Aircraft maintenance work requires a strategy to prevent human error. It is more important that the role of an organization whose mission is tries to build defenses to avert human errors by the system approach which concentrate on the conditions under which individuals work than the person approach that focus on individual errors. We analyzed dynamic relationship between the role of company policy （the role of practicing that safety is the most important element at front line） and occurrence of human errors using human error data of aircraft maintenance that retrieved from the Aviation Safety Reporting System （ASRS） , and were analyzed by time series analysis including autoregression and the text mining method. As a result, this study show that the deterioration or improvement of company policy affected the occurrence of human error over a 15-month period. Also we found the characteristics of human error and the safety awareness of workers caused by the influence.

In our previous study on the spray electrification of liquids, which may cause explosions or fires in facilities handling combustible organic solvent, we found that the charge generated by the spray electrification of ethyl acetate was larger than that of other liquids and that the spray electrification depended strongly on the conductivity of the liquid and peaked at 10^-8 S/m which is equivalent to the conductivity of ethyl acetate. In this study, we investigated the relationship between the spray electrification and various conditions for five different liquids including ethyl acetate. The results showed that the specific spraying conditions increased the charge of ethyl acetate and that the relationship between the charge and the conductivity of liquids was in the general agreement with the result of the previous study. However, the charge of ethyl acetate was significantly larger than that of the liquid sample used in the previous study （mixture of mineral spirit and conductivity improving additive）, indicating that factors other than conductivity may also have a significant effect on the spray electrification.

The proportion of elderly people aged 65 and over who died in house fire accidents reached 73% of all ages in 2017. Prevention of accidents due to "Misuse or Inadvertent Usage" by the elderly, which is the primary cause of fires, is an important issue. In this paper, we clarified three scenarios leading to accidents based on items of "Cause of Accidents" in each report of kerosene leak fire accident of kerosene stove from the accident information database of National Institute of Technology and Evaluation. From these results, we found points to stop the progress of the accidents, analyzed and evaluated the effectiveness of the requirements of applicable standards and the accident prevention function, and showed that these are not necessarily fool-proof for accident prevention. Then, we showed the effectiveness of the fool-proof designs in which the airtight kerosene tank cannot be removed until the temperature of the kerosene stove becomes lower than the ignition temperature of kerosene, and that prevents the lid of the refueling port from the loosening to is valid. Also, we showed that fool-proof design could prevent 66% of kerosene leak fire accidents.

For the chemical process, it is important to obtain the accurate reaction kinetics of thermal decomposition in order to decide the appropriate operating conditions and to design the safety system. ARC is the suitable equipment to measure the decomposition kinetics of chemical substance. However, in some cases it is difficult to obtain the accurate kinetics. So, as an alternative approach, thermal stability evaluation flow chart using model-free kinetics analysis is proposed after confirming its effectiveness using sealed cell DSC data.