Search Results (32)

With the promotion of national fitness, the requirements for regulating indoor environments during non-competition periods are low and relatively flexible under the trend of composite sports buildings. To maximize the use of natural ventilation and lighting for energy savings, passive optimization design based on building ontology has emerged as an effective strategy. This paper focuses on the spatial prototype of large- and medium-sized gymnasiums, optimizing key geometric design parameters and envelope structure parameters that influence energy consumption. This optimization employs a combination of orthogonal experiments and performance simulations. This study identifies the degree to which each factor affects energy consumption in the competition hall and determines the optimal low-energy consumption gymnasium prototype. The results reveal that the skylight area ratio is the most significant factor impacting the energy consumption of large- and medium-sized gymnasiums. The optimized gymnasium prototype reduced energy consumption by 5.3%~50.9% compared to all experimental combinations. This study provides valuable references and insights for architects during the initial stages of designing sports buildings to achieve low energy consumption. Full article

To address the limitations of traditional hardened concrete road surfaces in coal mine tunnels, which are prone to damage and entail high maintenance costs, this study proposes using modular concrete blocks composed of fly ash and coal gangue as an alternative to conventional materials. These blocks offer advantages including ease of construction and rapid, straightforward maintenance, while also facilitating the reuse of substantial quantities of solid waste, thereby mitigating resource wastage and environmental pollution. Initially, the mineral composition of the raw materials was analyzed, confirming that although the physical and chemical properties of Liangshui Well coal gangue are slightly inferior to those of natural crushed stone, they still meet the criteria for use as concrete aggregate. For concrete blocks incorporating 20% fly ash, the steam curing process was optimized with a recommended static curing period of 16–24 h, a temperature ramp-up rate of 20 °C/h, and a constant temperature of 50 °C maintained for 24 h to ensure optimal performance. Orthogonal experimental analysis revealed that fly ash content exerted the greatest influence on the compressive strength of concrete, followed by the additional water content, whereas the aggregate particle size had a comparatively minor effect. The optimal mix proportion was identified as 20% fly ash content, a maximum aggregate size of 20 mm, and an additional water content of 70%. Performance testing indicated that the fabricated blocks exhibited a compressive strength of 32.1 MPa and a tensile strength of 2.93 MPa, with strong resistance to hydrolysis and sulfate attack, rendering them suitable for deployment in weakly alkaline underground environments. Considering the site-specific conditions of the Liangshuijing coal mine, ANSYS 2020 was employed to simulate and analyze the mechanical behavior of the blocks under varying loads, thicknesses, and dynamic conditions. The findings suggest that hexagonal coal gangue blocks with a side length of 20 cm and a thickness of 16 cm meet the structural requirements of most underground mine tunnels, offering a reference model for cost-effective paving and efficient roadway maintenance in coal mines. Full article

To investigate the anchoring performance of self-drilling anchors in gravel-cobble strata, this study conducted indoor orthogonal tests based on soil grouting experiments to simulate actual construction conditions. The influence of fine particle content, grouting pressure, and water-cement ratio on anchoring parameters was analyzed. Additionally, a grouting simulation model was developed using PFC2D 5.0 numerical software to examine the effects of grouting pressure, drilling speed, and grout viscosity on the grout diffusion radius through orthogonal and single-factor experimental schemes. The results demonstrate that: fine particle content exerts the most significant impact on anchoring performance, with higher content reducing peak pullout resistance; the grout diffusion radius exhibits a positive correlation with grouting pressure but a negative correlation with drilling speed and grout viscosity, with viscosity having the strongest influence, followed by pressure and speed; the diffusion pattern follows a gradually decreasing trend along the drilling direction, while the radius increases at a diminishing rate with elevated pressure; when viscosity ranges from 83.3 to 833.3 mPa·s, the diffusion radius decreases by 72%; and multivariate regression analysis indicates a power function relationship between the diffusion radius and these three parameters. Full article

Architectural vertical green walls can mitigate the urban heat island effect, provide shade and cooling, reduce energy consumption, improve a microclimate, and increase indoor comfort. However, an excessive pursuit of high coverage may diminish the benefit ratio and adversely affect ventilation and lighting. Field measurements were conducted in the hot and humid Guangzhou area to investigate the thermal benefits of external vertical green walls with varying green coverage and diverse layouts, encompassing effects such as shading, insulation, cooling, and humidification. Analyses were conducted using ENVI-met, orthogonal experiments, and SPSS to quantify the moderating effects of planted green coverage (PGC), leaf area density (LAD), and air interstitial layers on the environmental thermal benefits. The results indicated that the cooling and humidifying effects of 100% PGC and 75% PGC were comparable and superior to those of 50% PGC, yet 75% PGC outperformed 100% PGC in terms of indoor humidification. Among the layout modes, the horizontal layout was the most effective for cooling and humidification, followed by the point layout, with the vertical layout being the least effective. A global sensitivity analysis revealed that PGC had the greatest impact on wall cooling and outdoor humidification, LAD significantly influenced humidification, the width of air interstitial layers had a minor impact, and the two architectural vertical greening design ratios of 75% PGC × 4.60 LAD and 75% PGC × 2.70 LAD were particularly effective for cooling and humidification. Incorporating horizontal or point-like layouts can enhance façade design diversity while preserving the desired environmental thermal benefits, thereby contributing to the overall aesthetics of a building. Full article

Contamination from light nonaqueous phase fluids (LNAPLs) and their derivatives during mining, production, and transportation has become a concern. Scholars have extensively studied LNAPL contamination, but the role of water content variation on its migration process in the unsaturated zone has not been sufficiently researched. The specific issue addressed in this study is the impact of water content on the migration of light nonaqueous phase liquids (LNAPLs) in sandy soils, a critical yet under-researched aspect of subsurface contamination. To tackle this, we employed indoor simulated vertical, one-dimensional, multiphase flow soil column experiments, utilizing the orthogonal experimental method to systematically evaluate the effects of varying water contents on the occurrence state and migration rate of LNAPLs. The experimental results indicate the following: (1) The migration rate of LNAPL exhibits an L-shaped trend during subsurface imbibition and a nonlinear relationship with migration time. The migration rate and migration time of surface infiltration have a linear growth relationship. (2) The residual rate of LNAPL is negatively correlated with water content and positively correlated with oil content in the homogeneous non-saturated state. With the increase in the amount of leaked oil, 40% of the leaked LNAPL is sorbed within the soil. (3) When the water content of the test medium is below 14%, and the oil content is below 11%, LNAPL appears in the unsaturated zone in a solid phase. As the water content increases, the adsorption rate of the oil phase gradually decreases and eventually reaches the oil saturation point. (4) When the water content of the medium exceeds 8%, over time, LNAPL will be subject to oil–water interfacial tension, and the rate of LNAPL movement first decreases and then increases, displaying nonlinear growth. The innovation of this work lies in the comprehensive analysis of LNAPL migration under controlled laboratory conditions, providing results that enhance the understanding of LNAPL behavior in sandy soils. These quantitative insights are crucial for developing targeted remediation strategies for LNAPL-induced pollution in the unsaturated zone. Full article

Ultra Wide-Band (UWB) sensing has gained popularity in relative localization applications. Many localization solutions rely on using Time of Flight (ToF) sensing based on a beacon–tag system, which requires four or more beacons in the environment for 3D localization. A lesser researched option is using Angle of Arrival (AoA) readings obtained from UWB antenna pairs to perform relative localization. In this paper, we present a UWB platform called ReLoki that can be used for ranging and AoA-based relative localization in 3D. To enable AoA, ReLoki utilizes the geometry of antenna arrays. In this paper, we present a system design for localization estimates using a Regular Tetrahedral Array (RTA), Regular Orthogonal Array (ROA), and Uniform Square Array (USA). The use of a multi-antenna array enables fully onboard infrastructure-free relative localization between participating ReLoki modules. We also present studies demonstrating sub-50cm localization errors in indoor experiments, achieving performance close to current ToF-based systems, while offering the advantage of not relying on static infrastructure. Full article

This study investigates the skid resistance performance of asphalt mixtures containing composite aggregates of basalt and limestone. The research aimed to predict the service life of the asphalt mixtures and identify the optimal basalt content for enhanced performance. Using an accelerated friction tester, friction indices such as the British pendulum number (BPN), mean texture depth (MTD), and dynamic friction coefficient (Dµ) were measured. The study conducted accelerated wear tests on mixtures with varying basalt contents under different water flow rates and loads. Results indicate that anti-skid performance decreased with increasing water flow, load, and wear cycles, initially showing a sharp decline followed by a gradual stabilization. Orthogonal experiments determined that basalt content had the most significant impact on skid resistance, followed by load and water flow rate. By converting skid resistance and MTD values into IFI values, a four-area diagram was created to illustrate skid resistance deterioration. The four-area IFI diagram also demonstrated that higher basalt content significantly enhances the skid resistance and service life of asphalt mixtures. Cost analysis based on life prediction showed that a 40% basalt content mixture is cost effective while maintaining excellent skid resistance. A test section study further validated that a 40% basalt content ensures good skid resistance, with indoor test predictions aligning closely with field data. Although the test section has been operational for only two years, ongoing monitoring will provide further insights into long-term skid resistance performance. Full article

Current research on rural houses in China mainly focuses on improving energy efficiency, with relatively few studies addressing energy-saving measures and enhancing thermal comfort for residents. Therefore, this paper focuses on existing rural houses in Nantong City, Jiangsu Province, as the research object. Through on-site measurements and questionnaire surveys, it was found that the average indoor temperature of rural houses is 28.5 °C in summer and below 10 °C in winter, failing to meet the comfort needs of the villagers. To further study human thermal comfort, a linear regression method was used to establish an indoor Mean Thermal Sensation (MTS) model for Nantong’s rural houses. The neutral temperature in summer was found to be 26.46 °C, and an adaptive thermal comfort model for rural residents in the Nantong area was established. Through single-factor simulation and orthogonal experiments, the optimal comprehensive energy-saving renovation scheme was proposed. Finally, a typical rural house in Zhangzhuang Village was used as a case for building renovation practice. After the renovation, the number of thermal comfort hours increased by 145 h per year, the thermal comfort compliance rate reached 47.07%, and the overall energy-saving rate was 57.41%. Full article

Traditional potato grading in China relies mostly on manual sorting, which is labor-intensive, time-consuming, costly, and inefficient. To enhance the operational performance of potato-grading devices, this paper focuses on optimizing the slide rail structure, which is the key component of a self-developed first-generation potato-grading device. A five-factor, three-level orthogonal experiment was designed, with the experimental factors being the height of the horizontal slide rail, angle of the first-stage inclined slide, angle of the second-stage inclined rail, chain horizontal movement speed, and conveyor belt speed. The indoor experiments were conducted using grading accuracy and grading efficiency as the experimental indicators. On the basis of the analysis of the orthogonal experiment results, two relatively optimal solutions were obtained, and validation experiments were conducted. The validation results show that when the height of the horizontal slide rail was 185 mm, the angle of the first-stage inclined rail was 4°, the angle of the second-stage inclined rail was 2.5°, the horizontal movement speed of the chain was 700 mm/s, and the movement speed of the conveyor belt was 275.60 mm/s, the performance of the movable rotating plate (MRP)-type grading device for potatoes reached its optimum. At this point, the grading accuracy was 94.88%, and the grading efficiency was 13.9477 t/h. Compared with the first-generation grading device, the optimized grading device achieved an improvement of 3.84% in grading accuracy and 12.94% in grading efficiency. The research methodology provided in this paper serves as a reference for the performance optimization of potato-grading devices. Full article

In the context of China’s dual-carbon goals, energy efficiency in public buildings has become a focal point of public concern. As large-scale public transportation buildings, the indoor thermal comfort and the current state of energy consumption of coach stations are increasingly being emphasized. This research used existing coach stations in the Xi’an region as the object; through on-site investigations and field tests of indoor thermal environments in winter and summer seasons, it was found that the coach stations had energy waste and high energy consumption; the enclosure structures had poor thermal performance; and the stations lacked effective energy-saving measures. Energy-saving transformation strategies were proposed from two aspects: enclosure structures and renewable energy utilization. Using DeST-C for energy consumption, the external walls, roofs, insulation materials, and glass materials were simulated, and nine different combinations of energy-saving schemes were simulated using orthogonal experiments. The optimal scheme was selected based on the comprehensive energy-saving rate and economic analysis results, which included using 80 mm XPS external insulation for the external walls, low-e hollow glass for the windows (low transmittance type), and an 80 mm PUR board for the roof insulation. The energy-saving rate of this scheme was 26.84%. The use of rooftop solar photovoltaic power generation and fresh air heat recovery devices can effectively reduce building energy consumption, and the investment payback period is less than 5 years. The research applications have practical significance for improving the indoor environment of existing coach stations and saving energy consumption. Full article

Region-function combinations are essential for smartphones to be intelligent and context-aware. The prerequisite for providing intelligent services is that the device can recognize the contextual region in which it resides. The existing region recognition schemes are mainly based on indoor positioning, which require pre-installed infrastructures or tedious calibration efforts or memory burden of precise locations. In addition, location classification recognition methods are limited by either their recognition granularity being too large (room-level) or too small (centimeter-level, requiring training data collection at multiple positions within the region), which constrains the applications of providing contextual awareness services based on region function combinations. In this paper, we propose a novel mobile system, called Echo-ID, that enables a phone to identify the region in which it resides without requiring any additional sensors or pre-installed infrastructure. Echo-ID applies Frequency Modulated Continuous Wave (FMCW) acoustic signals as its sensing medium which is transmitted and received by the speaker and microphones already available in common smartphones. The spatial relationships among the surrounding objects and the smartphone are extracted with a signal processing procedure. We further design a deep learning model to achieve accurate region identification, which calculate finer features inside the spatial relations, robust to phone placement uncertainty and environmental variation. Echo-ID requires users only to put their phone at two orthogonal angles for 8.5 s each inside a target region before use. We implement Echo-ID on the Android platform and evaluate it with Xiaomi 12 Pro and Honor-10 smartphones. Our experiments demonstrate that Echo-ID achieves an average accuracy of 94.6% for identifying five typical regions, with an improvement of 35.5% compared to EchoTag. The results confirm Echo-ID’s robustness and effectiveness for region identification. Full article

A more efficient attention recovery of workers during their break time is essential for achieving higher productivity and wellness. In recent years, the biophilic design that introduces indoor plants has become one of the solutions to these problems. This study aims to determine the impact factors and corresponding levels related to indoor planting design concerning workers’ attention recovery. Firstly, the volume ratio, layout, and leaf size of indoor plants and the corresponding levels were put forward by a focus group study with ten participants. Secondly, the orthogonal experiment method established nine virtual recovery scenarios based on characteristics extraction of staff break areas in the factory. Thirdly, eighteen participants were guided to feel fatigued by experiencing the sustained attention to response test to measure the baseline attention level of participants. Then, participants rested in the virtual scenarios. Lastly, the attention test was conducted again to observe participants’ attention recovery degree. The difference values of participants’ sensitivity, reaction times, and the number of correct responses between the two detection targets were applied to evaluate the attention recovery. Results showed that the volume ratio of indoor plants had the most significant effect on workers’ attention recovery; 3% by volume ratio, mixed floor and wall plants and floor planting with large leaves were demonstrated as the optimal indoor planting design for attention recovery. Full article

This study proposes an air circulation system that can forcibly circulate the lowest cold air to the top of indoor smart farms, and it has a width, length, and height of 6, 12, and 2.5 m, respectively, to reduce the effect of temperature differences between the upper and lower parts on the growth rate of plants in winter. This study also aimed to reduce the temperature deviation generated between the upper and lower parts of the target indoor space by optimizing the shape of the manufactured outlet of the air circulation system. A table of L9 orthogonal arrays, which is a design of experiment methodology, was used, and it presented three levels of the following design variables: blade angle, blade number, output height, and flow radius. Flow analysis was performed for the experiments on the nine models to minimize the high time and cost requirements. Based on the derived analysis results, an optimized prototype was manufactured by applying the Taguchi method, and experiments were conducted by installing 54 temperature points in an indoor space to identify the temperature difference between the upper and lower parts over time for the performance experiment. Under natural convection, the minimum temperature deviation was 2.2 °C and the temperature difference between the upper and lower parts did not decrease. For a model without an outlet shape, such as a vertical fan, the minimum temperature deviation was 0.8 °C and at least 530 s were required to reach a difference of less than 2 °C. When air was circulated in the air circulation system with the proposed outlet shape, the minimum temperature deviation was 0.6 °C and the time required to reach a difference of less than 2 °C was 440 s. Using the proposed air circulation system, cooling and heating costs are expected to be reduced in summer and winter because the arrival time and temperature difference between the upper and lower parts can be reduced using the outlet shape compared with the case without the outlet shape. Full article

Hui-style architecture is a mature architectural school in the late period of ancient Chinese society with distinct regional cultural characteristics. Especially as the most direct carrier of Huizhou people’s living culture, Hui-style architecture is the witness of ancient Huizhou society, history, and culture. However, with the continuous development of society, residents gradually put forward higher requirements for the living environment. In this paper, the indoor light environment of Huizhou dwellings is measured and found to have problems such as poor indoor light environment and low light quality. In order to improve the indoor lighting quality, this study extracts the key design parameters (window edge height, window width, patio length, and patio width) that affect the indoor lighting quality through field research and literature analysis, and then uses Honeybee to carry out multi-factor orthogonal experiments and single factor quantitative comparative analyses on the key design parameters to determine the degree of influence. The results show that reducing the window edge height can improve the lighting effect near the window, and increasing the window width and patio width can improve the overall lighting quality of the room, thus providing a reference for optimizing the lighting effect of Huizhou traditional dwellings. Full article

In recent times, we have been witnessing the development of multiple applications and deployment of services through the indoors location of people as it allows the development of services of interest in areas related mainly to security, guiding people, or offering services depending on their localization. On the other hand, at present, the deployment of Wi-Fi networks is so advanced that a network can be found almost anywhere. In addition, security systems are more demanded and are implemented in many buildings. Thus, in order to provide a non intrusive presence detection system, in this manuscript, the development of a methodology is proposed which is able to detect human presence through the channel state information (CSI) of wireless communication networks based on the 802.11n standard. One of the main contributions of this standard is multiple-input multiple-output (MIMO) with orthogonal frequency division multiplexing (OFDM). This makes it possible to obtain channel state information for each subcarrier. In order to implement this methodology, an analysis and feature extraction in time-domain of CSI is carried out, and it is validated using different classification models trained through a series of samples that were captured in two different environments. The experiments show that the methodology presented in this manuscript obtains an average accuracy above 90%. Full article