To improve the measurement and subsequent use of human skin temperature (Tsk) data, there is a ne... more To improve the measurement and subsequent use of human skin temperature (Tsk) data, there is a need for practical methods to compare Tsk sensors and to quantify and better understand measurement error. We sought to develop, evaluate, and utilize a skin model with skin-like thermal properties as a tool for benchtop Tsk sensor comparisons and assessments of local temperature disturbance and sensor bias over a range of surface temperatures. Inter-sensor comparisons performed on the model were compared to measurements performed in vivo, where 14 adult males completed an experimental session involving rest and cycling exercise. Three types of Tsk sensors (two of them commercially available and one custom made) were investigated. Skin-model-derived inter-sensor differences were similar (within ±0.4 °C) to the human trial when comparing the two commercial Tsk sensors, but not for the custom Tsk sensor. Using the skin model, all surface Tsk sensors caused a local temperature disturbance wit...
Knowledge of an individual's skin condition is important for pressure ulcer prevention. Detec... more Knowledge of an individual's skin condition is important for pressure ulcer prevention. Detecting early changes in skin through perfusion, oxygen saturation values, and pressure on tissue and subsequent therapeutic intervention could increase patients' quality of life drastically. However, most existing sensing options create additional risk of ulcer development due to further pressure on and chafing of the skin. Here, as a first component, we present a flexible, photonic textile-based sensor for the continuous monitoring of the heartbeat and blood flow. Polymer optical fibres (POFs) are melt-spun continuously and characterized optically and mechanically before being embroidered. The resulting sensor shows flexibility when embroidered into a moisture-wicking fabric, and withstands disinfection with hospital-type laundry cycles. Additionally, the new sensor textile shows a lower static coefficient of friction (COF) than conventionally used bedsheets in both dry and sweaty conditions versus a skin model. Finally, we demonstrate the functionality of our sensor by measuring the heartbeat at the forehead in reflection mode and comparing it with commercial finger photoplethysmography for several subjects. Our results will allow the development of flexible, individualized, and fully textile-integrated wearable sensors for sensitive skin conditions and general long-term monitoring of patients with risk for pressure ulcer.
The heat and mass transfer in the functional sport and protective garments is not only affected b... more The heat and mass transfer in the functional sport and protective garments is not only affected by the fabric properties but also by air gap distribution between the body and the garment and its change. Until now several studies have been conducted to analyse the impact of clothing fit, moisture content and body posture on the distribution of the air within garment. However, used methods are limited to only a stationary position of the manikin, whereas the air gap changes dynamically with body movement during sport activities due to bending joints. The present study addressed the quantitative and comprehensive evaluation of the 3D garment simulation tool and simulation of air gap distribution change during various activities. In the first step the 3D garment simulation software was quantitatively validated by comparing these parameters obtained from this tool with the ones obtained from accurate 3D scanning method to assess its capability and accuracy [1]. Next, for the first time, ...
The concurrent development of simulation tools and thermal manikins has been progressing rapidly ... more The concurrent development of simulation tools and thermal manikins has been progressing rapidly and continuously over the past two decades. Recent advances in computation technologies have facilitated computer simulation of sophisticated human physiological regulation mechanisms at high spatial and temporal resolution. Improvements in manufacturing techniques and control strategies have resulted in the development of highly sophisticated thermal manikins. These versatile evaluation instruments combine fine spatial resolution with high measurement reliability and system responsiveness. When coupled with a thermo-physiological model, a thermal manikin becomes a human simulator that is capable of mimicking realistic dynamic human thermo-physiological responses to a given environment. There are already several such manikins in operation, mainly in clothing research field but also in built environment research. This chapter aims at discussing the opportunities and constraints of thermo-...
Abstract An analytical clothing model is developed to consider the effect of body movement on hea... more Abstract An analytical clothing model is developed to consider the effect of body movement on heat transfer. This model quantifies the impact of forced convection in an enclosed air layer and the effect of ventilation (through fabric pores and ensemble openings) on clothing insulation. The internal air speed (inside an enclosed air layer) caused by human movement is used to calculate the internal forced convective heat transfer coefficient. The model is validated for various combinations of walking speeds, ambient air speeds, and clothing fits. A validation study covering 15 experimental cases compares the local heat transfer coefficients for different parts of the body and for the entire body. These validation cases consist of standing (0 m/s) and two walking speeds (0.27 m/s, and 0.69 m/s), three ambient air speeds: still air (0.17 m/s), 1 m/s and 2 m/s, and three clothing ensembles with different designs. All the experiments were performed on an agile thermal manikin. The average relative error in simulated whole body heat flux was 11%. The presented model has ability to simulate heat transfer with high spatial resolution such as individual body segment, which is the major advantage over existing models.
Mass transfer due to perspired moisture in a clothing system is critical for the understanding of... more Mass transfer due to perspired moisture in a clothing system is critical for the understanding of thermo-physiology and thermal protection of a clothed body. Previous studies usually investigated moisture transfer without considering the effect of liquid sweating or external heat hazards. To understand the mechanisms of sweat evaporation, accumulation and dripping with continuous sweating under radiant heat, a multi-phase experiment was designed with a sweating Torso. The concept of clothed wettedness was proposed to understand sweat evaporation of the clothed body. Results showed that the evaporation rate of the clothed body increased with increasing perspiration rate and the rate increase can be explained by the material properties (e.g., material composition, hydrophilicity and evaporative resistance ([Formula: see text])), which affected the sweat accumulation ability. Results also demonstrated a dual relationship of [Formula: see text] with the evaporation rate of the clothed b...
Clothing and the enclosed air layers highly affect heat dissipation from the body and thus, are c... more Clothing and the enclosed air layers highly affect heat dissipation from the body and thus, are crucial factors when it comes to thermal comfort. The heat and moisture transfer is affected by the variation of the size and the shape of air gaps between the garment and the human body. In addition, the fabric and garment design properties can affect the amount of heat loss from different body parts. In this study, we investigated the effect of fabric properties (different raw materials and weave types) and the garment fit on the heat loss through the garment combinations (undershirt and shirt) for the different parts of the upper body (trunk, chest, and back) using a sweating thermal manikin. The undershirt fit and the raw material of the shirts showed strong effects on the dry thermal resistance of the garment combinations. Moreover, the undershirt properties affected the evaporative heat loss from garment combinations, and the magnitude of these effects varied over different body reg...
Perspired moisture plays a crucial role in the thermal physiology and protection of the human bod... more Perspired moisture plays a crucial role in the thermal physiology and protection of the human body wearing thermal protective clothing. Until now, the role of continuous sweating on heat transfer, when simultaneously considering internal and external heat sources, has not been well-investigated. To bridge this gap, a sweating torso manikin with 12 thermal protective fabric systems and a radiant heat panel were applied to mimic firefighting. The results demonstrated how the effect of radiant heat on heat dissipation interacted with amount of perspired moisture and material properties. A dual effect of perspired moisture was demonstrated. For hydrophilic materials, sweating induced evaporative cooling but also increased radiant heat gain. For hydrophilic station uniforms, the increment of radiant heat gain due to perspired moisture was about 11% of the increase of heat dissipation. On the other hand, perspired moisture can increase evaporative cooling and decrease radiant heat gain fo...
To improve the measurement and subsequent use of human skin temperature (Tsk) data, there is a ne... more To improve the measurement and subsequent use of human skin temperature (Tsk) data, there is a need for practical methods to compare Tsk sensors and to quantify and better understand measurement error. We sought to develop, evaluate, and utilize a skin model with skin-like thermal properties as a tool for benchtop Tsk sensor comparisons and assessments of local temperature disturbance and sensor bias over a range of surface temperatures. Inter-sensor comparisons performed on the model were compared to measurements performed in vivo, where 14 adult males completed an experimental session involving rest and cycling exercise. Three types of Tsk sensors (two of them commercially available and one custom made) were investigated. Skin-model-derived inter-sensor differences were similar (within ±0.4 °C) to the human trial when comparing the two commercial Tsk sensors, but not for the custom Tsk sensor. Using the skin model, all surface Tsk sensors caused a local temperature disturbance wit...
Knowledge of an individual's skin condition is important for pressure ulcer prevention. Detec... more Knowledge of an individual's skin condition is important for pressure ulcer prevention. Detecting early changes in skin through perfusion, oxygen saturation values, and pressure on tissue and subsequent therapeutic intervention could increase patients' quality of life drastically. However, most existing sensing options create additional risk of ulcer development due to further pressure on and chafing of the skin. Here, as a first component, we present a flexible, photonic textile-based sensor for the continuous monitoring of the heartbeat and blood flow. Polymer optical fibres (POFs) are melt-spun continuously and characterized optically and mechanically before being embroidered. The resulting sensor shows flexibility when embroidered into a moisture-wicking fabric, and withstands disinfection with hospital-type laundry cycles. Additionally, the new sensor textile shows a lower static coefficient of friction (COF) than conventionally used bedsheets in both dry and sweaty conditions versus a skin model. Finally, we demonstrate the functionality of our sensor by measuring the heartbeat at the forehead in reflection mode and comparing it with commercial finger photoplethysmography for several subjects. Our results will allow the development of flexible, individualized, and fully textile-integrated wearable sensors for sensitive skin conditions and general long-term monitoring of patients with risk for pressure ulcer.
The heat and mass transfer in the functional sport and protective garments is not only affected b... more The heat and mass transfer in the functional sport and protective garments is not only affected by the fabric properties but also by air gap distribution between the body and the garment and its change. Until now several studies have been conducted to analyse the impact of clothing fit, moisture content and body posture on the distribution of the air within garment. However, used methods are limited to only a stationary position of the manikin, whereas the air gap changes dynamically with body movement during sport activities due to bending joints. The present study addressed the quantitative and comprehensive evaluation of the 3D garment simulation tool and simulation of air gap distribution change during various activities. In the first step the 3D garment simulation software was quantitatively validated by comparing these parameters obtained from this tool with the ones obtained from accurate 3D scanning method to assess its capability and accuracy [1]. Next, for the first time, ...
The concurrent development of simulation tools and thermal manikins has been progressing rapidly ... more The concurrent development of simulation tools and thermal manikins has been progressing rapidly and continuously over the past two decades. Recent advances in computation technologies have facilitated computer simulation of sophisticated human physiological regulation mechanisms at high spatial and temporal resolution. Improvements in manufacturing techniques and control strategies have resulted in the development of highly sophisticated thermal manikins. These versatile evaluation instruments combine fine spatial resolution with high measurement reliability and system responsiveness. When coupled with a thermo-physiological model, a thermal manikin becomes a human simulator that is capable of mimicking realistic dynamic human thermo-physiological responses to a given environment. There are already several such manikins in operation, mainly in clothing research field but also in built environment research. This chapter aims at discussing the opportunities and constraints of thermo-...
Abstract An analytical clothing model is developed to consider the effect of body movement on hea... more Abstract An analytical clothing model is developed to consider the effect of body movement on heat transfer. This model quantifies the impact of forced convection in an enclosed air layer and the effect of ventilation (through fabric pores and ensemble openings) on clothing insulation. The internal air speed (inside an enclosed air layer) caused by human movement is used to calculate the internal forced convective heat transfer coefficient. The model is validated for various combinations of walking speeds, ambient air speeds, and clothing fits. A validation study covering 15 experimental cases compares the local heat transfer coefficients for different parts of the body and for the entire body. These validation cases consist of standing (0 m/s) and two walking speeds (0.27 m/s, and 0.69 m/s), three ambient air speeds: still air (0.17 m/s), 1 m/s and 2 m/s, and three clothing ensembles with different designs. All the experiments were performed on an agile thermal manikin. The average relative error in simulated whole body heat flux was 11%. The presented model has ability to simulate heat transfer with high spatial resolution such as individual body segment, which is the major advantage over existing models.
Mass transfer due to perspired moisture in a clothing system is critical for the understanding of... more Mass transfer due to perspired moisture in a clothing system is critical for the understanding of thermo-physiology and thermal protection of a clothed body. Previous studies usually investigated moisture transfer without considering the effect of liquid sweating or external heat hazards. To understand the mechanisms of sweat evaporation, accumulation and dripping with continuous sweating under radiant heat, a multi-phase experiment was designed with a sweating Torso. The concept of clothed wettedness was proposed to understand sweat evaporation of the clothed body. Results showed that the evaporation rate of the clothed body increased with increasing perspiration rate and the rate increase can be explained by the material properties (e.g., material composition, hydrophilicity and evaporative resistance ([Formula: see text])), which affected the sweat accumulation ability. Results also demonstrated a dual relationship of [Formula: see text] with the evaporation rate of the clothed b...
Clothing and the enclosed air layers highly affect heat dissipation from the body and thus, are c... more Clothing and the enclosed air layers highly affect heat dissipation from the body and thus, are crucial factors when it comes to thermal comfort. The heat and moisture transfer is affected by the variation of the size and the shape of air gaps between the garment and the human body. In addition, the fabric and garment design properties can affect the amount of heat loss from different body parts. In this study, we investigated the effect of fabric properties (different raw materials and weave types) and the garment fit on the heat loss through the garment combinations (undershirt and shirt) for the different parts of the upper body (trunk, chest, and back) using a sweating thermal manikin. The undershirt fit and the raw material of the shirts showed strong effects on the dry thermal resistance of the garment combinations. Moreover, the undershirt properties affected the evaporative heat loss from garment combinations, and the magnitude of these effects varied over different body reg...
Perspired moisture plays a crucial role in the thermal physiology and protection of the human bod... more Perspired moisture plays a crucial role in the thermal physiology and protection of the human body wearing thermal protective clothing. Until now, the role of continuous sweating on heat transfer, when simultaneously considering internal and external heat sources, has not been well-investigated. To bridge this gap, a sweating torso manikin with 12 thermal protective fabric systems and a radiant heat panel were applied to mimic firefighting. The results demonstrated how the effect of radiant heat on heat dissipation interacted with amount of perspired moisture and material properties. A dual effect of perspired moisture was demonstrated. For hydrophilic materials, sweating induced evaporative cooling but also increased radiant heat gain. For hydrophilic station uniforms, the increment of radiant heat gain due to perspired moisture was about 11% of the increase of heat dissipation. On the other hand, perspired moisture can increase evaporative cooling and decrease radiant heat gain fo...
Psikuta, A., Kuklane, K., Bogdan, A., Havenith, G., Annaheim, S. and Rossi, R.M., 2016. Opportuni... more Psikuta, A., Kuklane, K., Bogdan, A., Havenith, G., Annaheim, S. and Rossi, R.M., 2016. Opportunities and constraints of presently used thermal manikins for thermo-physiological simulation of the human body. International journal of biometeorology, 60(3), pp.435-446.
Combining the strengths of an advanced mathematical model of human physiology and a thermal manikin is a new paradigm for simulating thermal behaviour of humans. However, the forerunners of such adaptive manikins showed some substantial limitations. This project aimed to determine the opportunities and constraints of the existing thermal manikins when dynamically controlled by a mathematical model of human thermal physiology. Four thermal manikins were selected and evaluated for their heat flux measurement uncertainty including lateral heat flows between manikin body parts and the response of each sector to the frequent change of the set-point temperature typical when using a physiological model for control. In general, all evaluated manikins are suitable for coupling with a physiological model with some recommendations for further improvement of manikin dynamic performance. The proposed methodology is useful to improve the performance of the adaptive manikins and help to provide a reliable and versatile tool for the broad research and development in domains of clothing, automotive and building engineering.
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Papers by Rene M Rossi
Combining the strengths of an advanced mathematical model of human physiology and a thermal manikin is a new paradigm for simulating thermal behaviour of humans. However, the forerunners of such adaptive manikins showed some substantial limitations. This project aimed to determine the opportunities and constraints of the existing thermal manikins when dynamically controlled by a mathematical model of human thermal physiology. Four thermal manikins were selected and evaluated for their heat flux measurement uncertainty including lateral heat flows between manikin body parts and the response of each sector to the frequent change of the set-point temperature typical when using a physiological model for control. In general, all evaluated manikins are suitable for coupling with a physiological model with some recommendations for further improvement of manikin dynamic performance. The proposed methodology is useful to improve the performance of the adaptive manikins and help to provide a reliable and versatile tool for the broad research and development in domains of clothing, automotive and building engineering.