Several daytime radiative cooling materials involving various structures and composed using multilayer thin films, polymers, and nanoparticles have been fabricated and studied. However, their surface is of white or some other monotonous color because of the requirement for most of the incident sunlight to be reflected. A temperature‐sensitive colored radiative cooling (TCRC) material that provides efficient cooling while preserving the aesthetic properties of the surface has been developed. The TCRC material is manufactured as a bilayer structure for efferent cooling applied on a colored radiative cooling emitter. The bottom layer reflects as much light as possible using polyvinylidene fluoride and alumina particles, and the top layer uses a thermochromic color pigment to display color. The optical properties of the TCRC material, in response to temperature changes, are evaluated and its efficient cooling ability is confirmed. The temperature cooling is confirmed for TCRC emitters of yellow, magenta, and blue colors, using an outdoor temperature measurement system, and it is experimentally confirmed that the TCRC emitters provide more cooling (by 1.75, 2.67, and 4.31 °C, respectively) than conventional paint of the same color.
Abstract Conventional cooling systems, that is, air conditioners, should be replaced because they consume a substantial amount of energy and cause environmental pollution. In this context, radiative cooling systems, which perform cooling without consuming any energy or causing environmental pollution, are emerging as an alternative. However, most of the radiative coolers explored thus far include metals, such as silver, that are used as solar reflectors, thereby entailing problems in terms of practicality, mass production, cost, and light pollution. Herein, we propose calcium carbonate (CaCO 3 ) micro-particle-based radiative cooling, which utilizes the high-energy band gap of CaCO 3 for high-performance radiative cooling. As the cooler has only a single layer of a CaCO 3 composite without any metal reflector, it is mass-producible, cheap, and does not cause light pollution. To demonstrate the cooling performance of CaCO 3 , optical properties and temperature changes are measured and compared with those of commercial white paint. As a result, it is demonstrated that the CaCO 3 -based radiative cooler has cooling power 93.1 W/m 2 in calculation and can be cooled 6.52 ℃ and 3.38 ℃ under ambient temperature in daytime and nighttime respectively. Thus, it can perform as radiative cooler in entire day.
The recent growth in e-commerce has significantly increased the demand for indoor delivery solutions, highlighting challenges in last-mile delivery. This study presents a time-interval-based collision detection method for Four-Wheel Independent Steering (4WIS) mobile robots operating in human-shared indoor environments, where traditional path following algorithms often create unpredictable movements. By integrating kinematic-based robot trajectory calculation with LiDAR-based human detection and Kalman filter-based prediction, our system enables more natural robot–human interactions. Experimental results demonstrate that our parallel driving mode achieves superior human detection performance compared to conventional Ackermann steering, particularly during cornering and high-speed operations. The proposed method’s effectiveness is validated through comprehensive experiments in realistic indoor scenarios, showing its potential for improving the efficiency and safety of indoor autonomous navigation systems.
The side-stream generated recycled water in the wastewater treatment plants is characterized as high in both nitrogen concentration and fluctuation of load. Thus, the design approach for recycle water management became an important part of the biological nutrient removal system design. The application of nitrogen removal from recycled water using the nitritation process has recently been increased due to economical reasons associated with an effective carbon allocation as well as the minimization of aeration cost. The concept of nitritation reactor design related to an inhibition of nitrite oxidizer has not been fully practiced in reality because of the limited field experiences. In this paper, a new approach has been proposed to determine reactor size and oxygen requirement in nitritation process design. The SRT-based design approach has been examined based on a series of laboratory experiments.
Abstract Daytime radiative cooling is an eco‐friendly cooling technique that does not consume additional fuel and is a promising technology now being developed using various materials and methods. Existing radiative cooling emitters are typically in the form of multilayered or mixed thin films and photonic structures, which are difficult to apply in industrial fields. Moreover, the complicated processes and materials used increase the cost. Herein, a dual‐modal radiative cooling emitter in the form of a cover sheet developed by electrospinning polyacrylonitrile (PAN) with alumina (Al 2 O 3 ) and silica (SiO 2 ) nanoparticles is reported; it is an easily accessible and highly practical architecture that can be applied and used in daily life. Additionally, this radiative cooling cover sheet exhibits dual selective‐ and broadband‐like optical properties in the IR region depending on the substrate characteristics for efficient cooling. The cooling power is numerically proven to be 89.51 W m −2 , and experimentally, a temperature drop of 9.67 °C could be measured on a daily car model.
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