Clothing temperature changes of phase change material-treated warm-up in cold and warm environments

The purpose of this study was to investigate the appropriate amounts of phase change materials to give objective and subjective wear sensations. Vapor-permeable water-repellent fabrics with (WR-PCM) and without (WR) octadecane containing microcapsules were obtained by wet-porous coating process. Then, calculating the area of the WR-PCM treated clothes, we estimated the total calories of the clothing by multiplying the heat of fusion and heat of crystallization of PCM to the calculated area. Wear tests were conducted in both warm environment (30°C, 65 % RH) and cold environment (5°C, 65 % RH) with sports warm up style experimental garments made with WR and WR-PCM fabrics. Rectal, skin, and clothing microclimate temperatures, saliva and subjective evaluation measurements were done during the wear test. There was no difference of rectal and mean skin temperatures between WR and WR-PCM, but the clothing microclimate temperature of WR-PCM under warm environment was slightly lower than that of WR. In cold environment, WR-PCM showed much higher temperature than in WR. Saliva change did not appear between clothes, but did between two environments. Although subjective sensation between WR and WR-PCM was not significantly different, WR-PCM was rated as cooler than WR in warm environment and as warmer than WR in cold environment. The results of this study indicated that octadecane containing microcapsules in water-repellent fabric provide cooling effect.     

Quantitative thermographic analysis method for evaluating the thermal properties of PET irradiated by ultra-violet

A thermograph is used to determine the real-time temperature distribution on the skin temperature wearing clothing treated by different ultra-violet (UV) energy. The thermogram images of body wearing clothing with the 4-channel PET knit fabric irradiated by UV, were compared visually with each other and analyzed quantitatively with image analysis. We analyzed the thermogram in a color image. For image analysis, the Inspector 4.0 (Matrox Electronic System, Ltd.) was used. The surface temperatures, calculated based on the percentage surface area of a given temperature range with an interval of 1 °C, were averaged of five subjects’ surface temperature. From the results of the microclimate temperature, there were not significant differences among the subjects’ surface temperatures wearing different time treated clothes. However, subjective evaluation shows that the clothing treated by UV for 90 min had the lowest thermal sensation and the highest comfort sensation. Based on the image analysis of the thermogram, the calculated thermal sensation of the clothes irradiated by UV for 0 min, 30 min and 90 min, were coincident with the subjective thermal sensation.     

The psycho-physiological response of polyethylene terephthalate irradiated by ultra-violet: Subjective fabric hand and wear comfort

The purpose of this study was to compare the subjective fabric hand evaluation and wear comfort of PET treated by Ultraviolet and to evaluate the subjective results from the investigation of microclimate temperature. The subjective hand evaluation was performed by 20 subjects (age: 20–25) with 5-point scale questionnaires to investigate the change of PET knit fabrics treated for different times, specifically, 0, 30 and 90 minutes. The questionnaires were composite with 8 questions; roughness, smoothness, wetness, stiffness, coolness, touch, preference, and comfort. In order to evaluate sensations of wear comfort, we made garments with UV treated fabric and five female students were tested. They walked at the speed of 6.7 km/hr for 15 minutes in an environment, which was controlled at 29°C, 75±5 % RH. Before and after exercising, the microclimate under clothing and subjective wear comfort was measured. The results of subjective evaluation of fabric hand were that untreated and treated for 30 minutes PET were recognized as similar and have a good evaluation on comfort, preference, and touch. According to the result of wear comfort, clothing treated by UV for 90 minutes had the lowest value on the thermal and humidity sensations. In addition, the value of tactile and comfort sensation was the highest on the clothing treated by UV for 90 minutes. In the case of objective evaluation, PET treated for 90 minutes was the lowest on microclimate humidity. PET irradiated by UV for 90 minutes was more ‘cool’ in thermal sensation and more ‘dry’ in wet sensation. Accordingly, it was consistent with the result of subjective wear comfort.     

Effects of thermal and moisture transport properties of T-shirts on wearer’s comfort sensations

Little work has been done in the past on how clothing thermal and moisture transport properties affect human comfort sensations during different periods of an exercise. In this work, by correlating the thermal and moisture transport properties of T-shirt fabrics and garments with the comfort sensations during different stages of exercises, we found that thickness, thermal insulation and warm/cool feeling of the T-shirt fabrics are important to warmth sensation, skin wetness sensation and overall comfort throughout the entire period of exercise and immediately after the exercise. Water vapor transmission properties of T-shirt fabrics or garments are not important to comfort sensations at the start of the exercise, but become an important factor to comfort sensations in the middle of the exercise up to the resting period after the running exercise, probably due to the fact that sweating occurs during these periods. Fabric water absorption and air permeability are not significant factors at the start and during the exercise, but are important after exercise, probably because these properties determine how quickly the skin can be dried after sweating.     

Effect of clothing constructions on core temperature during exercise and recovery at an ambient temperature

In this paper we investigated the human thermoregulatory responses, especially core temperature behavior during exercise and recovery at ambient temperature of 10 °C and 50 % R.H. under the conditions of wearing three kinds of clothing with same weight and different constructions. Six healthy men wore three kinds of clothing: one insulating the upper half of the body thinly and the lower half of the body heavily (clothing A, the weights in the upper and lower halves of the body were 489 g and 1278 g, respectively.), the second one insulating the upper half of the body heavily and the lower half of the body thinly (clothing B, 1212 g and 559 g, respectively.), and the third one insulating the upper and lower halves of the body moderately (clothing C, 899 g and 879 g, respectively.). The level of rectal temperature was the greatest during exercise in clothing C and the lowest during recovery in clothing A. The increasing and decreasing rates of core temperature during exercise and recovery, respectively, were the smallest in clothing B. These findings are discussed in terms of different cooling efficiency from the lower extremities and disfunction of counter current heat exchange system among clothing A, B, and C.     

Assessing the performance of a conceptual tight-fitting body mapping sportswear (BMS) kit in a warm dry environment

The main objective of this study was to evaluate the actual performance of a conceptual body mapping sportswear (BMS) kit while doing different activities in a warm dry condition. Eight subjects participated in this study and each subject underwent two trials. Each trial was composed of 40 min treadmill walking at 5.0 km/h, 10 min resting, 20 min treadmill running at 10.0 km/h and a final 20 min resting. All trials were performed in a chamber where the T _a =30±0.5 °C, RH=40±5 % and v _air =0.17±0.05 m/s. Human physiological and perceptual responses in CON (i.e., traditional cotton sportswear) and BMS were measured and compared. It was found that both physiological responses (such as core temperature, mean skin temperature, mean torso temperature, mean body temperature and hear rate) and local subjective sensations (e.g., thermal sensation) were improved in BMS during the running phase as well as the second recovery phase. It was thus concluded that the conceptual BMS kit does have advantages over traditional cotton sportswear in terms of improvements on both physiological responses and local subjective sensations.     

Evaluating the cold protective performance (CPP) of an electrically heated garment (EHG) and a chemically heated garment (CHG) in cold environments

This study investigated the cold protective performance (CPP) of two types of heated garments using a Newton manikin operated in constant temperature mode (CT) and thermoregulatory model control (TMC) mode. The effect of two levels of air velocity (i.e., 0.4±0.1 m/s and 1.0±0.1 m/s) on the CPP was discussed. Five scenarios were chosen, the traditional cold protective ensemble (CON), the electrically heated garment (EHG), the non-heated electrically heated garment (EHG_CON, heating was turned off), the chemically heated garment (CHG) and the non-heated chemically heated garment (CHG_CON) (completely oxidized body warmers were used). All experiments were performed at t _a =2.0±0.3 oC and RH=80±5 %. Results demonstrated that both EHG and CHG could provide improved cold protection compared to the nonheated garments, evidenced by the significantly higher thermal insulation in EHG and CHG at both two air velocities (p<0.01). The air velocity has a minor effect on the effective heating power and the heating efficiency, but it significantly reduced the total clothing thermal insulation. EHG exhibited a significantly higher effective heating power and thermal insulation compared to the CHG only under the low air velocity (p<0.05). Additionally, higher skin temperatures and improved whole body and local thermal sensations were observed in both EHG and CHG compared to CON. The EHG compared to CHG, showed similar thermophysiological and psychological responses at 1.0±0.1 m/s (p>0.05). It was thus anticipated that both two heated garments could improve human wear thermal comfort in cold environments.     

A study on heat insulation of composites made of recycled far-infrared fibers and three-dimensional crimped hollow polyester fibers

Far-infrared polyethylene terephthalate (FPET) fibers have been commonly used in clothing in order to attain heat retention, and the combination of three-dimensional crimped hollow polyethylene terephthalate (TPET) fibers makes the clothing to be fluffy and air permeable, and thereby improves the wearing comfort. This study aims to make thermally insulating nonwoven composites by using recycled far infrared fibers. The composites are used to cover the heat transfer lines and prevent the heat emissivity. A specified amount of low-melting-point polyethylene terephthalate (LPET) fibers and FPET and TPET fibers at different ratios are blended, followed by being needle punched at 100-300 needles/min, and then hot pressed at 120 °C, in order to form thirty nonwoven composite types. These nonwoven composites are measured for their porosity, thickness, and air permeability, and are tested for thermal insulation and temperature-rise slope under a constant ambient temperature.     

Effects of fabric surface energy on human thermophysiological responses during exercise and recovery

The present paper reports a study on influences of fabric surface energy of cotton and polyester garments on clothing microclimates and human thermophysiological responses during intermittent exercise and recovery. Eight healthy males wearing the garments prepared performed exercises and rest according to the following protocol: rest for 30 min, run on treadmill for total 60 min of three sessions with different intensity and duration, and then sit quietly for 30 min for recovery, all at 30 °C and relative humidity of 30 %, while the microclimate humidity (H _mc ) and temperature (T _mc ), the clothing outside surface humidity (H _co ) and temperature (T _co ), the skin temperatures and ear canal temperature (T _{ear_canal} ) were measured. The garments are made of: (a) hydrophilic and hydrophobic cotton knitted fabrics, and (b) hydrophilic and hydrophobic polyester knitted fabrics. During and after exercise, for cotton, hydrophilic garment resulted in significant lowerΔH _mc , ΔH _co , ΔT _mc during recovery, higher , lowerΔT _{ear_canal} andΔT _forehead . For polyester, hydrophilic garment resulted in significantly lowerΔH _co , ΔT _co , higher , higherΔT _forehead during E1, E2 and recovery session but lower during E3. In summary, surface energy of cotton garments had significant influences on human thermophysiological responses during exercise and recovery, and hydrophilic cotton garment was better than hydrophobic one to reduce heat stress. Surface energy of polyester garments had influences of lower significance, and hydrophilic garment appeared better than hydrophobic garment.     

Effects of athletic T-shirt designs on thermal comfort

This paper reports on an experimental investigation of the effects of T-shirts design on clothing thermal comfort measured in terms of clothing thermal insulation and moisture vapour resistance. Ten short sleeved T-shirts of varying opening styles and mesh styles were designed and produced for testing on the sweating fabric manikin-Walter. Clothing thermal insulation and moisture vapour resistance of the T-shirts were measured when the manikin simulates walking motion and standing posture. The results showed that, the positions of openings and ventilation panels affects the total thermal insulation and vapour resistance; among the various designs tested, openings applied at two vertical side panels along the side seams can most effectively release heat and moisture from the body.     

Changes in Ensembles’ Thermal Insulation According to Garment’s Fit and Length Based on Athletic Figure

The purpose of this paper is to analyse the impact of design solutions on the thermal insulation of the garments and the ensembles. Previous studies investigated the microclimatic air gaps and volumes, however only under the first - and the second - layered clothing. Since none of the previous studies covered three - layered ensembles, in this study ensembles were accompanied by jackets of different fit and length to investigate the ensembles’ thermal insulation. Variants of bomber jacket differ in the amount of the ease allowance, while variants of the parka differ in length. The thermal insulation of the ensembles increased for 21.6 to 59.7 % when one of the jacket variants was added as the outerwear garment. A threshold volume, after which the thermal insulation will start to decrease due to convection, wasn’t determined for the outerwear third - layered garments nor was the impact of the length of the garment on the thermal insulation clearly stated. This study involved laboratory testing of garments and ensembles by 3D body scanning and thermal manikin measurements. To evaluate the volume of the microclimatic air volume the accurate 3D body scanning was used and the impact of the microclimatic volume on the ensemble’s insulation was tested. The thermal insulation for the selected outerwear garments and afterwards ensembles was measured by resting thermal manikin. Analysis of the results obtained from tests, showed that the garments’ fit and length can be used to model the overall thermal insulation of the ensembles. The ensembles insulation enlargement was measured for microclimatic volumes up to 33.57 dm³ (measured with ensembles accompanied with bomber jacket). The study proved that the limiting microclimatic volume is greater for three - layered clothing, than previously reported. The overall ensembles’ insulation increased simultaneously with the length enlargement (measured with ensembles accompanied with parka jacket). Findings will be of help in the future research on garments and ensembles thermal properties modelled through the design process and the construction.     

A new approach to evaluate the effect of moisture on heat transfer of thermal protective clothing under flashover

It’s urgent to investigate moisture effect on thermal protection of thermal protective clothing in simulated fire scene as accurately as possible. The current bench top tests can’t evaluate thermal protective performance (TPP) of fabrics under microclimate with high temperature and relative humidity (RH). In this paper, to well investigate effect of different RH under microclimate on thermal protective performance of flame-retardant fabrics exposed to flashover, a new modified TPP testing apparatus was developed. It consisted of a typical TPP tester and RH adjustable microclimate chamber. Three kinds of air gaps under fabrics were also employed to simulate different spaces between skin and clothing. The results showed that the temperature increment under microclimate of 35 % RH was highest, and that of 95 % RH was lowest. There was significant temperature difference found among above three adjusted environment. Time required of temperature rise to 12 oC highly prolonged as RH became higher. It could be deduced that the effect of RH on heat transfer became significant as air gap increasing; if the air gap width still increased, the moisture effect diminished. The newly developed testing apparatus could be well used to evaluate the moisture effect on thermal protective performance of flame-resistant fabrics.     

Characteristics of double-layer coated fabrics with and without phase change materials and nano-particles

Stability in a low temperature environment is needed for a textile to be used as winter wear. This research was presented the characteristics of fabrics by double-thin-layered coating with and without phase change materials (PCM) and several nano-sized inorganic particles (N-particles). Silica, Ag, Zr, and carbon types of N-particles were used for investigating the N-particles effect. For the experimental method, the PCM and N-particles were coated consecutively in the wet and dry coating process, respectively. The N-particles on the surface of the coated fabrics were confirmed by energy dispersive spectroscopy (EDS), and after double-layer composite coating, the adhesion durability, water vapor permeability, water penetration resistance, DSC, thermographic photography, far infrared (FIR) emission effect, and the thermal insulation of the coated fabrics were tested for investigating the performances. Their compatibility and adhesion were superior when the add-on of N-particles was 10 %. From the DSC reproducibility results, we verified that the N-particles coated fabric preserved its thermal stability by absorbing latent heat. On the other hand, the FIR emission rate and energy of the Ag N-particle based sample were not better than the control sample.     

Mathematical simulation and experimental measurement of clothing surface temperature under different sized air gaps

The influence of air gap thickness on clothing surface temperature is analyzed by means of experimental and simulated methods. A three-dimensional body scanner is used to determine the air gap distribution between different-sized garments. The clothing surface temperature is measured by an infrared thermal camera to evaluate the heat transfer through air gap layer. The combination of two non-contact measuring techniques is a novel way to investigate the relationship between air gap thickness and clothing surface temperature. A mathematical model is set up to simulate the heat and moisture transfer from skin to environment by including the sensible and latent heat transfer through air gap layer under clothing, fabric layer and boundary air layer adjacent to the fabric. The established mathematical model is used to forecast the surface temperature and evaluate the heat transfer capacity of different sized garments.     

The physiological response on wear comfort of polyethylene terephthalate irradiated by ultra-violet

The purpose of this study was to evaluate the comfort of PET clothing treated by UV. The physiological responses of the human body were investigated. Mean skin temperature and physiological signals such as Electroencephalogram (EEG), and heart rate (Electrocardiogram, (ECG)) were examined for 20 minutes during stable wearing conditions. Mean skin temperature was measured every two seconds using Ramanathan’s method. Physiological responses were measured using Biopac MP100 series and analyzed using the software, Acqknowledge 3.5.2. Psychological effects were analyzed every five minutes. Comfort of untreated PET clothing decreased with the passage of time. Compared with PET clothing untreated, treated for 30 minutes, and treated for 90 minutes, the analysis of EEG showed that PET clothing treated for 90 minutes was the most comfortable after 20 minutes. In addition, the interval of the heart rate shown on the ECG was the highest in PET clothing treated for 90 minutes. Skin temperature was the lowest in PET treated for 90 minutes. We thus conclude that suitable UV irradiation would improve comfort.     

Antioxidant Compounds Recovery from Juçara Residue by Thermal Assisted Extraction

This study aimed to recover bioactive compounds by solid-liquid extraction from the agro-industrial residue obtained during juçara fruits processing into pulp. A preliminary study using different solvents (methanol, ethanol and water) indicated ethanol in aqueous solution as the best solvent for antioxidants recovery. Then, a Box-Behnken design was applied considering as independent variables the solvent composition (30–70% ethanol in water), temperature (30–70 °C) and time (30–60 min), in order to evaluate the effects of these factors on antioxidant activity in juçara extract. Results showed that the extracts with higher antioxidant activity were obtained using 30% ethanol at 70 °C for 60 min; measurements included ABTS and DPPH assays, determination of total phenolic content and total monomeric anthocyanins. Furthermore, the effect of pH in antioxidants recovery was evaluated. For this purpose, the 30% ethanol solution was acidified to pH 1 and 2 with HCl. Principal component analysis showed the formation of three distinct groups: one characterized by high bioactive compounds content (pH 1.0), another with superior antioxidant activity (pH 5.75, non-acidified), and finally the group at pH 2 presenting the worst concentrations in the evaluated responses. HPLC analysis showed the presence of cyanidin-3-O-rutinoside and cyanidin-3-O-glucoside in the extracts. Therefore, the conventional solid-liquid extraction using renewable solvent can be successfully applied to recover bioactive compounds from juçara residue, which can be used by different food industries.     

Effects of bending properties and drapability on the hand and appearance of wool-blended Fabrics: Comparison of real clothing with online and 3D virtual garments

The purpose of this study was to investigate the effects of bending properties and drapability on the hand and appearance of wool-blended fabrics for comparison of real clothing with online and 3D virtual garments. Objective evaluations were performed by measuring mechanical properties of fabrics, while subjective evaluations were performed by subjects evaluating sensory images of fabrics; real clothing evaluations were performed offline and online, and 3D virtual garments were evaluated. Bending properties and drape coefficients of fabrics were affected by wool blending ratio, and fabrics with high wool blending ratio showed low stiffness, warm-cool, weight, and high smoothness, drapability image. In the real clothing evaluation, stiffness image showed many differences with online evaluation with respect to wool blending ratio. Objective bending properties and drape coefficients showed no correlation with subjective sensory images offline. For the online results, objective mechanical properties had good correlations with all sensory images except smoothness. Stiffness and warm-cool online scores were higher than the offline ones and the offline drapability was higher than the online one for 100 % wool fabrics. Thus, clothing was generally evaluated online as more hard and moist than real clothing. For the virtual garment evaluation, sensory images had no difference according to wool blending ratio compared with real clothing. Many differences in subjective sensory images between real clothing and virtual garments were observed, except for smoothness and weight images. The results showed that it is difficult to exactly predict the hand and appearance of clothing according to fabric properties using 3D virtual garment system.     

浅析冬季低温割胶与橡胶树死皮的增长

进入冬季低温期割胶是形成胶乳长流,致使橡胶树的排胶时间延长,造成排胶强度过大,橡胶树体内的大量营养物质伴随胶乳长流而流失,导致橡胶树排胶过度疲劳引起死皮增加。本文主要介绍勐腊农场对冬季低温割胶与橡胶树死皮增长的调查结果,告诫植胶者引起高度重视,决不要只顾眼前利益,而违反规程采用短期行为取胶,以免造成更大的经济损失。要正确树立遵章割胶、守规割胶意识,严格控制生产技术经济指标,才能延长橡胶树的经济寿命,获得长期持续的经济收益。     

Study of moisture and thermal transfer properties as a function of the fiber material variation

The properties of moisture transfer and the comfort of mesh-structured fabrics with various knit compositions and properties were investigated. The comfort effects of the double knitted fabrics combined with different cross-shaped fibers composed of dyeable-polypropylene (PPd) and regular polyester (PET) double-knitted fabrics were studied. A series of PET, PPd, Coolmax^® (Cm) with single knitted fabrics and PPd/Cm with double knitted fabrics were evaluated to determine the physical properties and wearing performance for comfortable clothing. To compare the structural properties involving the vapor transfer of 4 types of fabrics with different fiber compositions, fiber types, weights, and thicknesses, the surface structure and pore characteristics were evaluated by scanning electron microscopy and a capillary flow porometer. The properties of moisture transfer were tested using vertical wicking and gravimetric absorbent testing system (GATS). In addition, the comfort performance measured by the thermal insulation value (Rt) and moisture permeability index (im) with a thermal manikin in a conditioned walk-in environmental test chamber was predicted. The result showed that the PPd/Cm sample has potential applications as good comfort fabric materials.