that chemical treatment improved the physical, mechanical, and thermal properties of the manufactured composites. PP composites had better properties as compared to PE composites, while higher Fiber loading resulted in better mechanical properties of the resultant composites. POLYM. COMPOS., 2015. © 2015 Society of Plastics Engineers
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effect of reinforcement and chemical treatment of Fiber on the properties of jute Coir Fiber reinforced hybrid polypropylene composites
Fibers and Polymers, 2014Co-Authors: Salma Siddika, Mahbub Hasan, Fayeka Mansura, Azman HassanAbstract:Present research investigates the mechanical properties of jute-Coir Fiber reinforced hybrid polypropylene (PP) composite with Fiber loading variation and observes the effect of chemical treatment of Fiber on property enhancement of the composites. Composites were manufactured using hot press machine at four levels of Fiber loading (5, 10, 15 and 20 wt%). Fiber ratio’s were varied (jute:Coir=1:1, 3:1 and 1:3) for 20 % Fiber loaded composites. Both jute and Coir Fiber was treated using 5 % and 10 % NaOH solutions. Composites were also prepared using treated Fiber with jute-Coir Fiber ratio of 3:1. Tensile, flexural, impact and hardness tests and Fourier transform infrared spectroscopic analysis were conducted for characterization of the composites. Tensile test of composite showed a decreasing trend of tensile strength and increasing trend of the Young’s modulus with increase in Fiber loading. During flexural, impact and hardness tests, the flexural strength, flexural modulus, impact strength and hardness values were found to be increased with increase in Fiber loading. All these properties enhanced with the enhancement of jute content except impact strength. 5 % NaOH treatment provided an improving trend of properties whereas, 10 % NaOH treatment showed the reverse one. The FTIR analysis of the composites indicated decrease of hemicelluloses and lignin content with alkali treatment.
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chemical treatment of Coir Fiber reinforced polypropylene composites
Industrial & Engineering Chemistry Research, 2012Co-Authors: Md Mominul Haque, Mahbub Hasan, Md Nazrul IslamAbstract:Agro-based renewable materials have received significant attention in recent years because of their low cost, light weight, ecofriendliness, and worldwide environmental awareness. In the present work, Coir Fiber reinforced polypropylene composites were manufactured using injection molding method. Raw Coir was chemically treated with benzene diazonium salt in alkali, acidic, and neutral media separately in order to increase the compatibility between the Coir Fiber and polypropylene composite. During chemical treatment, hydrophilic -OH groups in the raw Coir cellulose were converted to hydrophobic -O–Na groups. Both raw and treated Coir at 10, 15, 20, 25, 30, and 35 wt % were utilized during composite manufacturing. Microstructural analysis and mechanical tests were conducted. Alkali treated specimens yielded the best set of mechanical properties. On the basis of Fiber loading, 30% Fiber reinforced composites had the optimum set of mechanical properties among all composites manufactured.
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chemical modification effect on the mechanical properties of Coir Fiber
Engineering Journal, 2012Co-Authors: Syed M N Hasan, Md Jahangir Hossain, Mahbub HasanAbstract:Natural Fiber has a vital role as a reinforcing agent due to its renewable, low cost, biodegradable, less abrasive and eco-friendly nature. Whereas synthetic Fibers like glass, boron, carbon, metallic, ceramic and inorganic Fibers are expensive and not eco-friendly. Coir is one of the natural Fibers easily available in Bangladesh and cheap. It is derived from the husk of the coconut (Cocos nucifera). Coir has one of the highest concentrations of lignin, which makes it stronger. In recent years, wide range of research has been carried out on Fiber reinforced polymer composites [4-13].The aim of the present research is to characterize brown single Coir Fiber for manufacturing polymer composites reinforced with characterized Fibers. Adhesion between the Fiber and polymer is one of factors affecting the strength of manufactured composites. In order to increase the adhesion, the Coir Fiber was chemically treated separately in single stage (with Cr 2 (SO 4 )3•12(H 2 O)) and double stages (with CrSO 4 and NaHCO 3 ). Both the raw and treated Fibers were characterized by tensile testing, Fourier transform infrared (FTIR) spectroscopic analysis, scanning electron microscopic analysis. The result showed that the Young’s modulus increased, while tensile strength and strain to failure decreased with increase in span length. Tensile properties of chemically treated Coir Fiber was found higher than raw Coir Fiber, while the double stage treated Coir Fiber had better mechanical properties compared to the single stage treated Coir Fiber. Scanning electron micrographs showed rougher surface in case of the raw Coir Fiber. The surface was found clean and smooth in case of the treated Coir Fiber. Thus the performance of Coir Fiber composites in industrial application can be improved by chemical treatment.
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Coir Fiber reinforced polypropylene composites physical and mechanical properties
Advanced Composite Materials, 2010Co-Authors: Md Mominul Haque, Mahbub Hasan, Nazrul Islam, Monimul Huque, Saiful Islam, Sakinul IslamAbstract:Coir Fiber reinforced polypropylene composites were manufactured using a single extruder and an injection molding machine. Raw Coir was chemically treated with benzene diazonium salt to increase its compatibility with the polypropylene matrix. Both raw and treated Coir Fiber was utilized and five levels of Fiber loading (15, 20, 25, 30 and 35 wt%) were used during composite manufacturing. Microstructural analysis (Fourier transform infrared spectroscopy and scanning electron microscopy) and mechanical (tensile, flexural, impact, hardness and water absorption) tests were conducted. Chemically treated Coir Fiber reinforced specimens yielded better mechanical properties compared to the raw ones. For the Fiber loaded samples, 30% Fiber reinforced composites had the optimum set of mechanical properties. Authors propose that the bonding between the polypropylene matrix and chemically treated Coir Fiber must be increased in order to have improved mechanical properties at higher Fiber content.
Rozli Zulkifli - One of the best experts on this subject based on the ideXlab platform.
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A practical acoustical absorption analysis of Coir Fiber based on rigid frame modeling
Acoustical Physics, 2012Co-Authors: M Ayub, Mohammad Hosseini Fouladi, Rozli Zulkifli, Nowshad AminAbstract:An analytical study based on rigid frame model is demonstrated to evaluate the acoustic absorption of Coir Fiber. Effects of different conditions such as combination of air gap and perforated plate (PP) are studied in this work. Materials used here are treated as rigid rather than elastic, since the flow resistivity of Coir Fiber is very low. The well-known rigid frame Johnson-Allard equivalent-fluid model is applied to obtain the acoustic impedance of single layer Coir Fiber. Atalla and Sgard model is employed to estimate the surface impedance of PP. Acoustic transmission approach (ATA) is utilized for adding various consecutive layers in multilayer structure. Models are examined in different conditions such as single layer Coir Fiber, Coir Fiber backed with air gap, single layer PP in combination with Coir Fiber and air gap. Experiments are conducted in impedance tube on normal incidence sound absorption to validate the results. Results from the measurement are found to be in well agreement with the theoretical absorption coefficients. The performance of the rigid frame modeling method is checked more specifically in all conditions, by the mean prediction error rate of normal incidence sound absorption coefficients. Comparison between the measured absorption coefficients and predicted by rigid frame method shows discrepancy lower than 20 and 15% for most of the conditions in the frequency range of 0.2–1.5 and 1.5–5 kHz, respectively. Moreover, acoustic absorption of various single and multilayer structures is compared with the simpler empirical methods such as Delany-Bazley and Miki model; and complicated method such as Biot-Allard Model and Allard Transfer Function (TF) method. Comparisons show that the presented method offers a better accuracy of the results than the empirical models. Subsequently, it can provide almost same absorption plot with Biot-Allard model (single layer combination) and TF method (multilayer combination) proving it to be a comprehensively easy and general analytical tool. Therefore, the rigid frame model can be implemented relatively easier than other similar models to analyze the acoustic absorption of Coir Fiber in most of the conditions.
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A practical acoustical absorption analysis of Coir Fiber based on rigid frame modeling
Acoustical Physics, 2012Co-Authors: Md Ayub, Mohd Jailani Mohd Nor, Mohammad Hosseini Fouladi, Rozli ZulkifliAbstract:An analytical study based on rigid frame model is demonstrated to evaluate the acoustic absorption of Coir Fiber. Effects of different conditions such as combination of air gap and perforated plate (PP) are studied in this work. Materials used here are treated as rigid rather than elastic, since the flow resistivity of Coir Fiber is very low. The well-known rigid frame Johnson-Allard equivalent-fluid model is applied to obtain the acoustic impedance of single layer Coir Fiber. Atalla and Sgard model is employed to estimate the surface impedance of PP. Acoustic transmission approach (ATA) is utilized for adding various consecutive layers in multilayer structure. Models are examined in different conditions such as single layer Coir Fiber, Coir Fiber backed with air gap, single layer PP in combination with Coir Fiber and air gap. Experiments are conducted in impedance tube on normal incidence sound absorption to validate the results. Results from the measurement are found to be in well agreement with the theoretical absorption coefficients. The performance of the rigid frame modeling method is checked more specifically in all conditions, by the mean prediction error rate of normal incidence sound absorption coefficients. Comparison between the measured absorption coefficients and predicted by rigid frame method shows discrepancy lower than 20 and 15% for most of the conditions in the frequency range of 0.2-1.5 and 1.5-5 kHz, respectively. Moreover, acoustic absorption of various single and multilayer structures is compared with the simpler empirical methods such as Delany-Bazley and Miki model; and complicated method such as Biot-Allard Model and Allard Transfer Function (TF) method. Comparisons show that the presented method offers a better accuracy of the results than the empirical models. Subsequently, it can provide almost same absorption plot with Biot-Allard model (single layer combination) and TF method (multilayer combination) proving it to be a comprehensively easy and general analytical tool. Therefore, the rigid frame model can be implemented relatively easier than other similar models to analyze the acoustic absorption of Coir Fiber in most of the conditions. © Pleiades Publishing, Ltd., 2012.
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A study on the acoustical absorption behavior of Coir Fiber using miki model
International Journal of Mechanical and Materials Engineering, 2011Co-Authors: M Ayub, Mohammad Hosseini Fouladi, Rozli Zulkifli, Nowshad AminAbstract:Sound absorption capacity of natural Coir Fiber collected from coconut husk has been explored and predicted using Miki’s empirical model. Experiments are conducted in impedance tube to validate the analytical outcomes for three samples having different thickness backed with and without air gap. Results show that the empirical model can estimate the absorption coefficient of Coir Fiber favourably well and shows higher accuracy than the Delany-Bazley model. Discrepancies between the predicted and measured absorption coefficient is very low although some inevitable irregularities is observed in the peak positions. However, presented Miki model can evaluate the overall acoustic behavior of Coir Fiber. This approach can be considered as a very simple and preliminary analytical solution for Coir Fiber acoustical characterization without considering several physical parameters of porous media. In addition, as a result, no complicated measuring procedure has to be followed to initiate the preliminary study for this material.
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Studies on Flame Retardants on Malaysian Coir Fiber
International Journal on Advanced Science Engineering and Information Technology, 2011Co-Authors: Elwaleed Awad Khidir, Rozli Zulkifli, Mohd Faizal Mat Tahir, Zulkarnain Ali LemanAbstract:In this study to the effect of the utilization of urea and diammonium phosphate as fire retardant on Malaysian Coir Fiber was evaluated. Flammability and thermogravimetric analysis (TGA) tests were used to evaluate the fire retardancy. Weight loss and percentage of mass residue were used as a measure from the results of flammability and TGA, respectively. The results revealed the effectiveness of using urea and diammonium phosphate as fire retardant for Malaysian Coir Fiber. However, for the samples treated with retardant high concentration the weight loss is not significant with the time of dipping treatment. This indicates that the just dip application for the fire retardant of higher concentration is sufficient.
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effect of compression on the acoustic absorption of Coir Fiber
American Journal of Applied Sciences, 2010Co-Authors: Rozli Zulkifli, Mohammad Hosseini Fouladi, Nowshad Amin, Subang Jaya, Saudi ArabiaAbstract:Problem statement: The absorption characteristics of Coir Fiber were analyzed previously. Analytical method to predict the acoustical behavior of Coir Fiber has already been developed. However, compression effects of Coir Fiber were not explored which might significant for acoustics absorption during seat padding. In this study, compression effect on the sound absorption characteristics of Coir Fiber are demonstrated based on the previous analytical approach such as rigid frame method with the modification in the physical parameters. Approach: The verification of the estimated acoustical absorption coefficient in uncompressed condition using rigid frame Johnson- Allard Model are shown for three different thicknesses of industrially processed Coir Fiber mixed with binder latex. Measurements were conducted in impedance tube on normal incidence sound absorption of Coir Fiber. It is well known that the absorption behavior of a porous material varies during compression and affects the physical parameters. In these analyses, formulas proposed by Castagnede are employed to predict the compression effect on the absorption of Coir Fiber which takes into account the modifications of the physical parameters during compression. Results: The agreement between the analytical and measured results is justified for all three sample thicknesses in uncompressed condition. Analyses on the acoustic behavior of material during compressed condition show that compression has a substantial effect on the absorption of Coir Fiber. It also indicates that the absorption of Coir Fiber can be enhanced by compressing the material. In addition, the absorption performances are compared by varying the compression rate on material at uncompressed and compressed condition. Conclusion: From overall analyses, it is evident that compression of Coir Fiber can significantly change the absorption behavior of Coir Fiber from the actual acoustical characteristics as estimated at normal condition. Moreover, compressing the material might be considered as a possible approach to improve the absorption coefficient of Coir Fiber. An additional example is presented to show a potential way of enhancing absorption coefficient of Coir Fiber utilizing compression effect.
Mohammad Hosseini Fouladi - One of the best experts on this subject based on the ideXlab platform.
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Enhancement of Coir Fiber fire retardant property
Journal of Engineering Science and Technology, 2015Co-Authors: Mohammad Hosseini Fouladi, Chong Chien Hwa, Pang Zong Xin, Sim Yeng Peng Xin, Satesh Narayana Namasivayam, Masomeh Ghassem, Hamidreza Soheili NajafabadiAbstract:© School of Engineering, Taylor’s University.Application of porous material in acoustic panel has shown its effectiveness to control noise in term of sound absorption. Optimizing synthetic Fiber as resource in current market contributed several issues related to the depletion of environment. Hence, engineer has turned to natural Fiber from agriculture waste as alternative strategic solution. Despite having certain beneficial properties in acoustical field, to fulfill the building standard, property of fire retardant are yet to be implemented. This study has focused on three potential fire-retarding chemicals on Coir Fiber, namely, Di-Ammonium Phosphate (DAP), Borax and urea. Vertical burning experiment was executed based on standard of ASTM E69–02 (Standard Test Method for Combustible Properties of Treated Wood) using Fire-tube Apparatus prior to chemical treatment. Based on experimental results, DAP, Borax and urea-treated Fiber shows mass loss of 6.67%, 7.60% and 9.48% respectively. Compliance with NFPA 704, DAP was shown to exhibit superior ability to retard fire in Coir Fiber over other additives based on mass loss and low degree of hazards in terms of health, flammability and reactivity. In conclusion, fire retardant chemical like DAP is an essential component to be improved on to bring about the success commercialization of the acoustic panel.
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enhancement of Coir Fiber normal incidence sound absorption coefficient
Journal of Computational Acoustics, 2012Co-Authors: Mohammad Hosseini Fouladi, M Ayub, Masomeh GhassemAbstract:Coir Fiber from coconut husk is an important agricultural waste in Malaysia. The porous structure of Fiber makes it an eligible material for acoustical absorption. In previous studies at Universiti Kebangsaan Malaysia, single layer Coir Fiber showed low acoustical absorption in medium and low frequencies; e.g. absorption coefficient of a 20 mm industrial prepared Coir Fiber sample was below 0.3 for frequencies less than 1.5 kHz. Current research was initiated to improve the shortcoming by mixing industrial prepared Coir Fiber with air gap layers. Analyzes were based on two approaches, namely; Delany–Bazley with acoustic transmission analysis (ATA) and Allard elastic model with transfer matrix analysis. Experimental measurements were conducted in impedance tube to validate the analytical results. Outcomes described that Delany–Bazley-ATA technique was an approximate solution showing overall absorption path without giving any accurate information about the peaks and resonances. Allard method took the elasticity of material into account and transfer matrices were able to characterize the whole structure as a combination of single layers. Results were close to experimental values and predicted the path and resonances very well. Further analyzes were conducted by Allard method and derived that having a Fiber layer backed by an air gap was better than leaving the same gap in between that layer. The explanation was that, in the first arrangement, the sound field impacted a solid layer with higher thickness and followed a longer transmission path which caused a higher acoustical absorption. Furthermore, it was noticed that a reasonable thickness of backing air gap improved the overall sound absorption. Increase in the gap thickness produced more peaks and moved them to lower frequencies which caused better absorption in low frequencies. The cause of this phenomenon was increase in impedance of the panel due to rise in the air-gap thickness. This moved the acoustical resonances to lower frequencies and improved the sound absorption in this frequency span. Finally, it was concluded that other acoustic absorption techniques such as adding perforated plate may be combined with Coir Fiber-air gap structure to improve the low frequency acoustic absorption coefficient without any need to highly increase the air gap thickness.
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A practical acoustical absorption analysis of Coir Fiber based on rigid frame modeling
Acoustical Physics, 2012Co-Authors: M Ayub, Mohammad Hosseini Fouladi, Rozli Zulkifli, Nowshad AminAbstract:An analytical study based on rigid frame model is demonstrated to evaluate the acoustic absorption of Coir Fiber. Effects of different conditions such as combination of air gap and perforated plate (PP) are studied in this work. Materials used here are treated as rigid rather than elastic, since the flow resistivity of Coir Fiber is very low. The well-known rigid frame Johnson-Allard equivalent-fluid model is applied to obtain the acoustic impedance of single layer Coir Fiber. Atalla and Sgard model is employed to estimate the surface impedance of PP. Acoustic transmission approach (ATA) is utilized for adding various consecutive layers in multilayer structure. Models are examined in different conditions such as single layer Coir Fiber, Coir Fiber backed with air gap, single layer PP in combination with Coir Fiber and air gap. Experiments are conducted in impedance tube on normal incidence sound absorption to validate the results. Results from the measurement are found to be in well agreement with the theoretical absorption coefficients. The performance of the rigid frame modeling method is checked more specifically in all conditions, by the mean prediction error rate of normal incidence sound absorption coefficients. Comparison between the measured absorption coefficients and predicted by rigid frame method shows discrepancy lower than 20 and 15% for most of the conditions in the frequency range of 0.2–1.5 and 1.5–5 kHz, respectively. Moreover, acoustic absorption of various single and multilayer structures is compared with the simpler empirical methods such as Delany-Bazley and Miki model; and complicated method such as Biot-Allard Model and Allard Transfer Function (TF) method. Comparisons show that the presented method offers a better accuracy of the results than the empirical models. Subsequently, it can provide almost same absorption plot with Biot-Allard model (single layer combination) and TF method (multilayer combination) proving it to be a comprehensively easy and general analytical tool. Therefore, the rigid frame model can be implemented relatively easier than other similar models to analyze the acoustic absorption of Coir Fiber in most of the conditions.
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A practical acoustical absorption analysis of Coir Fiber based on rigid frame modeling
Acoustical Physics, 2012Co-Authors: Md Ayub, Mohd Jailani Mohd Nor, Mohammad Hosseini Fouladi, Rozli ZulkifliAbstract:An analytical study based on rigid frame model is demonstrated to evaluate the acoustic absorption of Coir Fiber. Effects of different conditions such as combination of air gap and perforated plate (PP) are studied in this work. Materials used here are treated as rigid rather than elastic, since the flow resistivity of Coir Fiber is very low. The well-known rigid frame Johnson-Allard equivalent-fluid model is applied to obtain the acoustic impedance of single layer Coir Fiber. Atalla and Sgard model is employed to estimate the surface impedance of PP. Acoustic transmission approach (ATA) is utilized for adding various consecutive layers in multilayer structure. Models are examined in different conditions such as single layer Coir Fiber, Coir Fiber backed with air gap, single layer PP in combination with Coir Fiber and air gap. Experiments are conducted in impedance tube on normal incidence sound absorption to validate the results. Results from the measurement are found to be in well agreement with the theoretical absorption coefficients. The performance of the rigid frame modeling method is checked more specifically in all conditions, by the mean prediction error rate of normal incidence sound absorption coefficients. Comparison between the measured absorption coefficients and predicted by rigid frame method shows discrepancy lower than 20 and 15% for most of the conditions in the frequency range of 0.2-1.5 and 1.5-5 kHz, respectively. Moreover, acoustic absorption of various single and multilayer structures is compared with the simpler empirical methods such as Delany-Bazley and Miki model; and complicated method such as Biot-Allard Model and Allard Transfer Function (TF) method. Comparisons show that the presented method offers a better accuracy of the results than the empirical models. Subsequently, it can provide almost same absorption plot with Biot-Allard model (single layer combination) and TF method (multilayer combination) proving it to be a comprehensively easy and general analytical tool. Therefore, the rigid frame model can be implemented relatively easier than other similar models to analyze the acoustic absorption of Coir Fiber in most of the conditions. © Pleiades Publishing, Ltd., 2012.
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A study on the acoustical absorption behavior of Coir Fiber using miki model
International Journal of Mechanical and Materials Engineering, 2011Co-Authors: M Ayub, Mohammad Hosseini Fouladi, Rozli Zulkifli, Nowshad AminAbstract:Sound absorption capacity of natural Coir Fiber collected from coconut husk has been explored and predicted using Miki’s empirical model. Experiments are conducted in impedance tube to validate the analytical outcomes for three samples having different thickness backed with and without air gap. Results show that the empirical model can estimate the absorption coefficient of Coir Fiber favourably well and shows higher accuracy than the Delany-Bazley model. Discrepancies between the predicted and measured absorption coefficient is very low although some inevitable irregularities is observed in the peak positions. However, presented Miki model can evaluate the overall acoustic behavior of Coir Fiber. This approach can be considered as a very simple and preliminary analytical solution for Coir Fiber acoustical characterization without considering several physical parameters of porous media. In addition, as a result, no complicated measuring procedure has to be followed to initiate the preliminary study for this material.