International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

This study examines the effects of light-emitting diode (LED) lanterns and partition colors on the psychological condition of individuals in evacuation shelters. A previous questionnaire survey involving 193 participants evaluated emotional responses to four LED colors (yellow, green, blue, and red). Yellow light was most frequently perceived as calming and comfortable, whereas red light was strongly associated with tension and anxiety. Building on these emotional findings, we investigated environmental factors through an experiment involving blue, pink, and green partitions. The participants stayed inside each partition for 25 min, and their vital signs, including body temperature, pulse rate, and blood pressure, were measured every 5 min. The results indicate that blue partitions produced the most stable physiological responses, including lower systolic blood pressure and steady pulse rates, reflecting parasympathetic nervous system activation. In contrast, the pink and green partitions increased pulse rates and led to greater fluctuations, indicating higher stress. These findings demonstrate that appropriate lighting and partition colors can promote psychological stability and improve shelter environments. This study also highlights the importance of simple, low-cost environmental design strategies for stress reduction during prolonged evacuations.

In recent years, natural disasters have occurred almost annually in Japan, causing great damage. Power outages in disasterstricken areas have occasionally forced victims to resort to outdoor campfires or indoor candles for lighting. Prolonged bad weather during such events makes it difficult to safely secure lighting, which could have a negative influence on people’s health. To address this issue, we used white light-emitting diodes (LEDs) as the light source and fabricated handmade lanterns by filling a 500 mL plastic bottle with tap water and adding 1–2 drops of milk. In this study, an LED light source casing was constructed using a three-dimensional printer, achieving a stable light scattering effect. Red, green, blue, and yellow LEDs were used for the lantern, considering people’s preferences for colored handmade lanterns. An additional light source case was easily made from cardboard, and a bamboo light source case was also constructed.

In recent years, natural disasters have frequently occurred in Japan, almost yearly, causing enormous damage. In Hiroshima Prefecture, heavy rains in August 2014 and July 2018 caused large-scale landslides. Power outages continued in the affected areas, and some survivors had been lighting campfires outdoors and using candles indoors. In times of disaster in which bad weather persists, it is difficult to safely secure lighting, which can adversely affect health. Lanterns can be created by putting a few drops of milk into a PET bottle filled with water and shining light from the bottle’s bottom. In this study, we used a light emitting diode (LED) as a light source to evaluate the luminance of handmade lanterns. Results suggested that when using tap water with one LED lamp and a 500 ml PET bottle, 1–2 drops of milk are suitable to achieve the optimal light scattering effect.