Fuzzy Bayesian reliability and availability analysis of production systems

To have effective production planning and control, it is necessary to calculate the reliability and availability of a production system as a whole. Considering only machine reliability in the calculations would most likely result unmet due dates. In this study, a new modelling approach for determining the reliability and availability of a production system is proposed by considering all the components of the system and their hierarchy in the system structure. Components of a production system are defined as production processes; components of the processes are defined as sub-processes. In this hierarchical structure we could model all kinds of failures such as material and supply, management and personnel, and machine and equipment. In the analysis, a fuzzy Bayesian method is used to quantify the uncertainties in the production environment. The suggested modelling approach is illustrated on an example. In the example, also a separate reliability and availability analysis is conducted which only considered machine failures, and the results of both analyses are compared.     

Analytical modeling of imperfect bond between coated fibers and matrix material

The present study is intended to find the stress intensity factors (SIF) and strain energy release rates (SERR) at the tips of an interface crack in a non-homogeneous medium. The boundary-value problem governing a three-phase concentric cylinders model is used to analyze annular interfacial crack problems with Love's strain functions. The complex form of a singular integral equation of second kind is formulated using Bessel's functions in Fourier domain. Stress intensity factors (SIF) and total strain energy release rates (SERR) are calculated using Jacoby polynomials. For validity of the equations of Stress Intensity Factors, the Singular Integral Equation (SIE) of a three concentric cylinders model is reduced to the SIE for a two concentric cylinders model and results are compared with previous results of Erdogan.     

Natural radioactivity measurements in soil samples of central Kutahya (Turkey)

Measurement of the natural radioactivity of surface soils at 20 locations in central Kutahya has been made using gamma ray spectroscopy. Natural gamma ray radioactivity of the terrestrial nuclides in soil samples and the absorbed gamma ray dose rates of these radionuclides in the air have been calculated throughout different areas of central Kutahya. The average annual effective dose equivalent for a person living in central Kutahya was found to be approximately 57 microSv.     

Inorganic constituents in barks of Abies bornmülleriana and Castanea sativa

Barks of Abies bornmülleriana and Castanea sativa were investigated for inorganic constituents by flame atomic absorption spectrometer. 18 elements were detected in the barks of the two species. While Ca was found as the main constituent, 68.7% of the total elements in fir and 76.6% in chestnut, K,Mg,Al and Mn were seen as other predominating elements.