Abstract: A fixation mechanism in which a first thread groove extending in one turning direction and a second thread groove extending in a turning direction opposite to the one turning direction and intersecting the first thread groove are formed in a first member-side thread portion of a first member. The thread divided portion being formed as a result of the first thread groove and the second thread groove intersecting each other. A second member-side thread portion of a second member can be screwed to the first thread groove of the first member-side thread portion. The second member is fixed at a suitable angle 0 relative to the first member.

Abstract: A method for operating a blast furnace by inferring the operating conditions in the blast furnace, on the basis of data supplied from sensors set in the blast furnace and also on the basis of the knowledge base formed by experience on the operation of the furnace by a small-scale computer and various processing units provided within the computer. Prior to the inference, the data from the sensors are processed by a large-scale computer and various processing units provided within the large-scale computer. The inference is performed by using certainty factor values, thereby making diagnosis of slip, hanging and channeling.

Abstract: A method for controlling heat conditions in a blast furnace wherein the heat conditions are inferred and judged in comparison of data output from sensor means provided for the blast furnace with knowledge base means formed by accumulated experience on the operation of the blast furnace. The heat conditions are inferred and judged from levels of heat conditions and from levels of transition of heat conditions, wherein data regarding molten metal temperature and those regarding sensors are used. The inference and judgement are carried out by inference engine means included in a small-scale computer.