Person: GÜLLÜOĞLU, ARİF NİHAT
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GÜLLÜOĞLU
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ARİF NİHAT
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Publication Metadata only Effect of irradiation by 140 Mev Ag11+ ions on the optical and electrical properties of polypropylene/TiO2 composite(ELSEVIER, 2009) GÜLLÜOĞLU, ARİF NİHAT; Qureshi, Anjum; Singh, Dolly; Singh, N. L.; Ataoglu, S.; Gulluoglu, Arif N.; Tripathi, Ambuj; Avasthi, D. K.Changes in the optical, structural, dielectric properties and surface morphology of a polypropylene/TiO2 composite due to swift heavy ion irradiation were studied by means of UV-visible spectroscopy, X-ray diffraction, impedance gain phase analyzer and atomic force microscopy. Samples were irradiated with 140 MeV Ag11+ ions at fluences of 1 x 10(11) and 5 x 10(12) ions/cm(2). UV-visible absorption analysis reveals a decrease in optical direct band gap from 2.62 to 2.42 eV after a fluence of 5 x 10(12) ions/cm(2). X-ray diffractograms show an increase in crystallinity of the composite due to irradiation. The dielectric constants obey the Universal law given by epsilon proportional to integral(n-1), where n varies from 0.38 to 0.91. The dielectric constant and loss are observed to change significantly due to irradiation. Cole-cole diagrams have shown the frequency dependence of the complex impedance at different fluences. The average surface roughness of the composite decreases upon irradiation. (C) 2009 Elsevier B.V. All rights reserved.Publication Metadata only Processing and mechanical properties of B4C reinforced Al matrix composites(ELSEVIER SCIENCE SA, 2009) GÜLLÜOĞLU, ARİF NİHAT; Topcu, I.; Gulsoy, H. O.; Kadioglu, N.; Gulluoglu, A. N.Aluminum matrix composites are emerging as advance engineering materials due to its high specific strength and stiffness, good wear resistance and high temperature properties. Properties of Al reinforced with Al2O3 and SiC are widely investigated. In the present study, mechanical properties of B4C reinforced Al matrix is investigated due to higher hardness and lower density properties than SiC and Al2O3. The high temperature deformation behavior of 5, 10, 15 and 20wt% B4C powder having an average particle diameter of about 10 mu m aluminum matrix composite sintered at 650 degrees C was investigated by creep tests at temperatures ranging from 400 to 450 degrees C and creep resistance of Al alloy is enhanced by the presence of B4C particles. Measurement of impact and hardness properties of composites showed that impact values decrease and hardness values increased with increase in weight fraction of reinforcement. (C) 2009 Elsevier B.V. All rights reserved.Publication Metadata only Dielectric properties of polymer composites filled with different metals(TAYLOR & FRANCIS INC, 2008) GÜLLÜOĞLU, ARİF NİHAT; Qureshi, Anjum; Mergen, Ayhan; Eroglu, Mehmet S.; Singh, N. L.; Gulluoglu, ArifElectrically conductive composite systems based on polyvinyl chloride (PVC) and polymethyl methacrylate (PMMA) filled with metal powders of Al and Cu have been studied. The composite preparation conditions allow the formation of a random distribution of metallic particles in the polymer matrix. Dependence of the dielectric and conductivity properties of the PVC and PMMA/fillers was studied over a broad range of frequency and volume fraction of metal fillers. The experimental results could be explained by means of the conductivity of fillers and the interface polarization between polymers and fillers. Percolation was also seen in this study when the volume fraction of conducting fillers was close to critical value, in which the composites undergo an insulator-conductor transition. The relation among the dielectric property and the fillers with different conductivity was proposed.Publication Metadata only Temperature Dependent Mechanical Characterisation of Styrene-Acrylonitrile(RAPRA TECHNOLOGY LTD, 2009) GÜLLÜOĞLU, ARİF NİHAT; Solakoglu, Ilker; Ataoglu, Senol; Gulluoglu, Arif N.; Kadioglu, NeclaPoly(styrene-co-acrylonitrile) (SAN) which is a random, amorphous, linear copolymer produced by copolymerising styrene and acrylonitrile was investigated experimentally. Specimens were supplied from a private company and they were analysed using a differential scanning calorimetry machine (DSC). The behaviour of the material in creep, tension and hardness experiments was investigated experimentally at several temperatures. The creep response of SAN was also evaluated.Publication Metadata only An Analytical Model for Compressive Creep Behavior of HDPE Used in Plastic Pipe Manufacturing(TAYLOR & FRANCIS INC, 2008) GÜLLÜOĞLU, ARİF NİHAT; Sezer, S.; Ataoglu, S.; Gulluoglu, A. N.; Kadioglu, N.The creep behavior of high-density polyethylene has been studied by low compressive creep tests, and empirical results were analyzed and compared with analytically predicted results. The tests are performed upon ASTM standard specimens at various stress levels in the linear region. After these analyses, a mathematical model is derived and used to predict creep strain for long periods of time from the strain-time data obtained at different stresses over a time interval of 24h.