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Poor lubrication is known as an important factor in the bearings failure. Therefore, it is very important to detect the lubrication condition. Hydrodynamic lubrication, mixed lubrication and boundary lubrication are the basic regimes of the fluid film lubrication. In a proper condition, development of hydrodynamic pressure is adequate to support the load and the bearings operate under hydrodynamic lubrication condition. However, in most situations, they operate in mixed lubrication or boundary lubrication regime and have metal-to-metal contact. To establish these regimes, using the so-called Stribeck curve is a useful method. In this curve, the oil film thickness is proportional to the lubricant viscosity and sliding velocity and inversely proportional to the applied load. However, distinguish of the exact range of hydrodynamic lubrication regime from mixed and boundary regime using this curve and relation related to the sliding bearings, due to high number of affecting design factors and operating parameters is difficult. The present study focused on the acoustic emission measuring method in order to monitoring the lubrication conditions in a type of journal bearings. Thus, condition monitoring of the journal bearing lubrication is provided and the numerical value of operating variables of the bearing for lubrication regime change from hydrodynamic to mixed is achieved. Using wavelet method, frequency features for each regime is identified. Then, for each lubrication regime, metal-to-metal contact detection is performed.

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Different methods are being used for monitoring of crack growth and failure mechanism in rock fracture. Acoustic Emission (AE) is one the methods used for micro crack monitoring in samples under pressure. Existence of porosity and humidity in rock and soil structure cause different effects on process of micro cracks and growth of micro cracks and finally their fracture. In this study, effects of porosity and humidity in micro crack growth and rock fracture are being analyzed. Four parameters which are highly effective in AE method namely hit, count, wave durability and fracture energy are used. Mortar (synthetic rock) was used to have a constant porosity ratio in samples. Cylindrical samples with 54 mm diameter and 110 mm length with 5 different porosity ratios ranging from 17 to 35 percent were made using Panplast lubricant. Samples were subjected to uniaxial compression test in two dry and saturated conditions and AE data were recorded. Data analysis showed that the dominant failure mode on samples of dry mortar with increasing porosity, increase toward the tension mode. With increasing of porosity and moisture content the numbers of micro crack decreases. Different methods are being used for monitoring of crack growth and failure mechanism in rock fracture. Acoustic Emission (AE) is one the methods used for micro crack monitoring in samples under pressure. Existence of porosity and humidity in rock and soil structure cause different effects on process of micro cracks and growth of micro cracks and finally their fracture. In this study, effects of porosity and humidity in micro crack growth and rock fracture are being analyzed. Four parameters which are highly effective in AE method namely hit, count, wave durability and fracture energy are used. Mortar (synthetic rock) was used to have a constant porosity ratio in samples. Cylindrical samples with 54 mm diameter and 110 mm length with 5 different porosity ratios ranging from 17 to 35 percent were made using Panplast lubricant. Samples were subjected to uniaxial compression test in two dry and saturated conditions and AE data were recorded. Data analysis showed that the dominant failure mode on samples of dry mortar with increasing porosity, increase toward the tension mode. With increasing of porosity and moisture content the numbers of micro crack decreases. Different methods are being used for monitoring of crack growth and failure mechanism in rock fracture. Acoustic Emission (AE) is one the methods used for micro crack monitoring in samples under pressure. Existence of porosity and humidity in rock and soil structure cause different effects on process of micro cracks and growth of micro cracks and finally their fracture. In this study, effects of porosity and humidity in micro crack growth and rock fracture are being analyzed. Four parameters which are highly effective in AE method namely hit, count, wave durability and fracture energy are used. Mortar (synthetic rock) was used to have a constant porosity ratio in samples. Cylindrical samples with 54 mm diameter and 110 mm length with 5 different porosity ratios ranging from 17 to 35 percent were made using Panplast lubricant. Samples were subjected to uniaxial compression test in two dry and saturated conditions and AE data were recorded. Data analysis showed that the dominant failure mode on samples of dry mortar with increasing porosity, increase toward the tension mode. With increasing of porosity and moisture content the numbers of micro crack decreases