明治・大正期におけるセメントの生産管理について : 小野田セメント製造株式曾社を例として  [in Japanese] CEMENT PRODUCTION MANAGEMENT IN THE MEIJI AND TAISHO ERA : A case of Onoda cement company  [in Japanese]

The resources left in Onoda Cement Company, such as its history, documents, and letters, were examined in order to explore the transition of the cement production management between 1883 and 1925. The study specifically focuses on the company's manufacturing as well as quality control items for a variety of firing kilns. The findings are as follows: 1) The process control items initially included only "the amount of both fuel and raw materials" and "the cement production volume." A few years later, "the operating time of the main manufacturing devices" were added to the original process control items. Furthermore, while the measurement of the pressure in the kilns began to be conducted by the end of the Taisho era, the firing condition of the cement was only being discerned. 2) The outline of the quality control items was formed between 1898 and 1899 and it was completed in the Taisho era. The completed list of the items is similar to the one adopted today. 3) For the chemical analysis (one of the quality control items), the existence of CaCO_3 in both the limestone and the raw materials was measured and confirmed first, and then the analysis of the cement powder was followed. 4) The diameter of the raw materials and the cement powder became smaller as the time proceeded. By the beginning of the Taisho era, the size of the mesh of the sieve used for measuring the diameter became almost the same as the one used today. 5) When the cement production originally started in the early Meiji era, the physical test of the cement included only "the verification of possible cracks and the strength test on the cement paste" and the stiffness of the cement was being measured only roughly. Approximately ten years later, "the tensile and compressive strength of the cement mortar" were included in the physical test. In another ten years, morever, "the specific gravity of the cement powder" became one of the items and started to be measured. By the end of Thaisho era, after the careful consideration the completed list of control items was refined and became almost the same as the one employed today.