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- MakaleYalnız künye2019Scopus SJRQ2Experimental investigation of transverse loading on composite panels coated with different gelcoat colors subjected to UV radiation and hygrothermal aging
Dogan, Akar; Arman, Yusuf; Ozdemir, Okan
This study focuses on the effects of hygrothermal and UV radiation aging on the reinforced epoxy composites coated with gelcoat. The aim of this study is to investigate the influence of gelcoat colors on the tensile properties, impact behavior and thermodynamic properties of the composite panels after the aging process has been performed. Two different gelcoat colors were chosen as black and yellow. Unidirectional E-glass fiber fabrics with an areal density 300 g m-2 as reinforcement and epoxy matrix were used. Vacuum-assisted resin infusion molding (VARIM) method was used to manufacture composite panels. The tensile test specimens were prepared according to ASTM standards. Tensile strength of both fiber and transverse directions, the impact perforation threshold, and stroge modulus of the aged samples decreased compared to unaged (virgin) samples. However, the drop in mentioned properties for coated materials is less than for uncoated materials, especially in yellow coated materials. The temperature of hygrothermal conditions significantly affected the perforation threshold. Moreover, the tensile strength in transverse direction in yellow samples decreased approximately 13%, while it decreased 23% in the black coated samples. Impact perforation threshold of unaged (virgin), uncoated, coated with yellow gelcoat and coated with black gelcoat is obtained to be 75, 57, 65 and 61 J, respectively.
AtıfScopus12WoS9OpenAlex11
İncele - MakaleAçık Erişim2019Scopus SJRQ2Effect of MgO,Al2O3 and FeCr2O4 on microstructure and wear resistance of Babbitt metal (Sn-Sb-Cu)
Tasgin, Yahya
In this study, the Sn-Sb-Cu alloy known as Babbitt metal and used as the coating material for the screw die surface of the journal bearings of the hydroelectric plants was reinforced with magnesium oxide (MgO), aluminium oxide (Al2O3) and ferrochromium (FeCr2O4) in order to ensure more efficient use of this alloy, formation were examined. The Babbitt prevent contact of the surface of the coating alloy with each other by acting as a separating oil layer having a 150 bar pressure. It is desired that the coating surface both resists against the high pressure applied and some part of the coating surface is asked to prevent from separating the surface of screw die as a result of high speed rotational motion and thus, damaging the shaft. Then, it was aimed to determine the wear resistance of the material as coating and the effects of the added%10 MgO,%10 Al2O3 and%10 FeCr2O4 on wear of material. As a result of the assessments carried out, it was suggested that the wear resistance of the coating would increase when the compound of Al2O3 was added into Babbitt metal. Purpose of the article used as coating material of babbitt metal, being investigated how to exert strong posture affected, under high pressure.
AtıfScopus8WoS7OpenAlex7İncele - MakaleYayıncıda açık erişim2018Scopus SJRQ1Doping assessment in GaAs nanowires
Goktas, N Isik; Fiordaliso, E.M.; Lapierre, R.R.
Semiconductor nanowires (NWs) are a candidate technology for future optoelectronic devices. One of the critical issues in NWs is the control of impurity doping for the formation of p-n junctions. In this study, beryllium (p-type dopant) and tellurium (n-type dopant) in self-assisted GaAs NWs was studied. The GaAs NWs were grown on (111) Si by molecular beam epitaxy using the self-assisted method. The dopant incorporation in the self-assisted GaAs NWs was investigated using Raman spectroscopy, photoluminescence, secondary ion mass spectrometry and electron holography. Be-doped NWs showed similar carrier concentration as compared to thin film (TF) standards. However, Te-doped NWs showed at least a one order of magnitude lower carrier concentration as compared to TF standards. Dopant incorporation mechanisms in NWs are discussed.
AtıfScopus42WoS41OpenAlex48
İncele - DergiMaterials Research Express
- DergiNanotechnology