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Effects of Aspect Ratio and Loading on the Mechanical Properties of Prosopis Juliflora Fibre-reinforced Phenol Formaldehyde Composites

Sujin Jose A., Athijayamani A., Ramanathan K., Sidhardhan S.

Fibres & Textiles in Eastern Europe

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2017

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Vol. 25, no. 4 (124)

59--64

EN

In this paper, an attempt was made to use Prosopis juliflora fibres (PJFs) as a reinforcing agent for phenol formaldehyde (PF) composites. Mechanical properties of the composites were studied for various fibre aspect ratios (FAR) and fibre loadings (FL). A scanning electron microscope (SEM) was used to study the fractured surface of the composites. The peak range of mechanical properties was identified for composites with a FAR of 136 and fibre loading of 23.53 wt%. This study shows that the optimum FAR and fibre loading for PJFs were found to be 136 and 23.53 wt% in order to achieve good reinforcement with better mechanical properties in the PF resin matrix. Experimental results were observed to be in very good agreement with the theoretical.

PL

W pracy podjęto próbę wykorzystania włókien Prosopis juliflora jako środka wzmacniającego żywice fenolowo-formaldehydowe. Przy użyciu elektronowego mikroskopu skaningowego zbadano powierzchnie przełomu kompozytów. Dla różnych wartości wydłużenia włókien (46, 136 i 227 mm) i udziału procentowego włókien w matrycy (4.88, 10.34, 16.51, 23.53 i 31.58 wt%) zbadano właściwości mechaniczne kompozytów. Na podstawie badań stwierdzono, że optymalne wydłużenie i zawartość włókien w matrycy to odpowiednio 136 mm i 23,53 wt%. Wyniki eksperymentalne charakteryzowały się dobrą korelacją z wynikami teoretycznymi.

2

Tensile, Flexual, Impact and Water Absorption Properties of Natural Fibre Reinforced Polyester Hybrid Composites

Prasanna Venkatesh R., Ramanathan K., Srinivasa Raman V.

Fibres & Textiles in Eastern Europe

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2016

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Vol. 24, no. 3 (117)

90--94

EN

In this paper, tensile, flexural, impact properties and water absorption tests were carried out using sisal/unsaturated polyester composite material. Initially the optimum fibre length and weight percentage are estimated. To improve the tensile, flexural and impact properties, sisal fibre was hybridised with bamboo fibre. This work shows that the addition of bamboo fibre in sisal/ unsaturated polyester composites of up to 50% by weight results in increasing the mechanical properties and decreasing the moisture absorption property. In this research work, the effects of fibre treatment and concentration on the mechanical properties of a short natural fibre reinforced polyester hybrid composite are investigated. The fibres were subjected to 10% sodium hydroxide solution treatment for 24 h. The mechanical properties of composites with treated fibres are compared with untreated fibre composites. The fractured surface of the treated fibre composite specimen was studied using Scanning Electron Microscopy (SEM).The treated hybrid composite was compared with an untreated hybrid composite, with the former showing a 30% increase in tensile strength, 27.4% - in flexural strength, and 36.9% - in impact strength, along with an extreme decrease in moisture absorption behaviour.

PL

Badania przeprowadzono stosując kompozyty sizal/poliester i sizal/nienasyconą żywicę poliestrową. Początkowo określono optymalną długość włókien oraz udział procentowy masy w materiale kompozytowym. Dla polepszenia właściwości mechanicznych do włókien sizalowych dodawano włókna bambusowe aż do 50% wagowych. Stwierdzono polepszenie właściwości mechanicznych i, co jest bardzo ważne, zmniejszenie absorpcji wilgoci. Włókna poddawano działaniu 10% roztworu wodorotlenku sodu przez 24h. Badano kompozyty niemodyfikowane i modyfikowana zwracając szczególną uwagę na przełomy obserwowane za pomocą SEM. Stwierdzono polepszenie właściwości mechanicznych hybrydowych kompozytów poddanych modyfikacji, przy czym wytrzymałość na rozciąganie zwiększyła się o 30%, na zginanie 27,4% a wytrzymałość na uderzenia o 36,9%, a jednoczenie absorpcja wody zmniejszyła się znacznie

3

Structural, morphological and electrochemical characterization of electron beam deposited Li 1+xMn2O4 (x = 0, 0.05) thin films

Balaji S., Shanmugan S., Mutharasu D., Ramanathan K.

Materials Science Poland

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2010

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Vol. 28, No. 2

583--593

EN

Li1+xMn2O4 (x = 0, 0.05) powders were synthesized using the microwave assisted co-precipitation method. Materials were evaporated using an electron beam gun. Structural analyses of thin films coated over platinum substrates revealed their cubic structure. The lattice constant of Li1.05Mn2O4 thin film was found to be around 8.2475 A. The lattice constant of Li1.05Mn2O4 Powder was found to be 8.2488 A. Morphological properties of the coated films were studied by SEM and the obtained micrographs were analyzed using the Image-j software. The roughness and the porosity were observed to be higher for the samples containing an excess of Li. The thin films were subjected to electrochemical characterization in aqueous LiNO3 solution; cyclic voltammograms obtained for the samples revealed two sets of well defined redox peaks around 0.07 and 0.1 V in LiNO3 solution. The redox peaks in Li1.05Mn2O4 thin film samples had lower intensities than those of the stochiometric compound.

4

Particle Swarm Optimisation of hardness in nickel diamond electro composites

Ramanathan K., Periasamy V.M., Pushpavanam M., Natarajan U.

Archives of Computational Materials Science and Surface Engineering

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2009

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Vol. 1, nr 4

232-236

EN

Purpose: This paper presents an efficient and reliable swarm intelligence-based approach, namely particle swarm optimization (PSO) technique, to optimize the hardness and the parameters that affect the hardness in the Ni-Diamond composite coatings. Design/methodology/approach: Particle swarm optimizers are inherently distributed algorithms, in which the solution for a problem emerges from the interactions between many simple individuals called particles. Nickel-diamond composite coatings are produced by electro deposition using sedimentation technique on mild steel substrate at various cathode current densities, pH and temperatures. Electro deposition was carried out from a conventional Watts bath. Natural diamond powder of 6-12 µm size was used in the study . Findings: The hardness value of composite coated specimens were measured using Vickers micro indentation technique. Non linear Regression model was developed using experimental data and was used as an objective function for optimizing hardness and their influencing parameters. The optimized hardness of Ni-diamond metal matrix was found to be 431VHN at pH = 2.5, Current density = 1 A/dm2 and temperature = 300°C. Research limitations/implications: The key advantage of PSO is its computational efficiency and less parameter required to be adjusted in order to get the optimum result compared to related techniques. A non linear regression model was developed for the unconstrained optimization of hardness in Ni-diamond composite coated metal matrix using experimental data and it was used as objective function in the maximization problem. Originality/value: The proposed approach utilizes the global exploration capabilities of PSO to search for the optimal solution.