It is known that the reaction between magnesium powder and water can result in explosions and fire incidents. The reaction, which generates heat and flammable gases, exhibits spontaneous combustion, and makes firefighting challenging. To implement appropriate measures for preventing explosions and fire incidents, an understanding of the thermal hazards of the reaction is necessary. Thermal analysis is an effective method to investigate the thermal hazards of chemical reactions, but consideration must be given to the fact that the latent heat of water evaporation affects thermal behaviour which is estimated by thermal analysis. In this study, the effect of latent heat was observed in the reaction between magnesium powder and water. Therefore, a correction method to eliminate the effect of latent heat was proposed. The correction method was applied to the reaction of magnesium powder with water, and it was revealed that the effect of the latent heat decreased the reliability of the kinetic analysis. Moreover, the effect changed the apparent activation energy and pre-exponential factor. It was found that this change resulted in either underestimation or overestimation of the thermal hazard of the chemical reaction. The effect of latent heat decreased with the decreasing rate of heat generation of the reaction.

When demolishing a building, a method called the fall-down method is implemented. In this method, the lower section of the exterior wall is manually weakened by the workers, and the exterior wall is pulled down using wire ropes. At a small-scale demolition site, the exterior wall is pulled down manually using wire ropes. However, it is possible for the exterior wall to fall down inward during the weakening of the lower section of the wall, leading to accidents and casualties. The wire rope also functions to prevent the fall-down of the exterior wall in the outward direction. However, there is no way to prevent fall-down of the exterior wall in the inward direction. In this study, to prevent such inward fall-down when the workers are still working on weakening the lower section of the exterior wall, a fall-down prevention method using temporary members has been proposed. The effectiveness and useability of this method were examined using a full-scale test. The results confirmed that this method can reliably prevent the fall-down of the exterior wall of a medium-sized building in the inward direction.

Purpose: This study examined the effective methods or tools that support the voluntary and systematic implementation of measures in the workplace against "Karoshi (death from overwork)." A literature and document survey for existing tools was conducted. Method: Tools (e.g., checklist, guidelines) to prevent physical and mental health problems caused by long working hours were collected using academic literature databases (MEDLINE, PubMed, JMEDPlus). The search formula was composed of the logical product of terms indicating tools (checklists, guidelines, management systems, etc.) and working hours. We researched academic papers published from 2000 to 2019 and conducted an exploratory internet search on existing tools provided by public or nonprofit organizations. Results: In the literary database, the search formula led to 72 English and 67 Japanese hits. Documents that developed, proposed, or mentioned tools to support preventive activities were selected based on their title and the abstract content. We selected one study on development of an action checklist to improve the systematic response to Japanese regulations that stipulate the implementation of interviews and guidance for long overtime workers, two studies on a practical toolkit to support the interviews and guidance, one on development of a checklist for shiftwork, and two on aviation safety (FRMS; Fatigue risk management system). An exploratory search on the internet resulted in ministries and public organizations releasing tools that target several specific industries and occupations, including compliance support tools for medical labor, guidelines for shift work, an action checklist to support voluntary improvement of the work environment, guidelines for improving work content in the transportation industry, and guidelines for the improvement of business practices in the construction. Collections of good practice cases were also provided to the medical and transportation industry. Since the guidelines for shift work include tips for preventive and comprehensive measures, the contents of the four identified guidelines were summarized in a table and discussed. All collected tools were categorized and discussed based on comprehensiveness, assumed direct users, main targets for improvement, and methods of intervention. Discussion: Currently, few tools have been developed to support voluntary and preventive efforts related to long working hours. Some cases exist of support tools for improving organizational structure, participatory ergonomic improvement , improving consideration of psychosocial factors related to stress, and addressing occupation or industry-specific problems. Each tool has its own characteristics. We collected reference materials for building comprehensive countermeasure tools to prevent death from overwork.

The number of deaths by the industrial accident is continuing reduction. In order to further advance decrease of this number of deaths, the serious industrial accident which may lead to death needs to be prevented. Then the number of the serious injuries requiring at least six months off work was investigated. As a result, the number of serious injuries was increasing clearly. Next, about the serious industrial accidents which occurred in 2017, the type of industry was classified into four and the accident was analyzed. These four types of industry are the manufacturing industry, the construction industry, the traffic transportation business, and the tertiary industry. And the accident type which had many serious injuries became clear. The typical accident patterns were also shown. In addition, future preventive measures were proposed about these typical industrial accidents.

Based on the statistics by Japanese Ministry of Health, Labour and Welfare, falls are the leading cause of occupational accidents. Since the launch of the fall prevention project in 2015, various measures, such as, improving safety in the workplace, have been promoted. However, the number of fall incidents at workplaces is not decreasing. As the working population is aging, fall incidents in older workers are prevailing. This study developed the new calisthenics for fall prevention in workers and the tools for dissemination, based on the literature and the expertise of the specialists in rehabilitation and occupational health fields. The calisthenics also include the movement targeting low back pain. In workers who performed the calisthenics, the scores of physical performance tests (one leg standing with eyes closed, 2-step test, and standing from a chair on one leg) increased, which inferred the improvement in balance, the range of motion of the lower limbs, and muscle strength of the lower limbs and trunk. The study results suggested that the calisthenics for fall prevention which target the individual risk factors for falls would be effective in improving the physical function of workers.