Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Lubricants Having Zinc Borate by Homogeneous Precipitation and Span 60 in Spindle Oil(Turkish Energy Nuclear and Mining Research Institute, 2021) Gönen, Mehmet; Alp, Burcu; Savrık, Sevdiye; Balköse, Devrim; Alp, Fatma Burcu; Balkose, DevrimNano particles of zinc borate were obtained by homogeneous precipitation method which is based on dissolving zinc borate in ammonia and precipitating it as nano particles by slow evaporation of ammonia. The synthesized zinc borates were characterized by advanced analytical techniques. Zinc borate nano particles were used as a lubricant additive to spindle oil having Span 60 dispersant. The particles were well dispersed in spindle oil as shown by optical microscopy of the oils. Four ball tests of the lubricants indicated zinc borate lowered (61.8%) the wear scar diameter significantly. The hardness of wear surfaces of test balls was reduced from 688 HV to 618 HV and presence of zinc borate particles embedded on the surface indicated a flexible skin was formed. Therefore the pressure was decreased due to increase of the contact area of the balls. The surface roughness was also decreased from 35.63 nm to 27.60 nm by the addition of zinc borate to spindle oil having Span 60. Zinc borate prepared by homogeneous precipitation technique lowered the wear of the surfaces that rub to each other.Article Citation - WoS: 4Citation - Scopus: 5Dynamic Heat of Adsorption of Water Vapour on Zeolitic Tuff and Zeolite 4a by Flow Microcalorimetry(Scibulcom Ltd., 2006) Ülkü, Semra; Balköse, Devrim; Alp, BurcuIn this study a practical method for measurement of heat of adsorption of water vapour on adsorbents was developed to evaluate the feasibility of substitution of a zeolitic tuff with zeolite 4A in air drying and heat pumps. The change of heat of adsorption with inlet humidity of the air passing through the calorimeter was investigated. Samples were characterised by X-ray diffraction and thermal gravimetric analysis techniques. Specific heats of the zeolitic tuff and zeolite 4A were measured as 1.01 and 1.42 J/g K, respectively. Adsorption isotherms fitted to the Langmuir model with regression coefficient 0.93 and 0.94 with monolayer capacities, Xm 9.68% and 26.35% H 2O for the zeolitic tuff and zeolite 4A, respectively. The energy storage intensity was measured in the range 48-97 J/g and 464-201 J/g for the tuff and zeolite 4A, respectively. Heat of adsorption of zeolite decreased with surface coverage and it was in the range 1750-2835 and 1104-2640 J/g H 2O for the zeolitic tuff and zeolite 4A, respectively.