Abstract: A cylinder block has a cylinder block body and a cylinder liner block mounted by casting in the cylinder block body. The cylinder liner block is formed from a material having a rigidity larger than that of the cylinder block body, and the cylinder liner block comprises a liner section mounted by casting in position in a cylinder barrel portion of the cylinder block body, and a reinforcing wall section mounted by casting in position in a bearing wall of a crank case portion of the cylinder block body. Thus, it is possible to increase the wear resistance of cylinders in the cylinder block, as well as to provide an increase in performance by reductions in vibration and noise of the engine including the cylinder block, and to provide reductions in size, weight and cost of the cylinder block by a reduction in thickness of the bearing walls.

Abstract: A cylinder block has a cylinder block body and a cylinder liner block mounted by casting in the cylinder block body. The cylinder liner block is formed from a material having a rigidity larger than that of the cylinder block body, and the cylinder liner block comprises a liner section mounted by casting in position in a cylinder barrel portion of the cylinder block body, and a reinforcing wall section mounting by casting in position in a bearing wall of a crank case portion of the cylinder block body in a. Thus, it is possible to increase the wear resistance of cylinders in the cylinder block, as well as to provide an increase in performance by reductions in vibration and noise of the engine including the cylinder block, and to provide reductions in size, weight and cost of the cylinder block by a reduction in thickness of the bearing walls.

Abstract: A method for treatment of waste water by an activated sludge process wherein the aeration tank system is composed of three tanks: a first tank, a second tank and a third tank, in which sludge microorganisms adsorb the organic substances in the waste water to be treated and a part of them begin oxidation and decomposition of the substances in the first tank, the organic substances which are adsorbed by the sludge microorganisms are further decomposed by the microorganisms of the second tank, and the sludge microorganisms are activated in the third tank, is disclosed. The aeration amount to the respective tanks is controlled to fall within specified ratios. Further, the pH value in the aeration tank system is controlled to be slightly acidic, and the pH of the tanks increases in order from the first tank to the third tank. The process may also be carried out in a single tank using a three-step batchwise process, where the batches are subject to the aeration and pH requirements.