Breaks can protect workers exposed to high temperatures from heat stress and other health risks. However, the most suitable recovery conditions and how the body physiologically responds to them remain uncertain. The aim of this study was to provide scientific evidence of the human physiological response to step changes in environmental parameters of recovery stage through climate chamber experiments and to develop a predictive model. Volunteer subjects experienced 60 min of walking exercise in air temperatures of 32 and 36 degrees C, RH 60%, and an air velocity of 0.2 m/s to form two heat stress levels, and then moved into a resting space under designated environmental conditions, such as a standard effective temperature (SET) range of 15.6-26.0 degrees C. The results showed that the recovery time for physiological parameters decreased with decreasing SET, accompanied by a simultaneous increase in thermal discomfort rate. Correlation analysis suggested that recovery time was related to the physiological stress index at the beginning of the recovery phase (PSI0; r = 0.86) and the SET (r = 0.75) of the recovery environment. A predictive model of heat stress recovery time was developed based on PSI0 and SET, with a determination coefficient of 0.9. According to the model, a SET of 18.8-24.9 degrees C was suitable for people with high heat stress requiring full recovery in 15-30 min. The research findings contribute to the regulation of health and safety in high-temperature working environments and the operation of restroom environmental conditions.

The present study aims to further understand the effect of surface properties of vertical textiles indoors on the particle deposition. A 512 L cubic aluminum experimental chamber was built to obtain the deposition loss rate coefficients for 0.37, 0.54, 0.75, 0.9, 1.3, and 1.6 µm particles under three different airflow conditions. Eight curtain fabrics—four window voile fabrics and four curtain cloths—were selected as the deposition surfaces in investigating the effect of fabric porosity on particle deposition. The total fabric porosity can be roughly divided into inter-yarn porosity and inter-fiber porosity. The experimental results reveal that both the near-surface airflow velocity and the particle size affect the deposition loss rate coefficient. The trend of the deposition loss rate coefficient with increasing inter-yarn porosity differs from that with increasing inter-fiber porosity.

Daily transitions between indoor and outdoor environments involving temperature step changes have been extensively studied in young people, but little attention has been given to age-related differences and the development of thermal prediction models specifically for the elderly. To address this knowledge gap, a study was conducted in a climate chamber using warm-neutral-warm experimental sessions. Twenty-four elderly participants were selected from volunteers who met the health and body shape requirements. Thermal sensation vote (TSV) and mean skin temperature (MST) responses of the elderly were collected and analyzed. The results demonstrate that temperature step changes (3-9 degrees C) and neutral thermal experiences significantly influence the thermal responses of the elderly. Compared to the young, the elderly exhibit lower TSV, lower MST, lower skin heat loss, and different associations between TSV and skin heat loss. Leveraging these age-related differences, an MST prediction model was established for the elderly. The predicted MST can also serve as an input for the TSV prediction model established in this study. The TSV prediction model is based on skin heat loss and applicable to both transient and steady-state conditions. This study introduces a new approach for predicting the thermal responses of the elderly and enhances understanding of age-related differences in thermal responses.

在温度为(20±2)℃、相对湿度为(40±3)％的环境条件下,采用试验方法研究了织物在不同摩擦次数下产生的电荷量的多少,重点研究了窗帘与金属、玻璃、其他织物的摩擦,以反映窗帘等织物表面在实际生活中的可能带电的大小,为研究静电对颗粒物在织物表面上沉积的影响提供数据支撑.结果表明:织物摩擦所产生电荷量主要由织物的材质、结构特点和摩擦功决定;织物上所带电荷量的大小与摩擦次数呈对数函数关系或常函数关系;在(40±3)％相对湿度情况下,涤纶窗帘在日常生活中产生的电荷量面密度为0.109μc/m2～2.19 μ c/m2.

Particle deposition on building internal surfaces has been extensively studied; however, common indoor textile surfaces have been rarely mentioned. Thus, the main goal of this study was to evaluate the effects of surface properties of textile materials on particle deposition. Two special surface analysis techniques were introduced to measure the surface roughness of textile materials. The deposition loss rate coefficients of different size of particles on vertically oriented textile surfaces were determined experimentally. A 512-L aluminum cubic experimental chamber (0.8 m×0.8 m×0.8 m) was built to measure the deposition loss rate coefficient of 0.37, 0.54, 0.75, 0.9, 1.3, and 1.6 μm particles under three airflow intensity levels. The deposition loss rate coefficients for eight single-layer curtain cloths with different surface roughness were measured. The results show that the deposition loss rate coefficient increased with the near-surface airflow velocity and exhibited a V-shaped distribution with the increase in particle size. The degree of influence on the particle deposition of textile surface roughness is related to the tightness of textile material, near-surface airflow velocity, and particle size. The effect of particle size on deposition loss rate coefficient is much larger than that of the near-surface airflow velocity and surface roughness of the textile material.