Search Results (23)

Sheep wool is a natural fiber from various sheep breeds, mainly used in clothing for its insulation properties. It makes up a small share of global fiber production, which is declining as synthetic fibers replace wool and meat farming becomes more profitable. Wool from slaughter sheep, often unsuitable for textiles, is treated as biodegradable waste. The aim of the study was to develop a fully biodegradable composite of natural origin from a polylactide (PLA) matrix reinforced with sheep wool and to select the optimal modifications (chemical) of sheep wool fibers to obtain modified properties, including mechanical properties. The behavior of the composites after exposure to aging conditions simulating naturally occurring stimuli causing biodegradation and thus changes in the material’s performance over its lifespan was also examined. Dynamic thermal analysis was used to describe and parameterize the obtained data and their variables, and the mechanical properties were investigated. The research culminated in a microscopic analysis along with changes in surface properties. The study demonstrated that wool-reinforced composites exhibited significantly improved resistance to UV degradation compared to pure PLA, with samples containing 15% unmodified wool showing a 54% increase in storage modulus at 0 °C after aging. Chemical modifications using nitric acid, iron compounds, and tar were successfully implemented to enhance fiber–matrix compatibility, resulting in increased glass transition temperatures and modified mechanical properties. Although wool fiber is not a good choice for modifications to increase mechanical strength, adding wool fiber does not improve mechanical properties but also does not worsen them much. Wool fibers are a good filler that accelerates degradation and are also a waste, which reduces the potential costs of producing such a biocomposite. The research established that these biocomposites maintain sufficient mechanical properties for packaging applications while offering better environmental resistance than pure polylactide, contributing to the development of circular economy solutions for agricultural waste valorization. So far, no studies have been conducted in the literature on the influence of sheep wool and its modified versions on the mechanical properties and the influence of modification on the degradation rate of PLA/sheep wool biocomposites. Full article

Overwintering frost damage is a major challenge for the wine grape industry in northern China. This study investigates overwintering treatments to improve survival rates and mitigate frost damage in the wine grape production area of the northern foothills of the Tianshan Mountains. Seven overwintering treatments were tested: soil-covered striped cloth, striped cloth, sandwiched striped cloth, thickened striped cloth, double-layered striped cloth, heat-insulating striped cloth, and heat-insulating sandwich striped cloth. Temperature and humidity were continuously monitored during the overwintering period, both aboveground and at depths of 20 and 40 cm underground. By analyzing temperature trends, the duration of low temperatures, and temperature fluctuations, comprehensive overwintering indices were derived through principal component analysis to assess heat retention, moisture preservation, and the impact on grapevine survival. The results showed that the sandwiched striped cloth treatment provided the best insulation, with a 4.4 °C higher minimum daily temperature and a 356% increase in overwintering indices compared to striped cloth alone. The double-layer striped cloth treatment also improved safety, with a 130% increase in overwintering indices. Other treatments, including the soil-covered and the heat-insulating striped cloth, showed reduced performance. The sandwiched striped cloth and double-layer striped cloth treatments are recommended for northern China’s wine grape regions, with further research needed to evaluate their economic viability. Full article

Current thermal comfort constructs are perceptional, and their relationships to the physiological responses are not fully understood. The latter are very important, not only to indicate personal comfort perception but also to protect personal health against cold and heat stresses. This paper combined a two-node bioheat model with the metabolic-based predicted mean vote index (MPMV) to uncover the relationships between the physiological responses and perceptional thermal sensation at steady-state conditions. The MPMV index accounts for sweating and non-shivering thermogenesis (NST) at the neutral comfort state and handles both core and skin cooling cases. Simulations were conducted for adults in typical indoor environment conditions. The physiological responses investigated included the body, core and mean skin temperatures, skin evaporative heat flux, shivering metabolic rate, and skin blood flow. The study revealed that only the mean skin temperature and skin blood flow can discriminate between comfort perception levels and can therefore be used alone or combined with other variables as alternative physiological indicators. The comfort range (MPMV within ±1) in terms of the mean skin temperature is maintained by regulatory sweating and/or NST and gets wider with increasing activity levels. The study also offered important insights for practical applications and future research. Full article

This study proposes an occupant-centric control strategy for residential heating systems, aiming to enhance thermal comfort and reduce energy consumption. A sensor station utilizing a frequency-modulated continuous wave radar sensor was developed to detect occupancy and infer activities within residential spaces. By analyzing field measurement data, schedules for occupancy and activities were established. These schedules were then used to implement a variable control strategy for the hydronic radiant heating system, adjusting its operating characteristics based on the identified activities. The proposed control strategy, which includes resetting the indoor set temperature during unoccupied periods and adjusting it during sleep to account for changes in metabolic rate and clothing insulation, resulted in significant energy savings. Compared to continuous operation, the hydronic radiant heating system’s energy consumption was reduced by approximately 21% on peak load days and up to 34% over three winter months. This study demonstrates the potential of occupant-centric control for achieving substantial energy savings in residential buildings while maintaining occupant thermal comfort. Full article

In order to prepare flexible thermal protection aerogel materials, using dimethyldimethoxysilane (DMDMS) and methyltrimethoxysilane (MTMS) as co-precursors, isocyanate-propyltrimethoxysilane (CFS-006) was added to the co-precursor as a coupling agent, and resorcinol and formaldehyde were added to the sol solution to prepare a phenolic silicone hybrid aerogel (FAS) by the sol–gel method. The prepared FAS aerogel had no phase separation problem, the density was only 0.118 g/cm³, the hydrophobic angle reached 155.3°, and it had certain flexibility. It could be compressed to 70% and still be restored to its original state. The FAS aerogel also had a low thermal conductivity of 0.0318 W/(m·K) and good high temperature insulation. The introduction of phenolic groups improved thermal stability; Tmax increased to 643.7 °C, and the residual carbon rate was 24.5%. This work has positive significance for the future combination of aerogels and textiles in the preparation of firefighting protective clothing. Full article

A favorable thermal environment in fitness centers is important to attract more members and is beneficial to the health of exercising people. The purpose of this study was to research the actual thermal environment of a typical fitness center in different seasons and the thermal requirement of exercising people. A field investigation covering winter, spring, and summer was conducted. The environmental parameters were measured. Subjective questionnaires involving individual information, clothing insulation, thermal sensation, etc., were collected. Participants’ heart rates were tested to estimate their metabolic rate (MR). A total of 740 valid questionnaires were collected. The results showed that a scissors gap existed between the predictive mean vote (PMV) and the thermal sensation vote (TSV) for the exercising people. For the higher MR group, there was a separation between the TSV and thermal preference vote, e.g., most participants would not prefer to cooler or warmer thermal environment when they felt hot or cold. The CO₂ concentration changed greatly among seasons and the distribution in the fitness center was not uniform. With mechanical ventilation, the CO₂ concentration in summer was the lowest. In other seasons it became much higher due to limited natural ventilation. However, subjective response to indoor air quality showed no significant difference among seasons. The participants felt more satisfied to the overall thermal environment in the transition season. The results can be referenced in the thermal environment management in fitness centers during seasonal changes. Full article

Rayon is an extremely valuable cellulosic fiber in the global textile industry. Since cuprammonium rayon is more eco-friendly than other types of rayon fabrics, it was synthesized by regenerating α–cellulose isolated from wastepaper using a novel gaseous-ammoniation injection (GAI) process. This was achieved by preparing tetra–ammine copper hydroxide (cuoxam solution) via reacting copper sulfate and sodium hydroxide to produce copper hydroxide that was, finally, ammoniated by injecting the gas directly to the reaction vessel instead of using ammonium hydroxide applied by prior art. After that, the air-dried cellulose was chemically generated by dissolving it in a freshly prepared cuoxam solution and, subsequently, was regenerated by extruding it within a hardening bath constituted mainly from citric acid, producing the cuprammonium rayon (c. rayon). The properties of the fibrous, structural (XRD and mechanical), physical, and chemical features were investigated. It was found that the rayon was produced in a high yield (90.3%) with accepted properties. The fibrous properties of the rayon staple length, linear density, and fiber diameter were found to be 44 mm, 235 Tex, and 19.4 µm, respectively. In addition, the mechanical properties determined, namely tensile strength, elongation at break, modulus of elasticity, and breaking tenacity, were found to be 218.3 MPa, 14.3 GPa, 16.1%, and 27.53 cN/Tex, respectively. Based on this finding, and upon injecting the ammonia gas through the α–cellulose saturated and immersed in the Cu (OH)₂ to complete producing the cuoxam solvent, we find that theuse of an injection rate of 120 mL/minute to obtain the highest fibers’ tensile strength for the final product of the c. rayon is preferable. Utilization of higher rates will consume more amounts of the ammonia gas without gaining noticeable enhancement in the c. rayon’s mechanical quality. Accordingly, the GAI invention rendered the c. rayon favorable for use in making sustainable semisynthetic floss for either insulation purposes or spun threads for woven and nonwoven textile clothing. Full article

Past investigations have assessed gender variations in thermal comfort and adaptation in different buildings. However, no reported study has evaluated differences in gender perceptions of the thermal environment in US Colonial Revival-style homes. As a result, this study aims to provide an understanding of variations in gender perceptions of summer comfort and adaptation in the buildings. The study evaluated data collected during the field studies of thermal comfort (FSTC), including physical measurements of environmental variables and subjects’ votes. In this study, 67% females and 33% males participated in the field surveys in summertime. The mean neutral temperature of 25.5 °C and preferred temperature of 24.9 °C were noted for females. For males, the mean neutral and preferred temperatures of 25.8 °C and 25.6 °C were observed. Females feel neutral and prefer “no change” to the thermal environment at lower temperatures than males. A difference of 0.3 °C was noted between the average heat indices for females and males. Male respondents who feel warm perceive less air quality more than females. Females and males who perceive being thermally comfortable also perceive good air quality. Females and males who are thermally comfortable rated air humidity to be acceptable. There are similarities and differences between gender perceptions of the thermal environment. The investigation suggests interventions that can help users regulate their skin temperatures and use control measures that are sensitive to clothing insulation. The research also calls for policies that can promote building users’ pivotal adaptive measures to improve their indoor thermal environment. The study enhances our understanding of sustainable indoor environments and how to improve living conditions and adaptive modifications among different groups of occupants in buildings. Full article

The various wastes generated by silkworm silk textiles that are no longer in use are increasing, which is causing considerable waste and contamination. This issue has attracted widespread attention in countries that use a lot of silk. Therefore, enhancing the mechanical properties of regenerated silk fibroin (RSF) and enriching the function of silk are important directions to expand the comprehensive utilization of silk products. In this paper, the preparation of RSF/Al₂O₃ nanoparticles (NPs) hybrid fiber with different Al₂O₃ NPs contents by wet spinning and its novel performance are reported. It was found that the RSF/Al₂O₃ NPs hybrid fiber was a multifunctional fiber material with thermal insulation and UV resistance. Natural light tests showed that the temperature rise rate of RSF/Al₂O₃ NPs hybrid fibers was slower than that of RSF fibers, and the average temperature rose from 29.1 °C to about 35.4 °C in 15 min, while RSF fibers could rise to about 40.1 °C. UV absorption tests showed that the hybrid fiber was resistant to UV radiation. Furthermore, the addition of Al₂O₃ NPs may improve the mechanical properties of the hybrid fibers. This was because the blending of Al₂O₃ NPs promoted the self-assembly of β-sheets in the RSF reaction mixture in a dose-dependent manner, which was manifested as the RSF/Al₂O₃ NPs hybrid fibers had more β-sheets, crystallinity, and a smaller crystal size. In addition, RSF/Al₂O₃ NPs hybrid fibers had good biocompatibility and durability in micro-alkaline sweat environments. The above performance makes the RSF/Al₂O₃ NPs hybrid fibers promising candidates for application in heat-insulating and UV-resistant fabrics as well as military clothing. Full article

The intensive use of air conditioning systems, primarily refrigerating, to promote thermal comfort in countries such as Brazil (a hot climate country) is changing the electrical energy consumption patterns and peak demand. Even with the increased number of appliances, we must learn to consume less energy to achieve similar outcomes with higher energy efficiency. Consequently, exergy analysis is used to evaluate the quality of these energy conversion systems. Four computational human thermal models were used to assess thermal comfort conditions: one man wearing lighter clothing, one man wearing traditional office clothing, and two women in the two types of clothing. We chose these four models since the body composition and basal metabolism rates for males and females differ. In addition, the insulation of clothes influences the temperature of the thermal environment, leading to a significantly lower percentage of people being unsatisfied, from 12.8% to values close to 5%. The outputs of these occupants are used as inputs for a computational model of the room to calculate its associated thermal loads and evaluate different temperature setpoints and their effects on thermal comfort and energy consumption. Results indicate that environmental temperatures above 24 $°$C and below 26 $°$C may lead to thermal comfort conditions, depending on the occupants’ clothing. Clothing would represent a thermal resistance of 0.7 CLO for men and women (when in the luteal phase of the menstrual cycle) and 0.8 CLO for women in the follicular phase when the environment is at 25 $°$C. Therefore, there is a significant reduction in the compression power of the central cooling system by about 2.2% compared to 24 $°$C and around 8% compared to ambient temperatures around 21 $°$C. Full article

Energy poverty, defined as difficulty meeting the minimum requirements for a thermal environment, is becoming a significant social issue. To provide efficient welfare services, information provision and monitoring are required. However, characteristics of energy poverty, such as inconsistent residential patterns, small living spaces, and limited electricity and telecommunication resources, lead to a lack of information. This research introduces the empirical results of the development of the system. Based on the feedback from welfare workers and experts supporting energy poverty, a monitoring system combining various sensors was prototyped. This system measures temperature, humidity, illuminance, air velocity, CO₂, black bulb temperature, occupancy, and noise and generates indicators for occupancy and thermal environment monitoring. Applicability assessment was conducted across 55 energy poverty households in Korea during the duration of cooling and heating. Subjects were living in spaces averaging 6.3 sqm within buildings over 43 years old and renting on a monthly or weekly basis. Electricity and communication are partially supplied. Based on the actual measurement data and field surveys, the configuration of an energy poverty monitoring system was proposed. In particular, the applicability of the simple methodology for the determination of black bulb temperature, metabolic rate, and clothing insulation required for a thermal environment evaluation was assessed. The proposed system can be efficiently used for taking care of energy poverty where the installation of conventional monitoring systems is restricted. Full article

Thermal wear comfort for workwear clothing plays a vital role in maintaining comfortable water- and moisture-vapor-permeable properties while wearing clothing. In particular, thermal wear comfort measured using a thermal manikin is required in the protective workwear clothing market because their use provides objective data concerning the actual wearing performance of the clothing. This paper investigated the thermal wear comfort properties of various ceramic-embedded composite fabrics for workwear clothing worn in gas and oil industries produced from new schemes. The thermal insulation rate (Clo value) of Al₂O₃(Aluminum oxide)/graphite, ZnO(zinc oxide)/ZrC(zirconium carbide) and ZnO/ATO(antimony tin oxide)-embedded clothing was greater (25.5, 24.7 and 16.9%, respectively) than that of regular clothing (control), which was in accordance with the results (15.0, 13.8 and 11.3% higher, respectively) of the heat retention rate (I) of fabric specimens. It revealed that ZnO- and ATO-embedded yarns mixed with ZrC particles enhanced thermal wear comfort and had superior anti-static and UV-protective properties. Considering UV-protective and anti-static protective clothing worn in gas and oil industries and cold weather regions, it can be concluded that ZnO/ZrC-incorporated fabric is suitable because it showed superior thermal wear comfort with excellent UV-protective and acceptable anti-static properties. Meanwhile, assuming high functional performance for protective clothing worn in winter and factories, ZnO/ATO-incorporated fabric is pertinent to fabricating protective clothing for cold weather regions. Full article

Physical work increases energy expenditure, requiring a considerable elevation of metabolic rate, which causes body heat production that can cause heat stress, heat strain, and hyperthermia in the absence of adequate cooling. Given that passive rest is often used for cooling, a systematic search of literature databases was conducted to identify studies that reported post-work core temperature cooling rates conferred by passive rest, across a range of environmental conditions. Data regarding cooling rates and environmental conditions were extracted, and the validity of key measures was assessed for each study. Forty-four eligible studies were included, providing 50 datasets. Eight datasets indicated a stable or rising core temperature in participants (range 0.000 to +0.028 °C min⁻¹), and forty-two datasets reported reducing core temperature (−0.002 to −0.070 °C min⁻¹) during passive rest, across a range of Wet-Bulb Globe Temperatures (WBGT). For 13 datasets where occupational or similarly insulative clothing was worn, passive rest resulted in a mean core temperature decrease of −0.004 °C min⁻¹ (−0.032 to +0.013 °C min⁻¹). These findings indicate passive rest does not reverse the elevated core temperatures of heat-exposed workers in a timely manner. Climate projections of higher WBGT are anticipated to further marginalise the passive rest cooling rates of heat-exposed workers, particularly when undertaken in occupational attire. Full article

There are two types of occupants in nursing homes: older adults and caregivers. Because the former has different physiological qualities, they are more sensitive to high and low temperatures, presenting discrepancies with caregivers regarding thermal sensation. The objective of this exploratory research was to determine to what extent the range of thermal comfort differed between older adults and caregivers in three nursing homes in Gran Concepción. Indoor and outdoor temperature and relative humidity were monitored during winter and spring. Simultaneously, a thermal sensation and preference survey was applied while clothing insulation, metabolic rate, and adaptive responses were observed. Neutral temperature was calculated using Griffiths’ method for both groups to determine the comfort ranges and compare them. The older adults presented a higher neutral temperature than the caregivers with a difference of 0.8 °C in winter and 1.74 °C in spring. Regarding the adaptive response, both occupant types performed the same actions to achieve comfort, but older adults had less control over these. It is hoped that this study can lay the groundwork regarding comfort temperatures for older adults in Chile and integrate a discussion regarding their well-being on a local and global scale. Full article

A fireproof insulation board can be recycled, and the raw materials used in its production are very environmentally friendly, non-toxic and non-hazardous, and bring no harm to the human body and the surrounding environment. One practical application of fireproof insulation board is in an integrated composite structural fire protection system, which is a multidimensional comprehensive structural fire protection system proposed for the combined construction of buildings with different functions, such as horizontal and vertical, to ensure overall safety in the event of a building fire. The specific new technology of this new system includes an integrated structural fire protection system composed of a 3.00 h fire insulation board, which comes from the collection of textile scraps consisting of metals and buttons removed from clothes. To prove the effectiveness of this fireproof insulation board, its parameters were collected and put into FDS (FirG Dynamics Simulator, a CFD model of fluid flow during combustion developed by the National Institute of Standards and Technology), the fire safety goals considering the safety of building and personnel were established, and fire scene design based on the statistics of fire data and building codes was generated to test the safety of evacuation. To ensure the reliability of simulation results, an on-site physical fire test was conducted with the recycled insulation board. The result shows that the function of recycled board optimizes the phased evacuation design plan of personnel and solves the design difficulties of expanding fire zones and long evacuation distances when used in warehouses. Through the innovative design of the roof opening rate set at 30% and a hole spacing of 60 m, this underground fireproof insulation board is guaranteed to possess natural smoke exhaust conditions and can be used to improve public safety areas. Full article