Browsing by Publisher "EMERALD GROUP PUBLISHING LIMITED"

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    Determination of tribological properties at CuSn10 alloy journal bearings by experimental and means of artificial neural networks method
    (EMERALD GROUP PUBLISHING LIMITED) Ünlü, BS; Durmus, H; Meriç, C
    Purpose - It is important to know the friction coefficient and wear loss for determination of tribological conditions at journal bearings. Tribological events that influence wear and its variations affect experimental results. The purpose of this paper is to determine friction coefficient and wear loss at CuSn10 alloy radial bearings by a new approach. In experiments, effects of bearings have been examined at dry and lubricated conditions and at different loads and velocities. Design/methodology/approach - In this study, friction coefficient and wear losses of journal and bearing have been determined by a new approach with a radial journal bearing test rig and artificial neural networks (ANNs) method. The ANN typifies a learning technique that enables the hidden input-output relationship to be mapped accurately. Bronze-based materials have been used as bearing material. Effects of friction coefficient and wear losses have been examined at same load and velocity and at dry and lubricated conditions. Findings - The results obtained in ANN application are close to friction test results for dry and lubricated conditions. Therefore, by using trained ANN values, the intermediate results that were not obtained in the tests can be calculated. Experimental studies will be increased and research with ANN will be continued. Originality/value - By using trained ANN values, the intermediate results that were not obtained in the tests can be calculated. The training finished on 30 min whereas experimental study had continued day after day.
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    Determination of synthesis conditions of neutral calcium sulfonate, so-called detergent-dispersant
    (EMERALD GROUP PUBLISHING LIMITED) Celik, A; Besergil, B
    In this study, the conditions of obtaining neutral calcium sulfonate which is added to engine oils as a detergent-dispersant was studied. For this purpose, post-dodecyl benzene sulfonic acid, obtained from post-dodecyl benzene which remains as the bottom product during the production of dodecyl benzene sulfonate was used as the initial substance. Additionally, the reactor to be used in the production of neutral calcium sulfonate was designed and the amounts of spindle-oil, toluene, raw sulfonic acid solution and Ca(OH)(2) used during neutralization were determined.
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    Tribological studies of ZrO2-implanted on stainless steel substrate
    (EMERALD GROUP PUBLISHING LIMITED) Dogan, H; Findik, F; Oztarhan, A
    The tribological properties such as surface hardness, friction and wear have been studied for AISI 316L stainless steel substrates which were co-ion implanted with zirconium and oxygen ions. It is found that the wear resistance for AISI 316L stainless steel substrates implanted with zirconium and oxygen ions increased quite a lot. It is concluded that the increase in surface microhardness and the decrease in friction coefficient of AISI 316L stainless steel substrates play an important role in improving the wear resistance, and the relationship between relative wear volume and microhardness is correlated for zirconium and oxygen co-ion implantation.
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    Investigation of wear behaviour of thixoformed and conventional gravity cast AlSi8Cu3Fe alloys
    (EMERALD GROUP PUBLISHING LIMITED) Saklakoglu, N; Irizalp, SG; Ercayhan, Y; Birol, Y
    Purpose - In the present work, thixoformed AlSi8Cu3Fe alloy was investigated for its tribological properties. The tribological analysis reveals good sliding wear behaviour for thixoformed alloy due to thixotropic microstructural character. The results are compared with sliding wear behaviour of conventional gravity cast alloy. This paper aims to discuss these subjects. Design/methodology/approach - In this study, thixoforming and gravity casting methods are used to produce materials. The ball-on-disc CSM tribometer was used to carry out the tribological tests that were performed under dry sliding conditions, under two different loads of 1N and 5N. Wear tests were performed first on the conventional gravity cast samples and then on the thixoformed counterparts in exactly the same fashion to facilitate a comparison. The microstructural characterizations are performed in optical microscopy, scanning electron microscopy and energy dispersive X-ray spectrometry. Findings - Thixoformed samples have better wear resistance than conventional gravity cast samples. The wear performance improves in thixoformed AlSi8Cu3Fe alloy thanks to changing the microstructure. The superiority of the former is attributed to its structural features. Originality/value - In this study, the thixoforming of AlSi8Cu3Fe alloy can provide important wear performance in comparison with conventional casting of AlSi8Cu3Fe alloy. This alloy is known to be used widely in automotive industry. Therefore, the alloy is highly exposed to wear and it is thought that thixoforming method can increase the wear resistant.
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    Determination of synthesis conditions of alkali calcium sulfonate
    (EMERALD GROUP PUBLISHING LIMITED) Besergil, B; Celik, A
    In this study, alkali calcium sulfonate which is added to engine oils as a detergent-dispersant was obtained. A definite amount of Ca(OH)(2) and water was added to the mixture of neutral calcium sulfonate (NCS) and spindle-oil (SO), and the mixture was taken into an appropriate reactor. CO2-air mixture was passed through the mixture for definite periods at 85degreesC and the appropriate parameters affecting the qualities and efficiency of the product were determined. Thus, after the mixture of CO2 + air (having the ratio of 1/8.5) was passed through the mixture of 180 g NCS + 600 g SO + 60 g Ca(OH)(2) + 90 g water with the velocity of 108 L/h for 200 min, transparent alkali calcium sulfonate with a total base number value of 28.6 mg KOH/g was obtained.
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    Transient dynamic analysis of dam-reservior interaction by coupling DRBEM and FEM
    (EMERALD GROUP PUBLISHING LIMITED) Küçükarslan, S; Coskun, SB
    In this paper, time domain dynamic analysis of dam-reservoir interaction is presented by coupling the dual reciprocity boundary element method in the infinite fluid domain and the finite element method in the solid domain. An efficient coupling procedure is formulated by using sub-structuring method. Sommerfeld's boundary condition for far end of the infinite domain is implemented. To verify the proposed scheme, numerical examples are carried out to compare with the available exact solutions and results of the finite-finite element coupling.