Search

The development of advanced unmanned robots is of great significance to promote scientific progress and innovation, expand application fields, and improve efficiency and safety. Complex perception, motion, and navigation systems consisting of numerous sensors and powerful processors enable robots to monitor various sophisticated environments. However, the available commercial batteries cannot satisfy the long endurance and safety requirements of robots. Herein, we propose the application of metal–air batteries to power robot devices considering their advantages of higher energy density, lower cost, and better safety compared to lithium-ion batteries. Furthermore, the technological development of metal–air batteries in terms of specific energy, cycle life, fast charging, environmental adaptability and flexibility has increased the possibility of their application in next-generation unmanned devices. Accordingly, we present an outlook on the application of metal–air batteries in all fields of robotics, including land, air and sea, embodying the temporal and spatial infinities of these batteries. It is expected that the application of metal–air batteries will promote the advancement of the robot industry. [ABSTRACT FROM AUTHOR]

Flexible zinc‐air batteries have received widespread attention due to their high specific energy and eco‐friendly environment. However, the water in the hydrogel is easily lost to the external environment because of the semi‐open structure zinc‐air batteries, leading to performance degradation of the batteries. Here a saline gel of NaCl‐KOH‐PAA (sodium chloride‐potassium hydroxide‐polyacrylic acid) without soaking in the alkaline solution before use is designed, refining the grid structure of the hydrogel and reducing water loss through NaCl doping. Meanwhile, the gel exhibits no significant decrease in ion conductivity before and after NaCl doping and can maintain stability of around 170 and 150 mS cm−1 at room temperature and −20 °C, respectively. The results demonstrate that the lifetime of flexible zinc‐air batteries with NaCl‐doped hydrogel can be extended by nearly 50%. The NaCl doping gel also displays superior flexibility under extreme physical deformation conditions. Moreover, the phenomenon of hydrogel delamination with NaCl doping is observed and the mechanism of gel water retention is uncovered. These findings will pave the way for developing flexible zinc‐air battery. [ABSTRACT FROM AUTHOR]

Volatile organic compounds (VOCs) emitted from building and vehicle cabin materials seriously affect indoor and in-cabin air quality, as well as human health. Previous studies revealed that some VOCs from building materials could react with ozone to affect the concentration levels of the indoor environment, but seldom refers to vehicle cabin materials. In this study, we performed experimental investigation for two kinds of vehicle cabin materials (car carpet, sealing strip) and one furniture material (medium-density fiberboard) by conducting small-scale chamber tests under two different conditions, with ozone (about 110 μg/m3) and without ozone (about 10 μg/m3), to explore the effect of in-cabin chemistry on VOC emissions. We observed the VOC concentration changes in the two scenarios and found that ozone had a significant impact on the concentrations of aldehydes and ketones while having little impact on the concentrations of benzene series. We introduced a gain ratio to quantitatively reflect the concentration changes in the presence of ozone. The gain ratio for aldehydes and ketones is greater than one, while that for the benzene series is basically around one with a small fluctuation range. This study demonstrates that ozone can react with VOCs containing unsaturated carbon–carbon bonds or carbon–oxygen bonds emitted from varied materials to produce aldehydes and ketones, which will further reduce indoor and in-cabin air quality. [ABSTRACT FROM AUTHOR]

To avoid a sharp rise in temperature in the cabin of parked vehicles exposed to solar radiation, experienced drivers leave some windows partly open when the vehicle is parked in the sunlight to achieve cooling through natural ventilation. However, the effectiveness of this measure to reduce the temperature under different weather conditions has not been verified. To this end, this study investigates the effect of open windows on the thermal environment of a vehicle under different environmental conditions. A field measurement, in which two identical vehicles with and without window gaps were used, was carried out in Daxing District, Beijing. The measurements were conducted for 15 days under different window gaps and ambient conditions. The results revealed that open windows resulted in a maximum temperature reduction of 6.7 °C in cabin air temperature under high temperature and high solar radiation, while only 0.6 °C can be reduced under low temperature and low solar radiation. The results also showed that when window gaps effectively reduce the air temperature, lower air temperature can be obtained with larger open-window areas. [ABSTRACT FROM AUTHOR]

Semi-volatile organic compounds (SVOCs) are widely used in materials employed in vehicle interiors, causing poor in-cabin air quality. The emission characteristics of SVOCs from vehicle cabin materials can be characterized by two key parameters: the gas-phase SVOC concentration adjacent to the material surface (y0) and the convective mass transfer coefficient across the material surface (hm). Accurate determination of y0 and hm is fundamental in investigating SVOC emission principles and health risks. Considering that the steady state SVOC concentration (y) in a ventilated chamber changes with the ventilation rate (Q), we developed a varied ventilation rate (VVR) method to simultaneously measure y0 and hm for typical vehicle cabin materials. Experimental results for di(2-ethylhexyl)phthalate (DEHP) emissions from test materials indicated that the VVR method has the merits of simple operation, short testing time, and high accuracy. We also examined the influence of temperature (T) on y0 and hm, and found that both y0 and hm increase with increasing temperature. A theoretical correlation between y0 and T was then derived, indicating that the logarithm of y0T is linearly related to 1/T. Analysis based on the data from this study and from the literature validates the effectiveness of the derived correlation. Moreover, preliminary exposure analysis was performed to assess the health risk of DEHP in a vehicular environment. [ABSTRACT FROM AUTHOR]

We investigate source characteristics and emission dynamics of volatile organic compounds (VOCs) in a single‐family house in California utilizing time‐ and space‐resolved measurements. About 200 VOC signals, corresponding to more than 200 species, were measured during 8 weeks in summer and five in winter. Spatially resolved measurements, along with tracer data, reveal that VOCs in the living space were mainly emitted directly into that space, with minor contributions from the crawlspace, attic, or outdoors. Time‐resolved measurements in the living space exhibited baseline levels far above outdoor levels for most VOCs; many compounds also displayed patterns of intermittent short‐term enhancements (spikes) well above the indoor baseline. Compounds were categorized as "high‐baseline" or "spike‐dominated" based on indoor‐to‐outdoor concentration ratio and indoor mean‐to‐median ratio. Short‐term spikes were associated with occupants and their activities, especially cooking. High‐baseline compounds indicate continuous indoor emissions from building materials and furnishings. Indoor emission rates for high‐baseline species, quantified with 2‐hour resolution, exhibited strong temperature dependence and were affected by air‐change rates. Decomposition of wooden building materials is suggested as a major source for acetic acid, formic acid, and methanol, which together accounted for ~75% of the total continuous indoor emissions of high‐baseline species. [ABSTRACT FROM AUTHOR]

In-cabin air pollution may be mainly ascribed to the emissions of volatile organic compounds (VOCs) from vehicular cabin materials. Some measurement methods have been proposed by organizations around the world to evaluate the quality of cabin materials. According to the widely used German Standard VDA278, the emission quantity of VOCs from cabin materials over a certain period is taken as an indicator of quality. The VOC emission quantity is generally related to temperature, but the quantitative association between emissions and temperature has not been previously reported. In this paper, we derive a theoretical relationship between the short- and mid-term VOC emission quantity (M) and temperature (T) and show that the logarithm of MT−1/8 is linear with 1/T. Experimental data in the literature on VOC emissions from four vehicular materials at varying temperatures were used for analysis. The logarithm of MT−1/8 and 1/T was found to follow a good linear association with R2 being 0.89–0.99, which is in agreement with the theoretical relationship. Using this relationship, the VOC emission quantity at a temperature different from the test condition can be predicted. In addition, preliminary exposure analysis was conducted to predict the health risks from selected VOCs detected from emissions in vehicular cabin environments under various temperature scenarios. [ABSTRACT FROM AUTHOR]

Among many environments, the motor vehicle cabin microenvironment has been of particular public concern. Although commuters typically spend only 5.5% of their time in vehicles, the emissions from various interior components of motor vehicles as well as emissions from exhaust fumes carried by ventilation supply air are significant sources of harmful air pollutants that could lead to unhealthy human exposure due to their high concentrations inside vehicles' cabins. This review summarizes significant findings in the literature on air quality inside vehicle cabins, including chemical species, related sources, measurement methodologies and control measures. More than 90 relevant studies performed across over 10 countries were carefully reviewed. These comprised more than 2000 individual road trips, where concentrations of numerous air pollutants were determined. Ultrafine particles, aromatic hydrocarbons, carbonyls, semi-volatile organic compounds and microbes have been identified as the primary air pollutants inside vehicle cabins. Air recirculation with high-efficiency air filter has been reported as the most effective measure to lower air pollutant concentrations. Future work should focus on investigating the health risks of exposure to various air pollutants inside different vehicles and further developing advanced air filter to improve the in-cabin air quality. [ABSTRACT FROM AUTHOR]

Temperature and relative humidity can simultaneously change in indoor environment, which significantly affect the emission rate of formaldehyde and volatile organic compounds (VOCs) from building materials. Prior studies generally focus on the single effect of temperature or relative humidity, and the combined effect is not considered. This paper investigates the comprehensive influence of temperature and relative humidity on the emission rate of pollutants from building materials. Correlation between the emission rate and the combined environmental factors is derived theoretically. Data in literature are applied to validate the effectiveness of the correlation. With the correlation, the indoor formaldehyde concentration in summer is predicted to be 1.63 times of that in winter in Beijing, which is approximately consistent with surveyed data. In addition, a novel approach is proposed to assess the human health impact due to pollutants emitted from building materials at varied temperature and relative humidity. An association between the human carcinogenic potential ( HCP ) and the environmental factors is obtained. By introducing a reference room model developed previously, it is calculated that the HCP of bedroom at high relative humidity (70%, 25 °C) for formaldehyde exceeds 10 − 4 cases, meaning high cancer health risk. This study should prove useful for evaluating the emission behaviors and the associated exposure of pollutants from building materials at varied environmental conditions. [ABSTRACT FROM AUTHOR]

[Display omitted] • Determination of parameters of VOC/SVOC from indoor/in-cabin materials are reviewed. • The available key parameters of VOC/SVOC found in the literature are summarized. • The impacts of different factors on VOC/SVOC emission behaviors are discussed. • The spatial scale and time scale of typical methods are compared and discussed. • An approach for indoor and vehicular air quality pre-assessment is introduced. The emissions of volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs) from indoor building and vehicle cabin materials can adversely affect human health. Many mechanistic models to predict the VOC/SVOC emission characteristics have been proposed. Nowadays, the main obstacle to accurate model prediction is the availability and reliability of the physical parameters used in the model, such as the initial emittable concentration, the diffusion coefficient, the partition coefficient, and the gas-phase SVOC concentration adjacent to the material surface. The purpose of this work is to review the existing methods for measuring the key parameters of VOCs/SVOCs from materials in both indoor and vehicular environments. The pros and cons of these methods are analyzed, and the available datasets found in the literature are summarized. Some methods can determine one single key parameter, while other methods can determine two or three key parameters simultaneously. The impacts of multiple factors (temperature, relative humidity, loading ratio, and air change rate) on VOC/SVOC emission behaviors are discussed. The existing measurement methods span very large spatial and time scales: the spatial scale varies from micro to macro dimensions; and the time scale in chamber tests varies from several hours to one month for VOCs, and may even span years for SVOCs. Based on the key parameters, a pre-assessment approach for indoor and vehicular air quality is introduced in this review. The approach uses the key parameters for different material combinations to pre-assess the VOC/SVOC concentrations or human exposure levels during the design stage of buildings or vehicles, which can assist designers to select appropriate materials and achieve effective source control. [ABSTRACT FROM AUTHOR]

The steady state VOC concentration in automobile cabin is taken as a good indicator to characterize the material emission behaviors and evaluate the vehicular air quality. Most studies in this field focus on experimental investigation while theoretical analysis is lacking. In this paper we firstly develop a simplified physical model to describe the VOC emission from automobile materials, and then derive a theoretical correlation between the steady state cabin VOC concentration (Ca) and temperature (T), which indicates that the logarithm of Ca/T0.75 is in a linear relationship with 1/T. Experiments of chemical emissions in three car cabins at different temperatures (24°C, 29°C, 35°C) were conducted. Eight VOCs specified in the Chinese National Standard GB/T 27630–2011 were taken for analysis. The good agreement between the correlation and experimental results from our tests, as well as the data taken from literature demonstrates the effectiveness of the derived correlation. Further study indicates that the slope and intercept of the correlation follows linear association. With the derived correlation, the steady state cabin VOC concentration different from the test conditions can be conveniently obtained. This study should be helpful for analyzing temperature-dependent emission phenomena in automobiles and predicting associated health risks. [ABSTRACT FROM AUTHOR]